Bruce's 9.4.2 Dedicated Screening Room

diverdog

Active Member
After many years and homes, I finally have a space for a dedicated room. I’m calling it a screening room rather than a home theatre because it won’t have any trappings like a popcorn machine, posters, bar refrigerator, etc. Every penny spent will help the video and audio take me to another place and time.

A bit about me first: I’m a retired AV engineer / manager. I have a solid STEM education and lots of specialized AV training. Early on my work was mainly in medium to large spaces and more recently very high-end AV presentation and videoconferencing suites. I also had the opportunity to be a live sound mixer for pop bands and theatrical presentations. Although I didn’t have a lot of opportunity to design and install home theaters, I did attend many Cedia, Infocom and AES lectures on applicable technologies. Hearing Dr Toole speak on a variety of subjects pertaining to getting optimal sound in small spaces was eye opening and inspiring for me. Over the last year I’ve been hitting the books and watching lots of Youtube. There are some really smart and experienced people sharing valuable knowledge freely. You just have to be able to separate the gold from the BS!

I’m very pragmatic and skeptical about performance reputation and reviews that are not conducted in a scientific way. I took part in many double-blind listening tests for wires, amps and speakers and learned firsthand about listener prejudice. If you think it’s going to sound better it will, especially if you just spent a big pile of money!! Today the difference between well engineered moderately priced equipment and very expensive equipment is small. I’m always looking for the biggest bang for the buck.

The existing room. Four years ago, I had a semi-custom home built. I couldn’t alter the dimensions of the game room but the external doors and windows where eliminated and I had extra power circuits, CAT6 and coax installed. It’s 19.5’ L x 19’ W x 10’ H.

I’m planning to do all of the construction myself except the drywall demo, HVAC install and projector calibration.

Coming next: room usage and design goals
 
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diverdog

Active Member
Room usage and design goals. The room will be primarily used by my wife and me. 85% TV, movies and sports, 15% music listing and no gaming. We are comfortable with a ~50 degree viewing angle and based on the room dimensions a 10’ viewing distance would dictate a ~130” diagonal 16:9 AT screen with masking for scope. Since the room will be a bit wider than it is long a single row with a two person central love seat and one single seat on each side will give great sight lines and the opportunity for a very even sound field, IE every seat is a money seat. LCR hidden behind the screen, subs recessed into the walls and no visible equipment to distract from the image. Since the room is light controlled and I’m more interested in great blacks than an extremely bright image I’m leaning toward JVC projectors.

I’m extremely picky about sound quality and my wife has a bit of hearing damage so a state-of-the-art listening experience is my number one goal. By that I mean crystal clear dialog, solid virtual imaging, diffuse side and rear sound field, properly located Atmos, and bass capable of THX reference level 115db @ 16hz at every seat. I do like action movies, but we watch way more drama with few explosions or train crashes, so I won’t be designing to get blown out of the room with bass slam.

Finally, the room does have HVAC but it’s quite noisy and provides a path for sound energy out of the room. Since we will be tearing out the existing ceiling the ductwork will be capped. A super quiet split system heat pump will be used. I installed a couple of these in my garages and they cool them down quickly on high speed and are whisper quiet on low speed.

Coming next: room sizing and wall construction
 
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diverdog

Active Member
Room sizing and wall construction.

I was less than excited by the prospects of having a nearly square room. Pretty far from the “golden ratio”. But on further review I discovered that contrary to the advice of some pretty impressive acousticians, “it ain’t necessarily so”. Todd Welti calculated and demonstrated in his AES paper that with properly placed seating and bass managed multi sub-woofers it's possible to cancel nulls and get very flat and uniform bass response. Adding a screen baffle wall and decoupled “room within a room” walls will give a room ~ 17’ L x 18’ W x 10’ H.

