Audio Myths Workshop

[Z1202]

What I was trying to do is to protect the points of views of the guys who claimed there are audible differences above 20kHz. Certain people tried to say that they are wrong, because it's proven that humans cannot hear above 20kHz. I tried to point out a missing implicit step in their conclusion, which is also (AFAIK) is not a commonly known fact.

Edit (addition): this is not to say, who's right and who's wrong. This is just to say that the "proof" that those guys are wrong is flawed itself.

[aka_bip]

nonlinearity of the human hearing

Please explain what you mean by that, exactly. You keep asserting that human hearing may not be linear but you haven't really explained what this means or why you believe it to be true.

[Z1202]

nonlinearity of the human hearing

Please explain what you mean by that, exactly. You keep asserting that human hearing may not be linear but you haven't really explained what this means or why you believe it to be true.

Linearity means that the effect of the sum is the sum of the effects of the parts. I also explain what this means in the context of the hearing a few posts above.

As to whether I believe the human hearing is linear or not, I tend to believe there might be some nonlinear elements. But I don't know how strong the nonlinearities are (if any), or what kind of those. That is I don't know either (linear or not) for a fact. Does anyone here?

[Z1202]

An common example of the effect of nonlinearity is the AM radio receiver's detector. The AM radio signal doesn't contain any audible frequencies (practically considered). By letting the signal through a nonlinear circuitry part, audible components appear (which is what is finally sent to the speaker).

[Nokenoku]

The human hearing is not linear, but again: This has nothing to do with your funny theorie.
http://en.wikipedia.org/wiki/Fletcher&# ... son_curves

You say:
"Sinewaves and everything else, which got tested so far, is not hearable above 20kHz, but maybe there's something above 20kHz, you can hear."
It's like saying:
"Nobody has ever seen him, nor there's a single hint for his existance, but maybe there's a god anyways."
Don't you think it's useless to start a discussion on something like that?

Besides that EVERY wave is nothing different than an addition of sinewaves. Read up about Fourier.

[Z1202]

The human hearing is not linear, but again: This has nothing to do with your funny theorie.
http://en.wikipedia.org/wiki/Fletcher-Munson_curves

You say:
"Sinewaves and everything else, which got tested so far, is not hearable above 20kHz, but maybe there's something above 20kHz, you can hear."
It's like saying:
"Nobody has ever seen him, nor there's a single hint for his existance, but maybe there's a god anyways."
Don't you think it's useless to start a discussion on something like that?

Besides that EVERY wave is nothing different than an addition of sinewaves. Read up about Fourier.

The link you posted refers to the linearity of the curve of the loudness perception which has nothing to do in regards to the linearity of the audio spectrum perception by humans. A more relevant link is:

http://en.wikipedia.org/wiki/Linearity

The term linearity can be used in lots of different contexts with different meanings. Not my fault though, I didn't invent it.

As to Fourier, I believe to have a decent knowledge of the subject (including the calculus-based math, and not simply having read "about it").

Edit: more precise wordinig.

PS. I would appreciate if we refrained from using words "BS", "funny" etc, in this thread. Let's be constructive and stay on the point and not call each other names.

[Z1202]

Don't you think it's useless to start a discussion on something like that?

I didn't start the discussion. Someone said that people who claim to hear differences above 20kHz are imagining things, and gave his "proof". I'm just pointing out the flaw in that proof, nothing more.

[eduardo_b]

It's not as if people are even aware of whether they hear above this frequency or not. Rolling off audio at 17 kHz has no meaningful effect on audio experience. Rather an esoteric concern imo.

[poonna]

OK, Z1202, by non-linearity, I guess you mean that human hearing might construct some audible signals (either by the mechanics of ears or in the brain) out of the mix of inaudible signals above hearing range, right? Just like IMD in analog circuits that constructs non-harmonic components above and below the frequencies of the constituent sine waves. Am I getting your point correctly?

[aka_bip]

Don't you think it's useless to start a discussion on something like that?

I didn't start the discussion. Someone said that people who claim to hear differences above 20kHz are imagining things, and gave his "proof". I'm just pointing out the flaw in that proof, nothing more.

You're not really pointing out anything. You said yourself that linearity means many different things but you haven't specified what you mean by it. Your arguement seems to be: Nonlinearity exists, therefore anything is plausible.
The only substance I can find is completely circular. You state:
A linear combination of inaudible sines may be audible because hearing may be nonlinear.
I asked what you mean by nonlinear in this context. You reply:
If hearing is nonlinear a linear combination of inaudible sines may be audible.

There's no argument here. You're simply stating that a linear combination of inaudible sines may be audible without providing any reason or evidence.

[Z1202]

OK, Z1202, by non-linearity, I guess you mean that human hearing might construct some audible signals (either by the mechanics of ears or in the brain) out of the mix of inaudible signals above hearing range, right? Just like IMD in analog circuits that constructs non-harmonic components above and below the frequencies of the constituent sine waves. Am I getting your point correctly?

Exactly.

[Z1202]

There's no argument here. You're simply stating that a linear combination of inaudible sines may be audible without providing any reason or evidence.

I don't need any evidence to say that it might be audible (that is to say, that we don't know, and the question is open). Who needs the evidence are the guys who state that the opposite is always the case (which is implicitly done in the mentioned "proof").

The ironic part in that, is the guys who say that I don't have any evidence, are the very same guys who are discarding the results of the hearing sessions, where people claim to hear the difference. I don't know whether the results in the sessions referred to at the start of this topic are correctly obtained, but the criticizing guys do not even seem to mention any details of the experiment. They simply discard it, because "it's impossible" and "here's the proof that it's impossible". So they are asking me for the evidence, but they refuse to have a careful look at something which might be exactly the evidence they are asking for.

[aka_bip]

I don't need any evidence to say that it might be audible (that is to say, that we don't know, and the question is open).

And I dont need any evidence to say there might be a teapot orbiting the sun between Earth and Mars. We dont know, the question is open.
If you have evidence, point me to it.

[Meffy]

And I dont need any evidence to say there might be a teapot orbiting the sun between Earth and Mars.

Even so, wearing a tee-shirt illustrating the point couldn't hurt, could it?

[Z1202]

I don't need any evidence to say that it might be audible (that is to say, that we don't know, and the question is open).

And I dont need any evidence to say there might be a teapot orbiting the sun between Earth and Mars. We dont know, the question is open.
If you have evidence, point me to it.

I didn't make any statement, whose correctness depends on the presence of the said teapot. On the other hand, the claim that anything above 20kHz doesn't make any difference, requires either the proof of the hearing linearity, or a more complicated proof for the nonlinear case.

So, yes, the question is open. Can we therefore agree, that the statement about people imagining things when they claim to hear things above 20kHz is open too?