HydrogenAudio

I've been using full sized headphones for a long time.  Lately (over the last few years), it seems like just about everybody and their brother is releasing IEMs.  I realize there is a large profit motive to do so because of the explosion of portable media devices.  For a long time I've simply dismissed them as devices that sacrificed sound quality for size and portability.

However, it seems like IEMs are changing and improving by leaps and bounds.  It's quite easy to find multiple driver IEMS, and one new device even has 6 balanced armatures!  Considering the size of the drivers, I assume they have physics (less inertia) in their favor in comparison to the large diaphragms of full sized headphones.

Certainly, it seems there is a lot more actual technological changes in the IEM world than in the full sized headphone world.

Does anybody have any person experiences comparing IEMs to full size headphones? Would your replace your full sized headphone with an IEM?  How is the sound in terms "in your head?"  What other comments do you have?

It really intrigues me to think that an IEM could best a full sized headphone.  I think I'd gladly ditch my full sized cans if IEMs did this with the comfort of a full sized headphone.

I realize I should ask these questions on one particular website that is more inclined to this topic.  But that site has way too much fantasy and it's hard to separate truth from placebo.

one new device even has 6 balanced armatures!

Do you mean 3 in each enclosure?

In any case, I've been very happy with IEMs. Comfort is probably the biggest issue, but certainly no complaints for sound. I've tried Westone UM2, Shure E4, E500 (SE530), SE420, Ultimate Ears Super.fi 5EB. Full-sized headphones haven't been too interested. I've tried briefly the Bose Triport (very comfortable, don't know about sound quality) and I have Grado SR80's which I only use when I need to hear what's going on outside. Bass is lacking compared to all the IEMs above, and it's a tad too bright for my taste, but you get used to it after a while.

After testing all those IEMs, my favorites are the Westone UM2. I even bought them twice, cause I got rid of the first ones I bought. I sold the E500's cause they were pretty redundant, and for the price the build was finicky. My first pair had one of rubber cable holders break off easily, luckily I could claim warranty, but never used them again. Also sold the E4's, and now I keep the UM2, the SE430 (for no particular reason, I just like to keep them around, they look very cool too and the design is much better than previous generation E500) and the Super.fi 5EB for movies. The SF has wicked deep and strong bass.

I  got one full-sized headphones: sennheiser hd595
And one IEM: sennheiser ie7.

This IEM, use a dynamic driver, unlike majority of IEMS  that are balanced armature.
Most likely this means  better bass, and less analytical sound.

I find the sound from the full-sized headphone more neutral, natural, and detailed.
Nevertheless, I  won't use my HD595  with my portable mp3, nor sleep with them on my ears 

I'm pretty satisfied with my IEM, and I  don't care if my full-size headphone might have better sound quality.
This is just enough for me to enjoy every kind of music. And that's all what matters to me.
With cheap ipod earbuds, some music are unlistenable (example : emilie simon, album vegetal).

However, it seems like IEMs are changing and improving by leaps and bounds. It's quite easy to find multiple driver IEMS, and one new device even has 6 balanced armatures!

There's no proof that more balanced armatures always means better sound. It certainly means more expensive. The recent phonaks, are single balanced armature, and are quite popular at head-fi.
Don't forget that single balanced armature are evolving too ..

Would your replace your full sized headphone with an IEM?

No, sound signature is not exactly the same, and I enjoy both differently.

It really intrigues me to think that an IEM could best a full sized headphone. I think I'd gladly ditch my full sized cans if IEMs did this with the comfort of a full sized headphone.

Sometimes IEMs  can be uncomfortable too...  If you listen more than hour , with them stuck on your ears, you might have enough of them. Because your ears need to "breath".

Quote from: odigg on 2009-10-12 17:21:57

one new device even has 6 balanced armatures!

Do you mean 3 in each enclosure?

6 in each enclosure!  The JH Audio 13 Pro (http://www.jhaudio.com/promusic/) is the recent favorite at that unnamed headphone site, but at $1099 it's quite a bit out of the price range I could seriously consider.  People are making all sorts of claims about them including them having the soundstage (read, out of head experience) of full sized headphones.  They are the current favorite, assuming you can afford them.

Let it be known that I have no affiliation with JH Audio, I have never heard any of their gear, and am not offering any sort of recommendation for their stuff.  It's just that the claims about them have got me wondering about the capabilities of IEMs.

I've heard about the Westone UM2.  I'm currently considering them and the UM3X, just because they are supposed to have a fairly neutral sound.

Thanks for the info.

Well that 6-driver thing just seems blatantly overkill. The Westone 3 seem like a bargain then.

In my experience the Sennheiser IE 8's seem much better than the same company's HD555's or the noise canceling PCX 450's, considering only pure sonics.  They really sound quite fabulous and, to me, listening to my iPod with them feels like a genuine high end experience.  The imaging is really quite spectacular though, of course, hardly natural.

BUT: when wearing them the sounds of chewing and swallowing are made so prominent that I really can't eat anything comfortably with them on, and they also often make my pulse disconcertingly audible.  So I often turn to the others instead.  Now that the weather is cooling I usually take the 450's on the bus with me because the sound is pretty good and the noise canceling helps with the road roar.

But only the IE8's give me that "high end thrill".

So I would say that some IEMs can sound better than some expensive over the ear headphones.  How the IE8's would compare with the HD 650's or 800's is beyond the power of my wallet to know.

I've owned the Shure E4 and E500, and I had a bad experience.  My oddly shaped ear canals may have had something to do with this, but the bass rolloff in the E500 and the bass and treble rolloffs in the E4 put the E4 somewhere below ipod earphones for me and the E500 somewhere between those earbuds and all of the full-sized headphones I can remember owning (which are too many).  I don't believe my experience is representative of that of most listeners, however.

I've been a longtime head-fier and am very pleased to have finally found this forum, which seems free from all of the BS that poisons head-fi and the other forums I've frequented, and expect, for that reason, that it will it will be much more useful to me.  That said, I've been on head-fi a lot recently and the buzz surrounding the JH13 seems so widespread an unanimous that I think there's actually something to it.  From what people have been saying, it seems like its better frequency response, together with its being a custom IEM (like I said, I had serious fit issues), might rectify all of the problems I had with universals.  I think I'm going to give the JH13 a try.

There's no proof that more balanced armatures always means better sound. It certainly means more expensive. The recent phonaks, are single balanced armature, and are quite popular at head-fi.
Don't forget that single balanced armature are evolving too ..

At least IEMs are evolving, which is a much more than can be said for full sized headphones.  But it's hard to know why exactly manufactures are increasing the number of armatures in a IEM.  Consumers may assume that it's purely for "sound quality" but certainly manufacturers have many things to consider including the marketing of 3 drivers versus 1.

Compare this to full sized headphones.  It seems like manufacturers have been just changing sound signatures for 10+ years and just making marketing claims.  Senn quite literally made a cosmetic change to the HD580 and started charging quite a bit more for the HD600.  There are some recent exceptions with the driver designs of the Senn HD800 and Beyer T1, but it's hard to separate fact from fiction in reviews and marketing.

In my experience the Sennheiser IE 8's seem much better than the same company's HD555's or the noise canceling PCX 450's, considering only pure sonics.

What about in terms of "soundstage."  After trying a lot of headphones I've come to appreciate the sense that I'm listening in a wide space (compared to earbuds), albeit a space that is still much smaller than you get from speakers.  Some headphones have a very flat sound.  How does the IE8 compare to the HD555 in this regard?

Well that 6-driver thing just seems blatantly overkill. The Westone 3 seem like a bargain then.

It would be nice to know how all this works.  Is 6 really better than 3 or is it just marketing?  Is it another 5.1,7.1,9.1,11.1 game?  Do musicians really pay $1K+ for an IEM? 

That said, I've been on head-fi a lot recently and the buzz surrounding the JH13 seems so widespread an unanimous that I think there's actually something to it.

It's hard for me to tell.  In the past many headphones have seen as the greatest gift to audioland.  Any negative comments were seen as the rantings of a person with defective hearing.  But, a year later, some of these same headphones are almost universally panned.  Any claims of their perfection are seen to be made by people with defective hearing!

So I don't know.  $1100 is a lot of money of a custom IEM that probably cannot even be resold or returned.

@odigg

6 in each enclosure! The JH Audio 13 Pro is the recent favorite at that unnamed headphone site, but at $1099 it's quite a bit out of the price range I could seriously consider

The custom utimate ears 11, are around the same price. But they are only four balanced
armature, so for the price you get "less" (just kidding)
The high end earsonics have also similar price,  but only with three balanced armatures ...

The big price does also from that they are all "customs molded iems", same for JH13.
You have to add at least 500$, to get customs.

Senn quite literally made a cosmetic change to the HD580 and started charging quite a bit more for the HD600.

The hd6xx serie need an amplifier to get the best of them (according to head-fi comments),
while hd5xx not, so I  guess there's more than a cosmetic change.

What about in terms of "soundstage."

If you want the IEMs  with the best "soundstage" , take Sennheiser simple as that.
When I  listen to my IE7, the "3d sound" can be incredibly immersive.
On some music this can be even disturbing: "Did someone open the door?
No this just comes from the music I  listen".

Is 6 really better than 3 or is it just marketing?

Here's how I  would explain things:
each balanced armature reproduce more or less faithfully a range of frequency.
The better are the balanced armature you use, the less you need to use
multiple balanced armature to cover faithfully all frequencies.
I  guess each Brand are using their own "proprietary" balanced
armature, so according to their lab experiments, they might need more or less
balanced armature to reach the sound quality they are expecting.
Off course, I guess there's some marketing.  I'm quite skeptical
for the need of 6 drivers.

Do musicians really pay $1K+ for an IEM?

The big price is more justified by the fact they are customs,
than the big number of balanced armatures.

Here are my comments:

IEMs and headphones can both sound great.

IEMs give you isolation which gives you improved S/N in many situations. Improved S/N is improved S/N - doesn't matter to me whether it is from cleaner electronics, more bit resolution or a good seal in the ear. (This also makes them dangerous for use while jogging etc.)

Headphones can give me a more stable sense of bass. If you're moving around with IEMs in, you hear a lot of low frequency interference from the movements of your body. You don't hear so much of that when you're ears are open into headphones.

I personally would like to know what is the justification for the existence of iPod style ear buds. I see people using these things on airplanes and subways and I'm thinking that either they can't hear the music/dialog or they have them cranked dangerously high. They hurt my outer ear too but apparently that's mostly just me. All I can figure is that they're popular because they're small and cheap.

@Notat

Headphones can give me a more stable sense of bass.

The iems have to be "sealed" properly with your ears, to get correct bass.
You have usually to test all the tips provided with your iems, to see wish one fit the best
for your ears. And for some people that's not enough, they buy separate tips
from different brand.

Usually "dynamic driver" reproduce deeper bass than balanced armature,
and I think they are less problematic if you don't get proper "seal".

If you're moving around with IEMs in, you hear a lot of low frequency interference from the movements of your body.

Commonly the word "microphonics" is used to describe this.
Some iems have more microphonics than others;  usually high end iems minimize this problem.

I personally would like to know what is the justification for the existence of iPod style ear buds.

Many people are just "satisfied" with whatever is provided with their mp3 player.
Also if they ear buds broke ,  they look for something similar.
One thing that is nice with cheap ear buds, is that you are not too much afraid to break them accidentally.

I love my Sennheiser CX500's.  Great sound quality IMO, less than $100 price tag and great for use with portable players.
JXL

The idea behind 2 and 3-way IEMs is that balanced armatures have a very limited frequency response, so this improves things.  Pretty simple.  As for the reasoning behind having more than one identical driver, Jerry Harvey of JH Audio said something about this.  Unfortunately I won't be able to find the quote, but basically he said that these balanced armatures distort more at higher SPL.  By using two drivers for each frequency range, as is the case with the JH13, the SPL of each driver can be halved at the same volume level for the listener.  He made a reference to how at big concert venues, speakers use lots of smaller drivers, rather than one huge one.  It's the same principle.

Jerry Harvey founded Ultimate Ears and designed their custom line, then sold the company to Logitech and founded JH Audio.  He confined the new company to the aviation business for a while, but recently returned to pro and consumer audio with redesigns of Ultimate Ears' line.

$500 extra is way too high an estimate of the premium you pay for going custom.  JH Audio's JH5 Pro only costs $399, and there are even less expensive IEMs from other manufacturers.  You can get custom earpieces for universal IEMs for around $100-200.  Keep in mind that you will be paying for the audiologist appointment as well, which should cost around $50-$150.

I've never heard of the HD580 being identical to the HD600 aside from cosmetics and doubt they are, but a few head-fiers saying that one is hard to drive and one is easy to drive is hardly a reason to believe that they aren't the same.  Those people are crazy.

Quote

In my experience the Sennheiser IE 8's seem much better than the same company's HD555's or the noise canceling PCX 450's, considering only pure sonics.

What about in terms of "soundstage."  After trying a lot of headphones I've come to appreciate the sense that I'm listening in a wide space (compared to earbuds), albeit a space that is still much smaller than you get from speakers.  Some headphones have a very flat sound.  How does the IE8 compare to the HD555 in this regard?

Well, I turn the bass control all the way up.  To me they then seem to be flat down to the deepest notes I have on any recording, but others complain about "mid bass bloat" that way.  We really don't yet know the "correct" response for headphones of any type to give an audibly flat response, it seems. 

The IE8's seem to float left and right channels a few inches outside my head, and on the occasional bit of binaural sound effects (such as on the children playing sounds after track 5 of "The Wall") they seem to float sounds quite a few feet to the left and right (but not ahead).  The image is very pleasing to me, but not really "natural".  I get no sense of sounds coming from in front of me, for instance.

I have not double blinded these or any other phone against anything, so take my impressions with that in mind.  Your mileage may vary!  On the other hand that different speaker-end transducers usuallly sound audibly different to one another is, I believe, not controversial.

Unfortunately I won't be able to find the quote, but basically he said that these balanced armatures distort more at higher SPL.  By using two drivers for each frequency range, as is the case with the JH13, the SPL of each driver can be halved at the same volume level for the listener.

This makes me ask another question. What SPLs are we talking about?  Are 3 driver designs audibly distortion free at hearing damage levels?  If so, what's the point of making them distortion free at even higher SPLs?

I've never heard of the HD580 being identical to the HD600 aside from cosmetics and doubt they are, but a few head-fiers saying that one is hard to drive and one is easy to drive is hardly a reason to believe that they aren't the same.

I believe the HD580 and HD600 share the same drivers and, at least to my eyes, a nearly identical (or identical) headband design.  The grills for the HD600 are metal and Senn claims the drivers are better matched.  So if the HD600 is basically the HD580 with a metal grill, I'd judge it as a cosmetic upgrade.  I recall the grills being a whopping $20.  The HD600 sells for twice what the HD580 sold for when new.

I don't mean to argue with you about this and I'm content if somebody demonstrates I'm talking out of my rear.

@steaxauce

The idea behind 2 and 3-way IEMs is that balanced armatures have a very limited frequency response, so this improves things.

That doesn't seem true with the recent phonaks for instance. People seems satisfied with them, for lows, mids, and highs. I rather have a recent iem model  with single balanced armature, than an old one with two balanced armature, because the technology is evolving.

Unfortunately I won't be able to find the quote, but basically he said that these balanced armatures distort more at higher SPL.

I didn't hear of the problem of distortion at high volumes, with dynamic drivers. That's an additional motivation for me to prefer dynamic drivers over balanced armatures.

By using two drivers for each frequency range, as is the case with the JH13, the SPL of each driver can be halved at the same volume level for the listener.

Then there's also the problem of interferences . That's not obvious.

$500 extra is way too high an estimate of the premium you pay for going custom. JH Audio's JH5 Pro only costs $399, and there are even less expensive IEMs from other manufacturers. You can get custom earpieces for universal IEMs for around $100-200. Keep in mind that you will be paying for the audiologist appointment as well, which should cost around $50-$150.

