I'm still in the planning stages of converting my current audio-only room to an Atmos audio-visual system.
20' wide x 32' long, with the screen to be on the 20' wall.
Listening position about 15' from that front wall.
Walls about 8 1/2" high at the sides, but with a vaulted ceiling 12' 6" high, running along the length of the room, with 3 horizontal beams across the width, placed at 8', 16', 24' from the front, respectively.
I have a 3D Model using free software from Sweet Home 3D
, which is the best way of seeing the room, placement of speakers, etc. The file containing my specs can be downloaded here
. This is the best way to visualize the room.
(And on this subject, this is perhaps an ideal way to design and share specs for these rooms, as verbal descriptions, and even 2D drawings can be imprecise and cumbersome.)
I will have Top Front and Top Rear Atmos speakers (most likely Polk OWM5's) mounted from the beam 8' from the front, and the beam 24' from the front (7' in front of the MLP and 9' in back of the MLP), at a height of about 102" from the floor, 60" above the ear position of 42". If my calculations are right, that gives me 30 degree TF (30-55 recommended) and 154 degrees TR (125-150 recommended). Reasonably close to the recommended angles.
I have no flexibility on moving the distance of the speakers from front to back, but can put them anywhere I want on the beams, in terms of the side-to-side dimension.
First question: is there any recommendation on horizontal placement of the Atmos speakers, relative to other speakers in the base level, or is it just a matter of getting the angles as close as possible to Dolby recommendations?
For Front Right/Left, I have fairly massive Duntech Sovereigns (with a JBL LSR-308 Powered Studio Monitor for the Center Channel). The horizontal position of these gives me about 28 degrees (recommended is 22 to 30) from MLP.
For the 4 Dolby Surrounds, I have older Wharfedale Diamond II's. The side ones can be readily placed at ear-height (42"), and pretty much at 90 degrees to the MLP.
The Rear Surrounds are more problematic due to room/furniture limitations. I can have them at the same width of the Duntech's, but much higher in in the room (86" from the floor, about 1 foot from the back wall).
Or I can put them at the same 42" ear-height as the sides, and about 2 feet from the back wall, but these would be closer to the center than the Duntech's (6' from the side walls for the surrounds, vs 4' from the walls for the Duntech's. This would give me about 165 degree placement (recommended 135 to 150).
Second Question: which of these 2 rear Dolby speaker configurations would be preferred: the higher, wider, closer to the back wall option, or the lower, narrower, a little further from the back wall configuration?
Third Question: In either case, the Dolby rears are about 15 feet back from the MLP. How much will this impact the overall experience?
Any other recommendations on how to achieve a better result is always welcome. Like they say, measure twice cut once.
Here are some 2D images if you don't want to deal with the 3D application: