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Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
I'm looking at subwoofers these days.   Many of the 'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB.

When playing music that was recorded live, like jazz in a church does a sub that goes down that low give any benefit at all since we can't hear it? I've read that the room acoustics of a recording can be recreated with subsonic subwoofers, but is that true?

Even if it helps on movies (does it?) what does it do for well recorded music?

Thanks.
Music lover and recovering high end audiophile

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #1
I'm looking at subwoofers these days.  Many of the 'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB.

When playing music that was recorded live, like jazz in a church does a sub that goes down that low give any benefit at all since we can't hear it? I've read that the room acoustics of a recording can be recreated with subsonic subwoofers, but is that true?

Even if it helps on movies (does it?) what does it do for well recorded music?

There is no doubt that sounds < 10 Hz are reliably perceived. Whether it is exactly the same as hearing sounds > 30 Hz may be disputed, but it is reliably perceived if it is loud enough.

This is a link to some provisional information about the threshold of hearing at very low frequencies: Provisional information about the threshold of hearing at very low frequencies

One fairly common source of such information is things like musicians tapping their feet while playing.



Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #2
I'm not sure i'm interpreting that graph correctly,  but it seems to be saying that 10 hz is audable at around 98dB.  That all well and good, but i certainly don't play anything that loud :")  I tend to play music around moderate listening levels.  It is percievable even at lower levels? That is to say if i'm playing a recording of a concert grand piano in a hall at a moderage level, is a subwoofer that has that much extension going to make any difference? 
Note, that i'm not restricting this to "hearing" per se.  Would i feel anything different even if i can't conciously hear it and it's at a moderate level?  This is starting to sound like the folks who claim that 'super tweeters make a difference, but i'm assuming that deep sound wave work differently.
Music lover and recovering high end audiophile

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #3
I'm not sure i'm interpreting that graph correctly,  but it seems to be saying that 10 hz is audable at around 98dB.  That all well and good, but i certainly don't play anything that loud :")

I can see two approaches to this question.

One is that not that many people have audio systems that are capable of 98 dB SPL at 10 Hz.   For example, check out this compilation of technical tests on commercial subwoofers: Data-Bass subwoofer system tests  Only a very few of many are even capable of 98 dB @ 10 Hz., particularly over the long term.

The other is that if you accept that 98 dB SPL at 10 Hz is barely audible, it is not all that surprising that you don't perceive it as being all that loud if you hear it. I've experienced this sort of thing many times, and its an odd experience. The sound is on the one hand very soft, but on the other hand there is a strong perception of something rather large going on in and around you.

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I tend to play music around moderate listening levels

98 dB SPL  is excruciatingly loud at 2-4 KHz, and it is still pretty loud at 100 Hz. But at 5 Hz, you may not be able to hear it at all.

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It is percievable even at lower levels? That is to say if i'm playing a recording of a concert grand piano in a hall at a moderage level, is a subwoofer that has that much extension going to make any difference?

It is not going to make that much difference to the music from the piano strings, because in fact their response is dropping off pretty fast well above 100 Hz, even for bassy pianos like a Bosendorfer grand.  However the sound of the musician operating the pedals and tapping his foot might be audible at frequencies well below that.

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Note, that i'm not restricting this to "hearing" per se.  Would i feel anything different even if i can't conciously hear it and it's at a moderate level? 

I can't underemphasize how problematical clean reproduction at very low frequencies is in terms of rattling things that aren't well padded or tied down, and the possibility that the paneling on room walls or even the floors are flexing in a nonlinear fashion.

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This is starting to sound like the folks who claim that 'super tweeters make a difference, but i'm assuming that deep sound wave work differently.

