Lenovo Y510 has go 4.1 sound system with a sub- woofer (Dolby Home Theater) Default installation of Ubuntu doesn't recognises all four speaker. There are few fix going on the Internet. There is one problem with those fixes, i.e. headphone doesn't mute the speakers. So you have to manually mute and un-mute the speaker while using the headphone. However I have found one fix, that recognises all four speaker and one sub-woofer, mutes and un-mutes them while using headphone, and produces 5.1 surround sound. Open /etc/modprobe.d/alsa-base for editing. (you need root access) Open /etc/modprobe.d/alsa.conf if you are using Fedora (Thanks to the Anonymous user) add the following line at the end options snd_hda_intel model=6stack-dell save and reboot. Now, go to Audio Preferences and select "6ch" under the options tab. You are all done, test it with the command "speaker-test -Dplug:surround51 -c6 -twav" Note: If you have updated your system