[sdiy] Phase shifts and instantaneous frequency

[cheater cheater]

Dear Aaron,

I know, appreciate, understand, and really like how this theory does
let you develop great things, and all the prople involved are doing a
magnificient job.
However, the causality isn't there, and just because 'it works' it
doesn't mean that you can definitely state that 'it's true' or that
'it's not true'.
For example, until modern chemistry was conceived, there was a theory
that all things that would burn had fire inside them, and it was
simply released. This theory worked quite well until it was abolished
by a theory yielding better results. It's still a theory, though, and
was abolished by what is merely another theory. Not disproven.

Even after going past the problem of our brains not doing
computational algebra in a well-ordered field, etc, looking at this in
a more relaxed fashion, and permitting using terms such as 'Fourier
analysis' and 'frequency domain' for lack of better words, there's
still a slight problem. You can't disprove either the 'inherent fire
theory' or chemistry or quantum chemistry. Just in the same way, you
can see that  [frequency-oriented approach](A)=>[works with the
ear](B) and that's a well established fact that's a wonderful
achievement, but there is no way that from this you can synthesize the
truth of the statement that `the ear works in a frequency-oriented
fashion` (B => A).

Nature doesn't solve Maxwell's equations - just like grass doesn't
chew itself in a cow's mouth - Maxwell's equations are a quite
simplified model of a system which is infinitely more complex. They're
still a great tool, because the simplification is done in the right
places enabling us a wholesome understanding of a problem at a certain
level, just simple enough for humans to understand. Go a bit further
and the problem becomes so wild that you can't make any sense out of
it, because you're looking at too many things at once.

Psychoaccoustics are a purely observational science and thus,
depending on what you observe, you will yield different theories (but
still the same results, which makes it a scientific theory). In this
way, I find that, until we get an envelope from God with a letter
describing how things work, we won't be able to grasp the true,
inherent, essence of the human auditory system, and there will be
always one more tiny element of the picture that we can't work out.
That's why I encourage not to get locked into thinking 'that's how the
ear works, period', as this can truly hamper the development of
alternate theories which could seem weird and unlikely to be true, but
could yield very good results. Actually, even generally untrue
theories sometimes have very narrow applications that yield great
results extremely easily.

And until I get the forementioned envelope, I feel free to believe
that wood contains fire.

But ears don't integrate and don't do Fourier analysis. 8^)

Best regards,
Damian

On 7/18/08, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
> On Jul 16, 2008, at 4:31 PM, cheater cheater wrote:
>
>
> > it is nearly impossible to prove that the way the human auditory system
> works is anywhere near frequency-oriented.
> >
>
>  Uh... Fred Juang, Mark Clements, and Chin Lee all have offices down the
> hall from me, and Tom Barnwell and Ron Schafer had offices down the hall
> from me before that before they retired, and having spent a good combined
> 140 or years between them working on audio and speech processing and
> recognition, I think they'd be awfully surprised to find that "it is nearly
> impossible to prove that the way the human auditory system works  is
> anywhere near frequency-oriented."
>
>  It's way near frequency-oriented.
>
>  I've been on a good dozen PhD committees involving speech recognition or
> audio enhancement or things along those lines, and they all start with
> extremely well developed models of the ear that center around frequency
> domain concepts. Understanding those concepts is what makes cochlear
> implants work. Google "Fourier cochlea," without the quotes. Go to Amazon
> and search on "psychoacoustics," and get any text you see. These principles
> have been established for decades. There a lot of complexities and
> subtleties (many of which we've been debating on this list), and much that
> is still not understood, but if it wasn't for that frequency-orientation of
> your ear, we wouldn't have iPods.
>
>
> > It might be oriented in any other of infinitely many possible domains, not
> the time domain, not the frequency domain. Certainly the ear does not have
> the facility to integrate numerically, much less do something like the
> Laplace transform.
> >
>
>  I don't want to sound harsh - please don't take my next statement like that
> - but there's really layers upon layers of misunderstanding there concerning
> how mathematics is used and can be useful in model physical systems. Mother
> nature may not be running trapezoidal integration calculations, but it
> solves Maxwell's equations in real time nontheless.
>
>  - Aaron
>
>
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