Most of the time , the overall cost for going to customs is $1k+
And I wouldn't be surprised  that each brand are boosting the price for the high end  models (i.e models that allow customs) ,  as much as they can. Because they are reserved for the "audiophile elite" (put any joke here).

Quote from: steaxauce on 2009-10-13 17:24:42

Unfortunately I won't be able to find the quote, but basically he said that these balanced armatures distort more at higher SPL.  By using two drivers for each frequency range, as is the case with the JH13, the SPL of each driver can be halved at the same volume level for the listener.

This makes me ask another question. What SPLs are we talking about?  Are 3 driver designs audibly distortion free at hearing damage levels?  If so, what's the point of making them distortion free at even higher SPLs?

I honestly don't know, but I think it would be a jump to assume that 3-driver designs have inaudible distortion levels at normal listening levels.  All I can say is that, from what JH said, it seems that they perform better at lower SPL.

Quote

The idea behind 2 and 3-way IEMs is that balanced armatures have a very limited frequency response, so this improves things.

That doesn't seem true with the recent phonaks for instance. People seems satisfied with them, for lows, mids, and highs. I rather have a recent iem model  with single balanced armature, than an old one with two balanced armature, because the technology is evolving.

I may have to look into those Phonaks; I hadn't heard of them.  Some armatures have better frequency responses than others, of course, but this nevertheless is the idea behind having a crossover network with multiple drivers.

Quote

Unfortunately I won't be able to find the quote, but basically he said that these balanced armatures distort more at higher SPL.

I didn't hear of the problem of distortion at high volumes, with dynamic drivers. That's an additional motivation for me to prefer dynamic drivers over balanced armatures.

That they have lower distortion at lower volumes doesn't mean they have particularly bad distortion at higher volumes.  It's pretty much impossible to extrapolate what a completely different technology will sound like based on measurements and design info.  Better to stick to listening tests.

Quote

By using two drivers for each frequency range, as is the case with the JH13, the SPL of each driver can be halved at the same volume level for the listener.

Then there's also the problem of interferences . That's not obvious.

He just implied that the SPL would be lower with multiple drivers.  I extrapolated that it would be halved without thinking about interference, so I apologize for that.  Though, since the two drivers are adjacent to each other and in phase, it would seem that they would only interfere constructively.

Quote

$500 extra is way too high an estimate of the premium you pay for going custom. JH Audio's JH5 Pro only costs $399, and there are even less expensive IEMs from other manufacturers. You can get custom earpieces for universal IEMs for around $100-200. Keep in mind that you will be paying for the audiologist appointment as well, which should cost around $50-$150.

Most of the time , the overall cost for going to customs is $1k+
And I wouldn't be surprised  that each brand are boosting the price for the high end  models (i.e models that allow customs) ,  as much as they can. Because they are reserved for the "audiophile elite" (put any joke here).

My guess is that pricing would be more based on what they can be marketed for than what they cost to produce, but custom IEM makers target professional musicians more than audiophiles (or at least it used to be that way).  The pros are generally a lot more sensitive to BS than the audiophools who buy such things.

Quote from: Notat link=msg=0 date=

If you're moving around with IEMs in, you hear a lot of low frequency interference from the movements of your body.

Commonly the word "microphonics" is used to describe this.
Some iems have more microphonics than others;  usually high end iems minimize this problem.

Microphonics is translation of vibration into electricity. The effect I experience is a telegraphing of vibration into my ears - there's no electricity involved. I use Etymotic ER-4's. How much more high end do I need to go?

Microphonics is translation of vibration into electricity. The effect I experience is a telegraphing of vibration into my ears - there's no electricity involved. I use Etymotic ER-4's. How much more high end do I need to go?

My Sennheiser IE8's exhibit the same effect, bur I don't know if they come in above or below your Ety's in the expensiveness sweepstakes.  I believe the effect is caused by bone conduction and is not a microphonic effect, whatever they call it.

@Notat

Microphonics is translation of vibration into electricity

In the context of IEMs, the word  "microphonics" is just used  to talk of  "the noise you get when your IEM cable brushes against clothing". I don't think there's any electricity involved here.

How much more high end do I need to go?

You have to gather informations or test what you buy.
Here's an interesting comparison of 21 popular iems, done by "dfkt" :
http://www.anythingbutipod.com/forum/showthread.php?t=15243 (http://www.anythingbutipod.com/forum/showthread.php?t=15243)
You can see on that comparison, that despite their relatively expensive price the Etymotics ER-6 have annoying microphonics.

If you really believe IEMs with multiple drivers perform better(wider freq range, lower distortion, etc) than IEMs with a single driver, you are quite wrong.

(http://i.imagehost.org/0766/0_1425_sz_1_i_203845_00.gif)
(http://i.imagehost.org/0612/zz.jpg)
Do UE-11Pro(3-way) & SE530(2-way) perform better than ER4(1-way)?

What you get from multiple drivers are bass boost & more distortion.

According to D.Wilson from Etymotic Research:

Do you need a dual driver IEM, or did some marketing genius convince you that two drivers are better than one? The argument for multiple drivers holds water when there are physical limitations to filling a large room with sound, and not a 1.4cc volume in your ear canal.
What do you plan to gain from dual driver?

@udauda
These graph don't tell anything about sound quality.

The apple earbuds are crap when compared to any serious IEM, there's no doubt about that;  and I can't see how you could deduce this from first graph.

Do UE-11Pro(3-way) & SE530(2-way) perform better than ER4(1-way)?

I guess that's hard to tell, without listening to them.

If you really believe IEMs with multiple drivers perform better(wider freq range, lower distortion, etc) than IEMs with a single driver, you are quite wrong.

This opposite statement is just as wrong. Basing a statement about the relationship of two types of tokens by looking at just two tokens is flawed logic. The existence of just one multi driver IEM that is worse than one with a single driver doesn't show anything.

[useless images]

You do know, that for the domain of IEMs the ideal, most neutral piece would have a non-flat frequency response (in contrast to speakers), right?

What you get from multiple drivers are bass boost & more distortion.

Just plain false. Compare top of the line IEMs as Westone's to your Etymotic darlings.

According to D.Wilson from Etymotic Research:

Quote

Do you need a dual driver IEM, or did some marketing genius convince you that two drivers are better than one? The argument for multiple drivers holds water when there are physical limitations to filling a large room with sound, and not a 1.4cc volume in your ear canal.
What do you plan to gain from dual driver?

So you have been tricked into drinking marketing Kool Aid B by the simple ploy of some other statement called Kool Aid A.

You do know, that for the domain of IEMs the ideal, most neutral piece would have a non-flat frequency response (in contrast to speakers), right?

You must be referring to the case of the missing 6dB (http://dx.doi.org/10.1121/1.387540). If you take a look at Here (http://www.etymotic.com/publications/erl-0060-1978.pdf), Here (http://seanolive.blogspot.com/2009/06/whole-body-vibration-associated-with_7561.html), and Here (http://www.etymotic.com/publications/erl-0049-2004.pdf), you'd realize a diffuse-field-compensated(a human diffuse-field HRTF deducted from a linear data) flat-FR is the most suitable, even with headphones, earphones, & IEMs. (flat-FR w/ an additional bone-conducted vibration would make the bass sound more natural though)

Just plain false. Compare top of the line IEMs as Westone's to your Etymotic darlings.

Did you know, DF-compensated, Westone3(UM3) outputs audio signal only upto 10kHz? And that's a 3-way IEM. If you get a chance to fiddle around with a ITU-T P.58 compliant HATS equipped w/ IEC-60318-4 ear simulators, you'll see what I mean.

You must be referring to the case of the missing 6dB (http://dx.doi.org/10.1121/1.387540).

Nope.

...a diffuse-field-compensated(a human diffuse-field HRTF deducted from a linear data) flat-FR is the most suitable, even with headphones, earphones, & IEMs. (an additional bone-conducted vibration would be nice though)

That's the point. For stereo signals, so about 99% of all listened music, without further processing a flat headphone FR is not optimal. A headphone with a FR approximating a DF compensated FR will sound more neutral. Else you'd have to bump a sticker on the box "This IEM's flat frequency response will cause non neutral perception of audio without further processing. Please do not use without applying a proper HRTF."

Did you know, DF-compensated, Westone3(UM3) outputs audio signal only upto 10kHz? And that's a 3-way IEM. If you get a chance to fiddle around with a ITU-T P.58 compliant HATS equipped w/ IEC-60318-4 ear simulators, you'll see what I mean.

Feel free to post detailed results and a comparison to your Etymotics. I have successfully measured the thresholds of my hearing around 16kHz with a pair of UM2 using sweeps. So I somewhat doubt this claim.

I'd love to do that, but I don't have the data with me now. Sorry to disappoint you there.

The closest thing you can get from the open public is:
(http://i.imagehost.org/0536/w3.gif)

I believe the measurement was done by a Japanese headphone enthusiast named Fuchinove, with a DIY-silicone tube. Since above data doesn't reflect an accurate occluded-ear impedance(half-wavelength resonance @ 13kHz), you'll have to account there should be a +10dB boost around @ 10kHz. Also, you gotta keep in mind it is not a ISO-11904 diffuse-field compensated data.

When everything is properly compensated, the graph would show W3 outputting upto 10kHz(+-6dB) in addition to the high-Q deep @ 3kHz. And your statement above:

For stereo signals, so about 99% of all listened music, without further processing a flat headphone FR is not optimal. A headphone with a FR approximating a DF compensated FR will sound more neutral.

is exactly what ER-4S is trying to simulate (http://www.etymotic.com/ephp/er4-ts.aspx), unlike the perfect DF-flat ER-4B. (Or if you're referencing this article (http://www.stereophile.com/features/808head/index2.html), arguing that equalizing somewhere between DF&FF is ideal, oh no.. Almost all of the high-end headphones from AKG, Sennheiser, Grado, Beyer are accurately DF-equalized.)

By the way, I am not trying to convince you that ER4 is the greatest of all IEMs. I'm just saying more drivers don't always guarantee better performances, especially in IEMs. If you can hear 16kHz with your UM2, it should mean UM2 should have a wider FR range than W3. (and I believe UM2 has less # of drivers than W3)

By the way, I am not trying to convince you that ER4 is the greatest of all IEMs. I'm just saying more drivers don't always guarantee better performances, especially in IEMs. If you can hear 16kHz with your UM2, it should mean UM2 should have a wider FR range than W3. (and I believe UM2 has less # of drivers than W3)

We can agree on that. I am just somewhat sceptic, that Westone would release such a bad high end product in their portfolio after the acclaimed UM2.

We can agree on that. I am just somewhat sceptic, that Westone would release such a bad high end product in their portfolio after the acclaimed UM2.

Maybe the Westone UM3X is better?  I've read some comments that the Westone 3 has a very "hi-fi" sound as compared to the more balanced sound of hte UM3X.  Of course, without FR graphs it's hard to know.

rpp3po - you've had experience with IEMs and full sized headphones.  Any comments comparing the two (beyond the obvious differences in sonic signature of two different products)?

@odigg

Maybe the Westone UM3X is better?

Yes, the Westone 3 are somehow a failure, and people at head-fi are not much interested by them.
The UM3X  have a lot more success, and there's no doubt that they are good IEM from the different reviews I've seen. Now, if the use of three balanced armature is justified, that's an other question.

rpp3po - you've had experience with IEMs and full sized headphones. Any comments comparing the two

Why not having both  ? I  think both are interesting differently.
Perhaps it would be just like comparing glasses vs contact lens, they do not provide the same comfort.

AFAIK , for the same sound quality, IEMs are much more expensive, than full sized headphones.

rpp3po - you've had experience with IEMs and full sized headphones.  Any comments comparing the two (beyond the obvious differences in sonic signature of two different products)?

I own Allesandro MS1 (about equivalent to Grado SR60/80), Sennheiser 595, and Westone UM2. I use the UM2 about 70% of the time, they are my greatest enjoyment. The higher SNR due to almost completely locked out external noise makes them great for recordings with a large dynamic range and for any place that is not completely silent (very rare where I live). Also most of my positive ABX results (lossy codecs) happened on the UM2. But while the UM2 are great bass players, I sometimes miss the "feeling" of bass. The MS1 and HD 595 also can't make your bones shake as speakers but at least your auricles. So for some music I still prefer my larger ones.

AFAIK , for the same sound quality, IEMs are much more expensive, than full sized headphones.

?  I've always heard the opposite is true.

@Soap

? I've always heard the opposite is true.

After a google search , I found this recent thread at head-fi:
Do IEM's match Traditional Can in the Sound Quality/$ Ratio? (http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/)

In this thread,  the overall consensus, is that in term of sound quality,
the full sized headphones are better for the the money.

I  wonder how you managed to only hear the opposite.

After a google search , I found this recent thread at head-fi:
Do IEM's match Traditional Can in the Sound Quality/$ Ratio? (http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/)

In this thread,  the overall consensus, is that in term of sound quality,
the full sized headphones are better for the the money.

If that's the consensus at head-fi then I am quite certain that the exact opposite is actually true.

Quote from: rpp3po on 2009-10-14 11:41:27

We can agree on that. I am just somewhat sceptic, that Westone would release such a bad high end product in their portfolio after the acclaimed UM2.

Maybe the Westone UM3X is better?  I've read some comments that the Westone 3 has a very "hi-fi" sound as compared to the more balanced sound of hte UM3X.  Of course, without FR graphs it's hard to know.

I have both Westone 3 and UM3X and I find UM3X clearly better and more neutral.  W3 has elevated mid-bass which is not something I enjoy, it just downs the mids and makes them sound a bit muddy to me.

Quote from: extrabigmehdi on 2009-10-14 19:39:34

After a google search , I found this recent thread at head-fi:
Do IEM's match Traditional Can in the Sound Quality/$ Ratio? (http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/)

In this thread,  the overall consensus, is that in term of sound quality,
the full sized headphones are better for the the money.

If that's the consensus at head-fi then I am quite certain that the exact opposite is actually true.

You cynic. How can you disagree with these slam-dunk arguments:

(http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/#post5962897)

Nope

[/url]
(http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/#post5962952)

NEVER. Portability ALWAYS comes at a cost. ALWAYS. No exception.

[/url]
(http://www.head-fi.org/forums/f103/do-iems-match-traditional-can-sound-quality-ratio-441889/#post5963034)

For under $150, IEM's will be hard pressed to outperform a good pair of full sized cans. As already mentioned, the ultra high end IEM's can outperform their full sized counterparts.The JH13's have been compared head to head against HD800's and have won, and this is coming from some people on this forum who I have a lot of respect for.

[/url]

Why not having both  ? I  think both are interesting differently.
Perhaps it would be just like comparing glasses vs contact lens, they do not provide the same comfort.

When I started this thread I was just trying to get a general idea of how IEMs compare to headphones.  I'm not a fan of owning 10 different pairs of headphones/IEMs so I don't want to buy stuff and just put it in the closet, which I have done already..  Compared to full sized headphones it's is also very difficult to demo IEMs and (depending on vendor) return options are limited.

I want an honest report of IEMs, the capabilities, and even technical information on armatures.  On other websites I can get plenty of opinions.  But they are intermixed with glorious reviews of cables, power supplies, fuses.  Beyond that, a deluge of favorable reviews on some new product can turn totally sour 3-6 months later.  Take the Westone 3.  When it first came out people were just raving about how great it was.  Now many see them as badly colored.

When you focus these trends on a $1000+ Custom IEM, purchases of this product will probably also (maybe I should run a correlation) be people who praise cables, expensive headphone amps, "audiophile" DACs, and who knows what else.  So if somebody says a certain IEM is better than full sized headphones, what in the world am I supposed to believe?

Anyway, I'm ranting.  The point it, if established members on HA tell me they like their IEMS, that just gives me a more balanced and honest viewpoint to work from.

