I could not find a resource on DIY Atoms/ DTS-X installations so I have done some research for my own system. These are my views and may be of assistance to you if you are considering an immersive system. This is not a definitive guide as I am not an expert but members can post their experience so to create a better resource for those interested. Please add to the resource list.
Recommend resources I found helpfull:
http://www.dolby.com/us/en/guide/dolby-atmos-speaker-setup/index.html
Also check out Twit.tv Home Theater Geeks episode 222, Q&A Dolby Atoms https://twit.tv/shows/home-theater-geeks/episodes/222?autostart=false
Also episode 233, Acoustics for immersive audio https://twit.tv/shows/home-theater-geeks/episodes/233?autostart=false. (This was very helpfull to me)
Speak to your preferred Hometheater electronics supplier but many have limited experience due to the relatively recent technology development of immersive home theater.
I felt that Dolby's recommendation, in relation to the in-line placement of ceiling/Atoms speakers to the front L/R, did not quite make sense due to closer proximity of the listener to Atoms speakers compared to the fronts.
I could not find any guide for DTS-X but DTS says that its system will work with what ever ceiling speaker setup you have and therefor relying on DSP in my view. I would rather then follow solid acoustic principles to give the DSP a hand and in that way getting the best that immersive technology has to offer. If you are like me, getting to the best possible sound experience is what it is all about.
My view on general considerations when planning an Atoms or DTS-X system are:
1. Ceiling or Atoms enabled speakers.
Atoms enabled is the type of speaker that sits on top of your front L/R and surrounds L/R and is aimed at the ceiling which then reflects of the ceiling back down to the listener. Ceiling speaker is mounted on the ceiling playing sound directly down at the listener.
IMHO, Atoms enabled, is a compromise and should only be used if you cannot place speakers in/on your ceiling or if you are looking for the easiest install.
My 5 main reasons for preferring ceiling speakers were:
a) None of the commercial Atoms theaters use Atoms enabled speakers.
b) The sound engineers design immersive object placement with precision within a actual speaker array located in ceiling. If they design the audio in that way, it makes sense to play it back as designed or their reference.
c) Comparative professional reviews clearly resulted in ceiling speakers having better definition, coherence and high frequency clarity. Makes sense as high frequency is very directional.
d) Enabled setups seems to have a narrower sweetspot. I have a dedicated hometheather room with multiple seats so I wanted an effective result over most seating positions.
e) I have acoustic ceiling defusers and absorption panels in my hometheater room which would all but destroy the Atoms enabled speaker effectiveness. It stands to reason that you would require a fairly reflective ceiling surface if you are considering Atoms Enabled speakers.
2. Speaker or driver type
A lot of AV enthusiasts in the USA favour concentric design speakers such as Kef, Tannoy or Monitor audio as dispersion is usually wider than traditionally designed speaker drivers. That makes sense to me for flexible placement, better coverage and sound stage when considering potentially close listener proximity to speakers and the limited angle adjustment that would improve staging.
Other issues that I considerred in respect of speaker selection were:
- voice matching. Ideally all speakers in you AV setup should be voice matched but with limited speakers available, choices were limited. So at least match your Atoms/ceiling speakers. There are many av enthusiasts that did not voice match the Atoms speakers to the existing brand used. They reported that they did not experience a break in the sound field or cocoon by using other speaker brands. I can confirm that I followed this route and integration is flawless.
- Power or SPL considerations
The ceiling speakers should be able to keep up with the SPL produced by your system at your reference level. Typically I would assume that the SPL capability of you selected Atoms speakers could be lower than the main front speakers and would typically be similar to your surrounds as they are closer to the listener than the fronts and centre.
- ceiling speakers need to be full range. I favor a speaker that is able to produce bass. I know sub bass is largely non directional but higher frequency bass is less so. This is my experience but you can cut/redirect all bass to your sub/s. It is a question of your own preferences. I have fairly serious subs and still prefer some bass from all speakers.
