How to unmute ALSA

ALSA drivers can use the muting facilities that most soundcards have. If you loaded the sound drivers and everything is fine but you get nothing but silence, then you probably forgot to unmute your card. You need amixer or alsamixer for this, both from the ALSA-util package.

amixer pcm 100 unmute

amixer set -c 1 Master 70 unmute
amixer set -c 1 PCM 70 unmute
amixer set -c 1 CD 70 unmute

should do for most applications. Please note that for the older amixer command you need to leave out the set in the command line.