[alsa-devel] [LAD] digiface vs. multiface vs. jack vs. other cards

Frank Smith frsmith at gmail.com
Tue Mar 30 00:48:45 CEST 2010

Hi Fernando
Can't help you on the coding but if you find a way to link two RME PCI hdsp
cards to show as one please pass this along.

I have two cards that I have to constantly change as the Bois seems to
change the order of the cards on Boot up ( I use jack to select the cards)


On 29 March 2010 18:49, Fernando Lopez-Lezcano <nando at ccrma.stanford.edu>wrote:

> At CCRMA we have several studios with linux computers in them (in
> addition to computers sprinkled throughout the building). Some of the
> studios have digiface interfaces, some multiface. All of them are
> connected to the sound system or mixer digitally through adat
> lightpipes. Workstations have Delta 66 or Gina3G soundcards.
> It would be nice for a user to be able to play, say, a stereo Ardour
> session in any of them without any changes to the session or routing.
> The digifaces send channels 1-24 out the adat ports. The multifaces on
> the other hand send 9-16 on the adat port. Deltas and Ginas send out
> stuff on channels 1-4 or 1-6.
> You can see the multiface interfaces are a problem. To get sound out of
> them you have to send on channels 9-16 which is different from _all_
> others!
> I tried several workarounds without much success:
> a) fix this at the alsa level. Should be the way to go, right? Create
> an /etc/asound.conf that uses ttable to translate channels for the
> multifaces so that the digital out is actually sent through channels 1-8
> (and create the same name plug interface in all other computers that
> does nothing so that the user can set that name as the default in
> qjackctl and will get the same behavior in all computers).
> Works, but not quite. When I try to use that "fake" plug interface with
> jack2 I get a warning that I'm using a plug interface (sort of fair) and
> jack only opens it with _2_ i/o channels (even though the ttable is 18
> channels wide!). If I _force_ input and output channels in jack to 18 it
> does work fine. But now it will _not_ work on other computers that have
> less (or more) than 18 channels. Argh.
> b) fix it in hdspmixer. Well, it turns out that hdspmixer does not read
> the default matrix gains from a file so I can't really override the
> default. AFAICT the gains are calculated algorithmically in the code and
> there is no command line option to load presets from a file.
> Or I could write a small script that will set the right gains for 1-8 to
> go out through 9-16 but if a user starts hdspmixer that gets undone with
> no warning.
> And, of course:
> c) give up and connect an 8 channel analog snake to the analog outputs
> of the multifaces and do away with a digital connection to the mixer...
> Anyone has any other suggestions??
> This should be easy to fix, right?
> :-)
> -- Fernando
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