55 lines
1.4 KiB
Markdown
55 lines
1.4 KiB
Markdown
# ALSA
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To use ALSA, install the `alsa-utils` package and make sure your user is a
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member of the `audio` group.
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The `alsa-utils` package provides the `alsa` service. When enabled, this service
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saves and restores the state of ALSA (e.g. volume) at shutdown and boot,
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respectively.
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To allow use of software requiring PulseAudio, install the `apulse` package.
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`apulse` provides part of the PulseAudio interface expected by applications,
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translating calls to that interface into calls to ALSA. For details about using
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`apulse`, consult [the project
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README](https://github.com/i-rinat/apulse/blob/master/README.md).
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## Configuration
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The default sound card can be specified via ALSA configuration files or via
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kernel module options.
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To obtain information about the order of loaded sound card modules:
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```
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$ cat /proc/asound/modules
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0 snd_hda_intel
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1 snd_hda_intel
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2 snd_usb_audio
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```
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To set a different card as the default, edit `/etc/asound.conf` or the per-user
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configuration file `~/.asoundrc`:
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```
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defaults.ctl.card 2;
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defaults.pcm.card 2;
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```
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or specify sound card module order in `/etc/modprobe.d/alsa.conf`:
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```
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options snd_usb_audio index=0
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```
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## Dmix
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The `dmix` ALSA plugin allows playing sound from multiple sources. `dmix` is
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enabled by default for soundcards which do not support hardware mixing. To
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enable it for digital output, edit `/etc/asound.conf`:
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```
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pcm.dsp {
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type plug
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slave.pcm "dmix"
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}
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```
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