My Ubuntu always boots up in mute. There is no explicit setting I am aware of that does this.
What should I change to boot in normal volume.
Also, worth mentioning, this happened recently after I upgraded to Karmic.
Your problem might be linked to the fact that Karmic and pulseaudio try to retrieve information about the dB settings of your card, and many linux drivers are broken in that regard.
If that is the problem, you could try to give ignore_dB=1 to module-udev-detect in /etc/pulse/default.pa. That means that your line should look something like:
This might or might not fix your issue, but it's easy to try! :)