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My sound set up used to be able to handle sounds from different applications simultaneously.

Currently, though, if one application is playing a sound, it takes exclusive control of the sound device. If I try playing any sound from a second application, that second application is likely to freeze. Sometimes the first application will freeze or crash too.

There has been no hardware changes at all so I assume simultaneous sounds is still possible. There have been various software upgrades and configuration settings over time, but I couldn't say when in all of that I lost the capacity for simultaneous sounds.

My system has a computer running Mythbuntu that acts as a Pulseaudio sound server. It has a USB digital sound system attached to it. All computers on my network send sound over the LAN to that machine, and so any sounds from any computer come out of the same speakers.

Where should I be looking in order to troubleshoot this problem of no longer being able to handle simultaneous sounds?

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Dave, did this start happening right after we fixed the network PA stutter issue? – izx Aug 24 '12 at 18:38
Dave, that comment has been removed :) – izx Aug 30 '12 at 2:04

This sounds* like you've removed or have otherwise broken or hobbled PulseAudio and things are connecting directly to ALSA. To work out what's going on, I would:

  • Stop X via sudo stop lightdm.

  • Check htop to make sure any graphical applications aren't lurking.

  • Attempt to run killall pulseaudio && pulseaudio This should run PA in the foreground so you can see any debugging output. If you see any errors at this point, that's where you go from... Be that reinstalling pulseaudio (if it's missing) or spotting the configuration errors.

  • If the above works without error, run sudo start lightdm in another TTY and play some audio from multiple places. This should all work. Assuming it all does, there's a problem in the way that PulseAudio is being loaded on normal boot. I'm ashamed to admit I don't know where PA is loaded from. Anwsers on a post card.

Past that it's anybody's guess but I'm fairly sure PulseAudio is crashing on boot or isn't being loaded.

* The pun wasn't originally intended but what the heck.

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