Feedback on L-shaped room plan: 3x Genelec 8341A, dual mid-wall subs, front false wall with treatment, and ceiling cloud?

[theshade]

I'm figuring out the acoustic build for a dual-purpose living room home theater and photography area. The room is an L-shape, and I am positioning my setup to fire down the long axis. The LCR will be on the short wall (330cm wide) of the long leg of the "L", firing toward the open kitchen area on short leg of the "L".

I will be measuring and applying EQ via REW. My goal is to avoid creating an unnaturally dead or very live room.

Here is my current build plan and the specific areas where I need objective advice:

1. Equipment

• LCR: 3x Genelec 8341As.
• Subwoofers: 2x SVS PC-2000 Pro cylinders. These will be placed at the mid-wall points of the left and right long walls.

2. False Wall with Xy 8k AT projector screen with rockwool and the genelecs inside

• I am building a shallow, open timber false wall (11-12" deep) across the short front wall to hold an acoustically transparent projection screen.
• I am leaving the area directly around and behind the speakers completely open except for some black felt or black thin foam to avoid using a black backing for the projection screen.
• I am stacking 8 inches of high-density rockwool (50kg/m³) on the top portion (above the monitors) and the bottom portion (around the speaker stands). The entire structure and the rockwool will be wrapped in black AT fabric except the part where the AT screen will hang on.

3. Side Walls & Rear Wall (Untreated)

• Side Walls: I am leaving the long side walls completely bare (just painted with limewash). I need the clean walls to also act as photography backdrops, and I am leaning on Dr. Floyd Toole’s research regarding non-absorption of side first reflections.
• Rear Wall: The rear of the listening position opens up into the kitchen area. I am treating this short leg of the "L" as an acoustic release, so zero treatment is planned for the rear.
• Floor: It is parquet wood but I can add a heavy, thick rug between the speakers and the MLP to tame the floor bounce.

4. The Ceiling Dilemma (Cloud vs. Photography Backdrop)

I plan to suspend a 4-inch thick broadband acoustic cloud at the ceiling first-reflection points. However, I want to use that exact ceiling real estate to install a ceiling-mounted seamless paper backdrop system. The backdrop would roll down in front of the false wall during photo shoots.

My questions for the community:

1. Front Wall: Does this partial 8" rockwool strategy (heavy absorption above and below, but completely blank directly behind the 8341As) make sense? Or I do not deal with bass trapping at all? Just a few inches of rockwool as absorption and just rely on the two subs with REW along with getting a thick carpet and a fabric couch? Is this enough or I need to compensate with heavy absorption on the front wall since the side walls and back wall are bare concrete with paint?
2. The Ceiling Cloud: Can I get away with skipping the ceiling cloud entirely? Given that the long side walls are totally bare, I am worried that adding overhead absorption might be needed. Are the vertical directivity controls of the 8341A combined with a thick floor rug enough to manage the vertical axis without treating the ceiling bounce?

I’d appreciate any feedback or empirical warnings. Thanks!

 

[kemmler3D]

Since you plan to measure with REW anyway, I would suggest holding off on decisions about treatment until you've had a chance to do that. It's tempting to fix problems in advance, but it's probably much more effective to find out what the problems are before fixing them.

 

[montyliam]

Have you considered building a baffle wall and using the Genelec flush mount boxes for the 8341a?

 

[Oddball]

I would not go below 5.x4 setup nowadays. Also not sure what you will use to bass manage the setup - not insignificant point. And overall room EQ is also a thing to explore.

 

[Sparky]

Have you considered building a baffle wall and using the Genelec flush mount boxes for the 8341a?

Oooooh good call!

 

[theshade]

Since you plan to measure with REW anyway, I would suggest holding off on decisions about treatment until you've had a chance to do that. It's tempting to fix problems in advance, but it's probably much more effective to find out what the problems are before fixing them.

Thanks! I totally agree with that as a general rule, and I definitely plan to rely heavily on REW for this build. I just like to hash out these ideas in advance instead of scrambling at the last minute once I move in and the renovation begins. I really want to minimize the total time spent on the renovation phase.

 

[theshade]

Have you considered building a baffle wall and using the Genelec flush mount boxes for the 8341a?

Yes. But the price of the Genelec 8351-450 Flush Mount Kit and doing a solid structure with sufficient mass is prohibitive and I forgot to add that the whole front wall is almost wall to wall windows with just the small right corner cement. I was thinking I can remove the projector screen if I wanted window light or am I being optimistic in the design of the screens that you just hang. I am also thinking about going just tv instead so the wall can have wall to wall drapes that I can easily close or open.

 

[theshade]

I would not go below 5.x4 setup nowadays. Also not sure what you will use to bass manage the setup - not insignificant point. And overall room EQ is also a thing to explore.

I am currently running an Auro 3D setup in my bedroom. My LCR are Genelec 8341As (the L/R are somewhat nearfield, and the center is behind a 120-inch AT spandex screen). For the rest, I use Genelec 8030Cs for the surround bed layer, and a mix of Energy C-3s and Wharfedales for the height layer. I rely on Genelec's GLM software to handle the EQ and integration for the three 8341As. For bass management, I use a MiniDSP combined with REW and integrate two SVS PC-2000 Pro cylinders alongside a massive, unsightly DIY 'coffin-sized' sub.

For room treatment, the right, front, and back walls are double-walled plywood with absorber fill acting as membrane absorbers over the concrete. The left wall, ceiling and floor are bare. But I guess mattresses work better than a carpet. I have a king-sized mattress (actually my bed) on the floor between my screen and recliner to tame the floor bounce, and I stash 1 queen, 1 double, and 1 single mattress directly behind the AT screen. I pull them out when relatives stay over, but they probably act as absorbers, which is incidental and not the main purpose; the main purpose is to put them out of the way and use the space behind the AT screen.

Regarding the channel count, even though I currently have an Auro 3D setup, I am honestly somewhat underwhelmed by the lack of meaningful height channel information in most movies more so when it is set to atmos rather than the auro upmixer which I find I like better. Furthermore, my actual time spent watching movies is much less than the time I spend on music and gaming. Because of this, I am seriously considering dropping the immersive channel count for the new living room. I might actually repurpose the Genelec 8030Cs and get ARC studio for a dedicated bedroom PC system (for my photography hobby) and just grab a cheap pair of ELAC Debut OW42s to serve as basic side surrounds for the living room.

 

[Mort]

Makes me cry that you aren't going to use SAM subs. No GLM.

 

[theshade]

Makes me cry that you aren't going to use SAM subs. No GLM.

Makes me cry too. But the price of Genelec subs will make me cry more.