Comb filtering sounds a little like fluttering when you hear a single musical note played thru two sources... you can hear the note 'flutter' as one note differs slightly than the other.
In home theater, the sound is dynamic so it would be difficult to determine that by ear, but mainly the filtering would cause some frequencies to be canceled and other frequencies to be 'summed' or heightened. I think it's probably easier to see with a graph than it would be to hear during play back.
At any rate, it never hurts to give it a try if your amp can handle it.