Quoth Colin Paul Adams on Pungenday, the 56th of The Aftermath:
I just tried RythmBox with an Audio CD - it plays but not sound :-(
The consensus seems to be (at least for MacBookAir2,1), that the
following in /etc/modprobe.d/sound.conf:
options snd_hda_intel model=mbp3
lets you use the headphone, but not the speakers.[1]
I forget now how I got sound working on the MacBookAir1,1.
Footnotes:
[1]
https://help.ubuntu.com/community/MacBookAir2-1/Jaunty