[chuck-users] pitch tracking in ChucK
haberg at math.su.se
Sat Dec 12 15:14:39 EST 2009
On 12 Dec 2009, at 19:32, Kassen wrote:
>> Do these track the overtones? - When checking the spectrum of an
>> oud, I noticed that the fundamental is missing if one passes to new
>> note by shortening the string with the finger against the board
>> without striking it with the other hand.
> Well, fft as such doesn't "track" anything.
In a past thread, when discussing using GPUs for getting extra
computing power, I forgot to mention this FFT that achieves 144 Gflop/
s on the now not so new GeForce 8800GTX:
Haven't looked at details, but I think it can be used as just an added
parallel computing resource.
> All you get is energy and phase for a certain band over that frame.
> From this we can quite easily determine the most prominent
> frequency, but as you know that need not be the fundamental. It
> quite likely is the fundamental for many signals but we don't *know*
> this and without more knowledge about the piece we can't say what
> the root of a certain chord is, even if we could manage to separate
> the notes. Pitch trackers often get very confused by chords (and may
> output all sorts of musically interesting "garbage" in response).
> What we can do -given enough frequency resolution- is try to find a
> series of harmonics and use that to calculate what the fundamental
> must have been. Harmonics will be integer multiples of the
> fundamental, after all. This is what our hearing psychology does
> when listening to something like your oud.
Actually, the cochlea produce difference tones which do not exist
acoustically. And if the input is a harmonic series with missing
fundamental, it will be restored by that.
So one idea might be to add such difference tones as a part of an
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