Audio Input & Output in PD

All objects which have audio inputs or outputs are written with a tilde as last character of their name(~). The two objects introduced in this minimal example get audio signals from the audio interface (adc~ - for analog-digital-conversion), respectively send them to the audio interface (dac~, for digital-analog-conversion):


Both adc~ and dac~ have one creation argument - the index of the input our output, counting from 1. The above shown example gets the left and the right channel from the audio hardware and swaps them, before sending them to the audio output.


When started on a laptop without headphones, the patch might generate a loud feedback-loop.

Activating DSP

PD patches will only process audio when DSP has been activated. This can be done in the Media section of the top menu or with the shortcut Ctrl+/ (Cmd+/ on Mac). DSP can always be killed using the shortcut Ctrl+. (Cmd+. on Mac).



  • Miller S. Puckette. Pure Data. In Proceedings of the International Computer Music Conference (ICMC). Thessaloniki, \\ Greece, 1997.
    [details] [BibTeX▼]


  • Miller S. Puckette. The patcher. In Proceedings of the International Computer Music Conference (ICMC). Computer Music Association, 1988.
    [details] [BibTeX▼]