Bob Cain wrote in message ...
Ryan wrote:


Well, maybe, I don't really know. I'd be surprised if some type of
math couldn't be rigged up that would do as good a job as a human.

Prepare, then, to be surprised. Our mechanisms for feature
extraction and interpretation remain largely a mystery. The
process is highly algorithmic and that is very different
than mathematical, although math can be employed in some
algorithmic process.

It's all analytical, and actually not too subjective. It will either
sound like a jet engine or not, and since the computer will "know"
what a jet engine sounds like thanks to the FFT and differential
analysis, it seems to me this shoud be as easy as asking a computer to
come up with a number that adds to 7 to make ten.

An FFT doesn't begin to disclose what you are looking for in
and of itself. It's no more than a view of the same data
with a different independant axis. It contains no
information at all about when things happen.

Is there any kind of analysis that does? I used FFT because that's
the only one I've really ever heard of. What if I perform a different
FFT for every second of the soundfile?


In any event, the ear brain does not do a Fourier analysis.
There are frequency dependant mechanisms but they are
totally ad hoc in terms of what nature found most useful for
subsequent analysis.

Was this a typo? I hope this doesn't offend, but every site I've
looked at about this says that indeed our ears do function as FFT
devices. If this is incorrect I'd very much like to know the turth
about the matter.


In a very real sense you are asking for an artificial ear
all the way through to the process of blind separation.
That problem remains a curiousity that researchers are
merely nibbling the edges of.

You might want to Google on "blind separation" to see how
much your problem involves that and how little progress has
been made.


Bob

Is this what I'm asking for? I really don't know myself. It seems to
me FFT would work ideally if the only instruments I wanted to score
for were flutes. Flutes have an almost perfect sine wave output. And
since FFT is a breakdown of the sound into sine waves, I'd think this
would work quite well, except of course for the limited bass range of
the flute family. No?

Regardless, thanks for giving me some new info to go on.