If nothing else really intense low bass at the right frequencies can literally rattle your guts. For example based on personal experience I dispute the relevance of the "Brown Note" tests by the Mythbusters. Their tests were done with SR speakers and in that realm it is not unusual for so-called subwoofers to start rolling off starting at 30-40 Hz. The tests I recall were done out-of-doors and that eliminates reinforcement from nearby walls and the floor which can be very significant.  People who put several long-stroke woofers into a small vehicle and apply kilowatts of power are doing it right if deep clean bass is the goal.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #4
Thank you Arnold. That answers a lot of questions.  I'm still wondering though about accoustics. I've read (probably in a stereofool magazine) that having a subwoofer that can reproduce <20hz frequencies can help reproduce the sound of the room that the performance was recorded in.  That is to say that i would sense the boundies of the chuch, jazz hall etc., because (according to the article) the accoustical cues are all relegated to deep bass frequencies, especially in naturally recorded surround material, such as used in Ambisonic recordings.

This is all assuming that the engineer didn't filter that out, but is there any truth to the idea that deep bass improves sound staging and presence?  (frankly, i'd bet you'd get a lot of mic noise in badly done recordings as well sometimes)
Music lover and recovering high end audiophile

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #5
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Many of the 'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB.

Is that really true? It is not what I recall.
Out of interest I just checked some well known manufacturers models in the $5000+ range. These are their top of the range models.

Neumann KH870 claims 18-300Hz (+/- 3dB) max 118.7dB
Genelec  7271 claims 19-100Hz (+/- 3dB) max 118dB
ADAM Sub2100  claims 18-150Hz (+/- 3dB) max 128dB

I mean this is genuine pro quality studio gear. If the guys who make the recordings cannot hear it themselves what's the point?

Not to cause a row or anything please.
If this stuff exists who is selling it and why?

  • Porcus
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #6
This is a link to some provisional information about the threshold of hearing at very low frequencies: Provisional information about the threshold of hearing at very low frequencies

https://hydrogenaud.io/index.php/topic,105844.0.html . In particular, xnor's graph in #2. Myself I got to 11 Hz with earbuds.

Wasn't "buttshaking movie chairs" a thing a few years ago?

  • drewfx
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #7
I mean this is genuine pro quality studio gear. If the guys who make the recordings cannot hear it themselves what's the point?

Not to cause a row or anything please.
If this stuff exists who is selling it and why?

Think video games and movies (typically with the sub set way too loud!).

  • PoisonDan
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  • Members (Donating)
Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #8
Wasn't "buttshaking movie chairs" a thing a few years ago?
If not, there's always this:
http://subpac.com/
Over thinking, over analyzing separates the body from the mind.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #9
Anyone able to identify any of the claimed to be many
Quote
'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB
.

Do they exist? OP?

  • KozmoNaut
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #10
Anyone able to identify any of the claimed to be many
Quote
'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB
.

Do they exist? OP?

I know of one subwoofer (10" driver, sealed cabinet, 300W amp) where the manufacturer claimed frequency response down to 16Hz. The manufacturer was approached on their official forum to explain how this was possible, with measurements to back it up, showing a -3dB point around 35Hz. Surprise surprise, we got banned, after being told that the manufacturer "relies on in-room listening tests, not measurements".
  • Last Edit: 18 May, 2017, 03:42:42 AM by KozmoNaut

  • milkshake
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #11
Anyone able to identify any of the claimed to be many
Quote
'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB
.

Do they exist? OP?

Danley Soundlabs make decent subs.
The TH221 has a claimed max output of 144dB with a frequency range of 22 Hz - 180 Hz - 3 dB and 18.5 Hz - 200 Hz -10dB. So that one doesn't cut it. Its their biggest commercial sub.
http://www.danleysoundlabs.com/products/subwoofers/tapped-horns/th-221/

But they also made a military grade sub called The Matterhorn that needed to produce a 15Hz-20Hz sine of 94dB at 250 meter. This should do it. Not for your average home theatre.
http://www.danleysoundlabs.com/the-matterhorn/

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #12
Anyone able to identify any of the claimed to be many
Quote
'high end' subs are rated (on paper) to go down to levels like 10 Hz at 126dB
.

Do they exist? OP?

The deepest loudest test results for an actual commercial product that I know of:

data-bass.com - ZOD Audio M.A.U.L. installed subwoofer

"During the loudest 185 volt nominal measurement the M.A.U.L. cabinet was audibly rattling the building behind me and producing in excess of 120dB at 14Hz, 125dB at 22Hz, greater than 130dB by 38Hz and 135db or greater from 68-99Hz."

