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Re: real-time pitch demonstration


Passaggio seems to fill all the requirements from your list. Well, maybe not for accuracy to a few cents. But that
could be done by using some interpolation. And so far, we don't do MIDI.

I thought you might be interested knowing that the periodicity range of the
Passaggio is eight octaves. Although Chris Shafer has used some filtering to
reduce artifacts above the soprano range, eight is useful for other applications. The periodictiy sorting matrix is
inherently like a well-tempered piano keyboard.

In fact, since there is so much interest in music, it occurred to me that the octave range of Passaggio's periodicity method can easily be extended downward to track musical rhythms. How about 16 octaves? And in real time, by which I mean locked to every zero crossing in the signal waveform as it passes through the system from the microphone. No delays. Your turn, Bob!

John Bates

At 12:08 -0500 29/3/09, James W. Beauchamp wrote:
What is needed is a system that is accurate to a few cents but can also
cover a wide range of pitch, at least 3 octaves, but 7 would be great.
It should be able to handle a wide variety of waveforms, drop outs, a
fair amount of noise and inharmonicity, and it should be able to handle
very fast changes in pitch, i.e., it should be able to accurately
transcribe virtuosic passages (64th notes, etc.), as well as glides,
vibrato, and portamento.

Besides displaying the data on a log(f0) vs. time chart, the system
should also be able to generate the data to a file for subsequent
post-processing research. Conversion to MIDI and musical notation are
nice features, but these are already available in programs once the
log(f) data is provided.