[linux-audio-user] Multiple sound cards

Mark Knecht markknecht at gmail.com
Wed Dec 8 17:51:54 EST 2004


On Wed, 8 Dec 2004 23:15:10 +0100, Christoph Eckert
<mchristoph.eckert at t-online.de> wrote:
> Hi,
> 
> > It is possible via an .asoundrc but you wont get it to work
> > with jack without xruns. xruns are when one soundcard needs
> > its new data (for playback) before the other card. It
> > happens because your soundcards won't run with _exactly_
> > the same frequency altough all clame to to 44.1kHz/48kHz.
> 
> short question: Is this also the case, if I have three cards
> but only one is used by jack?

No. This is not a problem. I have 2 or 3 cards or chips in most of my
machines. Jack just sync's to one and the others do not matter.

> 
> I also get xruns with my USB card. It's the third card,
> because I have an AC 97 and an USB2MIDI device.
> 
> When I try to run jack, it works, but I get some (but not too
> much) xruns. Should I disable the AC 97 card?

While I cannot speak too much about USB audio as I don't use it I was
able to help one individual the other day get rid of his xrun
problems. The newer kernels, 2.6.9'ish, along with patches for low
latency, allow you to set the interrupt processing of the sound card
to be non-threaded and therefore of higher priority in the machine.
This will give you a definiate leg up on getting rid of xruns whether
using USB as he was or PCI solutions as I do.

Good luck,
Mark
> 
>  Thanks & best regards
> 
> 
>     ce
>



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