The floor is poured concrete and I’ll talk about that in the acoustical treatment section

In a listening room designing walls for noise isolation and bass management are at cross purposes. Massive, stiff block or concrete walls are by far the best at blocking sound but are awful for creating huge nulls and peaks in the room. In my room I’m more concerned with bass management but effective noise isolation is a good thing too. Is there a way to do both? The method I choose is based on the Acoustic Science Corp IsoWall system IsoWall (asc-soundproof.com) mounted on new 2x6 studs and 2x8 joists not touching the existing framing. The sheetrock walls and ceiling float on clips. Layer one is ½” standard rock fastened to the clip rails. Layer two is ½’ waterproof rock (slightly different mass). Viscoelastic pads are placed between the layers and the top layer is also screwed to the rail system. The bottom of the walls sit on felt padding. The wall cavity fiberglass fill varies from 8” to 24” depending on location. The walls and ceiling act as very large diaphragmatic bass absorbers, smoothing nodal peaks and nulls. The viscoelastic system also greatly reduces wall re-radiation into the room reducing smearing. A sound isolation solid core door for the house access and a standard solid core door for the garage entrance finishes the wall construction.

Next: 9.4.4 Speaker system
 
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Praetorpwj

Active Member
Hello, always good to meet a Bruce. it sounds like an interesting project and a larger version of one I have planned for the near future.

I really don’t like shoebox shaped theatres so am creating a squarish shape room with the screen on the longer wall against all conventional wisdom.

Given that you have a good sized space (by UK standards) and are building a room within a room have you considered creating an internal trapezoid space to help overcome the square plan?

When you say the new studs and joists won’t touch the existing framing how exactly are they fixed structurally? I will be building a stud lining within a masonry cavity wall space. I assumed this would be fixed back to existing masonry with isolation clips but that is still technically ‘touching’.
 

diverdog

Active Member
Given that you have a good sized space (by UK standards) and are building a room within a room have you considered creating an internal trapezoid space to help overcome the square plan?

When you say the new studs and joists won’t touch the existing framing how exactly are they fixed structurally? I will be building a stud lining within a masonry cavity wall space. I assumed this would be fixed back to existing masonry with isolation clips but that is still technically ‘touching’.
Bruce is not a common name here in the US but it suits me fine. Yes, I've thought about non-parallel walls and was going to have a screen baffle wall with wings because I like the L&R a little wider than 45 degrees and with recessed speakers the wing is necessary to toe in the speakers. It turns out that non-parallel walls open a huge can of worms because you can't easily predict modal locations. But square rooms are just fine if you select the proper seating locations and use multi subwoofer management. REW will even predict your frequency response at multiple seats. The attached is my unequalized room seating frequency response at two locations with four corner subs. There are two traces, but they are so close its hard to see. I'm astonished how smooth it is. The broad bumps between 55-100hz will be very easy to EQ out and add additional headroom. Actual VS predicted will be very interesting

In my room the four inner walls and ceiling joists will be connected to each other and bolt to a concrete floor. I'm avoiding connecting to the old studs because of noise transmission. Since they will have no structural function with the rest of the house, I don't think it will be a code issue. I have a friend that's an architect and I'll be checking with him to see if it meets code and needs a stamp. In your case there is no issue connecting to the masonry walls since they don't transmit much noise.

I'm looking forward to following your build.
 

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diverdog

Active Member
9.4.4 Speaker system

So why a 9.4.4 speaker matrix? I always approach the speakers and room as a unit. I want to provide a physical interface that avoids acoustical issues that are difficult or impossible to fix with electronics or acoustical Band-Aids.

Speakers must be THX Ultra capable and be designed for flush or surface mounting. THX Ultra will make it simple to be sure that they will be capable of reaching reference levels in my 3,100 ft3 room and have a very good frequency response, power response and dispersion. Flush and or surface mount will eliminate or minimize SBIR (Speaker Boundary Interference Reflections). Unfortunately, this eliminates most speakers designed for two channel Hi-Fi use.

The bed layer arrangement is straight out of Dolby’s engineering documents.

L, C, R speakers. Will be identical inwalls flush mounted on curved baffles a minimum of 6” behind the AT screen. L & R will be separated by 45 degrees and toed about 22 ½ degrees toward the MLP. I’m going to use Monoprice Monolith THX-LCR. The spec’s and review of the in cabinet model are outstanding. Monoprice Monolith THX-365T Mini-Tower and THX-365C Center Speaker Review | Audioholics I paid $359 each with free shipping for these. I’d have to spend four to twelve times as much to get something better by Triad or JBL

Wides. I’ve included wides because in my listening experience they make a huge improvement in the integration between L, R and side speakers. I’m using the matching Monoprice Monolith THX-365T in a very compact cabinet that will hug the side walls very closely and be aimed approximately 45 degrees to the MLP. They have an installed Atmos speaker but I will not be using it. $399 each with free shipping. Monoprice Monolith THX-365T Mini-Tower and THX-365C Center Speaker Review | Audioholics I’ve been testing these with a 12” sub and they sound great.