Most of the time , the overall cost for going to customs is $1k+
And I wouldn't be surprised that each brand are boosting the price for the high end models (i.e models that allow customs) , as much as they can. Because they are reserved for the "audiophile elite" (put any joke here).

Custom IEMs can be purchased for less than $400.  So there clearly isn't some essential cost/labor factor driving the cost of some custom IEMs to $1K.

@odigg

I'm not a fan of owning 10 different pairs of headphones/IEMs so I don't want to buy stuff and just put it in the closet, which I have done already..

Well, people I've seen at head-fi are often owning multiple headphones. Instead of puting things on closet they try to resell.
When they are just curious about a headphone, some try to buy already used one at ebay.
Also it seems that some people return to the seller headphones, after quickly trying them.
But I  think it's hard to compare pairs of headphones/IEMs , without collecting a minimum.

.So if somebody says a certain IEM is better than full sized headphones, what in the world am I supposed to believe?

You have to test yourself.
You can never trust a single review. When  I  can't test, I  compare multiple reviews , with no warranty that I'll find the "truth".
Also , I  take a look at difference websites. This involve some work.

When it first came out people were just raving about how great it was. Now many see them as badly colored.

They call this at head-fi  forum , "fan of the month". When a new product is released everyone is excited about it, and after a month or two  not that much.

Frankly, I  don't feel the need to compare IEMs to full sized headphones, to enjoy them . I  mean, I  don't have the feeling to miss something by only using them. Portability is just  a  great convenience.

Also I  think that buying  $1k+ IEMs  is a waste of money.

@Notat

Quote

Microphonics is translation of vibration into electricity

In the context of IEMs, the word  "microphonics" is just used  to talk of  "the noise you get when your IEM cable brushes against clothing". I don't think there's any electricity involved here.

I can take usually care of most of the noise through the cables by routing the wires behind my ears. I was talking about LF noise created when your whole body is moved.

@Notat

I was talking about LF noise created when your whole body is moved.

Well,  from a guide at head-fi:

Bone conduction is the phenomenon where the IEM user can hear noise (caused by body motion such as eating and walking) transmitted with in the body. [...]
Bone conduction can be limited by stop eating and walking softly (changing shoe).

You can find the guide  here:
Basic Guide to In-Ear-Canalphones (http://www.head-fi.org/forums/f103/fyi-basic-guide-ear-canalphones-310723/)

Quote from: extrabigmehdi on 2009-10-13 23:34:41

@Notat

Quote

Microphonics is translation of vibration into electricity

In the context of IEMs, the word  "microphonics" is just used  to talk of  "the noise you get when your IEM cable brushes against clothing". I don't think there's any electricity involved here.

I can take usually care of most of the noise through the cables by routing the wires behind my ears. I was talking about LF noise created when your whole body is moved.

Obviously he is talking about when the cables hit/rub up against something... it prevents from loud thumping you get from pulling and such on the cables... the pinna dampens the sound traveling in the cable because of it resting on the ear.

Quote

Bone conduction is the phenomenon where the IEM user can hear noise (caused by body motion such as eating and walking) transmitted with in the body. [...]
Bone conduction can be limited by stop eating and walking softly (changing shoe).

Yes, bone conduction. Is this possibly a fundamental limitation with IEMs or is there a way to design around it? Good design can minimize acoustic transmission through the cable but how do you address transmission through your bones. You don't hear so much of this with conventional headphones or speakers. Perhaps sealed ears trap and magnify internal sounds.

When you focus these trends on a $1000+ Custom IEM, purchases of this product will probably also (maybe I should run a correlation) be people who praise cables, expensive headphone amps, "audiophile" DACs, and who knows what else.  So if somebody says a certain IEM is better than full sized headphones, what in the world am I supposed to believe?

Anyway, I'm ranting.  The point it, if established members on HA tell me they like their IEMS, that just gives me a more balanced and honest viewpoint to work from.

All we can do there is to tell you about our own personal experience with them; no one can know for sure what your experience will be until you try them yourself.  You can get the same thing over at head-fi.  Sure, you can't trust anyone, good reviews don't guarantee anything, yada yada.  But as long as HA members are doing nothing but stating their own unsubstantiated experience, without blind tests, etc, we're no more reliable than head-fiers (and still a hell of a lot more reliable than speculation based on the technical merits of the two technologies).  You're just going to have to jump in sooner or later.

Another important thing to remember is that particularly with IEMs, various people will have widely varied experiences.  How they end up sounding for you depends on what your ears are like; i.e. whether or not you can get a good seal and fit, and probably on how your ears/ear canals affect sound under normal circumstances (when they're not bypassed, as with IEMs).  For me, I had a great deal of trouble getting a good seal with the Shure E4 and E500, all of the tips were very uncomfortable for me, there was always a severe treble rolloff (I had to EQ the hell out of them to get them to have a frequency response that was anything like what I got with any of the full-sized or earpad headphones, or even earbuds that I've owned), and bass was boomy and dull.  Your mileage will vary.

Also, I want to say that in my experience, headphone reviews are much more likely to reflect their actual sound than reviews of products like DACs, amps, etc. because the differences between headphones, unlike the differences between those components, are usually above people's "psychological noise floor," i.e. the differences are pronounced enough that you can know they're not imagined.  The widely varied headphone reviews, and IEM reviews in particular, accordingly, reflect different tastes and anatomies more than they reflect the fact that human beings are psychotic, unlike reviews of components with more subtle or nonexistent sound signatures.

@Notat
You have the same "bone conduction" problem with what they call in french "Boules Quies" or "Oropax" , which are kind of earplugs (http://en.wikipedia.org/wiki/Earplug).

Perhaps sealed ears trap and magnify internal sounds.

Probably something like that.

The problem of bone conduction might  even be worse with customs IEMs.
I read on a review about  "Ultimate Ears UE 11 Pro" (cost around $1k+ ),
that "eating cornflakes while wearing the UE 11 can almost lead to noise-induced tinnitus".
The review here. (http://www.anythingbutipod.com/archives/2008/10/ultimate-ears-ue-11-pro-review.php)

By the way, I am not trying to convince you that ER4 is the greatest of all IEMs. I'm just saying more drivers don't always guarantee better performances, especially in IEMs.

Here is a FR chart from Phonak Audeo for their PFE.  This is a single driver model.  As you can see the FR range extends quite far (for an IEM) in both directions.

(https://www.nexternal.com/audeoworld/images/pfe-graph.png)

But as long as HA members are doing nothing but stating their own unsubstantiated experience, without blind tests, etc, we're no more reliable than head-fiers (and still a hell of a lot more reliable than speculation based on the technical merits of the two technologies).

I agree with you to a point but  I find even evaluations of transducers to be much more balanced here on HA.  On many audiophile sites there is the persistent belief that expensive speakers/headphones cost that much because of engineering.  People here are much more skeptical and ready to say that marketing and exclusivity can drive up MSRP, not just engineering or technical capabilities.  I've seen people on Head-Fi stubbornly support audible differences between two headphones (e.g. K701 and K702) even when the manufacturer says the differences as cosmetic or something else (e.g. a split cable versus a single cable).

One of my original questions with this thread was just an inquiry into the future of IEMs.  If, in the future, IEMs can sound like full sized headphones, that would be fantastic.  However, if there is some inherent design limitation, like when comparing full sized headphone soundstage to speakers, then full sized headphones will always be around.

Anyway, I have found a sub $150 IEM I'm willing to experiment with and compare with my full sized cans.  I'll just have to wait till it comes back in stock so I can order!

Quote from: extrabigmehdi on 2009-10-15 18:16:17

Quote

Bone conduction is the phenomenon where the IEM user can hear noise (caused by body motion such as eating and walking) transmitted with in the body. [...]
Bone conduction can be limited by stop eating and walking softly (changing shoe).

Yes, bone conduction. Is this possibly a fundamental limitation with IEMs or is there a way to design around it? Good design can minimize acoustic transmission through the cable but how do you address transmission through your bones. You don't hear so much of this with conventional headphones or speakers. Perhaps sealed ears trap and magnify internal sounds.

It's a fundamental problem with IEMs, can not be fixed. Personally, I can't stand it, so all the IEM-obsessed discussions at head-fi are irrelevant to me 

Btw, if you are looking for a small earphone that would rival full-size headphones I strongly suggest taking a look at the Yuin PK1. It's an "earbud", non-IEM, and sounds unbelievably good (actually the whole PK line is outstanding).

odigg, which one are you ordering?

Yes, bone conduction. Is this possibly a fundamental limitation with IEMs or is there a way to design around it? Good design can minimize acoustic transmission through the cable but how do you address transmission through your bones. You don't hear so much of this with conventional headphones or speakers. Perhaps sealed ears trap and magnify internal sounds.

The brain is an amazing thing.  I can no longer hear myself walk when wearing IEMs.  Bothered the piss out of me the first few days, and then slowly it disappeared.
Rough back of the envelope calc says I've worn IEMs for around 5000 hours, but my brain learned to filter it out way before then.
I even jog with them in.

Btw, if you are looking for a small earphone that would rival full-size headphones I strongly suggest taking a look at the Yuin PK1. It's an "earbud", non-IEM, and sounds unbelievably good (actually the whole PK line is outstanding).

I've heard either the PK or the OK series.  I was completely astonished by the sound as I imagine most people are when they hear them.  However, I've never found earbud style earphones comfortable as my ears always starting hurting after a while.  They also fall out quite easily and offer little isolation which completely defeats the purpose of a portable headphone. 

odigg, which one are you ordering?

At this point I've settled on the Audeo PFE.  The price is quite sensible (in the land of "audiophile" headphones at least), they are supposed to be fairly neutral sonically, and apparently compete quite well against more expensive models.  If nothing else, I'll get a taste for IEMs compared to full sized headphones.

Bone conduction is the phenomenon where the IEM user can hear noise (caused by body motion such as eating and walking) transmitted with in the body.

I believe the proper term of this phenomenon is called: microphonics.
(http://www.macworld.com/article/55152/2007/01/canalphones.html)
http://www.macworld.com/article/55152/2007...analphones.html (http://www.macworld.com/article/55152/2007/01/canalphones.html)

most in-ear-canal headphones suffer—to varying degrees—from microphonics , a phenomenon where, because the headphones seal so tightly against your ear canals, bumps and scrapes to the headphone cables are transferred up the cables directly to your ears...Related to microphonics, some people also experience what is known as the occlusion effect (http://www.hearingreview.com/issues/articles/2006-01_05.asp), where your voice and other bodily noises—breathing, coughing, eating, etc.—seem louder or unnatural while wearing canalphones.

Well, I happened to come across the statement Jerry Harvey made about the advantage to using two drivers per frequency band in his JH-13 Pro.  Here it is:

"The balanced armatures when coupled lower distortion. They also are working much more efficiently because of 2 drivers doing the work. Each driver does half the work which increases headroom. A concert PA system like a L Acoustics line array will have roughly 64 15" speakers,128 8" speakers and 32 2" high drivers hanging in the air. Also 64 18" sub bass speakers. In order to create headroom which is gain before distortion you need the work load distributed across multiple components. Yes you can distort all of the components but the sheer gain to do so would be at the threshold of pain. Headroom equals clean audio when operated at a normal spl. Jerry"

Also, you may be interested in checking out this list of head-fier impressions.  It seems unanimous that the JH-13 is at least in the league of the top ($1000+) full-sized headphones.

http://www.head-fi.org/forums/5911775-post3001.html (http://www.head-fi.org/forums/5911775-post3001.html)

This seems beyond FOTM.  Several long-time head-fiers have sold off their huge collections of gear because the 13 has made everything else moot.  Even if you think everyone on head-fi is crazy, it's tough to deny that there's got to be something to all this.  Also, check out the review on touchmyapps.com, below.

http://www.touchmyapps.com/2009/09/30/jerr...-for-your-ears/ (http://www.touchmyapps.com/2009/09/30/jerry-harvey-jh13pro-in-review-sex-for-your-ears/)

Thank you for quoting my review of the JH13Pro below. They are excellent sounding earphones, but for the price, I feel don't warrant the missteps in build quality. Do they sound good? Absolutely. But, one thing that must be taken into account is that Jerry Harvey, a pro though he is, is first of all, marketing a product. It may be true that the drivers themselves, matched up and paired do produce greater headroom and can make for less distortion. But, most people don't have the equipment which will drive these phones without distortion.

I don't have the distortion graphs set up yet, but am working on them. My tests have been done at the amplifier level simply because I don't have the proper equipment (Yet) to produce accurate representations of the sound from the transducers themselves. The JH13Pro induces a heavier load than any earphone I have seen, ever. No dedicated amp I have used with it produces anything even near optimal sound reproduction. At best, there is a massive bass roll off and always, treble spiking. Also, all amps (internal from daps to external, dedicated amps) are generating a lot of thd and imd distortion in comparison to ANY other headphone of any type and calibre.

While I think they are remarkable headphones, I wager that very few, if any have heard them optimally paired and run. My equipment is humble by some regards, but much better than quite a few people's and it gets walloped every time by this headphone.

Just for a reference, the USB/DAC/HEADPHONE AMP review below shows some results of the JH13Pro. Even though it is a cheap amp, its results fall in line with every single dedicated amp I have yet used with the JH13Pro.

Fireye II DAC/USB/HEADPHONE AMP in Reivew - Full Metal Amp (http://bit.ly/1ivbwy) -- TouchMyApps

Well, I happened to come across the statement Jerry Harvey made about the advantage to using two drivers per frequency band in his JH-13 Pro.  Here it is:

"The balanced armatures when coupled lower distortion. They also are working much more efficiently because of 2 drivers doing the work. Each driver does half the work which increases headroom. A concert PA system like a L Acoustics line array will have roughly 64 15" speakers,128 8" speakers and 32 2" high drivers hanging in the air. Also 64 18" sub bass speakers. In order to create headroom which is gain before distortion you need the work load distributed across multiple components. Yes you can distort all of the components but the sheer gain to do so would be at the threshold of pain. Headroom equals clean audio when operated at a normal spl. Jerry"

Also, you may be interested in checking out this list of head-fier impressions.  It seems unanimous that the JH-13 is at least in the league of the top ($1000+) full-sized headphones.

http://www.head-fi.org/forums/5911775-post3001.html (http://www.head-fi.org/forums/5911775-post3001.html)

This seems beyond FOTM.  Several long-time head-fiers have sold off their huge collections of gear because the 13 has made everything else moot.  Even if you think everyone on head-fi is crazy, it's tough to deny that there's got to be something to all this.  Also, check out the review on touchmyapps.com, below.

http://www.touchmyapps.com/2009/09/30/jerr...-for-your-ears/ (http://www.touchmyapps.com/2009/09/30/jerry-harvey-jh13pro-in-review-sex-for-your-ears/)

This seems beyond FOTM.  Several long-time head-fiers have sold off their huge collections of gear because the 13 has made everything else moot.  Even if you think everyone on head-fi is crazy, it's tough to deny that there's got to be something to all this.

No, it's really not all that hard to deny for people who have been on Head-Fi for a while.  Back in the start of 2008 people were raving about the AKG K701.  Anybody, and I do mean anybody, who made a negative comment about the K701 was greeted with a "you need a proper amp" answer and sure enough the people who purchased all this expensive eqiupment turned around and said the K701 was perfect.  A year later if you mention the K701 people start bashing it.

<edit>
My point it, when reviews of some product on Head-Fi are almost universally positive I always become skeptical.  This becomes even more pertinent to me when it's a very expensive product that only a select few individuals can afford.  There is a ton of curious behavior when it comes to negative opinions of expensive product on Head-Fi.  A lot of times people will simply refuse to accept that somebody can see a product as negative and any negative opinion will be overwhelmed by people who want to defend that expensive product.  I know (via private messages) of people who just have stopped posting negative comments on Head-Fi because they don't care to deal with the hostility towards them and their comments.
</edit>

I am very curious about the JH13Pro though even though it's way beyond what I want to pay for a headphone.

