How can I change the speed of a sound file? For example, if I have a sound like whistle.wav
and I want to make the playback either in slow-motion or in fast-motion. How to do this in Pure Data?

use tabread4~ with a soundfiler, array and phasor~
The output from soundfiler is the size of the audio file, the phasor~ multiplies this with a value between 0 and 1 to create an index for tabread4~ to play at the speed of the phasor~ frequency
play speed.zip

Thank you! This works!

@RayManiac a bit remiss of me not to mention a minus frequency value will play in reverse.
better late than never