Sides. A more diffuse non directional sound field is desired on the sides and as the outer seats are relatively close to the speakers I’m going to use a bipole and I have not made a decision on brand or model yet.

Backs. It’s 7’ from the listening position to the back speakers and I’m on the fence about using a bipole / dipole or direct radiator. Most likely will be monopole Monoprice Monolith LCR to match the front stage.

Atmos. I don’t have much experience with this so I’m going to go with the advice of Anthony Grimani. In smaller rooms he recommends just two speakers about 15 degrees in front of the MLP and horizontally spaced about halfway between the Center and Left and Right speakers. His experience is that the spacing between the back speakers and a rear Atmos pair does not play well psychoacoustically in smaller rooms. He’s done hundreds of Atmos rooms and I trust his expertise. These will be flush mount with aim-able HF. I'm going to install the rear set so I can experiment and see what arrangement I prefer.

LFE. Sub-woofers! Everyone’s favorite speaker! My target is to have smooth tight bass with minimum variation in all seats. THX reference is 115db peak at 20hz. I’m fine with that level but I want it a half octave lower @16 hz. Modeling shows that four corner subs will provide very smooth and even bass coverage in my room seating position. The front pair will be recessed into the baffle wall at the floor. I also have about 24” space between the back wall and the other interior house wall to flush mount the rear pair. I need to move quite a bit of air to hit my target. I’m OK with sealed or ported types. Unfortunately most commercially available ported cabinets with enough bass extension are too deep to fit. Most sealed units do not have the required output capability. I’ve heard the sealed HSU ULS15-MK2 and it’s a great performer at a great price, $879. It should come close to hitting my target at 20hz and its small enough so that I could just use two in each corner if I need more output! I’ve made many custom subs over the years, but I really don’t want to build from scratch with all the other construction. Another possibility is the Denevo 4 ft3 sealed enclosure flat pack with a Dayton 18" UM 18-22 driver. $600 for the parts and since they are hidden no worries about fancy finish or grills would make them very easy to bang together with the air nailer. I might even be able to fit mini Marty vented boxes with a good 18" driver but it would be really tight.

I’m going to make the decision when I get the existing drywall ripped out of the back wall and see exactly what I’m dealing with to get an accurate measurement. I’d love to install 4 Hsu VTF-15H MK II and be done with it.
 

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diverdog

Active Member
Power and Cabling

I’m going to try and anticipate any changes that I may want to make in the future such as self-powered or bi-amped speakers.

With open walls and a sub panel so close it’s easy and relative cheap to add extra circuits.

Equipment power will be handled by a 50 Amp 240 V sub-panel in the wall shared with the garage. In the US wall outlets are nominally 117 VAC. All 20A circuits will use #10 wire. Outlets are hospital grade. All circuits dedicated home run

Lighting and convenience outlets will be existing circuits

The equipment rack will be in the adjacent garage

LCR Speakers #12/4 and shielded twisted pair to each speaker. One CAT6, one 20A quad outlet

Wide, Side, Atmos and back #12/2

Subs (4). 20A outlet, #12/4, shielded twisted pair, CAT6

Projector- CAT6, HDMI, Trigger, RG6U, RS232, 15A power. Spare flex conduit

Equipment rack- Sub amps (2) 20 A, Speaker amps 20 A, Processing 20A

Next: The secret sauce! (Acoustical treatments)
 
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The Dreamer

Distinguished Member
Hi Bruce,

your room dimensions are just a little larger in width than mine, and an almost identical length.

I’m currently running a 9.2.4 setup, having recently added wides. I’m with you, in that, despite some naysayers, I really enjoy the spread of sound blending form the LCR’s to the side surrounds that the wides achieve. While there are limited movies that utilise wides natively, I’ve found that the latest iteration of DSU that the Marantz 8805 (and a few others) is equipped with, lights up the wides very nicely!

You can see what I ended doing with my room in my signature below, or to skip the build of the extension and jump straight into the ‘cinema’ build start here…


I‘m only running two sealed UM18-22’s at the moment, but have wired for another pair in the rear corners, should I feel the need.