As for the JH13Pro being hard to drive, I don't see why it should be. A 28 ohm output impedance is going to lead to some coupling capacitor induced bass rolloff.  However, after looking at those graphs shigzeo has posted, I wonder if the impedance of the JH13PRO varies a lot over the FR.  Coupled with a headphone jack with a higher than 0 impedance out, this can lead to all sorts of changes over the FR.

Is there something else going on here that I'm not aware of that leads to all these FR changes?  shigzeo - do you have a solid state desktop amp on which you can do a loaded RMAA test?  Something with a near 0 ohm output impedance?

Even test it with a CMOY as that has a near 0 output impedance

Thanks for posting, shigzeo.  Your JH13 review was very well written.  That truly is abysmal amp performance.  What exactly makes them so difficult to drive?  Something other than their low impedance?  What other amps have you tried?

Thanks for posting, shigzeo.  Your JH13 review was very well written.  That truly is abysmal amp performance.  What exactly makes them so difficult to drive?  Something other than their low impedance?  What other amps have you tried?

I have tested it with 5 amps now, 2 which are very cheap: the Fireye series, and 3 other dedicated headphone amps: all portable. This 28 OHM 119db machine is not an easy to drive earphone. Each of the amps are very good, one costing about 300$ USD. I will get a chance to do some more testing on really high end mains amps (I have only tested in on one mains amp so far) and ALL fare the same.

Though the JH13Pro sounds good, I think no one is hearing the true performance of the JH13Pro - no one unless they have a very very powerful amp.

Incidentally, the iPod touch 2G drives a reasonable frequency response with the JH13Pro (I won't yet release the charts simply because I am compiling a list of other portables for output performance comparison only), though it suffers from its usually near-perfect driving character.

Just for reference: here is a small graph RMAA graph of 3 amps driving the same 28 ohm JH13Pro. These fed into the Edirol FA66 (by no means a powerhouse, but a good recorder) via balanced TRS cables and through the amps using a Y-split from Jays of Sweden.

These are preliminary: I decided to do this test early as I wondered about the treble - it seems there are other things I should have asked. Keep in mind that this earphone sounds great, but what it does to any inboard or outboard amp proves that probably 99% of people are not hearing as it should sound:
(http://farm3.static.flickr.com/2736/4016357071_3b3ffc2ba5_o.png)
(http://farm3.static.flickr.com/2490/4016357069_99fce2cb5f_o.png)

Also interesting is that the cheapest of the amps did the best in controlling the frequency of the JH13Pro, at least internally. Again, these are taken at an amp level and do not represent what sound comes from the JH13Pro. In other words, they represent how inadequately these dedicated mainstream amps are at driving the earphone.

If it's only the earphones' low impedance that makes them difficult to drive, there are several amps that handle a 28 Ohm load very well; for instance, the mini3, a portable amp, successfully got an "excellent" on the Rightmark Audio Analyzer Test with a 33 Ohm load.  I can't link directly to the measurements, but go to the specifications page and then scroll down to the relevant measurements (I refer to the "high performance" version, as opposed to the "extended runtime" version):

http://www.amb.org/audio/mini3/ (http://www.amb.org/audio/mini3/)

The desktop version, the M3, got scores of "excellent" in all categories when driving a 33 Ohm load, and even when driving an 8 Ohm load.

Would you by chance have impedance graphs of the JH13?

If it's only the earphones' low impedance that makes them difficult to drive, there are several amps that handle a 28 Ohm load very well; for instance, the mini3, a portable amp, successfully got an "excellent" on the Rightmark Audio Analyzer Test with a 33 Ohm load.  I can't link directly to the measurements, but go to the specifications page and then scroll down to the relevant measurements (I refer to the "high performance" version, as opposed to the "extended runtime" version):

http://www.amb.org/audio/mini3/ (http://www.amb.org/audio/mini3/)

The desktop version, the M3, got scores of "excellent" in all categories when driving a 33 Ohm load, and even when driving an 8 Ohm load.

Would you by chance have impedance graphs of the JH13?

it isn't the low impedance that is doing it. These phones are the only earphones which do this to my amps. I have tried dozens, from 12 OHM to 150 or so in the span of 3 years. For example, the Victor/JVC FX500 (http://www.touchmyapps.com/2009/09/20/victorjvc-hp-fx500-in-review-low-dri-ver/) is almost picture perfect for both FR and everything else. While it is 16 ohms, it is a dream to drive in comparison.

shigzeo - Looking at the graphs on your Fireye II review, I'm wondering if there is some problem with your test setup that you are not aware of.

Let me point out only my first reason for saying this.  You have posted an loaded RMAA for 64 Ohm DJ1Pro.  According to specs this has a 102 db sensitivity.  Just from the following details I make the following statement.  The 64 ohm impedance is high enough that it will not induce any major (if any) of the effects of a high pass filter (bass roll off) or result in major increases in distortion.  The impedance and sensitivity is also high enough that an amp like the 5V fireye should be able to drive it to headache inducing volumes without distortion or clipping on the part of the amp.  I assume the impedance of the headphone is flat (or nearly flat) across the frequency range.

By this rationale your RMAA for this should be razor flat.  Yet, even with the Fireye II you've got a small bit of bass and treble rolloff and small variations in the whole FR.  Even your Macbook pro seems to have done a better job driving the Ultrasone than the Fireye.

Either that Fireye II is defective, poorly designed, or there is something off in your testing procedure.  Are you sure your Edirol is performing properly?

Beyond that, there is some reason why you are getting such erratic FR with the JH13Pros.  Low impedance headphones can change the FR from flat and increase distortion, but I've never seen anything like what you've found.  Headphones with a wide variation in impedance through the FR range. can also change the FR.

It's not just "hard to drive" because your RMAA measurements are so interesting.  There's a reason and I'd like to know.  I'd test it myself if I had the earphones to figure it out.

Well, I've been testing headphones with much better set ups till last year and I work mostly at a high end audio. Headphones induce these changes no matter the rationale. The test should not change to accomodate a certain headphone and no, there is no problem with my FA66 or the Fireye. Unloaded, both perform flawlessly (well, within reason).

Volume is no problem at all: each of the headphones go far louder than I want to hear - far louder. But, they each induce the signal differently. Headphones, just like speakers are actually very cumbersome on most audio-output equipment. My test procedure isn't out. I have controls taken, unloaded tests taken, and many headphones also taken, all pointing to the fact that the JH13Pro isn't driven properly by most dedicated amps.

I am not arguing that the Fireye is a perfect device. It has severe limitations even when compared with the other amps you see in the RMAA test results. Again, the same setup yields great results (as seen in the DJ1Pro). My test only tests the effects of headphones on amps; in other words, how well an amp can actually pusha  headphone. The JH13Pro is the only one with that poor of results across about 5 portable amps and now two mains amps.

EDIT:
Thank you for the input. I too am perplexed, but again will note that only the JH13Pro acts this way. The kenwood C700 is also harder to drive from the same amps, but nothing in the same class.

Just for reference, you can see the Fireye 1 performing the same tests (though I did not publish the JH13Pro results).
Fireye 1 Portable headphone amp in review - Heavy Metal (http://www.touchmyapps.com/2009/09/07/fireye-1-portable-headphone-amp-in-review-heavy-metal/)

shigzeo - Looking at the graphs on your Fireye II review, I'm wondering if there is some problem with your test setup that you are not aware of.

Let me point out only my first reason for saying this.  You have posted an loaded RMAA for 64 Ohm DJ1Pro.  According to specs this has a 102 db sensitivity.  Just from the following details I make the following statement.  The 64 ohm impedance is high enough that it will not induce any major (if any) of the effects of a high pass filter (bass roll off) or result in major increases in distortion.  The impedance and sensitivity is also high enough that an amp like the 5V fireye should be able to drive it to headache inducing volumes without distortion or clipping on the part of the amp.  I assume the impedance of the headphone is flat (or nearly flat) across the frequency range.

By this rationale your RMAA for this should be razor flat.  Yet, even with the Fireye II you've got a small bit of bass and treble rolloff and small variations in the whole FR.

Either that Fireye II is defective, poorly designed, or there is something off in your testing procedure.  Are you sure your Edirol is performing properly?

Beyond that, there is some reason why you are getting such erratic FR with the JH13Pros.  Low impedance headphones can change the FR from flat and increase distortion, but I've never seen anything like what you've found.  Headphones with a wide variation in impedance through the FR range. can also change the FR.

It's not just "hard to drive" because your RMAA measurements are so interesting.  There's a reason and I'd like to know.

There is something really odd going on with the JH13 RMAA.  Maybe it is something with the design or wiring of the IEM that is causing problems with the RMAA test suite?  Perhaps some interaction between the Edirol and the JH13?  I had a similar problem when I borrowed a modified amp from a friend.  Audibly there was no problem.  But RMAA was giving me wild results (10%+ THD, IMD).  I was never able to reconcile what I was hearing with the RMAA results.  I eventually concluded there was some odd interaction between the ADC and amp because I think the testing worked properly with different hardware.  It was a while ago so I don't remember the details.

Do you have a different ADC to test with?  How about just using the stereo in of a computer sound card, even if it's the built in sound card?  If nothing else at least you can see if the results between the computer stereo in and the Edirol are correlated.

Does anyone know what could cause this in a headphone?  What contributes to one being difficult to drive, other than impedance and sensitivity?

Does anyone know what could cause this in a headphone?  What contributes to one being difficult to drive, other than impedance and sensitivity?

Barring the typical problem (e.g. clipping) I've only seen this sort of FR nuttiness when you put together 2 types of devices.
1.  A headphone jack with a high impedance out (e.g. home receiver with a headphone jack powered by resistors off the main amp).
2.  A headphone with wide impedance variance over the frequency range.

Look at this Pio2001's thread (http://www.head-fi.org/forums/f133/headphone-outputs-lots-measurments-one-abx-429619/) on Head-Fi.  However, even those FR changes don't look half as nutty as the FR graphs for the JH13.

Right.  And he's tested a variety of amps, though all Firestone.  I'm not clear on how these measurements are done, so not that I know what I'm talking about, but if there were any other load in series with the earphones, this would have the same effect as increasing the amp's output impedance.

Right.  And he's tested a variety of amps, though all Firestone.  I'm not clear on how these measurements are done, so not that I know what I'm talking about, but if there were any other load in series with the earphones, this would have the same effect as increasing the amp's output impedance.

Yes.  Even resistors in series would do it.

Just from the FR graphs I would conclude the Mac Book pro actually has a lower output impedance than all the other dedicated amps.  It seems there are a lot of badly built headphone amps out there...

Based on specifications Firestone Audio Cute Beyond has a near 0 output impedance, but I don't know if shigzeo has access to that.  Even a CMOY, assuming the output is directly connected to the opamp, has a near 0 output impedance.

I've even tested 25 ohm headphones (Denon D5000,D7000) with a Cmoy and it can drive both with a flat FR.

The brain is an amazing thing.  I can no longer hear myself walk when wearing IEMs.  Bothered the piss out of me the first few days, and then slowly it disappeared.
Rough back of the envelope calc says I've worn IEMs for around 5000 hours, but my brain learned to filter it out way before then.
I even jog with them in.

Same here - I don't notice it much. What I do notice is that I can't really hear the bass when I'm moving. I know it is there but it is obscured by all this low frequency noise that my fine brain is ignoring. And that's what I was referring to when I complained about unstable bass response. I should add that I fully take advantage of the cone of silence created by IEMs and usually listen at very moderate levels.

i don't yet have access to a cmoy, but had one in the past. I will be borrowing more amps later for more reviews. It is intriguing. Remember, those graphs show max down and upswings of up to 6 dbl, so perceived sound effect is much, much less than shown I'll have some more preliminary tests up soon.

shigzeo - could you post an RMAA for the JH13 connected directly to a PMP?  Any player (as long as it measures well unloaded) is fine but if you have access to a Sansa Clip I that would be great.  I am very curious about the results.

I don't think the JH13PRO should be hard to drive.  I suspect something else is going on - I just don't know what!

The clip and the iPod touch 2G have no appreciable differences other than the Clip not performing as well on channel separation (on every hardware I have tested it on). I returned it to its owner for that reason (would take it back when it gets rockboxx)

These tests are not final, but I expect final tests not to change much:
(http://farm3.static.flickr.com/2521/4017733897_ea2301a19b_o.png)
(http://farm3.static.flickr.com/2534/4018495014_af462a8c90_o.png)

But not all 16 ohm phones are created equally: The FX500 is driven beautifully, though it too is only 16 OHMs. Sensitivity is 100dbl. B2 stands for Bass jumpers set to position '2' in the Fireye 1 which has some bass roll off (as you can see) in the image:
(http://farm4.static.flickr.com/3522/4017743623_9d9060fb48_o.jpg)

In the last 3 years (since 2006), I have done personal tests with 3 different professional soundcards and about 5 computes with a variety of shielded and unshielded cables following the same respected principles. Amps from Heed, Meier, Xin, Firestone, Graham Slee, Travagan's, and two prototypes. The only phone which has really provided these results has been:

Jerry Harvey Audio JH13Pro (http://www.touchmyapps.com/2009/09/30/jerry-harvey-jh13pro-in-review-sex-for-your-ears/)
Earsonics SM2 (http://www.touchmyapps.com/2009/08/12/earsonics-sm2-inner-earphones-in-review/)

As you can see, the deviation on the iPod touch versus these dedicated amps is far less, but not that good. The Clip fared a bit worse, but held up pretty well. Its Channel separation was worse than the Fireye 1. Official TMA results will go up at the end of the year with all the headphones I can scrounge together, but I won't be changing any hardware or testing methods as these have stood their ground for a long time. Keep in mind, the 'large' swings in frequency response represent only about 6 decibels (which admittedly is a lot), but far less than most people enjoy when they bump up their EQs. Trust me, they only reflect how the earphone stresses the amp, not so much on how 'off' or 'on' it sounds.

cheers

The balanced armatures when coupled lower distortion. They also are working much more efficiently because of 2 drivers doing the work. Each driver does half the work which increases headroom. A concert PA system like a L Acoustics line array will have roughly 64 15" speakers,128 8" speakers and 32 2" high drivers hanging in the air. Also 64 18" sub bass speakers. In order to create headroom which is gain before distortion you need the work load distributed across multiple components. Yes you can distort all of the components but the sheer gain to do so would be at the threshold of pain. Headroom equals clean audio when operated at a normal spl. Jerry

I've actually read about this on Loudspeaker and Headphone Handbook. Of course, multiple drivers yield more headroom, since the workloads on drivers are lessened! More # of drivers should help IEMs get more SPL w/o clipping, and hopefully more bass to compensate the 'missing 6 dB' effect. However, I believe there's a downside as well when multiple # of balanced armature transducers are coupled together.

I've seen many IEM measurements, but yet to see any multi-driver IEMs with a lower harmonic distortion figure than single-driver IEMs usually have. Moreover, balanced armature transducers are moving-iron transducers, and their distortion figures are very non-linear in their nature. From what I've seen, when these BA transducers were coupled together, the outcome was always more harmonic distortion, mostly at the frequencies where the crossover network takes place. (in turn, more headroom & sensitivity)

Quote

The balanced armatures when coupled lower distortion. They also are working much more efficiently because of 2 drivers doing the work. Each driver does half the work which increases headroom. A concert PA system like a L Acoustics line array will have roughly 64 15" speakers,128 8" speakers and 32 2" high drivers hanging in the air. Also 64 18" sub bass speakers. In order to create headroom which is gain before distortion you need the work load distributed across multiple components. Yes you can distort all of the components but the sheer gain to do so would be at the threshold of pain. Headroom equals clean audio when operated at a normal spl. Jerry

I've actually read about this on Loudspeaker and Headphone Handbook. Of course, multiple drivers yield more headroom, since the workloads on drivers are lessened! More # of drivers should help IEMs get more SPL w/o clipping, and hopefully more bass to compensate the 'missing 6 dB' effect. However, I believe there's a downside as well when multiple # of balanced armature transducers are coupled together.

