Forwarded message:

From: zoharargaman <machinadeoro@gmail.com>
To: csound@lists.bath.ac.uk
Date: Saturday, April 20, 2013 2:18:59 PM
Subject: interesting SOLA timeScale quick pitch shifting Issues

Hi guys,

first post for me. let me say, i love CSound!

Hans Mikelson posted on CSound magazine this interesting Time Domain

TimeScale algorithm based on SOLA

http://www.csounds.com/ezine/spring2000/processing/

I love his explanation and the sound is good, but i needed a dynamic pitch

shifting, that is, one that can change pitch in k-rate, i messed around with

his code but i made more mess than i can cleanup, so i need your help.

this is Mikelson's version. very clear and neat

now, how would you make a auto-tuner out of this?

youll have to have a pitch detection algorithm (PDA) and the complicated

thing is i want to scale a sample that runs in a loop, so... this is my code

with event flow at the bottom:

it became kind of global variable - p-rate nightmare ;/

the Init method initialize any global variable so the compiler wont be

angry.

setup initializes the Process instrument that runs as the Always On instr

while performance.

Pseudo Midi given by the note in i1.

i1 trigger the SOLA instr.

the SOLA instr takes global params from Process like the pitch of the

current k-frame, and creates global signal gashft1 that is picked up by

Process and mixes with the fade mechanism and heads out.

the original sound is a loop, since its beeing read by a table3 opcode, i

used a phasor to keep track of where is the pointer of the sample should be

on the table. the thing is, that phasor must stop running when activating a

note on SOLA, so the reinit section was added with hope to solve this.

now, what is the problem? simple, no sound!

i tried measuring rms of the ga coming out of SOLA, it measured 0.2 RMS.

that's wierd. im i reading the table wrong? what can cause this behavior?

how is best to debug this? what tools to use? is this idea possible anyway?

thanks to all readers and answerers.

--

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