Looking forward to seeing your progress.
 

diverdog

Active Member
Dreamer, took a quick look at your build and see we have a lot in common already. like you interleaving of the ceiling joists for isolation. Only two monster 18" subs! LOL

I'm targeting four for the smooth response at all seats. I doubt I'll ever push to reference level except to test so I hope the 15" sealed subs will do the trick.
 

diverdog

Active Member
The secret sauce! (Acoustical treatments)

Actually, the secret sauce isn’t so secret, perhaps just misunderstood.
There is a lot of excellent information available free of charge. I’m amazed that some experts like Anthony Grimani share so freely. He’s done over a thousand home theaters, control rooms, etc.

My experience with acoustics started in larger spaces focusing on speech intelligibility. Attending a bunch of SynAudCon seminars in the early 80’s I was introduced to diffusion by RPG systems. I was fascinated by acoustics and started reading everything I could find. Later on, I worked on mostly small and medium rooms and found them to be quite different.

Do you need treatment in a home theater? Once you hear a well treated room you will be hooked. I believe the room is at least 50% of great sound.

My room treatment.
  • Broad band absorption
    • 15-20% area 4”-6” fiberglass panel
  • Dispersion
    • About 20% area covered
  • Side walls
    • asymmetrical staggered 2D dispersion and 4”-6” absorption. IE first panel of right side is absorption, first on left is diffusion. 4’ tall entered on ear height.
  • Front wall
    • Area behind AT screen treated with absorption.
  • Rear wall
    • Mixed 3D diffusion and 4”-6” absorption.
  • Ceiling
    • Cloud absorbers at first reflection point. 3D diffusers over seats
  • Floor
    • Perimeter hard wood flooring. Center section carpet. Front section raised on 2”x 6” joists. At the first reflection point areas from LCR and wide’s the joist cavities are filled with 6” of fiberglass and covered with expanded metal. Carpet over the metal to form broadband absorption.
  • Bass management
    • Multi subwoofer null cancellation, ASC IsoWall damping system. I doubt I will need additional bass absorption.
 
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diverdog

Active Member
Electronics

I’m pretty pragmatic about electronics. My experience is that there’s not much difference between mid-priced and very expensive equipment. Stuff like Storm Audio or Trinov would not make a significant difference in my room.

Input devices
  • DirecTV I’m a NY Giants NFL fan. Since moving to the west coast the only way I can see these games is on DTV
  • Streaming device Need more research on this maybe Apple TV
  • Disk Player Something that can play 4k and SACD. Panasonic?
  • Media Server I don’t watch a lot of movies multiple times but I do have a lot of music. Another one that requires more research
Processor
  • Good DAC’s, max 16 channels, up to date HDMI, Dirac filters, stable software (Monoprice HTP1)
  • Sub-woofer Depending on final channel count MiniDSP HD
Power amps
  • LCR Stable at 4 ohms ~ 400w/ channel all driven (Emotiva or Monoprice)
    • LCR is moderately efficient 88db/1 W and is a 4 ohm load
  • Surrounds 65-100 WPC 8 channel (Emotiva or Monoprice)
Sub Amps (if used)
  • Rack mount, 1000W per sub @ 4 ohms (Crown)
Control system
  • RF/Infrared Harmony Elite I have one and it works well. But not sure if it will support the newer equipment since Logitec is in the remote business any more
 
D

Deleted member 901590

Guest
You clearly know what you're doing, this looks amazing, and you're obviously ten times more proficient than me at all of this. But I assume/hope you're open to comments, one of the reasons you've shared?

Some could say that the matching 365T for the front wides is overkill but I think you're being very wise, as it protects for these channels potentially being used more in future source material.

Your question of the surround backs. My opinion would be to use normal direct speakers. Firstly, because your surround speakers are already diffusing. Secondly, members on here I've spoken to have said that it works very well for surround backs due to the nature of the content that is often sent to them. I'd also say for them to be as sensitive as possible to they can give that additional shock/kick when discreet shock content is behind you.

Processing, are you sure about going for that combination, why that over a processor that can also run and EQ all of the sub channels. Cost?

Would you consider bass shakers (or similar)? I ask, as that would not only need the wiring but also something to connect them too!