I've seen many IEM measurements, but yet to see any multi-driver IEMs with a lower harmonic distortion figure than single-driver IEMs usually have. Moreover, balanced armature transducers are moving-iron transducers, and their distortion figures are very non-linear in their nature. From what I've seen, when these BA transducers were coupled together, the outcome was always more harmonic distortion, mostly at the frequencies where the crossover network takes place. (in turn, more headroom & sensitivity)

Your thoughts mirror my findings perfectly. Some BA phones don't offer as much hell to amps, but some like the JH13Pro do. The SM2 from Earsonics is another which I will show later, but these are simple findings on the effects on the amp, not the actual sound which comes from the earphone.

Shigzeo, would you mind explaining or linking to a page that explains the testing procedure you use to measure amps driving headphones?  I'm unclear on it.  Thanks.

Not sure about a specific scientific procedure, but to perform a LOADED test, you must:

source --> y split --> headphones/line to amp.

For UNLOADED:

source --> amp/line


That signal is recorded in an audio application in .wav and sent to RMAA to analyse. Even without RMAA though, after getting used to proper, perfect audio waveforms, you can 'see' the printed information does not match.

If you want a hell of a lot of these tests, anythingbutipod has a huge RMAA loaded test section:
Index of Loaded RMAA tests (http://rmaa.elektrokrishna.com/Comparisons/Comparison%20-%20Cowon%20D2%20-%2012%20-%2048%20Ohm.htm)

When I started this thread I was just trying to get a general idea of how IEMs compare to headphones.  I'm not a fan of owning 10 different pairs of headphones/IEMs so I don't want to buy stuff and just put it in the closet, which I have done already..  Compared to full sized headphones it's is also very difficult to demo IEMs and (depending on vendor) return options are limited.

I thought I'd share my experience:

I have a couple of pairs of Sennheiser CX400s as well as a pair of Grado S80's. 

Head to head with the Grados, the Grados win in sound quality.  I forget I have them on my head! (I love my Grados!).  The open backs give the music space to where I feel like I'm listening to speakers and not headphones.

Can I use my Grados at work, while I go to sleep, or mow the lawn?  Nope!  For those things, I used to use my ear buds from my iPod or from an older Sony mp3 player.

So, it's better to compare the CX400s with the ear buds I used to use.  The CX400's blow the doors off the ear buds hands down!

With the CX400s, I feel I get quality sound with great portability.  And it isn't that they don't sound as "good" as my Grados - they just sound different.  But for quality sound in a noisy or highly mobile environment, you can't beat the in ear headphones like the CX400s.

I also found that using foam tips help tone down the boominess and brightness I hear when using the standard rubber tips.

For portable use and for ultra details which are sometimes not audible from big phones (for a variety of reasons), IEMs are phenomenal. A hi-end IEM like the JH13Pro will be a great upgrade simply because it doesn't need all the dedicated equipment that a full-size needs in order to sound good, or be driven properly. However, what even a high-end IEM will not give is the sensation which help your ears experience bass and to a lesser extent, spacial dynamics. That can only be done by sound reaching all parts of the ear, inner and outer.

Still, IEMs have better bone-conducting transfer of sound which helps them recover soem of what they lose out in inherent ability to stimulate the outer ear.

Quote from: odigg on 2009-10-15 14:23:00

When I started this thread I was just trying to get a general idea of how IEMs compare to headphones.  I'm not a fan of owning 10 different pairs of headphones/IEMs so I don't want to buy stuff and just put it in the closet, which I have done already..  Compared to full sized headphones it's is also very difficult to demo IEMs and (depending on vendor) return options are limited.

I thought I'd share my experience:

I have a couple of pairs of Sennheiser CX400s as well as a pair of Grado S80's. 

Head to head with the Grados, the Grados win in sound quality.  I forget I have them on my head! (I love my Grados!).  The open backs give the music space to where I feel like I'm listening to speakers and not headphones.

Can I use my Grados at work, while I go to sleep, or mow the lawn?  Nope!  For those things, I used to use my ear buds from my iPod or from an older Sony mp3 player.

So, it's better to compare the CX400s with the ear buds I used to use.  The CX400's blow the doors off the ear buds hands down!

With the CX400s, I feel I get quality sound with great portability.  And it isn't that they don't sound as "good" as my Grados - they just sound different.  But for quality sound in a noisy or highly mobile environment, you can't beat the in ear headphones like the CX400s.

I also found that using foam tips help tone down the boominess and brightness I hear when using the standard rubber tips.

I've been using full sized headphones for a long time.

As have I. My first high quality stereo headphones were by Telex, and purchased some time prior to 1962.

Lately (over the last few years), it seems like just about everybody and their brother is releasing IEMs.

True, and how many of them are OEMed and rebranded is only known by the guilty parties. Compounding this are the facts that they are basically hearing aid technology in a slightly different wrapper, and that people like Knowles Research are openly selling the components on the electronic components market.

If I listed the really pretty good headphones I own and use frequently, this post would be considerably longer. If I added my list of IEMs, it would be longer still.

I realize there is a large profit motive to do so because of the explosion of portable media devices.

Consider this. One marketing report I've seen suggested that the market for add-on loudspeaker/amplifier products for iPods was larger than the entire home A/V component market.

For a long time I've simply dismissed them as devices that sacrificed sound quality for size and portability.

That seems to be pretty strange thinking to me. IEMs have their small size because they do a smaller job. Instead of filling a room or a earmuff with sound, they focus their efforts where it matters - the ear canal.

Not sure about a specific scientific procedure, but to perform a LOADED test, you must:

source --> y split --> headphones/line to amp.

For UNLOADED:

source --> amp/line


That signal is recorded in an audio application in .wav and sent to RMAA to analyse. Even without RMAA though, after getting used to proper, perfect audio waveforms, you can 'see' the printed information does not match.

If you want a hell of a lot of these tests, anythingbutipod has a huge RMAA loaded test section:
Index of Loaded RMAA tests (http://rmaa.elektrokrishna.com/Comparisons/Comparison%20-%20Cowon%20D2%20-%2012%20-%2048%20Ohm.htm)

Hm, are you sure you wrote that down correctly?  You didn't specify where the measuring device goes.  What I'd think the setup would be for a loaded test is:

source --> amp --> y split --> input of measuring device/headphones.

And for unloaded:

source --> amp --> input of measuring device

If you ever get the chance, I'd be interested in finding out how the iQube performs with the JH13.  It's a very different circuit design, which I'm cautiously optimistic won't have the same problems with the JH13 as other amps.  I'd also be interested in hearing about the ALO Rx. (And, you know, every other amp.  )

Consider this. One marketing report I've seen suggested that the market for add-on loudspeaker/amplifier products for iPods was larger than the entire home A/V component market.

If you combine this wiith my experience with cheap earbuds in the 80s and early-mid 90s, you can understand my skepticism of IEMs.  If you combine marketing, chance for profit, and lack of transparency about technical matters, and consumer ignorance and strange expectation, you end up with an industry where half cooked products are sold for super cooked prices and people assume there is some engineering (versus marketing) reason for this.

However, my opinion is changing.  I recently purchased a Klipsch S4.  I do not like it at all (far too much bass for my taste), but I sense a great potential with IEMS.

Arnold - You can help solve a mystery in this thread.  If you look at some of the later posts you'll see a bunch of RMAA measurements for the JH13 Pro IEM.  Why are we seeing the non-flat FR graphs, even with dedicated headphone amplifiers?  This seems to be something that is localized to this specific IEM.  What is going on?  Is it because it has a passive crossover?

source --> amp --> y split --> input of measuring device/headphones.

Yes, this is correct.  The Y splitter comes after the amp, not between the sound and amp.

A hi-end IEM like the JH13Pro will be a great upgrade simply because it doesn't need all the dedicated equipment that a full-size needs in order to sound good, or be driven properly.

If you ever get the chance, I'd be interested in finding out how the iQube performs with the JH13. It's a very different circuit design, which I'm cautiously optimistic won't have the same problems with the JH13 as other amps. I'd also be interested in hearing about the ALO Rx. (And, you know, every other amp. )

WHOA!  Let's not forget we are on Hydrogen Audio, a forum which explicitly states that claims need to be supported by controlled (blind, volume matched) tests and/or measurements.  Most of the claims of audible differences between, and benefits of, headphone AMPs, DACs, Cables, etc have been made after listening in uncontrolled tests.  All these differences tend to vanish in controlled listening tests.

Whenever people say "X headphone is hard to drive" they are basing such conclusions the faulty data of evaluations made in uncontrolled tests.  The large majority of dynamic (not planar) headphones are not hard to drive and they don't need a special amp or source to shine.  Generally, low impedance headphones are well driven by devices as simple as a IPOD or Sansa Clip.  High impedance headphones MAY need a amp is you are listening to highly dynamic music at high volume levels.  Even then, I suspect a decently made 9V amp should be enough for anything, even up to 600 ohms. 9 volts into 600 ohms is 135mW.  Good luck to your ears at that power level.

If you want to refute this with more examples than the JH-13 Pro measurements, feel free to provide some measurements or controlled listening results.  Even then, there is an explanation for why we are seeing the strange FR of the JH 13 Pro.  I don't think it's simply a matter of "hard to drive."

I'm sorry to be such a stickler about this.  But this is the only audio forum on the net where people are actually skeptical of claims about audio equipment.  I'd like that standard to be remembered and maintained.

odigg, I think you misunderstood me.  Since Shigzeo has the JH13 and performs measurements, I was simply asking him to perform measurements on those two amps if he ever had the chance, to find out whether or not they had the same FR problems with the JH13.

Edit:  What I meant by "how they perform with the JH13" was, "how they measure."  I suppose I should've just written that.

Arnold - You can help solve a mystery in this thread.  If you look at some of the later posts you'll see a bunch of RMAA measurements for the JH13 Pro IEM.  Why are we seeing the non-flat FR graphs, even with dedicated headphone amplifiers?  This seems to be something that is localized to this specific IEM.  What is going on?  Is it because it has a passive crossover? )

Measuring IEMs is still controversial, because as far as I know we don't yet really understand what measured FR corresponds to audibly flat response at the eardrums.  Most of the "dummy head" systems I have read about seem to merely imitate the external ear, which makes sense for over the ear headphones, but I don't know how well they imitate the ear canal, not to mention that I believe most of us have wide variations in just how our canals run. 

My IE8's sound "flat" to me, more or less,  with the bass turned all the way up,  and I find no need to equalize their response.  Yet the graphs at Headroom show a 15 db downward slope from 20 hz to 10 Khz.  With the large flange tips they do not sound more than very slightly bass heavy to me.  They do not boom and even deep male voices sound quite natural (except their positioning in the sound field of course).

Some links to actual studies of these matters would be very interesting.  But we should not assume that a measured "flat" response in a magazine equates to an actually neutral sound.

What we're seeing problems with is the frequency responses of amps when driving the JH13, not the frequency response of the JH13 itself.  For some reason, amps seem to have trouble outputting a flat frequency response when driving the JH13.  The frequency response of the sound produced by the earphones isn't what's being measured.  What's being measured is the signal the amp is outputting.

As far as I can comprehend, what shigzeo has discovered is an impedance interaction(impedance bridging (http://www.sengpielaudio.com/calculator-voltagebridging.htm)) between IEMs and amplifiers:

1. Balanced armatures have very low-Z by their nature. (usually no more than one-digit?)
-> Since input impedance is low, more current is drawn(i.e. current-hungry) from the amplifier where Z is lower. The amplifier(high output-Z) output follows the impedance curve of the BA.

2. You couple 2, 3, or even 6 of these low-Z BATs together with a cross-over network, Z goes up where transducers are joined together; the resulting impedance is extremly non-linear.
-> The amplifier output follows the drastic impedance curve (http://www.stereophile.com/images/archivesart/508ue2.jpg) of the IEM, especially if the amplifier has a high output-Z.

Thus if you'd like to drive JH13Pro or any multi-BA transducer IEMs with a close-to-flat amplifier output, you must have an amplifier with the output Z < 0.1 or even lower. Or add a serial resistance adapter to JH13Pro, so that less current is drawn. (adding a serial resistance will raise the input impedance of IEM, lowering the current drawn. However, will raise the ouput-Z of the amplifier as well, underdamping (http://www.audioholics.com/education/amplifier-technology/damping-factor-effects-on-system-response/damping-factor-effects-on-system-response-page-2) the resonant frequency of the IEM itself)

If anything is wrong with my analysis, you're more than welcome to correct & elaborate it further.


BTW, here's the RMAA result of iRiver H140 with ER-4P(&4S) loaded:
(http://i78.photobucket.com/albums/j92/udauda/1256014698-2.png)

ER-4P has a serial resistor(~20 ohms) inside, so its input impedance would be sufficiently high.(its resonant frequency is intentionally underdamped in order to simulate the ear canal resonance) Since most of DAPs have output Z of less than 10ohms (http://fuchinove.ninja-mania.jp/img563.gif), it wouldn't be so hard to obtain a flat response at their output ends w/ ER-4P.

the amp is a measuring device: whether a soundcard, or my Edirol FA66, the unit is a type of amplifier. My measuring device is the FA66

As I stated before

source --> ysplit -->> one to headphones, one to amp or FA66. The advantage of the FA66 is that I can accurately test noise levels whereas the MacBook Pro only tests accurately for frequency response.

Quote from: shigzeo on 2009-10-21 01:13:51

Not sure about a specific scientific procedure, but to perform a LOADED test, you must:

source --> y split --> headphones/line to amp.

For UNLOADED:

source --> amp/line


That signal is recorded in an audio application in .wav and sent to RMAA to analyse. Even without RMAA though, after getting used to proper, perfect audio waveforms, you can 'see' the printed information does not match.

If you want a hell of a lot of these tests, anythingbutipod has a huge RMAA loaded test section:
Index of Loaded RMAA tests (http://rmaa.elektrokrishna.com/Comparisons/Comparison%20-%20Cowon%20D2%20-%2012%20-%2048%20Ohm.htm)

Hm, are you sure you wrote that down correctly?  You didn't specify where the measuring device goes.  What I'd think the setup would be for a loaded test is:

source --> amp --> y split --> input of measuring device/headphones.



And for unloaded:

source --> amp --> input of measuring device

If you ever get the chance, I'd be interested in finding out how the iQube performs with the JH13.  It's a very different circuit design, which I'm cautiously optimistic won't have the same problems with the JH13 as other amps.  I'd also be interested in hearing about the ALO Rx. (And, you know, every other amp.  )

Good observations. I have noted in earlier tests with the ER4s that the same frequency response does not occur. As you have mentioned, it is likely that is due to the cross over network and a mismatch of Z. Even a dual-balanced armature presents a different load to the amps and as I stated, I have yet to see any amp which isn't negatively affected.

Even adding 75OHM resistance does little to correct the situation, and in the case of certain high-end balanced armature phones, dulls the high frequencies, while for many dynamic phones does little but bring out the bass a bit more since less current is needed and the single ended outputs aren't drained as much.

As far as I can comprehend, what shigzeo has discovered is an impedance interaction(impedance bridging (http://www.sengpielaudio.com/calculator-voltagebridging.htm)) between IEMs and amplifiers:

1. Balanced armatures have very low-Z by their nature. (usually no more than one-digit?)
-> Since input impedance is low, more current is drawn(i.e. current-hungry) from the amplifier where Z is lower. The amplifier(high output-Z) output follows the impedance curve of the BA.

2. You couple 2, 3, or even 6 of these low-Z BATs together with a cross-over network, Z goes up where transducers are joined together; the resulting impedance is extremly non-linear.
-> The amplifier output follows the drastic impedance curve (http://www.stereophile.com/images/archivesart/508ue2.jpg) of the IEM, especially if the amplifier has a high output-Z.

