Selon Olaf Matthes olaf.matthes@gmx.de:
You should try:
% pd -outchannels 4 -audiooutdev 2
The -audiooutdev 2 tells Pd to start with device #2, -channels 4 tells Pd that you want 4 channles, so it will also open the next device (i.e. #3) to get 4 channels. If you add a second -audiooutdev it overwrites the first argument, I think. At least it works like that in Windows land...
Olaf
This is the good solution, thanks a lot