using alsa for multiple outputs (onboard, bluetooth) [solved

s|mon · Last edited by s|mon on Sat Apr 03, 2021 10:21 am; edited 1 time in total

I recently got a bluetooth headset i'd like to also use for audio from my machine.
Till now I used the onboard soundcard to output via analoge or spdif.

I managed to get the bluetooth headset working with alsa (although not listed as soundcard - only as pcm device after i created the entry manually in asound.conf); not sure if this is expected or relevant.

What i want to achieve is that every sound is routed to all outputs simultaneously.
So multiple sources (musicplayer, videoplayer, ....) to all 3 hardware devices (speakers:analogue, headphones:spdif and headphones:bluetooth) and i just power-off/on the devices themselves.

From what i read so far it would be possible to achive with the following chain in asound.conf

psycho · Guru Joined: 22 Jun 2007 Posts: 534 Location: New Zealand

Hey Sjmon.

You've probably long since got this sorted, but as it's unanswered I'll post my .asoundrc which is working for me with two sets of bluetooth headphones (simultaneous output to both). The below setup (though obviously with actual identifiers in place of AA:AA:AA:AA:AA:AA and BB:BB:BB:BB:BB:BB) works perfectly...alsamixer provides access to independent volume controls for each headset.

s|mon · Posted: Fri Apr 02, 2021 10:35 am Post subject:

Hi psycho,

thanks for your reply. No i had not but with your setup i now managed to get it somehow working but not usable yet.
with the config below i was able to get sound on bluetooth and my analogue sound output using alsa.

The following problems/challenges remain:

If i deactivate my bluetooth headset output is broken. Also the sound via 'sourround' is stopped
mpd (music player daemon) does not play with a simple alsa output using default device. So it does not play at all with this setup although e.g. audacious does.
no reconnect if headphones went out of reach and bluetooth disconnects. And on reconnect audio is stopped.
no mixer control for bluetooth device (i need to manually enter the device name in alsamixer to reach it) - this i could live with. As i anyhow solve this with scripted restore commands

So still not usable for me but i might find some time to investigate again.
I would be interested if some of these also show up in your setup.

And of course i appreciate any hints on how to solve them.
Thanks once more,
s|mon

psycho · Guru Joined: 22 Jun 2007 Posts: 534 Location: New Zealand

Bear in mind that I'm using multiple .asoundrc configurations (i.e. .asoundrc is just a symlink to one of various possible files)...so I'm not having any problems (all my output and recording devices work perfectly) but I'm not achieving that with a single .asoundrc. I've got a range of alternatives and have set up a little yad panel menu script so I can select whichever one I want (one for speakers, one for each pair of bluetooth headphones by itself, and one for both at the same time). I guess I could automate it (have it so that the speakers are active when neither headset's connected, and then which/both headset's receiving audio is also determined by which ones are connected), but I like switching it manually...the panel indicator tells me what's active, and it means I can e.g. play something through the speakers for a while without having to disconnect the headphones.

Re the bluetooth volume control, here's an excerpt from my yad script for a volume slider:

s|mon · Posted: Sat Apr 03, 2021 10:15 am Post subject:

Getting closer thanks to your tips.

MPD:
I now found out that mpd can handle multiple outouts on it's own. I just need to create multiple audio_output blocks and specify not the multi-device from alsa but each device directly so in my case 'surround' and 'bt1'.

Volume:

psycho · Guru Joined: 22 Jun 2007 Posts: 534 Location: New Zealand

Yes, it does (with a bluealsa .asoundrc like the one above). For me just typing alsamixer goes straight to the bluetooth levels: if I hit F6 to select a sound card I can see the other two there (the integrated Intel audio via 3.5 stereo jack and the Nvidia via HDMI, numbered as sound cards 0 and 1 respectively)...but it's already set to "default" (with just a hyphen instead of a number, for the sound card). Basically just works (though of course the headphones also need to be connected...otherwise alsamixer reports "this sound device does not have any controls").

s|mon · Posted: Sun Apr 04, 2021 9:36 am Post subject:

i got it if use the ctl.!default set to bluealsa in my setup now. But it still does not show of as seperate device if i want to cycle sound cards. Not sure if that would be supported with bluezalsa anyhow.