12.2.8 immersive setup possible in a 12 feet long x 11 feet wide x 9.5 feet high room?

[Oddball]

Thanks. I'll look into WaveForming and its requirements.

By the way, 2 sets of surrounds even with 1 seat or 1 row of seats will help in the panning of Atmos objects, no? Atmos objects (at least with well designed Atmos mixes) use as many speakers as you have available. So, even with 1 seat and many speakers surrounding the seat will provide more "spatial resolution" with well designed Atmos mixes. At least that is my reasoning for have a high channel count.

As I said - no harm from 2 sets of side surrounds. But as you move from front/side to back, we just don't hear the sounds so clearly from that angle. Our ears are not made that way. If I had to drop a set of speakers from my larger HT, they would be the back surrounds. They definitely contribute to the overall resolution, but not nearly as other speakers in the system.

Best thing about Trinnov is its mic and raw data it gets that appears to be in excess of what other AVPs can get. But for your particular room, I actually think ART would do better. Do some reading on what ART does. It is a unique concept that works based on virtual channels and collaboration of all speakers engaged in support (you chose the pattern). It uses UMIC or similar mics, so probably not as good as Optimizer above ART range, but it you don't sort out the bass, it might be of little consequence as what you will likely hear above that as it will be muddied and concealed.

 

[Oddball]

Again, that really depends on the capabilities of the processor. With Trinnov, yes probably it will be able to map the Atmos objects to any available channels. (Although how this is done is proprietary information). In that case the Surround and Surround 1 speakers may receive slightly different signals.

However, that may not be true of all processors or configurations. I think sometimes the Surround 1 signal could be an exact duplicate of the surround signal. In that case I'd consider the surrounds and surround 1s to be a single pair of matrixed speakers. (You could achieve the same with a Y-splitter cable).

As was commented above, simple matrixing (duplicating the same signal to many speakers) can be an advantage in covering a large seating area. However, I don't really think those additional speakers should add towas the discrete channel count (i.e. the 12.2.8 description).

Trinnov would not do exact duplicate for second set of surrounds. If I recall correctly, D&M would do that (although never tried), which is not good. It introduces combing so definitively not optimal.

 

[dannut]

I asked the usual AI bots like ChatGPT and Gemini and they both said this would be a bad idea as it would result in a "blurry wall of sound" with speakers so close together. 12.2.8 is basically a 11.2.8 setup with a rear center speaker. Is this far too many speakers for this room size or can it work with some effort put into room treatments and calibration? There is someone on AVS that has a 9.1.6 setup in a 12 feet x 12 feet room with excellent results.

LLM bots have a GIGO pipeline. Did they scrape the info from the internet? There you go.

You have multiple issues compounding your setup. First is the content production side (still mostly a legacy channel based nightmare, no dedicated ambient channel output from rendering engine, bad decorrelation, bad panning techniques etc... so much depends on the 'artist' instead of engineering away the shortcomings by proper solutions). OTOH you have your local acoustic issues: how you deal with excess early reflections? How you deal with modal issues? Boundary interference? How you deal with the too short direct radiating speaker distances?

Starting from first principles, I wouldn't fixate on channel count at all at first stage. Little background on soundfield reconstruction - an array of 5+5 speakers can adequately cover perceptually the full hemisphere with proper production techniques. On multiple listening positions! With commercial content it's different. That means for direct sound you need to have speakers behind the pinna shadow (135deg+), on the sides (80-110deg) and the usual front 3 minimum. To make it easier for the mostly subpar panning engine and your short listening distances you can go denser. For indirect sound the speakers need to be ideally couple meters from the listening distance. As you are using direct radiating speakers they need to be at least 1.5-2m from the listening area. How do you do it for multiple listening positions?

And then you have content idiosyncrasies - some 'ATMOS' content is mixed on a fixed 7.1.4 channel based distribution. No objects. Some only for 2 upper layer speakers. How you deal with those without hot-spotting overhead?

 

[Kain]

LLM bots have a GIGO pipeline. Did they scrape the info from the internet? There you go.

You have multiple issues compounding your setup. First is the content production side (still mostly a legacy channel based nightmare, no dedicated ambient channel output from rendering engine, bad decorrelation, bad panning techniques etc... so much depends on the 'artist' instead of engineering away the shortcomings by proper solutions). OTOH you have your local acoustic issues: how you deal with excess early reflections? How you deal with modal issues? Boundary interference? How you deal with the too short direct radiating speaker distances?

