SONIDO GENERAL (Copy&paste de ubuntu-guide)
======================================

How to configure sound to work properly in GNOME

* Read #General Notes
* Read #How to add extra repositories

sudo killall esd
sudo cp /etc/esound/esd.conf /etc/esound/esd.conf_backup
gksudo gedit /etc/esound/esd.conf

* Find this section

...
auto_spawn=0
spawn_options=-terminate -nobeeps -as 5
...

* Replace with the following lines

auto_spawn=1
spawn_options=-terminate -nobeeps -as 2 -d default

* Save the edited file

sudo apt-get install libesd-alsa0
gksudo gedit /etc/asound.conf

* Insert the following lines into the new file

pcm.card0 {
type hw
card 0
}

pcm.!default {
type plug
slave.pcm "dmixer"
}

pcm.dmixer {
type dmix
ipc_key 1025
slave {
pcm "hw:0,0"
period_time 0
period_size 2048
buffer_size 32768
rate 48000
}
bindings {
0 0
1 1
}
}

* Save the edited file

sudo ln -fs /usr/lib/libesd.so.0 /usr/lib/libesd.so.1

System -> Preferences -> Sound
Sound preferences

General Tab -> Sounds for events (Un-Checked)

* Save and close all opened applications, Reboot computer

SONIDO EN FIREFOX
==================

Modificar el fichero /etc/firefox/firefoxrc
Contenido original:

# which /dev/dsp wrapper to use
FIREFOX_DSP="none"
# Note that "auto" and "esd" involve the use of esddsp, which
# is known to be buggy and to make Firefox unstable.
# See https://launchpad.net/malone/bugs/29760.
export XLIB_SKIP_ARGB_VISUALS=1

Cambiar en la segunda línea "none" por "aoss". Con eso podremos escuchar simultáneamente el sonido de firefox y el de otros programas.