Thus if you'd like to drive JH13Pro or any multi-BA transducer IEMs with a close-to-flat amplifier output, you must have an amplifier with the output Z < 0.1 or even lower. Or add a serial resistance adapter to JH13Pro, so that less current is drawn. (adding a serial resistance will raise the input impedance of IEM, lowering the current drawn. However, will raise the ouput-Z of the amplifier as well, underdamping (http://www.audioholics.com/education/amplifier-technology/damping-factor-effects-on-system-response/damping-factor-effects-on-system-response-page-2) the resonant frequency of the IEM itself)

If anything is wrong with my analysis, you're more than welcome to correct & elaborate it further.


BTW, here's the RMAA result of iRiver H140 with ER-4P(&4S) loaded:
(http://i78.photobucket.com/albums/j92/udauda/1256014698-2.png)

ER-4P has a serial resistor(~20 ohms) inside, so its input impedance would be sufficiently high.(its resonant frequency is intentionally underdamped in order to simulate the ear canal resonance) Since most of DAPs have output Z of less than 10ohms (http://fuchinove.ninja-mania.jp/img563.gif), it wouldn't be so hard to obtain a flat response at their output ends w/ ER-4P.

odigg, I think you misunderstood me.

Sorry.  I spent some time on Head-Fi today and probably became overly sensitive to the possibility of wild claims   

As I stated before

source --> ysplit -->> one to headphones, one to amp or FA66. The advantage of the FA66 is that I can accurately test noise levels whereas the MacBook Pro only tests accurately for frequency response.

I'm confused by this.  If you put the y split before the amp then you are changing the signal even before it reaches the amp.  How is this a valid test of the amp?  The headphone load is then on the source, not the amp.  So the amp is only going to amplify the FR deviations by the headphone load on the source.  Many sources have a higher than 0 output impedance so it is expected that the FR will change if you connect the IEM directly to it.

When you tested the Fireye II this should have been your setup

source -> Fireye II -> Y split -> JH13/FA66.

Did you do this?  If not, your measurements of the Fireye II are not valid.  Have I misunderstood what you are doing?

If anything is wrong with my analysis, you're more than welcome to correct & elaborate it further.

Your analysis is sound.  However, if this is the reason for the non-linear FR then the solution is quite simple.  As you have stated, use a device with a low Z out.  This is the typical output of an opamp, but in the "audiophile" world they've come to see opamps as bad.  So they make complex and expensive solutions without opamps that actually make the amp worse than cheaper, simpler, designs...

If this is the case then the JH 13s are not "hard to drive."  This is actually demonstrated with the RMAA measurements were the IPOD measures better than the dedicated amps.  You just need a device with a low impedance output.  If it were the case that the JH 13s are "hard to drive" then it would perform much worse with the IPOD and improve only with a dedicated amp.  These are not the results of the various RMAA tests.

odigg, I know you are only trying to get things straight, but again: source, ysplit, headphones and the opposite line going into the (in your terms) sound measuring tool (Edirol FA66).

As stated from the very beginning, I have been doing this for years with other, better-known colleagues based on reading evidence and experience. And, as you have pointed out yet again, the chain should be set up as I have listed.

Here is another graph:

Output: source (iPod, AMP3, MacBook Pro, Fireye II) feeding (Fireye I, Travagan's Red, Graham Slee Voyager, Heed Canamp)

Ysplit --> one end feeding line in of 'measuring device', another into headphones. For comparison's sake, unloaded tests are also presented.

I don't see how my tests and results could have been misinterpreted so many times, even if we use different language. The results speak for themselves as to the testing chain.

Quote

odigg, I think you misunderstood me.

Sorry.  I spent some time on Head-Fi today and probably became overly sensitive to the possibility of wild claims   

Quote from: shigzeo on 2009-10-22 02:38:23

As I stated before

source --> ysplit -->> one to headphones, one to amp or FA66. The advantage of the FA66 is that I can accurately test noise levels whereas the MacBook Pro only tests accurately for frequency response.

I'm confused by this.  If you put the y split before the amp then you are changing the signal even before it reaches the amp.  How is this a valid test of the amp?  The headphone load is then on the source, not the amp.  So the amp is only going to amplify the FR deviations by the headphone load on the source.  Many sources have a higher than 0 output impedance so it is expected that the FR will change if you connect the IEM directly to it.

When you tested the Fireye II this should have been your setup

source -> Fireye II -> Y split -> JH13/FA66.

Did you do this?  If not, your measurements of the Fireye II are not valid.  Have I misunderstood what you are doing?

Quote

If anything is wrong with my analysis, you're more than welcome to correct & elaborate it further.

Your analysis is sound.  However, if this is the reason for the non-linear FR then the solution is quite simple.  As you have stated, use a device with a low Z out.  This is the typical output of an opamp, but in the "audiophile" world they've come to see opamps as bad.  So they make complex and expensive solutions without opamps that actually make the amp worse than cheaper, simpler, designs...

If this is the case then the JH 13s are not "hard to drive."  This is actually demonstrated with the RMAA measurements were the IPOD measures better than the dedicated amps.  You just need a device with a low impedance output.  If it were the case that the JH 13s are "hard to drive" then it would perform much worse with the IPOD and improve only with a dedicated amp.  These are not the results of the various RMAA tests.

Adding serial resistance will not lower the current drawn.  The same current will be drawn, but the voltage will be higher.  The voltage-to-current ratio across the IEM with serial resistance will be higher than the voltage-to-current ratio of just the IEM, so effectively, the amp will have a higher-impedance, lower-sensitivity load, which will make certain amps perform better.  As far as the IEM is concerned however, adding, say, a 70 Ohm serial resistance, while it might lower THD, noise, etc. will effectively make the output impedance of the amp 70 Ohms plus whatever the amp's original output impedance is.  If the IEM's impedance varies widely with frequency, the serial resistance will therefore only skew the frequency response much more.  If you're measuring the effective frequency response of this configuration, your measuring device should be in parallel with the earphones, but in series with the serial resistance; i.e. the Y-splitter should be inserted after the serial resistance in the chain.

Shigzeo, the reason people are having trouble understanding your testing procedure is that the language you are using is ambiguous.  You're calling the headphone amplifier your "source" where in audio the word "source" generally designates the CD player/DAC/portable media player/what-have-you, and you're calling your measuring device your "amp."  Sure, it is an amplifier in a sense, but people think you're referring to your headphone amp.  This is what we thought you meant when we read your testing procedure:

"source" such as iPod, MacBook Pro, FA66 analog output, etc. --> Y-splitter --> headphone amplifier in parallel with headphones

Which would be a very odd setup!  I think we are all picturing the same setup, though, which is:

source (as I've defined the word) --> headphone amplifier --> Y-splitter --> FA66 input in parallel with headphones

Can you verify that this is correct?

The same current will be drawn, but the voltage will be higher. The voltage-to-current ratio across the IEM with serial resistance will be higher than the voltage-to-current ratio of just the IEM, so effectively, the amp will have a higher-impedance, lower-sensitivity load, which will make certain amps perform better.

I certainly have missed that. Appreciate your input.

Well, looking back, I will have to agree that my language was ambiguous. Even so, the same would be true however if I fed the entire thing into a preamp - the frequency response wouldn't change.

I began by saying source merely because the Fireye II is a source, not the macbook. It is a DAC supplying all audio output for the MacBook Pro. But later, I understand why I was misunderstood and am sorry for the confusion. In any case it is as you say:

source (as I've defined the word) --> headphone amplifier --> Y-splitter --> FA66 input in parallel with headphones
or
source (as I've defined the word) --> headphone amplifier --> Y-splitter --> FA66 input for unloaded tests.

Shigzeo, the reason people are having trouble understanding your testing procedure is that the language you are using is ambiguous.  You're calling the headphone amplifier your "source" where in audio the word "source" generally designates the CD player/DAC/portable media player/what-have-you, and you're calling your measuring device your "amp."  Sure, it is an amplifier in a sense, but people think you're referring to your headphone amp.  This is what we thought you meant when we read your testing procedure:

"source" such as iPod, MacBook Pro, FA66 analog output, etc. --> Y-splitter --> headphone amplifier in parallel with headphones

Which would be a very odd setup!  I think we are all picturing the same setup, though, which is:

source (as I've defined the word) --> headphone amplifier --> Y-splitter --> FA66 input in parallel with headphones

Can you verify that this is correct?

The only problem with all this is that the JH13 is far from the only headphone with extreme variations in impedance, and yet the others don't have this problem with the amps tested.

The only problem with all this is that the JH13 is far from the only headphone with extreme variations in impedance, and yet the others don't have this problem with the amps tested.

Pardon me, but what 'others' do you refer to? Other headphones? Amps? I am very interested in hearing an amp which doesn't fluctuate when driving the JH13Pro - very interested.

Quote from: odigg on 2009-10-21 20:34:59

Arnold - You can help solve a mystery in this thread.  If you look at some of the later posts you'll see a bunch of RMAA measurements for the JH13 Pro IEM.  Why are we seeing the non-flat FR graphs, even with dedicated headphone amplifiers?

I believe that is is pretty much standard for headphone amps to provide a moderate source impedance, with 16-32 ohms being a common range. If you load an amplfiier with a source impedance like this  with an earphone that presents a non-uniform load impedance, then of course the response is going to be non-flat.

I'm not sure that this is even a problem.

Quote

This seems to be something that is localized to this specific IEM.  What is going on?  Is it because it has a passive crossover? )

I might imagine that a headphone with a crossover presents a more complex load than one that does not. We see this with loudspeakers. Again, it is not necessarily a problem.

Measuring IEMs is still controversial, because as far as I know we don't yet really understand what measured FR corresponds to audibly flat response at the eardrums.  Most of the "dummy head" systems I have read about seem to merely imitate the external ear, which makes sense for over the ear headphones, but I don't know how well they imitate the ear canal, not to mention that I believe most of us have wide variations in just how our canals run.

In my travels I found a paper that was provided to people who fit hearing aid earpieces. As I've mentioned before, IEMs are very similar, and may even contain the same components.

The interesting thing about this paper is that it described how to modify various common components of hearing aid earpieces and earmolds so as to aptimize their frequency response for various listeners. There was a strong implication that ear canals varied quite a bit and this affected the perceived frequency response of the earpiece. Apparently there are standard procedures for measuring the user's perception of the frequency response of a hearing aid - perhaps by repeating hearing frequency sensitivity tests.

These days hearing aids seem to include very sophisticated DSPs, and this sort of mechanical modification may no longer be necessary or practiced. But my point is that this paper is evidence that people's ear canals and subtle details of the earpiece can signficiantly affect frequency response.

I know that the human brain is capable of making very strong adaptations to optimize sound quality and intelligitiblity. For example, its not unusual for me to sit down to listen, turn the TV or stereo up at first, and then turn it down as I my brain unconsciously adapts to it.

I think that our natural goal for music reproducers is sound quality that we perceive as natural sound. As our current listening situation becomes more different from being in a familiar and/or preferred music listening situation, the more unnatural it may seem. 

Since headphones short-circuit much of our usual daily listening context, it is more likely that they will sound unnatural, particularly until we "acclimatize our ears" Of course our ears may change very little during this process, its our brain that is adapting. IEMs short-circuit even more of your usual daily listening context, so it is likely that they will seem even more unnatural to us.

An anecdote: I just went on a 8 day camping/hiking/canoeing trip with my wife. I delayed finding my portable CD player in the house. At the last minute I couldn't find it. So, I ran over to RS  (a block away) and picked up a cheap but cheerful protable FM radio. I went upstairs to find my IEM collection, and picked something that I was familiar with. When I got out on the road, I found that one channel of my old reliable IEMs was dead. By then I was well away from urban centers where I would have my choice of good IEMs to purchase. I did find a RS store, and had to pick from their limited selection. Of course the new ones sounded pretty weird. However, after a week out in the woods of listening to them an hour or more a day, they sounded pretty natural.

shigzeo - I understand your test setup now.  I have no complaints about your setup.  Your previous diagram looked as if you had put the headphone before the amp.

Pardon me, but what 'others' do you refer to? Other headphones? Amps? I am very interested in hearing an amp which doesn't fluctuate when driving the JH13Pro - very interested.

I think steaxauce is trying to say that there are many headphones with fluctuating impedance.  If you use a low Z output amp the amp measures with a flat FR on a loaded test.  So there is one of two (or both) things occurring in your tests.

1.  The amps you are testing do not have near 0 output impedance.
2.  There is something very different about the JH13 Pro.

Do you have access to an amp you know has a near 0 output impedance?  Just about every (if not every) amp from AMB Labs is like this.  A number of solid state desktop amps are like this as well.  What amps do you have access to.  In one of your graphs is says "red."  Is this the Travagan's red?

Of course, manufacturers of such amps may not provide specifications or may provide selective (e.g. 0.1 ohm at 1khz) specifications.

Also, in a previous message I said a 9V amp should be enough to drive a 600 ohm headphone.  I fixed up my cmoy this morning and tested it with a 600 ohm AKG 240 DF.  This is a very inefficient headphone.  At very loud volumes (to me) I heard clipping.  So my previous statement is incorrect.

I'm not sure if this would happen with a Mini 3 as that amp can swing very close to the rail voltage.  The Cmoy is a very basic design and so maybe a 12 volt supply would do it.  I'd have to test it to be sure.

Pardon me, but what 'others' do you refer to? Other headphones? Amps? I am very interested in hearing an amp which doesn't fluctuate when driving the JH13Pro - very interested.

I was just referring to other headphones.  You said earlier on that the JH13 was about the only headphone you've tested that does this, and there are many headphones with wide impedance variations, which makes me think that there may be something odd about the JH13.

The lower the average impedance of the headphone, the more relevant these wide impedance variations become.

Shigzeo, have you measured any other earphones that we know have wide variations in impedance, so we can confirm that there is something different going on with the JH13?  Just for reference, headphone.com has impedance graphs of just about every headphone they sell, and many they don't.

Fuchinobe-san, whom I mentioned previously to reference W3 measurements, has actually measured the output Z of well-known DAPs as well:
Its output-Z is both relatively high & non-linear.

You said earlier on that the JH13 was about the only headphone you've tested that does this, and there are many headphones with wide impedance variations, which makes me think that there may be something odd about the JH13 ... Shigzeo, have you measured any other earphones that we know have wide variations in impedance, so we can confirm that there is something different going on with the JH13?

If I am remembering correctly, Triple.Fi 10 Pro from Ultimate Ears also shows a quite similar behavior. Dear Shigzeo, I want to see more RMAA measurements with different IEMs or headphones loaded, too.

I went through the IEMs tested on touchmyapps.com, and all of the ones I could find impedance graphs for have pretty much flat impedance.  If another IEM with widely varied impedance has been tested with those amps and has been observed to not have the same problems, something other than the 13's varied impedance is probably causing this, and I'd be interested in knowing about it.  In the mean time, since I don't know of any other mechanism that could cause this, I'm going to say that it's most likely that the Firestone amps have high output impedance and the JH13's impedance is widely varied, and that's the cause.

I went through the IEMs tested on touchmyapps.com, and all of the ones I could find impedance graphs for have pretty much flat impedance.  If another IEM with widely varied impedance has been tested with those amps and has been observed to not have the same problems, something other than the 13's varied impedance is probably causing this, and I'd be interested in knowing about it.  In the mean time, since I don't know of any other mechanism that could cause this, I'm going to say that it's most likely that the Firestone amps have high output impedance and the JH13's impedance is widely varied, and that's the cause.

I noticed nothing strange with most of the headphones, but indeed, cross-over laden balanced armatures do the same thing: each and every one have strange results. It isn't as bad with a dual cross over, not all the time, but with more than 2, the impedance fluctuations go mad. I will publish the results later, but now I have a few other reviews to complete which are... games... haha.

One point to note is that the impedance of these multi-BA phones (regardless of rating) probably actually dips quite low.  If you look at the UE11 graph the impedance starts out at 10 ohms!  It seems the 18 ohm UE11 rating is quite a fantasy...

I've tested devices with some variance over the impedance range where the lowest impedance is 25 ohms.  Even with a player like a Sansa Clip, they measure flat.

I think every headphone/IEMs has some variance over the impedance range, even if the variances are quite small.  Even so, some players can drive a 16 ohm load without issue.

16 Ohm comparison by dfkt (http://rmaa.elektrokrishna.com/Comparisons/16%20Ohm%20-%20iPhone,%20Clip,%20D2,%20%20H340.htm).  Sony devices are also supposed to be able to drive low impedance headphones with a flat FR as well.

However, if you look at output impedance  of the PMPs udauda posted, the UE11s 10 ohms is quite near the output impedance of some of these devices.  This would explain a lot.

If shigzeo was in the USA I would build or buy a Mini 3 and lend it to him for testing.

Also, the Fireye II specifications say it is rated for headphones 32-600 ohms.

I've emailed Jerry Harvey of JH Audio for impedance specifications for the JH 13 Pro.  I hope he replies.

Quote from: steaxauce on 2009-10-23 00:35:11

I went through the IEMs tested on touchmyapps.com, and all of the ones I could find impedance graphs for have pretty much flat impedance.  If another IEM with widely varied impedance has been tested with those amps and has been observed to not have the same problems, something other than the 13's varied impedance is probably causing this, and I'd be interested in knowing about it.  In the mean time, since I don't know of any other mechanism that could cause this, I'm going to say that it's most likely that the Firestone amps have high output impedance and the JH13's impedance is widely varied, and that's the cause.

I noticed nothing strange with most of the headphones, but indeed, cross-over laden balanced armatures do the same thing: each and every one have strange results. It isn't as bad with a dual cross over, not all the time, but with more than 2, the impedance fluctuations go mad. I will publish the results later, but now I have a few other reviews to complete which are... games... haha.

Then it is indeed the impedance issue.  All you need for flat frequency response, then, is an amp with close-to-zero output impedance, which is not hard to find or expensive at all.  You should get one!

I have had a few Sony models and it is true, the models from 2007-present have very little if any problems with frequency response even running low OHM phones. However, my iPod touch, subjected to the same tests with the same tests beats the pants off the Sony overall. 100% flat, lower distortion, wider stereo separation. That is why I was surprised to see the touch thrashed by the JH13Pro.

I have added the FitEars Private 333 to the mix and it ... has another interesting, but not as strange frequency dip. It loses a big chunk of the spectrum from about 8 or 10k to 13k, then comes back strong. The difference is that the FitEars 333 sustains the majority of its signal along 0 decibels rather than way under or way over. I don't have the tests with me now, but I can get a clip again and prove that it tests actually worse than the iPod touch for about 90% of the dynamic phones on the market. Similar to the touch and Sony models, however, it gets spanked by the JH13Pro and the FitEars Private 333.

The 333 is a 3 receiver, 3 driver, 3 crossover machine. The same FitEar company has a prototype 668 with (don't quote me) 6 receivers, 6 crossovers, 8 drivers in it. That, I am sure, will destroy any DAP, even the venerable iPod shuffle 1G (which is remarkable - manages to drive 84 decibels of stereo separation with the FitEars Private 333! and 94 decibels S/N!).

But, after all this testing in the last few years, I have found that the most 'pleasing' sound (noted by comments at headfi) earphones, often drive a hell of a lot of distortion from sources and amps. It isn't always the case, but heavily distorting sources tend to sound softer and in headfi terms, 'musical'. I don't really care for this or that, but it is interesting that people rant about distortion, trashing it, but in the end, they listen to phones which cause heaps of distortion at the source/amp level and love them.

My tests will be published in December and discussed at TMA's small forum (not up yet: should be a good place to host the files too because they will be easy to get at all in the same place).

Cheers.

One point to note is that the impedance of these multi-BA phones (regardless of rating) probably actually dips quite low.  If you look at the UE11 graph the impedance starts out at 10 ohms!  It seems the 18 ohm UE11 rating is quite a fantasy...

I've tested devices with some variance over the impedance range where the lowest impedance is 25 ohms.  Even with a player like a Sansa Clip, they measure flat.

I think every headphone/IEMs has some variance over the impedance range, even if the variances are quite small.  Even so, some players can drive a 16 ohm load without issue.

16 Ohm comparison by dfkt (http://rmaa.elektrokrishna.com/Comparisons/16%20Ohm%20-%20iPhone,%20Clip,%20D2,%20%20H340.htm).  Sony devices are also supposed to be able to drive low impedance headphones with a flat FR as well.

However, if you look at output impedance  of the PMPs udauda posted, the UE11s 10 ohms is quite near the output impedance of some of these devices.  This would explain a lot.

If shigzeo was in the USA I would build or buy a Mini 3 and lend it to him for testing.

Also, the Fireye II specifications say it is rated for headphones 32-600 ohms.

I've emailed Jerry Harvey of JH Audio for impedance specifications for the JH 13 Pro.  I hope he replies.

DFKT is also a member of headfi and not typical of the ranting and often clueless group. I recommend that same website as a good resource. Unfortunately, he doesn't have iPods and iPhone 3G and 3GS up along with Sony.

More than anything, the Sony impressed me because of its very good live recording engine which is better than many more expensive recorders. I have the 828, 615 and the 639 but they are all somewhere... I cannot stand players that don't have gapless playback simply because I listen to a lot of trance and any gaps are ruinous to my listening repose. I know that with SS and ATRAC, the sony can run gapless, but... it isn't worth it to boot up VMware, load windows, transfer the songs I want to listen to and with SS, carve my CD's to a format which only Sony supports.

I was a minidisc.org member and used ATRAC for about 6 years before giving in and getting a Cowon D2 (a disappointing machine).

Then it is indeed the impedance issue.  All you need for flat frequency response, then, is an amp with close-to-zero output impedance, which is not hard to find or expensive at all.  You should get one!

Doesn't this sum it up? I loosely followed this thread for a while. And I'm somewhat wondering what all the fuss is about and why shigzeo & others even got so much attention.

Speakers have always had non linear impedance, and rated impedance has always been just an estimation. That's fine and that's why amps are supposed to have a low output impedance for ages.

Varying impedance does not necessarily mean varying frequency response! It just means that more energy is burned at some frequencies*. This energy may be heat or air movement, but you cannot tell from the Y-voltage variation alone. Of course, there is often correlation between both. But the presented test setup fails to estimate the extend. With n-way balanced armature designs you necessarily have passive elements in the crossover that burn energy as heat and this electrical FR variation doesn't say anything about acoustical FR variation. That is why n-way balanced armature designs may look flawed when you test them like that, but it is the test itself that is flawed, when you draw conclusions from this about their FR.


* An inexpensive amp design without major flaws doesn't care.

Hey there,

Well I arrive a bit late to the party. Have been very occupied with studies.
To get back on track, I will explain a bit what I think regarding IEMs vs Full sized.

For the record I have two IEMs, the Shure se-210 and the Phonak PFE. I also own other full sized headphones from different brands. The main issue you encounter when trying to describe or to "compare" two different headphones (*when I type headphone I refer to both IEMs and full size*) is that your opinion depends in the position you wear them on, in how comfortable they are for you and in your mood plus predisposition towards the music you will be listening to.

The first problem I encountered when I put the Shure se-210 was that they were uncomfortable. It was a new sensation for me, to introduce something in my ear canal and to have my ear canals closed, without any airflow between my mouth and ears. To have the ear tips pressing my ear canals and having the sensation of getting most part of the sound get to my ear drums without it leaking outside. Where am I going with this? What I am trying to say is that you are facing a situation that is not the natural way of hearing sounds. And that needs adaptation. It took a few months to get used to the shure IEMs, and if I didn't wear them for some days, after I put them again I felt a bit uncomfortable again.

In the meantime, whilst I was listening to music, I had to play with the position of the IEMs in order to get a good seal plus comfortable position. Due to my ear canals I can bear IEMs better in my right ear than in my left one. And whilst changing position there is the time when the mids seem distant, or there is not enough bass (even if the se-210 lack in the bass department, IMO). With the Phonak PFE i had more luck. They are much more comfortable -didn't stay as deep as the shure-, I had got used to the feeling of having my ear canals blocked, and the FR was more to my liking.

Even so having other full sized cans after some months wearing only the IEMs showed me the big disadvantage IEMs (Universals) have. IEMs are very position dependent. They depend so much in the way they are resting in your ears that the true response the transducers give can not be easily heard. When you are wearing IEMs you are mostly moving your head and jaw, so they can also move if they are not well set. That gives some noticeable deviations in the FR. In my case getting a comfortable seal was difficult and more time consuming than putting some full sized HP. The latter needed a shorter adaptation period.

Full sized cans, on the other hand, don't depend so much on the position in the head. They do, but as well as it happens when you are sitting in your listening room and you change your head from the correct position. So speaking about the term "good" when speaking about headphone types is not the correct word for it IMO.

IEMs have another "presentation" different from full sized. It is easier to get "absorbed" by the music with the former because they avoid outside noises to get inside your canals. (That is if you have found a comfortable position which in my case is way more difficult than with full sized HPs). I dislike this sentence because I haven't had the opportunity to listen to music with both IEMs and Full sized under conditions of near silence, so I have my doubts about that.

To finish with this long post and due to me feeling tired as yesterday I came back from a live concert (Dream Theater + Opeth + Bigelf + Unexpect), I believe that the reason people say full sized HPs are "better" is because there position is not as crucial as with the former. I have spoken about open cans mainly. Closed cans share something similar to IEMs.

Sorry for not making too much sense due to my being tired. I will come back again to clear any doubts my opinion might bring up and hope you at least get  my point in what is going on between IEMs (universals) and full sized HPs (open mainly).

I respectfully disagree with almost everything ImBullseye said.
It isn't that one of us is right and the other wrong, but that people are varied.
I, personally, find it easier to get a proper fit with IEMs than cans.
I, personally, find it easier to move around and not vary frequency response while wearing IEMs.
I, personally, find it easier to get a comfortable fit with IEMs.

I do agree, though, that IEMs provide better isolation. 




PS - if there is EVER an airflow between your mouth and ear canal your eardrum has a hole in it.

Well, seems then it is all about taste

As in my own case, getting a good fit, without the ear tip moving out becomes quite difficult, whereas putting some headphones over my ears with the headband correctly attached doesn't take time at all. I have not tried custom IEMs, but I would like to do so some day.

Regarding the "airflow" I must say I did choose the wrong term. I wanted to say with that the sensation of always getting some noise reaching your ear drums. The feeling you have during all day of being surrounded by sounds. Getting absolute silence is impossible (-blocking every outside sound-). The reason I say that might be because I have a sensitive ear. I get to hear distant noises that other people around me normally don't. I am by no means a "golden ear" or some nonsense like that.

What I do like about IEMs is that they allow me to focus more in the music because they filter most sounds I can normally hear when wearing full sized cans. In the end, if the fit is good with IEMs, or if I am with open full sized HPs under silent conditions the degree of enjoyment can be quite similar. However due to comfort I always tend to go for a full sized rather than IEM.

And as I haven't been able to reproduce for my headphones good conditions for test, comparing bass, "soundstage", mids and highs becomes something absolutely subjective and biased.

I respectfully disagree with almost everything ImBullseye said.
It isn't that one of us is right and the other wrong, but that people are varied.
I, personally, find it easier to get a proper fit with IEMs than cans.
I, personally, find it easier to move around and not vary frequency response while wearing IEMs.
I, personally, find it easier to get a comfortable fit with IEMs.

I do agree, though, that IEMs provide better isolation. 




PS - if there is EVER an airflow between your mouth and ear canal your eardrum has a hole in it.

It occurred to me that we might be oversimplifying things a little.  Could it be that IEMs' impedance varies with the amplitude of the signal as well?

Though, I suppose it doesn't really matter.  Low output impedance would still be all that's needed for an otherwise well-designed amp to perform well with the IEM.

It occurred to me that we might be oversimplifying things a little.

Concerning what?

Could it be that IEMs' impedance varies with the amplitude of the signal as well?

Is this just baseless speculation or is there any data indicating this (amplitude is just voltage)? Not that it would matter, as you wrote. Else we could also speculate wether the impedance could vary as a function of the moon's position.

It's just baseless speculation, but how do we know that it doesn't?  There are some ( fairly obscure) types of drivers that certainly do.  Piezoelectric drivers act more like capacitors than resistors, but mostly what prompted my remark was the RLC circuit that is the 3-way passive crossover.

Bullseye - Thanks for the comments.  I suppose the fit and comfort issue is one of the biggest issues.  I recently tried a Klipsch S4 (disliked, extremely boosted bass) and found that after listening for a while I started to feel like something was stuck in my upper teeth.  The earphone was very comfortable so I was quite surprised to have this feeling.

IEMs have another "presentation" different from full sized. It is easier to get "absorbed" by the music with the former because they avoid outside noises to get inside your canals.

I think the way the sound seems to emanates also helps IEMs make you feel more absorbed in the sound.  With headphones you can get the "blob in the head" effect, but you still get some sort of sense that the music is coming from outside you.  With the Klipsch I had the distinct feeling like my head was the speaker or the speakers were actually in my head (which they were).  This was quite an interesting feeling (something I would have to get used to), but I can see how people can eventually like this sound.

I'm still not sold on Customs.  Maybe I just don't have enough disposable income to buy something I can't resell

I have found that the most 'pleasing' sound (noted by comments at headfi) earphones, often drive a hell of a lot of distortion from sources and amps. It isn't always the case, but heavily distorting sources tend to sound softer and in headfi terms, 'musical'.

I'm not sure what you mean by "hell of a lot of distortion."  From the measurements I've seen of various headphones and IEMs, the amp distortion loaded with low impedance headphones rarely exceeds 0.15%  What is the distortion of the transducers themselves?  Is 0.15% any more audible than lower numbers?

IEMs are in for an interesting future.  Brands from China seem to be releasing good products, including customs.  I imagine this is going to drive down the prices of all IEMs or at least force current major vendors to upgrade their products.

odigg, your welcome.

Sorry my post wasn't clear. I was quite tired at that time and I couldn't type what I thought.

Regarding your teeth hurting it is a similar sensation as the one I had at the left back side of my jaw. I felt something very unpleasant. It was related to SPL, as the lower the less noticeable it was. As in your case, my earpiece was correctly positioned. It could be called a "comfortable position", however that annoying feeling kept coming back to my jaw. It took some months for me to get used to it. With full sized cans the adaptation was faster, and I didn't face those issues.

You might have noticed that I barely spoke about SQ. If i didn't was because:
a) My listening experience is not the same with the headphones tested (SPL level matching)
b) I didn't face a comfortable position with both cases that would allow me to start some similar to a comparison. IEMs fault mainly.
c) Even if I had the correct conditions for testing equipment, the time in which I'd have to swap between IEMs and full sized would make me rely on my listening memory, which cannot be trusted.

Therefore if I now tell you that the bass coming from the PFE was not punchy enough -to my likings- but tomorrow I put them back again, in a different position (as getting the same position for anything is impossible) and I get the punch I like about it, or my mood helps me "feel it that way", the words used to describe the sound the transducers give would be completely useless. And as IEMs (universals) are much more POSITION DEPENDENT -more than full sized, in MY opinion and in my absolute terms - than full sized, the difference I might hear from one time to another is more prone to suffer from a bigger variation than the one I can experience using full sized cans.

I hope I explained myself correctly in this last paragraph.

However what I can say and I agree with you is the sensation of having the speakers inside your skull -more graphic that way  - can be pleasant. I enjoy much more wearing IEMs at bed and lying down than when sitting on my chair with the full sized on. I have lied down with full sized at bed, but it is not the same, and the head-band falls from my head.