Grimani's advice on going .2 for heights. Not criticising but would just say are you sure you don't want to make any provision for .4 heights and try it? Same with Auro's VoG or centre height speaker. I'm just saying it's easy to take something away later :)
 

diverdog

Active Member
Dobby, thanks for your input. I'm always happy to hear constructive comments and ideas.

I wanted to keep the front stage speakers as similar as possible The 365T has the same driver compliment as the LCR and the shallow cabinet will allow tight clearance to the wall minimizing SBIR. Overkill on maximum SPL but well matched and cost effective.

Since the single row of seating will be 7' away from the rear walls I'm strongly leaning to direct radiators for backs. I already have another set of the Monolith LCR's to use for that. Plenty of SPL and I think they would also blend better with back atmos.

I was planning to wire for back Atmos and upon further thought I might as well just install the speakers since it will be a trivial cost compared to the total project.

I didn't consider VoG but that's another low-cost possibility. I'll see how it works with the ceiling cloud layout.

I don't have strong feelings about butt-kickers but wiring for them would be easy and I'll add it to the plan.

The 16 channel HTP1 processor can handle the sub management using Dirac in 9.4.2 with one spare channel (butt-kickers?) So going to 9.4.4 would require more processor channels or external DSP for the subs. Moving up to a Trinnov, Storm or JBL is a rather large price bump for in my opinion limited benefit. The Emotiva processor would be a cost-effective way to get more channels, but I have very low tolerance for buggy software. Running the HTP1 in 9.1.4 and using a miniDSP-HD with Dirac bass management would be very cost effective and leave me two channels for VoG and bass shakers if I choose to add them

Thanks again for your thoughtful suggestions.
 
D

Deleted member 901590

Guest
Or connect two Minidsps then two separate settings out from one so you and your wife can tune each butt kicker.
And two spare sub channels ready for the two bigger subs when you want THX output at 10Hz 🤣
 

diverdog

Active Member
And two spare sub channels ready for the two bigger subs when you want THX output at 10Hz 🤣
I do like great bass but I've worked through that phase of my life with design and install of dance club systems. Now I'm more fascinated with the interaction of the subs and room. The ASC IsoWall is very good for damping out wall reradiation of bass energy. This really helps with smearing of bass notes. Quality over quantity.

In theory the low group delay of sealed boxes is superior to ported boxes but I think either can sound very good. I would like to have very deep bass extension but there is limited real estate and I'm not too anxious to build four large custom vented boxes to fit available space. Four JTR RS1 Capivator's would fit and do the job very nicely but $13k for subs doesn't look too good in the budget! A quick and dirty solution would be Denovo flat pack sealed cabinet kits with Dayton 18" drivers. The subs are hidden so no worries about fancy finishes. Parts cost each around $600. Add a couple of Crown amps and get pretty close to the captivators for around $5k
 
D

Deleted member 901590

Guest
I'm interested. With all your experience, why choose a mostly 88dB sensitivity figure all round? Do you see a compromise for higher sensitivity speakers?

Also note one of the reasons for my crappy cheapo system isn't just money it's also due to this...

Post in thread 'Who is unimpressed by more speakers (7.2.4) vs 5.2 ?' Who is unimpressed by more speakers (7.2.4) vs 5.2 ?

Are your height speakers up to it? Noting it's just my theory and I'm a bellend.
 

diverdog

Active Member
My criteria for speaker selection, flush mount to eliminate SBIR, good frequency and power response, able to hit THX ultra SPL and good value. I'd love to use speakers that are more sensitive but those that meet the other criteria and are more sensitive are massively more expensive.

As for the number of channels I can only really speak to the bed layer as I don't have a ton of experience with Atmos. In my experience 5.1 with dipoles can sound very good but 7.1 is clearly a step up. Wides are very nice if the room is right. I've heard Atmos bounce speakers (totally unimpressed) and a couple of overheads that I liked much better.

Of course, Atmos is more than just overheads. The object-oriented logic is a nice improvement

I'm still looking at overheads. I'd like them to be flush mount with aim-able drivers. Keeping up with the other speakers is a tall order. Probably need to be 8". Perhaps the Paradigm CI Elite E80-A

Truth be told I won't be listening at or near reference level very often. And how many low level jet flyovers are there? LOL
 

Triggaaar

Distinguished Member
This looks like it's going to be excellent, thanks for sharing.

I too have followed all that Anthony Grimani has shared, and I'm a fan.

