A few weeks ago I bought a new laptop: an ASUS N53JN.
After having some trouble finding the HDD which I wanted to replace by an OCZ Vertex 2 I also had difficulty getting my speakers to work. The headphones worked fine but no sound from the speakers. After searching for quite some time I finally found the solution:
sudo nano /etc/modprobe.d/alsa-base options snd-hda-intel model=auto
I also added the ubuntu-audio-dev repository but I’m quite sure this is not what fixed my problem…