  • Porcus
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #13
OK ... 1.2 m tall & wide and 250 kg. Not for everyone even if the price tag had its decimal point bumped one position to the left.

Of course there are stories like this good'old one: http://gizmodo.com/5025867/horn-subwoofer-takes-up-crazy-mans-entire-basement
I wonder, why not make it a bit bigger, put a mattress in, and you have a bedroom? No window though.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #14
OK ... 1.2 m tall & wide and 250 kg. Not for everyone even if the price tag had its decimal point bumped one position to the left.

Of course there are stories like this good'old one: http://gizmodo.com/5025867/horn-subwoofer-takes-up-crazy-mans-entire-basement
I wonder, why not make it a bit bigger, put a mattress in, and you have a bedroom? No window though.

The point is that if you *really* want deep clean bass, you will probably have to incorporate it into the structure of your listening room, and not rely on regular  commercial products. I've seen and heard this done several times, and it even can be fairly economical.

  • old tech
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #15
Whether or not sub sonic frequencies can be perceived, it is more likely to be so than weak, directional +20khz frequencies which vinyl fanbois bang on about.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #16
Whether or not sub sonic frequencies can be perceived, it is more likely to be so than weak, directional +20khz frequencies which vinyl fanbois bang on about.

Not to mention that there is no way that response at 20 Hz and below can be accurately reproduced by a LP.

  • Porcus
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #17
Not to mention that there is no way that response at 20 Hz and below can be accurately reproduced by a LP.
But maybe by an EP played back at 16 2/3. A switch every kid who had access to it just had to try, right?

IIRC there were some turntables where you had to remove the platter and gear the belt manually between 45 and 33 1/3. Certainly there must have been a demand among parents.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #18
Not to mention that there is no way that response at 20 Hz and below can be accurately reproduced by a LP.
But maybe by an EP played back at 16 2/3. A switch every kid who had access to it just had to try, right?

IIRC there were some turntables where you had to remove the platter and gear the belt manually between 45 and 33 1/3. Certainly there must have been a demand among parents.

Its not the turntable speed that is the key factor here. It is the tone arm resonance which is the same no matter what the rotational speed is.  The tone arm and cartridge compliance forms a modestly damped high pass filter.  The damping is enough so that the resonance is pretty broad and covers the first few octaves of the audible range. By convention, the corner (peaking) frequency is around 12 Hz or so. So, it has quite a bit of positive resonance at 20 Hz and the  next octave up.  The lightly damped curve then goes into its dip and is probably still has measurable effects up to around 100 Hz.  This would be for an optimal cartridge for that particular tone arm. 

How many cartridges and arms are actually optimal combinations in the field?  Given that typically only geometric measurements are done (which are irrelevant to this issue) are used during setup, probably not a heck of a lot. 

  • Porcus
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Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #19
Not to mention that there is no way that response at 20 Hz and below can be accurately reproduced by a LP.
But maybe by an EP played back at 16 2/3. A switch every kid who had access to it just had to try, right?

IIRC there were some turntables where you had to remove the platter and gear the belt manually between 45 and 33 1/3. Certainly there must have been a demand among parents.

Its not the turntable speed that is the key factor here. It is the tone arm resonance

Right. So it does not (only) matter what can be reproduced to the LP format, but what a turntable setup can get out of the groove.
To balance out their desire for supersonic hiss they cannot hear and which is only noise anyway, audiophiles must certainly equip themselves with a laser turntable in order to listen to those subsonic signals that never were intended to make it to the medium.

Re: Do we "need" those <20Hz subsonic frequencies for high-fidelity audio?
Reply #20
[Right. So it does not (only) matter what can be reproduced to the LP format, but what a turntable setup can get out of the groove.

Correct
.
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To balance out their desire for supersonic hiss they cannot hear and which is only noise anyway, audiophiles must certainly equip themselves with a laser turntable in order to listen to those subsonic signals that never were intended to make it to the medium.

Laser turntable doesn't help because the laser  system ends up containing an analogous mechanical system for tracking the disk.