As a general rule the default BIOS settings should be fine for the audio.
On Atom and Celeron class systems I've had issues with sound when both HDMI and 3.5mm jack audio were available, where I had to:
Add this to /etc/modeprobe.d/alsa-base.conf (or default.conf if there is no alsa config file)
options snd_hda_intel index=1
The index=N may be system dependent, so you will likely need to do a bit of Google
One more thing, have you tried the Preferences->Hardware->Sound or "Sound Settings" from the notification speaker icon? It has drop-downs to let you try what is available to see what works with the "Test Speakers" button.