Miscellaneous questions about sound settings

[Stegozor]

Hello everyone,

Just another newbie question: since I installed Ubuntu dapper drake, the 
default system sound (when you reach the bottom of a man page, or new 
mail sound with Thunderbird & SeaMonkey) comes from the... buzzer. In 
fact, I rather like that :) but I also would like to know why the buzzer 
is activated/used, and more generally how to set such sounds to the 
sound card or the buzzer. Note that the sound works quite fine (games, 
.ogg files).
I had a look in System>Preferences>Sounds but couldn't find how to 
replace the System beep by something else nor how to use the system beep 
for more events.

Also, one of my speakers is dying, so as in Windows, I'd like to tell 
the system to use mono sound instead of stereo. How can I do that? I 
searched, but couldn't manage to find anything until now.

(My computer: Asus A7V333 motherboard, AMD Athlon XP 2000+ CPU, 384 Mb 
of RAM, C-Media PCI CMI87738-MC6 sound card).

Miscellaneous questions about sound settings