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<div class="moz-cite-prefix">see the attached patch.</div>
<div class="moz-cite-prefix">I now think it is impossible to
compensate for the delay of a variable delay pitch shifter. Just
because it's variable :) Anyway, this is Miller's clear
explanation:
<a class="moz-txt-link-freetext" href="http://msp.ucsd.edu/techniques/latest/book-html/node115.html">http://msp.ucsd.edu/techniques/latest/book-html/node115.html</a> <br>
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<div class="moz-cite-prefix">best, Hans<br>
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<div class="moz-cite-prefix">On 11/24/20 2:59 PM, Maximiliano
Estudies wrote:<br>
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<div>Hi Hans,</div>
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<div>how are you measuring the delays?</div>
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<div>Cheers,</div>
<div>Maxi<br>
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<div dir="ltr" class="gmail_attr">El vie, 20 nov 2020 a las
15:25, <a href="mailto:info@hansroels.be"
moz-do-not-send="true">info@hansroels.be</a> (<<a
href="mailto:info@hansroels.be" moz-do-not-send="true">info@hansroels.be</a>>)
escribió:<br>
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<p>Hello,<br>
</p>
<p>Hopefully people with more knowledge of audio
processing can answer the following questions.
Background: I make patches in which the microphone input
is modified by different kinds of pitch-shifting, I
would like to compensate the delays caused by these
pitch-shifts and thus avoid artefacts. <br>
</p>
<p>1) How much delay does a pitch-shifter based on a
variable delay (the classic rotating-tape-head style)
produce? as in G09.pitchshift.pd in the audio.examples
folder. I did a quick test with a
one-sample-audio-trigger going immediately to the first
channel of a recording patch in Pd and simultaneously
going to a variable delay pitchshift (pp.pitchshift~
from AudioLab), routed into the second channel of the
recorder. The delays are quite large and vary between 30
and 80 milliseconds, there seems to be no relation with
the amount of pitch-shift. In the pitch-shifting patch I
also notice that the delay varies between zero and the
window size. Is there a way/patch to calculate and
compensate for this delay? (for example, if you want to
combine the original with the pitch-shifted signal in a
patch). Or is this impossible because the delay is
variable...<br>
</p>
<p>2) I'd like to know the delay in ms with FFT processing
if you have a 1024 sample window with overlap factor of
4, for example, in a pitch-shifting vocoder? I found
this info on a MAx/MSP mailing list, is it correct?:
"The I/ O delay is equal to the window size minus the
hop size (e.g., for a 1024-sample FFT window with an
overlap factor of 4, the hop size is equal to 256, and
the overall delay from input to output is 768 samples)";
at 44100 sampling rate this is around 17ms delay (for a
window of 1024 samples, overlap 4). <br>
</p>
<p>3) Conclusion: any pitch-shifting technique introduces
tens of milliseconds delay? (Pitch-shifting based on
granular synthesis is not a solution, I think it also
requires a buffer of at least 50ms.)</p>
<p>Hans<br>
</p>
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<div>Maximiliano Estudies</div>
<div><i>VDT Referat
Beschallung</i><br>
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<div>+49 176 36784771</div>
<div><span><a
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