Vérifier le matériel :
$ lspci -v | grep -A7 -i "audio"
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] RV635 HDMI Audio [Radeon HD 3600 Series]
Subsystem: PC Partner Limited / Sapphire Technology Device aa20
Flags: bus master, fast devsel, latency 0, IRQ 26
Memory at fddfc000 (64-bit, non-prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: snd_hda_intel
Sans changement matériel, ré-installer les pilotes :
Sometimes, sound might be configured correctly, but for some reason or another it stops working. If this is the case, you can purge your custom changes, and reset your system to a clean base. This may clear up your problem and restore your computer to a working state.
Open a terminal and type
sudo aptitude --purge reinstall linux-sound-base alsa-base alsa-utils linux-image-`uname -r` linux-ubuntu-modules-`uname -r` libasound2
This will purge any custom configurations that you’ve made, and any hand-compiled modules that you’ve built, and restore your sound stack to the “Official” Ubuntu core.