When designing my HT I was aiming for a 11’ finished ceiling for modal and large screen reasons. After many compromises I will end up with something like 8’ 10”. Bass wise I’m fairly sure it’s going to be fine given 4 subs to even things out but it’s going to be a bit tight screen wise. No problems with imaging ... right now the 1/2 finished height is 9’ 2” ... cement floor and plywood walls and ceiling.