FAQ004

From the ALSA wiki

The FAQs have been reorganized. The new location of this question is FAQ#My ALSA modules seem to be loaded fine but I hear no sound. Why's that?

My ALSA modules seem to be loaded fine but I hear no sound. Why's that?

Play around with alsamixer. The relevant audio channels are probably just muted and/or set to zero or a very quiet volume-level.

On some platforms, particularly the IBM Thinkpad T40 series, the Headphone Jack and/or Line Jack inputs need to be muted in order to hear sound at all. The alsamixer app can do this for you by using the 'm' toggle to mute/unmute. On my system the Headphone Jack appears as the 4th control from the left and is titled "Headphon", the same as the title for the 3rd control (the title is truncated). The same has been observed with SiS SI7012 card, where muting the IEC958 Capture Monitor item helps.

There is also another possibility. Maybe you have many devices that appear as soundcards. One of them may be a modem. Apparently, it can play stuff, but you probably won't hear anything and you certainly don't want to use a modem as the default soundcard. You can see whether this is your problem by examining /proc/asound/cards. See FAQ026 about how to change your default soundcard, or alias snd-modemmodule off in your /etc/modules.conf.