I just played around with this and here’s what I came up with:
Yes, I found a shortcut, but it not the SHORTEST cut.
Select on an audio clip you’d like to solo and press control-S.
This pushes the green audible buttons for every track except the one with the clip you just selected.
So the mute and solo buttons are not really in the equation and you can only do this for a clip at a time, rather than a whole track at a time.
Basically it’s the opposite of selecting a clip and pushing control-B (which is the same as right clicking on a clip and selecting Clip Enable).
If anyone out there knows of a mute and solo keyboard shortcut I’d be curious to hear about it.
Until then, the good news is that mute and solo are just a mouse click away.
Cheers,
Ari Feldman
Apple Certified Trainer