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

[Kain]

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.

 

[thcdru2k]

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

 

[Kain]

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

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?

 

[Mort]

I run 5.2 in a 10x10x10 room. I'd love to go from 5.2 to 5.2.4 with a few on the ceiling. I don't think I could even fit 15 more speakers (forget the subs) in my space. But yes, even with narrow dispersion high quality speakers I don't think you will hear meaningful separation with 20 speakers plus subs in a very small room.

Use high-quality narrow dispersion speakers and maybe 7.4.6 would be about the most I think could fit and actually contribute meaningfully.
.

 

[Oddball]

I have been moving my smaller 7.2.4 HT system across several rooms and locations. General observation is that did not really feel the benefit of additional speakers if distance between the speakers was not 70cm or more. But that would also depend on the dispersion pattern of the speakers. I think that AI is saying if they cross their paths by the time they arrive at MLP it might not be possible to localize them properly, which is the whole idea for Atmos.

 

[-Matt-]

12.2.8 immersive setup possible?

How would your bed channels be designated?

FL FR Front left & right
C RC Centre & Rear Centre
FWL FWR Front Wide left & right
SL SR Surround left & right
SBL SBR Surround Back left & right

This would leave you two short. According to the diagram below, the next pair is usually surrounds S1L and S1R ?

https://www.dolby.com/siteassets/ab...rs-setup-guide/sell-sheet-11.1.8-mounted2.pdf

Denon offers the option of a single surround back speaker (which could equate to your centre rear). However, I think it may be either SBL&SBR or single SB (RC). Don't think it will allow you to have both at the same time.

So the important question is, which processor do you intend to use?

Even the AVC-A1H only has 5ch & SB & FW for its maximum floor layout (I.e. 9.X.X channels). With single surround back it would become an 8.X.X floor layout.

 

[Kain]

I have been moving my smaller 7.2.4 HT system across several rooms and locations. General observation is that did not really feel the benefit of additional speakers if distance between the speakers was not 70cm or more. But that would also depend on the dispersion pattern of the speakers. I think that AI is saying if they cross their paths by the time they arrive at MLP it might not be possible to localize them properly, which is the whole idea for Atmos.

Thanks.

I just checked and my surround bed channels should be around 70 cm apart. Talking about the front wides, side surrounds, and second side surrounds.

 

[Kain]

How would your bed channels be designated?

FL FR Front left & right
C RC Centre & Rear Centre
FWL FWR Front Wide left & right
SL SR Surround left & right
SBL SBR Surround Back left & right

This would leave you two short. According to the diagram below, the next pair is usually surrounds S1L and S1R ?

View attachment 539149
https://www.dolby.com/siteassets/ab...rs-setup-guide/sell-sheet-11.1.8-mounted2.pdf

Denon offers the option of a single surround back speaker (which could equate to your centre rear). However, I think it may be either SBL&SBR or single SB (RC). Don't think it will allow you to have both at the same time.

So the important question is, which processor do you intend to use?

Even the AVC-A1H only has 5ch & SB & FW for its maximum floor layout (I.e. 9.X.X channels). With single surround back it would become an 8.X.X floor layout.

LCR
Front wides
Side surrounds
Second side surrounds
Rear surrounds
Rear center

Thinking of an AltitudeCI.

 

[Mort]

It's future proof anyway.

 

[Redacted]

If you have many, many speakers, and per-speaker control of time, phase, amplitude, FR, then you can literally make a room as big as you want, or even pretty much make an anechoic chamber for the purpose of hearing the the audio. Whether you like it is another matter.

 

[Kain]

It's future proof anyway.

I selected the CI due to its digital connections as all my speakers and subwoofers will be digital (Genelec).

 

[-Matt-]

LCR
Front wides
Side surrounds
Second side surrounds
Rear surrounds
Rear center

Thinking of an AltitudeCI.

Looks like Trinnov would have you covered for that.

https://kb.trinnov.com/en/knowledge-base/speaker-declaration

In their channel naming convention it would be:

L, R
C, Cs
Lw, Rw
Ls, Rs
Ls2, Rs2
Lrs, Rrs


Now let's look at the angles in the diagram I posted above. If we take the middle of each range...

Fronts: 26°
Front Wides: 60°
Surrounds: 100°
Surround 1: 122°
Surround Back: 142.5°

So between Surrounds and Surround 1s there are 22° and between Surround 1s and Surround backs there are 20.5°.

As the room is 11 feet wide (3.3m) if the speakers are installed in-wall then the distances (along the wall) between speaker centres would be:

Surround to Surround 1 = 74 cm
Surround 1 to Surround Back = 1m 12cm
(Would just meet @Oddball 's 70cm rule)

If the speaker front baffles are all 20cm from the wall, it would get a bit tight between surround and surround 1.

