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First things first: I'm running Xubuntu 13.04 on a VM on my iMac. I'm trying to learn how to use Linux and iron out bugs, because I'm hoping to switch from Mac OS to Linux in the future (when my ancient laptop dies.) As a musician an essential requirement of any OS I use is being able to work with MIDI sequencing and notation software. So I downloaded MuseScore and Qtractor.

Earlier today I was able to play back the sample MuseScore score no problem, and even made my own score to test a new soundfont I downloaded, and that worked great too. However, something weird happened a few hours ago and now I can't get any sound at all in MuseScore. I reverted to factory settings multiple times and even uninstalled and reinstalled, but I still have no sound. Also, since then MuseScore has been crashing every time I open it.

When I ran the terminal command to revert MuseScore to factory settings, I got this delightful list of errors (it did, however, revert to factory settings):

ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Capture Switch',0,0,0): No such file or directory
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7339:(snd_pcm_recover) underrun occurred

Additionally, when I open Qtractor it says:

The audio/MIDI engine could not be started. Make sure the JACK audio server (jackd) and/or the ALSA Sequencer kernel module (snd-seq-midi) are up and running and then restart the session.

and QJackCtl says:

Cannot connect to server socket err = No such file or directory Cannot connect to server request channel jack server is not running or cannot be started

Obivously there's an audio driver problem here. I read up on PulseAudio and Jack here: http://trac.jackaudio.org/wiki/WalkThrough/User/PulseOnJack and succesfully installed pulseaudio-module-jack but that was the only thing I managed to get working. The first step (modifying the config file) required root privileges and with my limited knowledge of command line I wasn't able to do this. There wasn't already a file of that name in the root directory or home folder; I found an 'example' asound.rc file hidden away in one of the subfolders, with instructions to move it to the root directory and name it .asoundrc. But because it required root privileges, when I edited it, it wouldn't let me save it, and I couldn't figure out how to do so in Terminal. I tried copying the contents of the file and making a whole new file to save it in, but apparently I'm not allowed to do that either.

As you can probably tell I'm terribly confused. I don't even know if anyone will be able to help me with this...

Update: It is DEFINITELY to do with Qtractor. I have 'ruined' several VMs just by opening Qtractor; as soon as I do so, I no longer have any sound in MuseScore. I think there is a conflict between PulseAudio and Jack; for now, I'm just not risking messing with any app that uses Jack.

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Which VM software are you using? –  searchfgold6789 Jul 25 '13 at 16:02
    
VirtualBox..................... –  dbaker Jul 26 '13 at 7:58
    
I don't have a specific solution to provide, but if you go into the Settings of your VM, you can go to Audio and try different sound cards or host audio drivers. Assuming your audio is working normally, you can try changing those settings. –  searchfgold6789 Jul 27 '13 at 1:57
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