Re: Playback using multiple devices

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One p0roblem with two sound cards is that the two frequencies may be out from
each other. Unless they are driven by the same crystal, if the two frequencies
are different by .01%, by a 1000 sec ( 15 min) they will be out by 1/10 of a
sec. Ie, one or the other will be producing sound 1/10 of a second before the
other. Highly audible.


William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/

On Thu, 24 Feb 2022, Christopher Brown wrote:

[CAUTION: Non-UBC Email] Hi Again,

So I guess I am looking for some closure on this. Can someone explain what the situation is? Does multi-card
no longer work? It clearly did at some point given the prevalence of sample rc files around the web, but is
this not the case anymore? I need a multi-card setup for my work, and the ffado firewire drivers for jack are
troublesome at best for me on Manjaro. Any insights, even if it is that it just doesn't work, would be
appreciated. 

Thanks,
Chris


Christopher Brown wrote:


      Hi List,

I have an updated Manjaro system and two RME Fireface 800 8-output-channel devices, both of which work
well. I would like to create a 16-channel virtual device for playback, but I am having quite a bit of
difficulty. I have tried many things, but the closest I have come to success seems to be with the
following .asoundrc, which allows me to use either ff800_1 or ff800_2 to playback sound with portaudio,
but ff800x2 (the intended 16-channel virtual device) does not show up and thus is not accessible. This
config file was adapted with minimal edits from post #19 at 
https://bbs.archlinux.org/viewtopic.php?id=109370 which claims to be a working example (although as
posted it duplicated 2 audio channels out to 4 hardware channels across 2 devices).

Any insights into what I am doing wrong are greatly appreciated. 

## Begin .asoundrc
pcm.!default plug:ff800x2

ctl.!default {
  type hw
  card 0
}

pcm.ff800x2 {
  type route;
  slave.pcm {
      type multi;
      slaves.a.pcm "ff800_1";
      slaves.b.pcm "ff800_2";
      slaves.a.channels 8;
      slaves.b.channels 8;

      bindings.0.slave a;
      bindings.0.channel 0;
      bindings.1.slave a;
      bindings.1.channel 1;
      bindings.2.slave a;
      bindings.2.channel 2;
      bindings.3.slave a;
      bindings.3.channel 3;
      bindings.4.slave a;
      bindings.4.channel 4;
      bindings.5.slave a;
      bindings.5.channel 5;
      bindings.6.slave a;
      bindings.6.channel 6;
      bindings.7.slave a;
      bindings.7.channel 7;

      bindings.0.slave b;
      bindings.0.channel 0;
      bindings.1.slave b;
      bindings.1.channel 1;
      bindings.2.slave b;
      bindings.2.channel 2;
      bindings.3.slave b;
      bindings.3.channel 3;
      bindings.4.slave b;
      bindings.4.channel 4;
      bindings.5.slave b;
      bindings.5.channel 5;
      bindings.6.slave b;
      bindings.6.channel 6;
      bindings.7.slave b;
      bindings.7.channel 7;

  }

  ttable.0.0 1;
  ttable.1.1 1;
  ttable.2.2 1;
  ttable.3.3 1;
  ttable.4.4 1;
  ttable.5.5 1;
  ttable.6.6 1;
  ttable.7.7 1;
  ttable.8.8 1;
  ttable.9.9 1;
  ttable.10.10 1;
  ttable.11.11 1;
  ttable.12.12 1;
  ttable.13.13 1;
  ttable.14.14 1;
  ttable.15.15 1;
}

ctl.ff800x2 {
  type hw;
  card 0;
}

pcm.ff800_1 {
   type dmix
   ipc_key 1024
   slave {
       pcm "hw:0"
       period_time 0
       period_size 1024
       buffer_size 16384
#       buffer_time 0
#       periods 128
       rate 44100
       channels 8
    }
    bindings {
       0 0
       1 1
       2 2
       3 3
       4 4
       5 5
       6 6
       7 7
    }
}

pcm.ff800_2 {
   type dmix
   ipc_key 2048
   slave {
       pcm "hw:1"
       period_time 0
       period_size 1024
       buffer_size 65536
#       buffer_time 0
#       periods 128
       rate 44100
       channels 8
    }
    bindings {
       0 0
       1 1
       2 2
       3 3
       4 4
       5 5
       6 6
       7 7
    }
}

ctl.ff800_1 {
   type hw
   card 0
}

ctl.ff800_2 {
   type hw
   card 1
}
## End .asoundrc


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