Originally Posted by LucidLight
They are about 2 feet behind the main listening position (I could not go farther back do to AC ductwork). I talked to support at Definitive Technology and they firmly stated re-purposing the RSS ii's as the rear ceiling Dolby Atmos was not recommended. So I had given up on the that idea, plus the fact I spent way too much on them to just use them in that manner.
I was going to put the atmos speakers about midway between front and rear sound speakers, since a have seating wrapped all away around the room to about 3 feet from the fronts. So that is why I was looking for a very large dispersion angle. Would this not be a good strategy? So far I have yet to see a enclosed coaxial speaker with 90+ angle. Does any one knows of one?
Well, you will get some panning effects by simply adding Atmos speakers in the middle of the ceiling, but you won't get a proper 3D sound field. I wouldn't recommend it. Having both Atmos and surround speakers in ceiling would be like placing surround speakers 4 feet in front of your listening position. You'll still get sounds panning to them, but it's not going to place the sounds where they were intended to be. I'm the kind of person who believes in doing things the right way, even if it means waiting an extra year or two to save up for it.
The RSS is a great speaker, but Dolby does recommend direct radiating speakers for Atmos since the intent is to place sounds as precisely as possible so I'm sure that's why Definitive tech support advised against using it. The RSS is obviously bipolar and not aim-able. While it's not ideal, I still don't think it would be terrible as an Atmos speaker. Having said that...
I know the thought of replacing the RSS speakers is a tough pill to swallow, but if you really want the ultimate Atmos experience it would be for the best. Assuming the grills haven't been painted, you'd be able to get a decent amount for them in the avsforum classifieds, eBay or wherever. You could place four coaxials in ceiling for Atmos. You could pick up some Def Tech Studio Monitors and place them on speaker stands for the ear level surrounds. You could also do Mythos or ProMonitor speakers on stands or on wall. The RSS holes as well as any other holes that would need to be cut to fish new wires for Atmos can be seamlessly patched by a good drywall guy.
I posted the Dolby 5.1.2 diagram before. Here is the 5.1.4 diagram. As it shows, you ideally want the ear level surrounds to be a bit behind the seating and further back than the Top Rear Atmos speakers. If this won't work in your room, it might be better to settle for a 5.1.2 layout. In that case you would put the Atmos speakers a bit in front of the Main Listening Position and the surrounds would be even with or a bit behind the seating if the room allows.
You really want to place your speakers so that you are getting the best experience possible in the main seats opposite the TV. The listening experience is going to be a bit compromised for the side seating no matter how wide the dispersion characteristics of your speakers.
One other thing you could consider is placing up-firing Atmos modules on your little tables in front of the windows instead of in ceiling Atmos speakers. The Definitive A90 is specifically designed to mount on top of Definitive towers, but there are models from other brands that will work as free standing modules such as the Klipsch RP-140SA
. There are a some other brands you can check out on this Dolby page
. (Use the drop down menu to show speakers only.) While I do think that in ceiling speakers are more convincing, bouncing sound off the ceiling with Atmos modules would probably provide you with a pretty wide coverage area. If you were to do this I'd still recommend that you replace the RSS speakers with ear level surrounds.
You can read through the entire Dolby Atmos Installation Guide
if you like.
One other thing. In my opinion, Atmos speakers should be of the same quality as your ear level speakers. While it is currently true that most Atmos mixes are only making use of Atmos speakers for big action sequences, I think in the near future it will be more common for engineers to mix atmospheric background sounds into them. They are likely to become as active as ear level surround speakers. Also, with Dolby Surround upmixing, the Atmos speakers will be extremely active when playing back 5.1 or 7.1 content. You want them to be able to play clean, loud and distortion free if you like to crank the volume near reference level on occasion. That doesn't necessarily mean super expensive. For instance, the RSL seems to be a well made bargain. However, I'd never settle for something any cheaper than that.
A coaxial speaker with an enclosure and 90+ degree dispersion is a tall order. JBL has some options in their pro line that might fit the bill. However, they were designed with distributed audio in mind, not Atmos. They have a phone number right at the top of their home page. You could give them a call and see what they have to say. jblpro.com