The speakers on my laptop (Lenovo T61) have a weird thing they do where when I'm booting into linux they make a kind of staticky whiny screeching noise, which is worse during boot but continues when I'm actually using the OS. I've tried using Ubuntus 8.04 through 9.04 and Linux Mint Gloria and they've all done the same thing. Anyone have any pointers for me to fix this?
Look at your mixer settings and start muting channels. If you mute a channel and the sound goes away, that's the one causing the problem.
I had a problem in Mandriva a while back where "analog loopback" was enabled and I'd hear a loud static hiss coming out of my speakers all the time. Very annoying. I had to mute the channel in the mixer to get it to go away.