- Atoms enabled speakers should not be installed on ceiling. This sounds obvious but with limited Atoms speakers being manufactured currently, I considerred the option. I looked at the Kef R50 for example. These are made to be a narrow dispersion or focused but widen when reflecting from the ceiling. Using these to mount on ceiling would reduce the soundstage and create hotspots of sound and would not integrate as well.
- Narrow dispersion speakers should be aimed towards the listening area. See Home Theater Geeks ep 233. (I am a fan of Anthony who is a Master Acoustician)
- How many
If space allows within the degree specification, go for 4. Also see Sound and Vision magazine's, Atoms vs Atoms enabled review. http://www.soundandvision.com/content/dolby-atmos-vs-dolby-atmos.
4 creates a better flow front to back. If you have a 7.x. system, using only 2 Atoms speakers could give a great result as the back surrounds will help with overhead flow. My recommendation is 4 for a 5.x system.
- Size
I chose 8 inch ceiling speakers because of my preferences and available space. Now having lived with the the system for a while, I can say that smaller would have been 95% as effective. There is a lot happening when the movies get going and you will soon forget the technical choices. I isolated the Atoms speakers by switching off external amplification and found that small satelite speakers would function pretty well with regard to dynamic range most of the time but consider the other factors set out in this document. Most of the time the sounds that emanate from these speakers is a not full range but subtleties would be lost with lower quality speakers. The reference scenes however was dynamic and larger in my view would be better.
- Placement
Check out the Dolby recommendations but roughly spoken, your fronts should be just over mid way between your fronts and your first seeting position. The rears should also be about midway between the first seeting position and your surround backs. Ideally, just before your second row seating position. If you have opted for 2 Atoms speakers, the placement should be just before the 1st seeting position.
In terms of required height, Dolby recommends 2x ear level plus. So if ear level is 80 cm, the ceiling speakers should be 1.6 m above ear level. There is a risk of hot spotting or the ceiling speakers over powering other speaker when too close to the listener but the effect of which can be counterred with wider dispersion speakers, such as concentric designs. My back row seats are raised and then I have a bulkhead/ suspended ceiling that combine to drop my setup below the ratio of 2x for my rear ceiling speakers. My front ceiling speakers are above the minimum 2x ratio. I really wanted to go for 4 and all worked out well with my choice. I settled on the adjustable concentric ceiling speakers. Note that a multi listener setup procedure will also help prevent hot spotting for those seats closer to the Atoms speakers.
- Surrounds
It was interesting to note that the height of the traditional surrounds are recommended by some to be around 1.2m from floor. This is lower than the design for none Atoms/DTS-X systems historically. So I dropped mine slightly. The higher positions were recommended to give some kind of an overhead experience but with Atoms/DTS-X this is no longer a consideration. Lowering the surrounds give better channel separation.
How wide
I did not placed my ceiling speakers per the Dolby recommendation in terms of width (inline with your fronts) but followed Anthony Grimani's recommendation and located mine about 35 cm towards the centre. I have also seen this layout at a major wholesaler in Jhb. In smaller rooms or rooms where the fronts are not wide appart, I would have followed the Dolby guideline. My fronts are wide due to the size screen and my preferences for stereo.
Bi/Tri/Di polar
In short, these surround speakers is not recommended for Atoms speakers as a diffused sound is not what you want for your Atoms/DTS-X speakers for the same reasons you do not use these for centre or fronts IE for imaging.
Toe/angle
I angled my ceiling speakers towards the main seating position (similar to my fronts) per my preferences and recommended by Anthony Grimani.
3. AVR
Ensure that your preferred AVR has sufficient channels for 2 or 4 Atoms speaker setups. Ensure that you get an AVR that can decode DTS-X and Dolby Atoms. Setup is critical so take your time to run the auto setup to its full extent but carefully check the results. Sometimes worth doing it twice and then tweaking to your own preferences.
My impressions of the technology
I recon its here to stay. I am impressed and loved the effect in closing holes in the sound field around you, although I did not feel that I had holes before. Immersive is an accurate description and a welcome dimension.