Starting from first principles, I wouldn't fixate on channel count at all at first stage. Little background on soundfield reconstruction - an array of 5+5 speakers can adequately cover perceptually the full hemisphere with proper production techniques. On multiple listening positions! With commercial content it's different. That means for direct sound you need to have speakers behind the pinna shadow (135deg+), on the sides (80-110deg) and the usual front 3 minimum. To make it easier for the mostly subpar panning engine and your short listening distances you can go denser. For indirect sound the speakers need to be ideally couple meters from the listening distance. As you are using direct radiating speakers they need to be at least 1.5-2m from the listening area. How do you do it for multiple listening positions?

And then you have content idiosyncrasies - some 'ATMOS' content is mixed on a fixed 7.1.4 channel based distribution. No objects. Some only for 2 upper layer speakers. How you deal with those without hot-spotting overhead?

Thanks.

I am not worried around the content production side of things and do know that most modern Atmos mixes are not well designed. However, there are some amazing mixes out there that use as many channels/speakers you have available and that is what I am designing for. I am not designing based on the "average" standard of modern mixes but the best of them. I don't mind if poorly designed Atmos mixes don't use all my speakers as long as the good ones do.

There will be only one seat/listening position in this setup. There will be no multiple listening positions, just one. Closest speakers (probably the two side surrounds) will be around 1.2 meters away. I know that is pretty close but I guess that is just something I'll have to deal with. Regardless of channel/speaker count, the side surrounds will be this close as I will have side surrounds even with a fewer speaker setup. All the additional speakers will be farther away.

On your last point, for Atmos content mixed on a fixed 7.1.4 channel based distribution, it will use the two middle overheads in a x.x.6 setup but four overheads in a x.x.8 setup. Again, I am not worried about poor mixes not using all the speakers as long as the best mixes do.

 

[BJL]

Ignoring the subwoofer count, do you think 12.x.8 would be doable in this room size? Will there be a "clear separation" between the speakers or will it all blur into a messy "wall of sound" like AI says?

If you use Dirac ART (preferably), or even just Dirac Live, your audio will sound just fine. You do not need multiple subs if you are using ART, and depending upon the usable frequency range of your main speakers, you may not need any subs.

 

[dannut]

Closest speakers (probably the two side surrounds) will be around 1.2 meters away. I know that is pretty close but I guess that is just something I'll have to deal with. Regardless of channel/speaker count, the side surrounds will be this close as I will have side surrounds even with a fewer speaker setup.

Your best bet would still be for direct sound to stick with Dolby recommendations wrt to angles and take account the 1/r sound pressure falloff. Involuntary head movements gets to annoyingly unmask 'nearfield' speakers due this. You could mitigate it with array speakers, but besides some JBL stuff it's all custom. If only the content would be proper immersive, your renderer could have taken it to account. But no.

You could deviate from reference angles (skews the panning) and try to put the sides either at 80- or 110+ degrees to somehow mitigate your issues (intensity differences and HRTF changes at small distance). Listen for the results while making slight head movements - if this unmasks the physical speaker location, the other stuff doesn't matter. You are out of the illusion. And if you learn it, then it gets difficult to ignore. Such is perception. That also means you have the room acoustics under control first. Then you can go crazy with the channel count. Is this a concrete/brick walled room? Good luck.

 

[Sal1950]

I asked the usual AI bots like ChatGPT and Gemini and they both said this would be a bad idea as it would result in a "blurry wall of sound" with speakers so close together. 12.2.8 is basically a 11.2.8 setup with a rear center speaker.

A lot has been said here already, much opinion based as is mine.
I do believe AI got it right in regards to the bed speakers, inside of 12' I think it would be best sticking to a 10 speaker bed with 3 surrounds per side to avoid blurring or confusion of side imaging. I know you said the speaker choice are Genelec actives, wonderful, still I highly recommend that all bed speakers be kept identical, most important with this many.
As to the overheads, having that many will allow you the ability to switch arrangements for Atmos, Auro, or to taste.. I'm not sure I can see a situation where having all 8 active at the same time would have any advantages but hard to say. For pure Atmos I believe a 6 speaker per Dolby recommendations would be sufficient. JMHO.
Good luck with this awesome immersive system !

 

[Descartes]

9.4.6 would be nice. Four subs to attack the axial modes

Yep

 

[Kain]

Your best bet would still be for direct sound to stick with Dolby recommendations wrt to angles and take account the 1/r sound pressure falloff. Involuntary head movements gets to annoyingly unmask 'nearfield' speakers due this. You could mitigate it with array speakers, but besides some JBL stuff it's all custom. If only the content would be proper immersive, your renderer could have taken it to account. But no.

