Originally Posted by mtbdudex
Also agree on the Auro ceiling, though I'd experiment with a single speaker vs some array....
Array would be better than a single overhead speaker.
Our human hearing perceives direction by comparing the input to both ears, taking into account phase/delays and intensity. If a sound arrives at your left ear sooner and louder than your right ear, then you'll reflexively perceive the sound towards your left. If it arrives at both ears at the same time and equally loud. then the natural reflex is to perceive it directly in front of you. But it might not be.
A single rear speaker behind the listener's centre line is psychoacoustically problematic. Since the sound from that speaker will be heard exactly the same (phase AND intensity) in both ears, it can induce momentary back-to-front reversals. Momentary because we humans make small involuntary head movements to constantly re-calibrate our surroundings. Problem is, movie sound effects can be so fleeting that by the time you recalibrate you'll already have mis-heard some of those sounds as being directly in front of you.
The solution to the reversal problem doesn't get simpler: use 2 rear speakers, spread at least 30 degrees from the centre line. This is why Dolby, DTS and THX all
recommended using 2 rear speakers to play back the mono surround-back channel of their EX/ES soundtracks (6 channels, 7 speakers). Note that it was the only
channel for which 2 speakers were recommended. Auro also changed their 13.1 layout from 6.1 mains + 6 heights + VOG
to 7.1 mains + 5 heights + VOG
(the centre-back and centre-back height are gone).
The only speaker placement worse than directly behind is directly above. Again, you'll hear those sounds equally in both ears, but those small head movements won't help this time (no matter which way you face, the sound will remain equally loud in both ears). In commercial cinemas, Auro uses 4 speakers to play back their mono VOG channel. For home, I would use at least 2 speakers, spread apart from the centre line.
2 speakers might be the worlds smallest array, but it's better than a single overhead speaker.