Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed? (Read 34681 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #50
One surprisingly poor cable was 10-GA SO cord.  The SO cord is the thick black neoprene jacketed cord (with many fine strands of copper) that is used for heavy duty AC power cords.  This cord is commonly used in long lengths (100 feet or more) for large commercial sound reinforcement systems.  This cord has lots of copper and had the lowest DC resistance, but surprisingly, it had the worst measured performance, and the most audible effect on the music played.  The reason for the poor performance is that the cable has far too much inductance, and far more inductance that the cheap 18-GA zip cord that we tested.  It turns out that the inductance of the speaker wire is much more of a factor than the DC resistance!

Hmmm, that's interesting!

The inductance of the cable varies roughly as the log of the ratio of the distance between the conductors to their diameter. If the distance between the conductors in the heavy-duty wire is larger, you would expect that to be somewhat canceled by the larger diameter.

Did you actually measure the inductance and what values did you see?


The series parameters for 10 gauge 2-conductor wire in this configuraiton (loose twisting) are around  0.17 uH, 1.7 milliohms, and 17 pF per foot.

The effective series impedance due to the inductance @ 20 KHz is about 0.02 ohms per foot. At the 100 foot length, the 2 ohm series impedance due to the cable could be audible.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #51
I can't believe I'm saying this, but I kinda wish JA were still around here. His existence is a pretty effective counterexample to this Manichean worldview about subjectivism/objectivism. He disagrees strongly with Beltists, and he believes in measurements enough to, well, still do them.


I'm still around.
 
John Atkinson
Editor, Stereophile



Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #53
The series parameters for 10 gauge 2-conductor wire in this configuraiton (loose twisting) are around  0.17 uH, 1.7 milliohms, and 17 pF per foot.

The effective series impedance due to the inductance @ 20 KHz is about 0.02 ohms per foot. At the 100 foot length, the 2 ohm series impedance due to the cable could be audible.

OK, so that would make the characteristic impedance of this cable 100 ohms (square root of L/C). Not surprising since cables consisting of two parallel wires are usually close to this impedance.

It also explains why 24 cables in parallel would work so well. Their combined characteristic impedance is on the order of four ohms, so it is not even inductive into an 8 ohm load, it is capacitive.

What I am asking is why would zip cord have a characteristic impedance significantly less than 100 ohms? I'm not saying that it is not possible, just surprising.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #54
What I am asking is why would zip cord have a characteristic impedance significantly less than 100 ohms? I'm not saying that it is not possible, just surprising.


Audioholics have taken some R, L and C measurements of various cables, including zip cord.  I haven't calculated the characteristic impedance of these though.  The data can be found here and here.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #55
So, yeah, I completely forgot about RBG's first post (and my response to it), but... why is he not responding? If I didn't know any better, I'd wonder if he was trolling.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #56
I don't know if he'll be coming back anytime soon.

http://www.hydrogenaudio.org/forums/index....showtopic=60079

As members aren't allowed to discuss their warning status in public, I think it is also fair that they're entitled to privacy about their status on this forum.  I do not intend to breach anyone's privacy and hope my post isn't seen this way.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #57
eheh eheh eheh heh heh heh heh

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #58
The series parameters for 10 gauge 2-conductor wire in this configuraiton (loose twisting) are around  0.17 uH, 1.7 milliohms, and 17 pF per foot.

The effective series impedance due to the inductance @ 20 KHz is about 0.02 ohms per foot. At the 100 foot length, the 2 ohm series impedance due to the cable could be audible.

OK, so that would make the characteristic impedance of this cable 100 ohms (square root of L/C). Not surprising since cables consisting of two parallel wires are usually close to this impedance.

It also explains why 24 cables in parallel would work so well. Their combined characteristic impedance is on the order of four ohms, so it is not even inductive into an 8 ohm load, it is capacitive.


If you are thinking about speaker cables 100' or more long, you need to explain why you don't just put the power amp(s) far closer to the load.

Quote
What I am asking is why would zip cord have a characteristic impedance significantly less than 100 ohms? I'm not saying that it is not possible, just surprising.


Got a specific example in mind?


Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #59
Characteristic impedance is a transmission line concept. Transmission line theory is applicable when the length of the transmission line is on the order of a wavelength or more. The wavelength of 20 kHz audio in copper cables is over 5 miles.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #60
Electronic communications seem to bring out the worst in some people. I'm sure most of us have had the experience of getting things fubar'd through e-mail and then using the phone or in-person meeting to quickly untangle things.


I wish it just boiled down to that.  There are a group of people who actively make it a point to have a point of view and a) argue in support of their point of view to death and b) use every dirty trick to do so.  There are a number of people like this on many "audiophile" forums and they just make sure to inject themselves into any discussion that even insinuates the idea of "snake oil," and "not worth it" and "objective testing and measurements."

You stand to lose all your credibility on a forum and a great deal of time if you choose to argue with these people.  So the more moderate people stand on the sidelines and don't do much more than make a comment (e.g. I tried a few cables and honestly I couldn't hear a difference with my equipment) that is not  provocative or result in a personal attack.  Note the excessive use of the subjective (I, my) in the example I gave above.

Unfortunately this means the moderate majority is drowned out by a smaller set of extremists.  So when newcomers visit these sites they (wrongfully) assume that all the BS stated in audiophile land is true and supported by the majority.  Of course many of these people become moderates when they actually buy all this eqiupment and their experiences do not match the extreme views.

My point to the OP is this.  Don't assume the fantasy audiophiles are the majority just because of how online forums seems to be skewed to support them.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #61
Unfortunately this means the moderate majority is drowned out by a smaller set of extremists.  So when newcomers visit these sites they (wrongfully) assume that all the BS stated in audiophile land is true and supported by the majority.  Of course many of these people become moderates when they actually buy all this eqiupment and their experiences do not match the extreme views.

My point to the OP is this.  Don't assume the fantasy audiophiles are the majority just because of how online forums seems to be skewed to support them.


I think this neatly sums up the situation.

Except that I think the significant downturn in the specialty audio world has made audio companies more willing to accept the unthinkable in order to keep in business. The fantasy audiophiles - for all their madness and over-the-top opinions about minutiae - do buy stuff. They buy completely crazy stuff, but they buy stuff nonetheless. It's like the drug store owner who hates the idea of stocking homeopathic remedies and other such nonsense, but also knows that without them, he might struggle to survive.

I imagine the same thing happens in the magazines. If the fantasy brigade form the bulk regular buyers of the magazines, and one of the magazines broke cover and said something contentious/honest, it wouldn't just lose advertising; the readers would go away too. Under those circumstances, we are about as likely to see an honest assessment of these products as we are likely to see a 'did you know these things cause mouth cancer?' feature in Cigar Aficionado.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #62
Characteristic impedance is a transmission line concept. Transmission line theory is applicable when the length of the transmission line is on the order of a wavelength or more. The wavelength of 20 kHz audio in copper cables is over 5 miles.

Characteristic impedance in this context merely refers to whether the cable present an inductive or capacitive load. Over 8 ohms (or whatever the speaker's impedance) and it presents an inductive load, less and the load is capacitive. Inductive means high-frequency rolloff due to the cable, while capacitive means possible instability in the amplifier's output.

Conventional cable construction, with two round, insulated conductors spaced fairly closely, will always be greater than 8 ohms so always inductive. If you replace the round conductors with flat, ribbon conductors then you can make the impedance much lower, but only if you make the spacing between the conductors much smaller than their width.

At least one manufacturer has made the mistake of lowering the cable's impedance too much, requiring additional components to provide stability, while another has gone the complete oposite direction, spacing the conductors so far apart that their inductance is actually much worse than with round conductors.

BTW, the effect of a transmission line becomes very significant at only one quarter wavelength.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #63
Except that I think the significant downturn in the specialty audio world has made audio companies more willing to accept the unthinkable in order to keep in business. The fantasy audiophiles - for all their madness and over-the-top opinions about minutiae - do buy stuff. They buy completely crazy stuff, but they buy stuff nonetheless. It's like the drug store owner who hates the idea of stocking homeopathic remedies and other such nonsense, but also knows that without them, he might struggle to survive.


There are definitely some people who believe that all audio products are made for some reason other than profit.  I don't know what to think of such an attitude as it's incredibly naive considering almost every market sector (even undergarments) has items that are basically snake oil.

But yes, enough people are buying this stuff.  If there was no market for them nobody would make them.  And I 100% agree with you that since the entry cost for "Hi-Fi" audio has become so low, the high-end has little choice but to make increasingly extravagant claims.  I guess it's easier now that there is probably a factory or company in China or India where a small business could run to to manufacturer their snake oil products at minimal cost.

It would be nice to see some sales statistics from a major "audiophile" eqiupment seller or from the manufacturer themselves.  Are people really buying that $2K+ CD demagnetizer?  I have a catalog from a major online store and some of the stuff they sell is just ridiculous.  What is the sales volume?  Does the catalog contain these items because people buy them or just so the store can demonstrate how "High End" they are and woo people into the $200 CD demagnetizer?

All I need is a good set of yearly sales data...

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #64
A cable made from 24-pairs of 24-GA twisted pair outperforms all of the other solutions tested (magenta curve).
I'm really confused. I recalled a thread where Cat5 cable was shown to be quite bad. After a lot of searching, I found it here...

http://www.hydrogenaudio.org/forums/index....st&p=148461

So what's the truth? What exactly does make decent speaker cable for long runs? Is Cat5 good or bad? How many twisted pairs in parallel? Braided or not?

What (if anything) matters for short runs? e.g. less than 0.1dB deviation 0-20kHz for "difficult" speakers?

Cheers,
David.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #65
A cable made from 24-pairs of 24-GA twisted pair outperforms all of the other solutions tested (magenta curve).
I'm really confused. I recalled a thread where Cat5 cable was shown to be quite bad. After a lot of searching, I found it here...

http://www.hydrogenaudio.org/forums/index....st&p=148461




As I read that thread, the listener obtained null results, which is what one expects in general in a comparison of two OK speaker cables.

Quote
So what's the truth? What exactly does make decent speaker cable for long runs? Is Cat5 good or bad? How many twisted pairs in parallel? Braided or not?


Speaker cable is all about primarily low resistance, and secondarily about low inductance. If you parallel enough CAT 5 strands, you can get low resistance. Basically CAT 5 is 24 gauge, so if you parallel 2 pair, you get a pair that is the equivalent of 21 gauge, and if you parallel 4 pair, you get the equivalent of 18 gauge pair.  Parallel 8 pair, and now you are down 15 gauge, and parallel 16 pair and you are at 12 gauge.  Their are 4 pair per cable. 

The desired equivalent wire gauge depends on length.

As others have pointed out, getting the centers of the conductors close together reduces series inductance (by increasing mutual inductance).  So 12 gauge equivalent made up of paralleled CAT 5 will generally have much lower series inductance compared to equal copper per foot in the form of lamp cord.

4 pieces of CAT 5 cable, outer wrap removed, and all 16 pairs twisted together gives you DC R equivalent to 12 gauge, but much lower series inductance.  I've made up 8 foot speaker cables like this, and measured their resistance and inductance. They perform as expected.

The importance of series inductance varies with the individual speaker. Since most speakers have impeddance curves that rise at high frequencies, inductance may not be much of a problem.

Quote
What (if anything) matters for short runs? e.g. less than 0.1dB deviation 0-20kHz for "difficult" speakers?


Certainly +/- 0.1 dB is very good and generally undetectable, but +/- 0.2 dB will be very hard to detect, indeed.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #66
Certainly +/- 0.1 dB is very good and generally undetectable, but +/- 0.2 dB will be very hard to detect, indeed.
Certainly. I meant, for the run in my living room (4m at most) or to the next room (10m at most), what, if anything, does the cable need to be to hit this performance.

(Which will, of course, be far better performance than any speakers are going to manage!)

Cheers,
David.


Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #67
One surprisingly poor cable was 10-GA SO cord.  The SO cord is the thick black neoprene jacketed cord (with many fine strands of copper) that is used for heavy duty AC power cords.  This cord is commonly used in long lengths (100 feet or more) for large commercial sound reinforcement systems.  This cord has lots of copper and had the lowest DC resistance, but surprisingly, it had the worst measured performance, and the most audible effect on the music played.  The reason for the poor performance is that the cable has far too much inductance, and far more inductance that the cheap 18-GA zip cord that we tested.  It turns out that the inductance of the speaker wire is much more of a factor than the DC resistance!

