Sound has gone to static

[Matthew B Philmon]

Something I updated via apt-get last night or sometime today has killed 
my sound. It's not GONE, instead it's constant loud hiss/static coming 
out of one speaker. The speakers are fine (I checked). I have no idea 
what has happened. Can anyone give me some pointers on how to trouble 
shoot this?

Some applications play no sound, others play it with the static. If I 
crank the volume to FULL Muine and MPlayer are both able to play 
(somewhat over the static). Totem and Rythymbox make no sound at all.

Matt