Writing down my thoughts once ince a while

Multiple audio outputs in MPD

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Today a Sound Blaster Live 5.1 PCI audio board dropped onto my lap. Don’t ask me how that happened because the only thing that matters to me now is how I will use this now in conjuction with my onboard Realtek ALC883 (on a Intel HDA bus). I now have 7.1 and 5.1 sound cards. The most amazing thing I could do with that setup is to run 14 speakers(!!). Not amazing? Well, only if you don’t use your computer as a playback system for live concerts (or small “parties” in my case, even weddings :P) or something like that. What I can do now is to playback a track on “stage speakers” (or two tracks, or three!) while I listen to another track on my headphones just like a DJ! and I think I can also record from multiple inputs (all 5.1?) because ALSA installs the card as 3 devices, ADC Capture/Standard PCM Playback, Multichannel Capture/PT Playback and just Multichannel Playback. That would be just awesome for such a cheap sound card.

OK, over with the childish excitement. I’m actually more interested in it’s low latency performace and it’s MIDI input (maybe not really, USB-to-MIDI is pretty common now but an extra interface doesn’t hurt). I plan to buy a MIDI controller keyboard sometime. I want to try my hands (and brains) out on the piano and synths since I used to make (probably lousy) music a long time ago using a QWERTY KB and Fruity Loops. So yeah… I haven’t had too much luck with the guitar I bought. I think you simply cannot learn how to play it without getting an instructor and that I cannot do for a while to come. Although I did learn some important music theory while trying to learn to play the guitar. There’s still more to learn though.

So for now I’m going to test to the audio board and see how it performs. Honestly, I think I will only have satisfactory results after I buy a real audio interface for music production.

I got both cards to work with the Music Player Daemon and you can enable/disable any of them at runtime (if your MPD client or client library supports it, otherwise use mpc).

audio_output {
type                    "alsa"
name                    "ALC883 Analog"
#        device                  "hw:0,0"
#        format                  "44100:16:2" # optional
#audio_output {
#        type                    "alsa"
#        name                    "ALC883 Digital"
#        device                  "hw:0,1"
#        format                  "44100:16:2" # optional
#audio_output {
#        type                    "alsa"
#        name                    "SB Live: ADC Capture/Standard PCM Playback"
#        device                  "hw:1,0"
#        format                  "44100:16:2" # optional
#audio_output {
#        type                    "alsa"
#        name                    "SB Live: Multichannel Capture/PT Playback"
#        device                  "hw:1,2"
#        format                  "44100:16:2" # optional
#audio_output {
#        type                    "alsa"
#        name                    "SB Live: Multichannel Playback"
#        device                  "hw:1,3"
#        format                  "44100:16:2" # optional

You have to uncomment each output if you want to enable them. You don’t really need to uncomment the line that starts with format unless you want to force a specific audio output format.

UPDATE: It performs better than I expected with the low latency JACK server with a latency of 10ms. It can go as low as 5ms but I get more frequent overruns that way. Here‘s a link with helpful info.


Written by brokenthorn

November 29, 2008 at 21:22

Posted in hardware, Linux, music

Tagged with , , , ,

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