Can anyone provide a quote from Dolby, one available online, that states tweeters should be aimed?
Here's what I found:
Dolby Atmos Home Theater Installation Guidelines
If the chosen overhead speakers have a wide dispersion pattern (approximately 45 degrees from the acoustical reference axis over the audio band from 100 Hz to 10 kHz or wider), then speakers may be mounted facing directly downward. For speakers with narrower dispersion patterns, those with aimable or angled elements should be angled toward the primary listening position.
Unfortunately it doesn't seem to say "plus or minus what". It does mention that expected ceiling height is 2-3x standard ear height, or ~8-12 feet, which I imagine relatively few HT rooms actually allow.
It seems to be a function of ceiling height among other things... if your ceiling is high enough then there's a reasonable chance you could find speakers with sufficiently wide dispersion to cover the listening positions without aiming, but in most rooms you are going to end up wanting to aim. Seems a lot like the "QS or directional rear" question where the answer is clearly "it depends". I never know what to put for title
BTW I am also still enjoying my Sanyo 720p and have no plans to upgrade until I use up some more of the bulb life. Haven't even used up the first bulb yet and still have the spare to think about...
Since my HT room has a vaulted ceiling with 45 degree angles going up to a point it occurred to me that I could hang the ceiling speakers from wires and not have to put any holes in walls/ceiling (weiling ?)...