I'm not sure he'd recommend only 2 Atmos speakers in a room your size. If limited to 11 speakers, he'd choose 9.x.2 over 7.x.4, but I think he'd rather have 13, giving 9.x.4

Re the percentages of absorption and diffusion: I think Anthony usually works with larger rooms than even yours, and diffusion doesn't work as well in smaller rooms. Depending on where you get your panels from, or if you make them, you might want to consider some combination panels in some areas. I'm building binary amplitude diffusers over some of my absorption panels, to work as combination panels.

Not sure if I've missed it above: what colour are you planning to make the room?
 

diverdog

Active Member
Triggaaar, thanks for the comments. As discussed above I'm going to add the rear Atmos since the additional expense will be trivial compared to the total project cost. Then I can experiment to see which I like better. It will mean adding a MiniDSP-HD for sub management but again it's a small additional cost.

I disagree with you on using diffusion in smaller rooms. Properly done it really helps the room fade away. Gives the sense of a much bigger space. Grimani's company offers packages of treatments for various size rooms and even the smallest have diffusion. Home Cinema Systems

I do plan on some combo panels at strategic locations. I'm going to buy all of the treatments pre-made as there is so much other construction work to do. I'm going to use a magnetic attachment system so I can change the treatment layout and experiment

I'll be posting some drawings showing the room treatments as I progress.

You didn't miss the room color. I've yet to post more detailed info on seating, lighting, screen, projector and room color. The room will be black with some flocking/ light absorbing material around the screen. Perhaps some dark red accents in the back of the room.
 

Triggaaar

Distinguished Member
I disagree with you on using diffusion in smaller rooms. Properly done it really helps the room fade away. Gives the sense of a much bigger space.
Fair enough.


I'll be posting some drawings showing the room treatments as I progress.
Excellent, I look forward to those. I haven't been posting during my build as I just don't have the time. The amount of time I've spent building is obscene.

You didn't miss the room color. I've yet to post more detailed info on seating, lighting, screen, projector and room color. The room will be black with some flocking/ light absorbing material around the screen. Perhaps some dark red accents in the back of the room.
Oo I like the idea of that. I'm sold on fully black rooms, as opposed to the lighter colours typically used by professional installers, but a touch of red at the back shouldn't really detract from the image, and could lift the feel of the room a little.
 

Triggaaar

Distinguished Member
Triggaaar, BTW love your "People VS the Horizontal centre channel" tag line. May we add tower L&R as well! LOL
:laugh: Yeah, may be a bit controversial, but most people would be better with a bookshelf speaker than a horizontal centre. There are of course exceptions, for example some manufacturers manage to stop the lobing with extra drivers.

What's your beef with towers? Their bass isn't really needed when you can accommodate a collection of subs, but if you crossover at a sensible point, they'll still sound good. It depends if you're going for the 'hidden equipment' look, as they are a bit harder to hide.
 

diverdog

Active Member
Like Hippocrates I believe "first do no harm". Almost all towers are designed for stereo use. They have narrow baffles to manage diffraction and because they need extended bass the cabinets are very deep. (my living room Polk LSiM towers are 24" deep!) Placing the drivers 18"-30" off the wall causes SBIR with nulls and peaks in mid bass that are difficult to treat. Think 8" of fiberglass on the walls behind the speakers. Other issues are setting the mid-hi drivers at ear level, less efficient mid bass, extra cost for no benefits and the visual distraction. A shallower cabinet designed for home theater offers many advantages over monster towers
 

Harkon321

Well-known Member
Diffusion in very small rooms can be tricky though, can’t it? Most, if not all, of that diffusers sold by GIK need a metre and a half minimum before they work. Ideally a fair bit more. My rear wall is just over 3ft from me, which I believe should therefore be absorption rather than diffusion. Following with interest though.
 
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diverdog

Active Member
Diffusion in very small rooms can be tricky though can’t it. Most, if not all, of that diffusers sold by GIK need a metre and a half minimum before they work. Ideally a fair bit more. My rear wall is just over 3ft from me, which I believe should therefore be absorption rather than diffusion. Following with interest though.
Yes, it does take some time for a diffuse field to form properly. If you are very close to the rear wall I would agree that some 4" absorption would be my first add.

Fortunately, I will be 7' away from my rear wall.
 

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