[PD] multiple devices help

Josh Steiner joschi at eds.org
Thu May 30 08:59:05 CEST 2002

> This, and you have to start pd with a list of the soundout devices you
> want to use like
> $ pd -soundoutdev 0,1
> starting from 0 as usual.
> > i did some archive searching and came up with this:
> > 
> > from IOhannes m zmoelnig about "pd-patch for (better) multidevice support"
> > 
> > http://iem.kug.ac.at/mailinglists/pd-list/2001-11/0316.html
> This is already included in PD 0.35 since at least test17. 

cool, thanks.

> I see another problem with your setup, and that is the hardware side.
> If you use several consumer soundcards without synchronization instead
> of a decent multichannel card, it might or probably will happen, that
> your audio will run out of sync. This means: the samples you send
> synchronized from the PD DSP-chain will come out of the four
> soundcards at different times, because each of the soundcards has a
> different understanding of absolute time because of slight differences
> in their clock chips.

i've read this in the archives.  I'm not overly concerned since the sound
design i've been working on has been of the ambient sound scape variety,
so a little bit of drift will be fine.   i am going to setup some test
patches and let them run for long periods of time (eventually over a
week) ... i'll keep you guys posted on how it goes.

> Depending on the things you do, this might be nasty, *especially* if
> your installation is running for a long time, because your audio data
> will differ more the longer it can run out of sync. Maybe stopping
> audio in PD from time to time could help.

thats a good idea... if turning the dsp on and off occastionally manages
to resync the cards, that could be worked into the piece ;-P


Josh .. Yoshi .. Joschi .. xiphoidprocess.com .. eds.org/~joschi

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