Linux sound alsa
From thelinuxwiki
A PCM stream is a digital representation of an analog signal
notes
files of interest...
/etc/conf.d/alsasound
/usr/bin/alsaucm
/usr/bin/alsamixer
/usr/bin/alsa-info
/usr/bin/alsaloop
/usr/share/doc/alsa-lib-1.0.26
/usr/share/doc/alsa-utils-1.0.26