Well, this confuses me for a long time. As far as I know, ALSA is a package of many sound card drivers, and PulseAudio is a audio application that operate the sound data like mixing or equalizer.
But why there is a control bar called PCM in the panel of alsamixer. Does that actually change volume by controlling the chip on the sound card? If not, why it isn't PulseAudio'a job?
What is the relation between ALSA and PulseAudio sound architecture?