Hmmm, that's interesting!

The inductance of the cable varies roughly as the log of the ratio of the distance between the conductors to their diameter. If the distance between the conductors in the heavy-duty wire is larger, you would expect that to be somewhat canceled by the larger diameter.

Did you actually measure the inductance and what values did you see?

Ok, I think I have it figured out.

The problem is that I was treating the DC resistance and inductive impedance as separate things, when in fact you have to look at the complex impedance, which is the square root of the sum of the squares of them.

The bottom line is that the 18 gauge wire may have similar inductance as the 10 gauge wire, but because of its higher DC resistance the R value dominates at 20 kHz and the effect of inductance is much less.

Someone please correct me if this analysis is totally off base, but the conclusion is that wire with very low DC resistance may in fact be undesirable! 

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #68
Certainly +/- 0.1 dB is very good and generally undetectable, but +/- 0.2 dB will be very hard to detect, indeed.
Certainly. I meant, for the run in my living room (4m at most) or to the next room (10m at most), what, if anything, does the cable need to be to hit this performance.

(Which will, of course, be far better performance than any speakers are going to manage!)

Cheers,
David.

Well let's see.

Looking first at the effect of DC resistance, 0.1 dB is a difference of 2.4%. If the speaker is 8 ohms and its impedance varies by 50% with frequency (this is a guess) then the maximum allowed DC resistance of the cable would be 8 * 2.4 / 50 = 0.38 ohms.

For a 4m cable this would require 14 gauge (0.33 ohms). For a 10 meter cable you would need 10 gauge (also 0.33 ohms). If your speaker's impedance varies less that 50% then you could get away with a higher gauge.

The above ignores the effect of inductance, which I will look at when I have time, but I predict that its effect will be negligible for the 4m cable.

Edit: Drat! I forgot that the resistance of the cable is twice the resistance of a single conductor. The above gauges would give more like 0.2 dB.

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #69
Certainly +/- 0.1 dB is very good and generally undetectable, but +/- 0.2 dB will be very hard to detect, indeed.
Certainly. I meant, for the run in my living room (4m at most) or to the next room (10m at most), what, if anything, does the cable need to be to hit this performance.


The RLC requirements for a sonically transparent speaker cable depend on the loudspeaker's impedance curve.  Usually, 12 gauge zip cord is more than sufficient.


Quote
(Which will, of course, be far better performance than any speakers are going to manage!)


Agreed. Just because your speaker cable is sonically transparent does not of course mean that the speakers themselves are transparent. 

The real point is showing that commodity speaker cables can overkill any reasaonble requirements that someone might come up with, particularly in a home audio environment.

In a live sound context, it is not too hard to come up with a requirement for 10-30 meter speaker cables.  In a home audio context, 2-8 meters should be about it.

 

Fantasy Audiophiles vs. Objective Audiophiles: Has the hobby changed?

Reply #70
Looking first at the effect of DC resistance, 0.1 dB is a difference of 2.4%.


You're thinking power. In this case we need to be thinking voltage.  For voltage, 2.4% is 0.211 dB


Quote
If the speaker is 8 ohms and its impedance varies by 50% with frequency (this is a guess) then the maximum allowed DC resistance of the cable would be 8 * 2.4 / 50 = 0.38 ohms.


Speakers often have 10x plus  variations in impedance within the audio band.  However, its not the peaks that you worry about, its the valleys.  We're thinking about a voltage divider composed of the speaker cable in series, and the minimum impedance of the speaker as the shunt.

Audibility wise, the dip in response just above resonance (ca. 100-200 Hz) , and the dip just above the midrange crossover frequency (ca. 2 KHz-6 KHz), are the usual bad boys.  They are at frequencies where the ear is reasonbly sensitive, and they are usually the lowest dips or among the lowest dips.

 
SimplePortal 1.0.0 RC1 © 2008-2021