Find a review list of available SA Dolby Atoms movies here
https://www.avforums.com/article/top-ten-dolby-atmos-blu-rays.11768
Recommend resources I found helpfull:
http://www.dolby.com/us/en/guide/dolby-atmos-speaker-setup/index.html
Also check out Twit.tv Home Theater Geeks episode 222, Q&A Dolby Atoms https://twit.tv/shows/home-theater-geeks/episodes/222?autostart=false
Also episode 233, Acoustics for immersive audio https://twit.tv/shows/home-theater-geeks/episodes/233?autostart=false. (This was very helpfull to me)
Speak to your preferred Hometheater electronics supplier but many have limited experience due to the relatively recent technology development of immersive home theater.
I felt that Dolby's recommendation, in relation to the in-line placement of ceiling/Atoms speakers to the front L/R, did not quite make sense due to closer proximity of the listener to Atoms speakers compared to the fronts.
I could not find any guide for DTS-X but DTS says that its system will work with what ever ceiling speaker setup you have and therefor relying on DSP in my view. I would rather then follow solid acoustic principles to give the DSP a hand and in that way getting the best that immersive technology has to offer. If you are like me, getting to the best possible sound experience is what it is all about.
My view on general considerations when planning an Atoms or DTS-X system are:
1. Ceiling or Atoms enabled speakers.
Atoms enabled is the type of speaker that sits on top of your front L/R and surrounds L/R and is aimed at the ceiling which then reflects of the ceiling back down to the listener. Ceiling speaker is mounted on the ceiling playing sound directly down at the listener.
IMHO, Atoms enabled, is a compromise and should only be used if you cannot place speakers in/on your ceiling or if you are looking for the easiest install.
My 5 main reasons for preferring ceiling speakers were:
a) None of the commercial Atoms theaters use Atoms enabled speakers.
b) The sound engineers design immersive object placement with precision within a actual speaker array located in ceiling. If they design the audio in that way, it makes sense to play it back as designed or their reference.
c) Comparative professional reviews clearly resulted in ceiling speakers having better definition, coherence and high frequency clarity. Makes sense as high frequency is very directional.
d) Enabled setups seems to have a narrower sweetspot. I have a dedicated hometheather room with multiple seats so I wanted an effective result over most seating positions.
e) I have acoustic ceiling defusers and absorption panels in my hometheater room which would all but destroy the Atoms enabled speaker effectiveness. It stands to reason that you would require a fairly reflective ceiling surface if you are considering Atoms Enabled speakers.
2. Speaker or driver type
A lot of AV enthusiasts in the USA favour concentric design speakers such as Kef, Tannoy or Monitor audio as dispersion is usually wider than traditionally designed speaker drivers. That makes sense to me for flexible placement, better coverage and sound stage when considering potentially close listener proximity to speakers and the limited angle adjustment that would improve staging.
Other issues that I considerred in respect of speaker selection were:
- voice matching. Ideally all speakers in you AV setup should be voice matched but with limited speakers available, choices were limited. So at least match your Atoms/ceiling speakers. There are many av enthusiasts that did not voice match the Atoms speakers to the existing brand used. They reported that they did not experience a break in the sound field or cocoon by using other speaker brands. I can confirm that I followed this route and integration is flawless.
- Power or SPL considerations
The ceiling speakers should be able to keep up with the SPL produced by your system at your reference level. Typically I would assume that the SPL capability of you selected Atoms speakers could be lower than the main front speakers and would typically be similar to your surrounds as they are closer to the listener than the fronts and centre.
- ceiling speakers need to be full range. I favor a speaker that is able to produce bass. I know sub bass is largely non directional but higher frequency bass is less so. This is my experience but you can cut/redirect all bass to your sub/s. It is a question of your own preferences. I have fairly serious subs and still prefer some bass from all speakers.
- Atoms enabled speakers should not be installed on ceiling. This sounds obvious but with limited Atoms speakers being manufactured currently, I considerred the option. I looked at the Kef R50 for example. These are made to be a narrow dispersion or focused but widen when reflecting from the ceiling. Using these to mount on ceiling would reduce the soundstage and create hotspots of sound and would not integrate as well.