The following is just speculation regarding the "in your head" effect. As the sound waves are getting directly in your ear canals to your ear drums and surrounding walls, sound waves get both absorbed (by the mucus *don't know if that is the correct word for it in english*), reflected and refracted in the canal walls and absorbed by your bones. Depending on the SPL, more of those waves get absorbed, and the ones that don't, can't get so far out of your ear. On a full sized can, the distance between the transducer and your ear drum is bigger, being the headphone open, reflected sound waves can get outside of your canals and those waves get "lost". Soundstage is related to the time lapse between two received sound waves. Your brain is capable of making a 3D image of where the sounds are coming from. That is where the distance between transducer and ear drum comes into play. Obviously I am over-simplifying what happens inside our ear canals, but where I am going at is that with IEMs, you are "forced" to process <more> sound waves than with full sized cans due to my early speculation.

That might be experienced as more "intimacy, closeness, presence, ..."

Then what I have written above might be trash (regarding my speculation). I believe more people here know way more than I do, therefore I'd like to hear some reasoning -more logical and reasonable- than my speculation stating what differences regarding transducers + ear drum + ear canals relations are.

Finally, we humans can get used to loads of things. From an "audiophile" or shall I say music lover point of view, we should strive to get the most life-like representation of music. That involves tonality, positioning (soundstage), ... Receiving sound waves directly from the instruments themselves (coming from their designs) will always be different than getting the sounds from some transducers with limitations, recordings with limitations, etc. And yet our brain can get used to a different way of receiving sounds and acknowledge it as being "correct". IEM and full sized presentation is a variation of a real live performance. Neither of them is correct or wrong, both of them are simply limited. Both are limited at a different degree when seeing them sperately (as mechanical artifacts they are), and at the same time limited by our brain capacity.

So in the end there are some objective aspects that can make something be tagged as "better", always putting live performance as the reference. (e.g. An outside sound presentation gets closer than a "blob in head"  presentation to real life, as you can't have a violin play inside your ear canal, but you can have one playing at the left side of your ear) In the end, however, it is you who has to decide if having an "inside your head" experience gives you more satisfaction than having one "at your left and right side". As comfort is one of my biggest concerns, and I have achieved that better with full sized HPs, I rate them above IEMs, plus I think the sensation of left/right ear is more truthful than in the head sensation. 

Now this is the end. Had a tiresome day and felt like thinking out loud here. Feel free to comment  Hope at least I give some good food for thought for someone... And odigg, hope this helps with your decision.

Bullseye - Thanks for the comments.  I suppose the fit and comfort issue is one of the biggest issues.  I recently tried a Klipsch S4 (disliked, extremely boosted bass) and found that after listening for a while I started to feel like something was stuck in my upper teeth.  The earphone was very comfortable so I was quite surprised to have this feeling.

I think the way the sound seems to emanates also helps IEMs make you feel more absorbed in the sound.  With headphones you can get the "blob in the head" effect, but you still get some sort of sense that the music is coming from outside you.  With the Klipsch I had the distinct feeling like my head was the speaker or the speakers were actually in my head (which they were).  This was quite an interesting feeling (something I would have to get used to), but I can see how people can eventually like this sound.

odigg, it seems as if my response was again as inarticulate as possible and I am sorry. What I meant by a hell of a lot of distortion is again, at the amp level. No amp I have seen drives the iems at better than 2% which is as much as 100x more distortion than some of my other earphones (FX500 16 ohm).

The only problem I have with the arguments that it is merely impedance mismatching which is causing the non-linear FR is that when adding impedance (75), the FR doesn't change that much. While my tests are purely experimental, they hold water simply as they have been the same since the beginning.

As far as iems vs full size, I am on both sides of the fence. The outer ear is important to me, but iems have a special and full presence from within the ear which radiates outward. I don't necessarily prefer one over the other except in certain situations. When I need isolation, there is no choice but iems, and at home, I would prefer to wear my BD DT880.

Chinese brands: are you speaking of Unique Melody and Sound Magic among others? Yeah, there are a lot of good iems hitting from all across the globe. China supplies 90% of the oem devices which other country's brands utilise, so it is no wonder that China is coming up in the market. I am a Phonak owner too, but I will admit that other than good fit and sound, they were disappointing. The angular tubes hurt my ears, and worse, the cable is susceptible to cracking and hardening.

My favourite universals are: Atrio M6, Audio Technica CK10, Earsonics SM2 (http://www.touchmyapps.com/2009/08/12/earsonics-sm2-inner-earphones-in-review/), the Monster Turbine (http://www.touchmyapps.com/2009/02/23/monster-turbines-earphones-in-review/), and the Victor FX500 (http://www.touchmyapps.com/2009/09/20/victorjvc-hp-fx500-in-review-low-dri-ver/). For customs, the FitEar Private 333 is hands down my favourite for sound (character), but the Sleek CT6 (http://www.touchmyapps.com/2009/04/11/sleek-audio-custom-iem-in-review-perfection/) for price/performance.

cheers,

Bullseye - Thanks for the comments.  I suppose the fit and comfort issue is one of the biggest issues.  I recently tried a Klipsch S4 (disliked, extremely boosted bass) and found that after listening for a while I started to feel like something was stuck in my upper teeth.  The earphone was very comfortable so I was quite surprised to have this feeling.

Quote

IEMs have another "presentation" different from full sized. It is easier to get "absorbed" by the music with the former because they avoid outside noises to get inside your canals.

I think the way the sound seems to emanates also helps IEMs make you feel more absorbed in the sound.  With headphones you can get the "blob in the head" effect, but you still get some sort of sense that the music is coming from outside you.  With the Klipsch I had the distinct feeling like my head was the speaker or the speakers were actually in my head (which they were).  This was quite an interesting feeling (something I would have to get used to), but I can see how people can eventually like this sound.

I'm still not sold on Customs.  Maybe I just don't have enough disposable income to buy something I can't resell

Quote

I have found that the most 'pleasing' sound (noted by comments at headfi) earphones, often drive a hell of a lot of distortion from sources and amps. It isn't always the case, but heavily distorting sources tend to sound softer and in headfi terms, 'musical'.

I'm not sure what you mean by "hell of a lot of distortion."  From the measurements I've seen of various headphones and IEMs, the amp distortion loaded with low impedance headphones rarely exceeds 0.15%  What is the distortion of the transducers themselves?  Is 0.15% any more audible than lower numbers?

IEMs are in for an interesting future.  Brands from China seem to be releasing good products, including customs.  I imagine this is going to drive down the prices of all IEMs or at least force current major vendors to upgrade their products.

I recently purchased a Westone UM3X.  Since this is a multi-BA device with a crossover, I just had to run it through RMAA.  I'm not posting the graphs because I used the onboard sound of a 5+ year old computer and the graphs are very easy to misinterpret.

I got the expected result.  When the UM3X is plugged straight into the onboard sound the FR graph looks like a roller coaster.  There is a 5db boost at 1khz!

When I used a Cmoy to drive the UM3X the FR is flat.  So a mighty CMOY was able to tame the UM3X!

What I meant by a hell of a lot of distortion is again, at the amp level. No amp I have seen drives the iems at better than 2% which is as much as 100x more distortion than some of my other earphones (FX500 16 ohm).

2%!  That is a lot of distortion.

I started this thread with a few questions and I suppose I can try to answer them now that I've purchased a Klipsch S4 and Westone UM3X.  I'll just compare it to my favorite full sized headphones - the Beyer DT880 and the Denon D7000.

The Good:  If we are talking purely in terms of frequency reproduction, IEMs can do it.  The treble, bass, midrange, it's all there.  They are fun to listen to, make your toes tap, sound good, etc. 

The Bad:  I'll try to explain this without dipping into too much verbal mumbo-jumbo.  There's just less of a sense of realism with IEMs compared to headphones.  For the first few seconds after I put IEMs in my ears there's a "telephone" like sound, as if the FR ends have been chopped out and everything sounds thin.  After my brain adjusts this goes away.  But there's just this sense (in comparison to full sized headphones) that everything is closed off and the sounds are very close together.  It sound "2D."

The best analogy I can think of right now pertains to the size of an orchestra on a stage.  Imagine a live concert and a large stage filled with musicians.  Then imagine this stage shrinking, so the space between the ends of the stage, and the space between the musicians, becomes smaller.  With headphones you can get the sense that the different sounds are very close together.  With IEMs it can almost sound like they are on top of each other.

There's just a sense of realism that, at least to me, is lost with IEMs.  That's not to say IEMs sound bad.  They can sound very good.  But compared to my full sized headphones, it just seems like something is missing.

If IEMs can overcome this (and I think they are starting to) then full sized headphones are going to take a serious beating.  As previously stated, there is an explosion of different IEMs and we're right in the middle of the game where people are shouting "Mine is best because it has more drivers!"  I'm sure a lot of this is probably pure marketing, but it seems other manufacturers are actually trying to change the industry.

We'll have to see

And how did you find IEMs comfort-wise? I still haven't been able to completely put IEMs on in a way that I don't have to move them, whereas with full sized cans I have been able to do so (for straight 4 hour listen)

I do not think that the evidence you presented is sufficient to reach the conclusion you reached.  The most you can say is that these particular IEMs, on your ears, to you, do not do the job as well as your particular over the ear phones.

Most of the effects you point to do not agree with my experiences at all.  Of course I use different IEMs, I am a different person, and I compare them to different over the ear phones.  I also do not generalize my particular experiences with one particular small set of headphones to make grand general conclusions about the whole class of similar items.

In my case, with the Sennheiser IE8, they are clearly better sound-wise, to me, in pretty well every way compared to the same company's PCX-450s, of comparable cost.  That of course says precisely nothing about the original question you asked.  Neither, in my opinion, does your posting.

By the way, bar the noise blocking, the Sennheiser HD437 sounds, to me, nearly as good as the IE8's, distinctly better (to me) than the PXC-450's, and cost a whole lot less than either.

I love iems, full-size, and on-ear headphones: all. but, when I am at home, I prefer large phones. One thing which iems cannot do is engage the outer ear, but that doesn't matter all that much as I don't think most people will really care after getting a nice iem into their ear and hearing ... its beauty. Odigg - thanks for the posts and no need for graphs. How is the hiss (white background noise) from the Penguin amp? I am auditioning an amp I may buy (ALO Rx) which is great for a variety of headphones, but which hisses with iems quite a bit. Also, how is the THD and channel separation with the Penguing (as compared to the soundcard)? I mentioned 2%, but that is a best-of in many cases. Many iems induce more distortion from a variety of sources, the worse I have seen is 17%.

That brings  up my biggest problem with iems - they reveal background noise where other headphones may not (as much). Each have their uses and each sound great, but for normal listening, I do prefer full-size.

I think I'm going to have to change some my opinions about IEMs.

I recently purchased a Audeo PFE.  Unlike other IEMs I have heard, this does not any of the usual sonic issues (e.g. rolled off high end, muffled sound, poor quality bass).  It sounds clean and clear without any excess in the upper midrange or treble.  They also offer quite a bit of external noise isolation - this suits me well as I purchased these mainly for airplane travel.  They have a slightly less bass than I would like but I can live with it or EQ it.

I still have some of the usual IEMs issues though - I can sometimes hear my pulse and there is too much sound if I do something like workout with them.

I still prefer my full sized cans to the PFE, but if I had to get rid of my full sized cans it wouldn't bother me too much.  It felt great to be able to do this dishes and listen to music without bothering my spouse.

I think I can now believe it when people say certain IEMs (IE8, JH13 Pro) can be as good as full sized or that they are good enough that the extra bit that is gained from full sized headphones is not worth it when you consider other factors like portability.  It'll be interesting to see (in the next couple of years) if some other company can create a universal version of the JH13 Pro for 1/4 the price.

shigzeo - The CMOY seems to be noise free with the PFE.  With the UM3X there was a lot of noise.  As far the measurements, I am not able to perform a good measurement of it.  I only have my motherboard's onboard sound for an ADC and I suspect the motherboard input is worse than the CMOY.  I don't know how the Penguin amp perform as as I just have a regular CMOY I built myself.

The PFE are very nice because they reduce a lot of background noise, they also do a bit better with a good amp. But noise is something I really dislike and cheap or expensive, some amps deliver noise - way too much of it and I cannot take it. I am testing a really expensive iem now, the audio technica CK100 which is an interesting listen for PFE fans as it is much more atmospheric (if I am to be vague) , favourite high mids with shimmer and shake.

And, unlike its older brother, the CK10, it lower impedance and hisses a bit more. But damn, the build quality is leaps and bounds above anything on the market - simply no comparison at all.

I also prefer my DT880 to any iem - even the JH13Pro. Despite all the love at headfi, even the JH13Pro does not deliver air space (to the ears at least) as much as a headphone, not to mention the fact that the outer ear is also engaged. But, it is very expensive to buy into that custom and for that reason, I am pretty satisfied with the 350$ Sleek CT6 (http://www.touchmyapps.com/2009/04/11/sleek-audio-custom-iem-in-review-perfection/), though it used to be only 300$. I will have to append my review to fit more recent customs reviews such as the FitEar 333 (http://www.touchmyapps.com/2009/12/07/fitear-private-333-custom-earphone-in-review/) (which bloody rocks).

It is hard to judge 'sound quality' particularly as everyone prefers different things, and as is evident in the headfi AMP3 Pro thread, has different tolerances to things like bass roll off (with any headphone) and hiss. I hate hiss and I know that HA isn't the place to get into expensive portable amps, but the reason I got away from cmoy (unless extremely modded) is that after about 10 different designs, each hissed more than I liked. Most of the wildly modded DIYs sold for about half the price of a boutique manufacturer and didn't have quite as nice: chassis, input settings, or other things, so in the end, I went for an ALO Rx, which is expensive, but I am really liking it.

One thing is for certain, suck out (fitear), bass roll off (CT6 and JH13Pro) don't happen with it and hiss is minimal.

I agree that many of the CMOY variants are overpriced.  The prices of some of these exceed the prices of far better designs (e.g. Mini 3).  I have the most basic build of the CMOY but I changed some parts (I don't remember which) when I built it.  It gives me a good baseline for testing and helped me discover just how little is really required for a headphone amp.

I don't know why the PFE would need a special amp.  It sounds fantastic out of a Nokia 5800 phone, a Ipod Nano, and a Sansa Clip.  I suspect if I got some loaded measurements it I would find good measurements with all three devices.  So I don't see how an amp would improve anything, but I'd have to do some RMAA tests to be sure.

I suppose I could could do a volume matched test to see if there are any sonic differences between devices and with/without a special amp but at this point I'm not interested.

Despite all the love at headfi, even the JH13Pro does not deliver air space (to the ears at least) as much as a headphone, not to mention the fact that the outer ear is also engaged.

Thanks for this comment - I really appreciate it.  It certainly helps put the JH13 Pro in perspective, espeically considering how difficult it is to even demo them.  Given the other issues (durability, ease of repair fit changing over time, etc) the price is incredibly high.

I absolutely love my Ultimate Ears Triple.fi Pro 10 IEM's.  They're tricky to put on, because you have to wrap the wires over your ears, but they sound amazing.

When I plug them into my Mackie mixer (with the included resistive load adapter for impedance matching), I get a nice sound.

However, when I plug them into my 5th generation iPod with the adapter, the iPod has trouble driving the IEM's, and I get a muddy sound.  Without the adapter, the the iPod can drive the IEM's, but they lack some bass and have too much treble.  Fortunately, I am running Rockbox on my iPod, so I can adjust the EQ parametrically and get a great sound.

I'm not about to get a portable amp for my iPod, because the Rockbox parametric EQ does the trick.

The Triple.fi's are roughly at the same price point in the U.S. as the Sennheiser HD600's, which I will be getting on Friday.  I'm going to use the Sennheisers for professional audio applications, where I will want to have somewhat of an industry standard for mastering applications in the 'not rediculously expensive category.'