> I have a file which contains a second's worth of sound of each of the 91

> tonewheels of a Hammond B-3 organ in order. (Hammonds have spinning disks

> whose edge is fluted in a shape of a desired output sound wave. This spins

> in front of a mechanical pickup, which converts that undulating edge into

> an electronic signal.)


> I want to do a harmonic analysis of each disk in turn.


> Given the volume of example sounds, I'm hoping for the utility program

> doing this analysis to be as automated as possible. I see the first

> project as a first step towards a utility that will let me conveniently

> analyze other sounds as well going forward, such as guitar notes.
i suspect that those tone wheel waveforms are close to sinusoidal.
but to find out from your .wav file, you can apply a pretty simple pitch 
detection to get the period of the waveform to a precision of
fractional sample.� then you can divide that period into N samples using 
interpolation and resampling techniques.� this is how i would advocate 
extracting a wavetable from a portion of a note (as opposed to the heterodyne 
oscillator approach).
from the N-sample periodic wavetable,
you can do an FFT.� bin 0 is DC, bin 1 is the fundamental, bin 2 is the second 
harmonic, etc.
if you simply window the segment and FFT is, you will not be spared the task of 
interpolation, if you want to do this right.� my preference is to interpolate 
between samples to get a
periodic wavetable.

r b-j� � � � � � � � � � � � �r...@audioimagination.com

"Imagination is more important than knowledge."

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