Tom said:

What do you know about ceiling heights, Dave? I'm building a house
and planning a home theater in the basement. I'm struggling
with whether to spend extra for a 10 ft basement. The room is 12 ft
wide and will be from 17 to 22 ft long.

My calculations-on-a-napkin tell me you probably want 13 feet for best
results. So I'd say 10 is much better than 8. You could also consider a
sunken pit at one end.