If some application accesses the sound card though one of the lower audio layers (see [[audio layers overview]]), the sound card might become inaccessible and other applications might fail to open the sound card, or even hang.

===== Finding out which application is holding your sound card =====

==== OSS ====

You can see which applications are using OSS (or the ALSA OSS Emulation layer) with:

  $ sudo fuser /dev/dsp*

==== ALSA ====

You can see which applications are using ALSA with:

  $ sudo fuser /dev/snd/pcm* 

===== Resolving the problem =====

==== Stopping the application holding the card ====

In most cases you can simply close or kill the application that is using your sound card.

=== PulseAudio ===

If [[apps:all:PulseAudio]] is holding your sound card, you can stop it with 'pulseaudio -k'.

=== TiMiDity++ ===

Some distributions start [[apps:all:timidity]] on startup. It can generally be stopped with 'sudo /etc/init.d/timidity stop'

==== Using Dmix ====

[[apps:all:ALSA]] has a [[http://alsa.opensrc.org/DmixPlugin|Dmix plugin]] that allows multiple applications to use the sound card.

Using [[http://alsa.opensrc.org/DmixPlugin|Dmix]] is not recommended for audio work, as it might increase latencies and reduce quality because of resampling.

==== Using a sound server ====

For audio work, use [[apps:all:JACK]].

For desktop audio, you might want to consider [[apps:all:PulseAudio]] or use the [[http://alsa.opensrc.org/DmixPlugin|Dmix plugin]] mentioned above.