You could deviate from reference angles (skews the panning) and try to put the sides either at 80- or 110+ degrees to somehow mitigate your issues (intensity differences and HRTF changes at small distance). Listen for the results while making slight head movements - if this unmasks the physical speaker location, the other stuff doesn't matter. You are out of the illusion. And if you learn it, then it gets difficult to ignore. Such is perception. That also means you have the room acoustics under control first. Then you can go crazy with the channel count. Is this a concrete/brick walled room? Good luck.

I will be following Dolby's recommendations regarding angles as closely as possible. Also, the room is concrete.

 

[Kain]

I highly recommend that all bed speakers be kept identical, most important with this many.

Will having the 8361A as LCR and the 8351B as all other channels including overhead count as identical?

 

[Mort]

Will having the 8361A as LCR and the 8351B as all other channels including overhead count as identical?

Yes 100% but it's overkill

 

[Sal1950]

Will having the 8361A as LCR and the 8351B as all other channels including overhead count as identical?

Knowing Genelec probably so, those 2 are very close in spec and pricing.
But if you chose to go with a 10 speaker bed over the 12, the cost savings would pay for 8361s all around and remove any doubt. JMHO
Dude, you looking to put together a world class immersive audio system here, one which most of us could only dream about. In the end whatever decisions you
make and are most comfortable with will be the most important. Mostly we all hear what we believe in.

 

[dannut]

Also, the room is concrete.

A new build or retrofit? Regular living space or purpose built? (is soft furniture in there, bookcases etc.)

Neither 'room correction' product is going to do much in this case - the modal issues are brought up above their 'design' frequency'. Luck is on your side, that the decorrelated ambiance in multichannel acts like a broadband Geddes/Welti multisub solution. But the direct sound doesn't have that.

Problems are in the 80-200Hz modal issues compounded by SBIR. An elegant solution is to let e.g. MIMO Dirac ART handle modal issues up as high as possible and use pressure based absorbers in combination with that. Or put deep velocity absorbers everywhere. Face them with plastic where appropriate. Otherwise you will get too much high frequency absorption, too little low freq. EQ the rest - for a singleseater it works kinda ok when the corrected sound wavelength is not short.

 

[Descartes]

Will having the 8361A as LCR and the 8351B as all other channels including overhead count as identical?

Just use 8351B all around that’s all! Would be fantastic but never been able to get discounts on them unfortunately and I refuse to pay full price especially because I know dealers cost!

 

[Kain]

A new build or retrofit? Regular living space or purpose built? (is soft furniture in there, bookcases etc.)

Neither 'room correction' product is going to do much in this case - the modal issues are brought up above their 'design' frequency'. Luck is on your side, that the decorrelated ambiance in multichannel acts like a broadband Geddes/Welti multisub solution. But the direct sound doesn't have that.

Problems are in the 80-200Hz modal issues compounded by SBIR. An elegant solution is to let e.g. MIMO Dirac ART handle modal issues up as high as possible and use pressure based absorbers in combination with that. Or put deep velocity absorbers everywhere. Face them with plastic where appropriate. Otherwise you will get too much high frequency absorption, too little low freq. EQ the rest - for a singleseater it works kinda ok when the corrected sound wavelength is not short.

It is a spare bedroom that will be used for the dedicated home theater/media room. My gaming PC will also be hooked up to the setup. Still trying to decide if I want a comfy chair + lap desk or a proper desk + chair for the keyboard and mouse.

 

[dannut]

Either a minimal lap desk or an angled large desk. You are pouring so much money in it already with your speaker choice, better to account for every acoustical issue you are facing. What do you mean by 'comfy chair'? If I think what you mean then a 'proper desk + chair' (Steelcase/Herman Miller style) would have lesser issues.

 

[Kain]

Either a minimal lap desk or an angled large desk. You are pouring so much money in it already with your speaker choice, better to account for every acoustical issue you are facing. What do you mean by 'comfy chair'? If I think what you mean then a 'proper desk + chair' (Steelcase/Herman Miller style) would have lesser issues.

Yeah, basically meant by a non-office type chair when I said "comfy chair" vs. for proper desk + chair.

 

[napfkuchen]

Just use 8351B all around that’s all! Would be fantastic but never been able to get discounts on them unfortunately and I refuse to pay full price especially because I know dealers cost!

Don't know where you are located ... Bax Music (Netherlands) offers EU delivery and regularly has good offers. Ordered a 8351B for 3250 €.