Try this link.
Its a link to an ubuntu forums post giving the solution to a similar problem.
Though I would recommend going through the links to solve the problem but as the person below asked me to put the instructions in the post itself, so here we go:
Find your sound card model using this:
cat /proc/asound/card0/codec#* | grep Codec
For me this outputs:
Codec: IDT 92HD73C1X5
The file /usr/share/doc/alsa-base/driver/HD-Audio-Models.txt.gz lists the sound card models with available modprobe modules to use.
The full model number wasn't in there, because the model has been wildcarded. I searched for:
options snd-hda-intel model=dell-eq
options snd-hda-intel model=dell-m6
into the file:
Now which line to put in the file will depend on the model of your laptop. In short, its the former line to put for dell studio 15xx models and latter for studio 17xx as indicated in this thread on ubuntu forums