Alsa notes

alsa config files

/etc/modprobe.d/alsa.conf (or /etc/modprobe.d/alsa-base.conf or similar) is the main ALSA configuration file in most linux systems. Its syntax and all the options and parameters are explained in /usr/src/linux/Documentation/sound/alsa/ALSA-Configuration.txt.

sound card 0

add the line below to alsa.conf. the parameter snd_usb_audio is the driver name for the device

# prevent usb from being card 0
options snd slots=,snd_usb_audio

saving mixer levels for a sound device

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