Jaunty 9.04, jackd and two Gina 24 soundcards

Richard Lamont richard at lamont.me.uk
Mon Aug 17 17:45:15 BST 2009

Luke Yelavich wrote:
> On Mon, Aug 17, 2009 at 07:14:13AM EST, Richard Lamont wrote:
>> After much googling several people say that the only way to get two
>> cards to work with jackd is to do the alsa pcm_multi thing. Is this
>> still the case or is it out of date? I suspect the latter, because
>> hw:0,1 appears as an option in qjackctl's setup screen.
> The first thing you need to do, is make one card the clock master, and slave the other card to it. When you set up multiple cards tied together with jack, you MUST make sure they both have the same clock so they don't drift appart. This is usually possible either via wordclock or S/PDIF.

Thanks for your reply.

With the Gina 24 there are jumpers on the PCI boards. This is a
proprietary Echo Audio thing they call Esync. I've connected SYNC OUT on
card 0 to SYNC IN on card 1 using the short connecting cable supplied
with the cards for the purpose.

To select the right clock source, and various other parameters, the
echomixer program (in package alsa-tools-gui) works very nicely. It
seems to be necessary to run a separate echomixer for each card,
supplying the card number as an argument when invoking the program (i.e.
 "echomixer 0" and "echomixer 1").

Sure enough, "Internal" appears as the only available clock source on
card 0 (with the unavailable ones greyed out), whereas card 1 also has
"Esync" and "Esync96" available. There's a reassuring click from the
speakers as I change between them.

> The next thing you need is some code in a .asoundrc file that you can tell jack to use, so you can use more than one sound card simultaneously. I know of a page that talks about this. It uses envy24 based cards, but its no different, you will just have to adapt the asoundrc code to suit your hardware. http://www.sound-man.co.uk/linuxaudio/ice1712multi.html

I'm tackling that now, but how do I get anything to take any notice of
my ~/.asoundrc file once I've written it? Is the creation of the virtual
device done by the kernel or something in user space?

Richard Lamont                        http://www.lamont.me.uk/
<richard at lamont.me.uk>
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