Surround to Surround 1 = 65 cm
Surround 1 to Surround Back = 98cm

Note that the above does not take into account the width of the front baffle. If that is 20cm then you would only have a gap of ~45cm between Surround and Surround 1 in the second calculation.

If you bring the surround backs closer to the listening position (as is normally done) then the Surround 1 to Surround Back gap would also become smaller.

 

[Kain]

Thanks.

Since all the speakers and subwoofers will be Genelec, would you recommend me using the Trinnov Optimizer or GLM?

 

[Mort]

Does glm even support that many?

Thanks.

Since all the speakers and subwoofers will be Genelec, would you recommend me using the Trinnov Optimizer or GLM?

 

[-Matt-]

Thanks.

Since all the speakers and subwoofers will be Genelec, would you recommend me using the Trinnov Optimizer or GLM?

If you are asking me, I don't have experience with either I'm afraid.

Hopefully someone who has used both can answer.

 

[Kain]

Does glm even support that many?

Didn't know there was a limit. Is there a limit to how many speakers GLM can "optimize"?

 

[Oddball]

Looks like Trinnov would have you covered for that.

https://kb.trinnov.com/en/knowledge-base/speaker-declaration

In their channel naming convention it would be:

L, R
C, Cs
Lw, Rw
Ls, Rs
Ls2, Rs2
Lrs, Rrs


Now let's look at the angles in the diagram I posted above. If we take the middle of each range...

Fronts: 26°
Front Wides: 60°
Surrounds: 100°
Surround 1: 122°
Surround Back: 142.5°

So between Surrounds and Surround 1s there are 22° and between Surround 1s and Surround backs there are 20.5°.

As the room is 11 feet wide (3.3m) if the speakers are installed in-wall then the distances (along the wall) between speaker centres would be:

Surround to Surround 1 = 74 cm
Surround 1 to Surround Back = 1m 12c
(Would just meet @Oddball 's 70cm rule)

If the speaker front baffles are all 20cm from the wall, it would get a bit tight between surround and surround 1.

Surround to Surround 1 = 65 cm
Surround 1 to Surround Back = 98cm

Note that the above does not take into account the width of the front baffle. If that is 20cm then you would only have a gap of ~45cm between Surround and Surround 1 in the second calculation.

If you bring the surround backs closer to the listening position (as is normally done) then the Surround 1 to Surround Back gap would also become smaller.

2 sets of surrounds are generally for 2 rows of seats. Otherwise probably not very useful. As you move to the back, you hear less of impact that on front/sides. Just how our hearing organs work. Obviously no harm done but not sure will be any great benefit if only 1 row of seats.

You should also give some thought to bass management. Have no first hand experience with Genelec, so can't provide any meaningful input. @Mort is the expert in that. Trinnov is obviously a top notch unit, but its bass management is not so effortless. In order to use their highest tier bass management, "wave forming" - you need a minimum of 4 subs placed in the corners. And this is the "junior" waweforming setup as the full setup would require more intrusive measures. Wave Forming will be reducing the decay in the room which could otherwise get too boomy with all the speakers in that space.

Alternative would be Storm processor if you are shooting for the high end. Storm can do the same configuration but will manage bass with Dirac ART that has less stringent sub placement requirements and otherwise works a bit different to control decay. Many happy ART users - and many threads across forums with measurements and user "reviews".

 

[Kain]

2 sets of surrounds are generally for 2 rows of seats. Otherwise probably not very useful. As you move to the back, you hear less of impact that on front/sides. Just how our hearing organs work. Obviously no harm done but not sure will be any great benefit if only 1 row of seats.

You should also give some thought to bass management. Have no first hand experience with Genelec, so can't provide any meaningful input. @Mort is the expert in that. Trinnov is obviously a top notch unit, but its bass management is not so effortless. In order to use their highest tier bass management, "wave forming" - you need a minimum of 4 subs placed in the corners. And this is the "junior" waweforming setup as the full setup would require more intrusive measures. Wave Forming will be reducing the decay in the room which could otherwise get too boomy with all the speakers in that space.

Alternative would be Storm processor if you are shooting for the high end. Storm can do the same configuration but will manage bass with Dirac ART that has less stringent sub placement requirements and otherwise works a bit different to control decay. Many happy ART users - and many threads across forums with measurements and user "reviews".

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.

 

[-Matt-]

Oops, duplicate post deleted. (See below).

 

[-Matt-]

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.

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 to the discrete channel count (i.e. the 12.2.8 description).