[PD] a little pitchshifter

Frank Barknecht fbar at footils.org
Mon Mar 5 19:31:43 CET 2007

Kyle Klipowicz hat gesagt: // Kyle Klipowicz wrote:

> Could aliasing be avoided by using a multi-pole low pass filter at
> nyquist before sending the signal to the dac?

No: Alias frequencies aren't too high, they are wrong frequencies,
that have been mirrored at the Nyquist border. As soon as you try to
play a sinewave at Nyquist + x, what you get is a sine at Nyquist - x,
and you cannot lowpass out this frequency after it has been

You can however upsample your signal first, then use a lowpass filter,
then downsample again. See this chapter in The Book for more info:
and J07.oversampling.pd

 Frank Barknecht                 _ ______footils.org_ __goto10.org__

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