I was experimenting a lot with my pd patch, by taking parts out and adding them again. By observing the IDE it came out that using the readsf~ file with 5.1 surround sound files results in continuous dropouts. I was using about 16 5.1files simultaneously + mono files. Nevertheless the CPU was at 40-50% with 8 analog inputs active (I need all of the analog ins by the way). Next step was to bounce the 5.0 files as 5 mono files and play each of them with a mono readsf~ object. that reduces the amount of dropouts. By adding panning calculations (in control rate) for those files the dropout rate increases again, while it has minimal affect on CPU. In another thread I read that dropouts occur, when a calculation needs more time than a blocksize length. But if so there should be many drop outs when using the panning calculations, because I do these calculations continuously (every 50 ms), but the drops occur only about every second.
Next I will try the -p 128 command. Thank you very much for the further information about that command. Hope this will work. Beside that I have altered the patch so that the panning calculation is done only if necessary, so I hope that this will help too. Updates about testing that will come tomorrow.
Greetings and thanks again for your help!!