[LAD] GuitarSynth

[Albert Graef]

Hi Gerald,

cool project, I'm looking forward to give it a try. :)

On Thu, Apr 23, 2015 at 7:24 AM, Gerald <gerald.mwangi at gmx.de> wrote:

> definately, but that comes with the cost of extra hardware (pickup,
> 6chan soundcard). I would build that into GuitarSynth if I had that gear.
> But I'm also rather interested  multipitch out of one signal. It's just
> more convenient too
>

Polyphonic pitch detection is much more involved and requires more advanced
algorithms which are computationally intensive and thus hard to perform in
real-time.

Commercial closed-source software like Melodyne can do this, at least in
off-line processing. AFAICT, the latest Melodyne versions also do some
real-time processing, but I haven't used Melodyne for some time and so I
don't know how well that works.

I'm not sure either whether there are any good open-source codes for this
available yet, maybe others can provide corresponding links. But here are
some relevant answers from Stackoverflow and Stackexchange:

http://stackoverflow.com/questions/9613768/multiple-pitch-detection-fft-or-other/9626849#9626849

http://dsp.stackexchange.com/questions/11433/polyphonic-detection-mulit-pitch-detection-chord-recognition

Also, here's an interesting recent DAFx paper on doing polyphonic pitch
detection using autocorrelation:

http://www.dafx14.fau.de/papers/dafx14_sebastian_kraft_polyphonic_pitch_detectio.pdf

And then there's the work of Anssi Klapuri and others at Tampere University:

http://www.cs.tut.fi/~klap/iiro/

Also, there are algorithms for doing spectrum estimation such as filter
diagonalization methods (FDM) and the classical Prony algorithm, but due to
their complexity these probably aren't well-suited for real-time processing
either (the Prony algorithm also suffers from numerical instabilities
IIRC), and you still have to do the partitioning of the overtone series
afterwards.

There's surely more, but that's what I could find with a quick Google
search or remember from the top of my head.

Hope this helps,
Albert

-- 
Dr. Albert Gr"af
Computer Music Research Group, JGU Mainz, Germany
Email:  aggraef at gmail.com
WWW:    https://plus.google.com/+AlbertGraef
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