- Narrow dispersion speakers should be aimed towards the listening area. See Home Theater Geeks ep 233. (I am a fan of Anthony who is a Master Acoustician)
- How many
If space allows within the degree specification, go for 4. Also see Sound and Vision magazine's, Atoms vs Atoms enabled review. http://www.soundandvision.com/content/dolby-atmos-vs-dolby-atmos.
4 creates a better flow front to back. If you have a 7.x. system, using only 2 Atoms speakers could give a great result as the back surrounds will help with overhead flow. My recommendation is 4 for a 5.x system.
- Size
I chose 8 inch ceiling speakers because of my preferences and available space. Now having lived with the the system for a while, I can say that smaller would have been 95% as effective. There is a lot happening when the movies get going and you will soon forget the technical choices. I isolated the Atoms speakers by switching off external amplification and found that small satelite speakers would function pretty well with regard to dynamic range most of the time but consider the other factors set out in this document. Most of the time the sounds that emanate from these speakers is a not full range but subtleties would be lost with lower quality speakers. The reference scenes however was dynamic and larger in my view would be better.
- Placement
Check out the Dolby recommendations but roughly spoken, your fronts should be just over mid way between your fronts and your first seeting position. The rears should also be about midway between the first seeting position and your surround backs. Ideally, just before your second row seating position. If you have opted for 2 Atoms speakers, the placement should be just before the 1st seeting position.
In terms of required height, Dolby recommends 2x ear level plus. So if ear level is 80 cm, the ceiling speakers should be 1.6 m above ear level. There is a risk of hot spotting or the ceiling speakers over powering other speaker when too close to the listener but the effect of which can be counterred with wider dispersion speakers, such as concentric designs. My back row seats are raised and then I have a bulkhead/ suspended ceiling that combine to drop my setup below the ratio of 2x for my rear ceiling speakers. My front ceiling speakers are above the minimum 2x ratio. I really wanted to go for 4 and all worked out well with my choice. I settled on the adjustable concentric ceiling speakers. Note that a multi listener setup procedure will also help prevent hot spotting for those seats closer to the Atoms speakers.
- Surrounds
It was interesting to note that the height of the traditional surrounds are recommended by some to be around 1.2m from floor. This is lower than the design for none Atoms/DTS-X systems historically. So I dropped mine slightly. The higher positions were recommended to give some kind of an overhead experience but with Atoms/DTS-X this is no longer a consideration. Lowering the surrounds give better channel separation.
How wide
I did not placed my ceiling speakers per the Dolby recommendation in terms of width (inline with your fronts) but followed Anthony Grimani's recommendation and located mine about 35 cm towards the centre. I have also seen this layout at a major wholesaler in Jhb. In smaller rooms or rooms where the fronts are not wide appart, I would have followed the Dolby guideline. My fronts are wide due to the size screen and my preferences for stereo.
Bi/Tri/Di polar
In short, these surround speakers is not recommended for Atoms speakers as a diffused sound is not what you want for your Atoms/DTS-X speakers for the same reasons you do not use these for centre or fronts IE for imaging.
Toe/angle
I angled my ceiling speakers towards the main seating position (similar to my fronts) per my preferences and recommended by Anthony Grimani.
3. AVR
Ensure that your preferred AVR has sufficient channels for 2 or 4 Atoms speaker setups. Ensure that you get an AVR that can decode DTS-X and Dolby Atoms. Setup is critical so take your time to run the auto setup to its full extent but carefully check the results. Sometimes worth doing it twice and then tweaking to your own preferences.
My impressions of the technology
I recon its here to stay. I am impressed and loved the effect in closing holes in the sound field around you, although I did not feel that I had holes before. Immersive is an accurate description and a welcome dimension.
Find a review list of available SA Dolby Atoms movies here
https://www.avforums.com/article/top-ten-dolby-atmos-blu-rays.11768
