My acoustically treated Home Theatre (updated)

[sarumbear]

What would you recommend then. Should I stick to Q950.

I do not like making suggestions as there are very large number of criteria that effects the decision.

Will it not work in 24" wide 48"tall enclosure. Wouldn't it be similar to as installed flush with the wall.

It’s the depth, the issue. When the baffle is flush with the wall you have perfect 2pi operation with no boundary discontinuity. Otherwise, at frequencies higher than the wavelength of the sound you have discontinuity. That causes issues which are eliminated with in-wall speakers.

 

[KING DRANZER]

I do not like making suggestions as there are very large number of criteria that effects the decision.


It’s the depth, the issue. When the baffle is flush with the wall you have perfect 2pi operation with no boundary discontinuity. Otherwise, at frequencies higher than the wavelength of the sound you have discontinuity. That causes issues which are eliminated with in-wall speakers.

Wouldn't that be negligible beyond a certain point. 2ft or 3ft is a lot of width. And the enclosure itself be flush mount to wall. Just asking.

 

[sarumbear]

Wouldn't that be negligible beyond a certain point. 2ft or 3ft is a lot of width. And the enclosure itself be flush mount to wall. Just asking.

Negligible below a certain point but not above. The wavelength at 4kHz is just 11cm.

In my room I built a false wall and mounted all speakers and the TV on it.

 

[Dj7675]

Trinnov sent me this link to answer my request for explanation of their new WaveForming tech. I’m sold. I started planning to double the subs on the front wall and to add two new subs to the rear wall. Front wall is easy as it’s a custom wall only for in-wall speakers and TV and there’s ample space. The rear wall will be tricky.

As things progress, it would be very interesting to share you experience and measurements along the way. I thought I had read minimum subs required 3 or 4 front and back. Can you do just 2 on the back wall?

 

[sarumbear]

As things progress, it would be very interesting to share you experience and measurements along the way. I thought I had read minimum subs required 3 or 4 front and back. Can you do just 2 on the back wall?

From what I read you need minimum 4 subs at the front but 2 maybe enough at the back. I will try that.

 

[Dj7675]

From what I read you need minimum 4 subs at the front but 2 maybe enough at the back. I will try that.

Looking forward to see how it goes. While not the same, I am using a Stormaudio with Dirac ART and it optimizes bass like I have never heard before. I won’t ever go back. I love how both Trinnov and Dirac are doing new and interesting things.

 

[sarumbear]

Considering replacing my two JBL subs with 6x KEF Ci3160RLb-THX units. I already use one in the ceiling that augments the rear surround and rear height speakers. They require much smaller space on the false wall then the boxed JBLs, which means I can use six of them instead of four JBLs.

This will be the third front wall…then I need a rear false wall…for another set of KEFs.

 

[Dj7675]

Considering replacing my two JBL subs with 6x KEF Ci3160RLb-THX units. I already use one in the ceiling that augments the rear surround and rear height speakers. They require much smaller space on the false wall then the boxed JBLs, which means I can use six of them instead of four JBLs.

This will be the third front wall…then I need a rear false wall…for another set of KEFs.

Always intrigued by the possibility of in wall subs… It looks like 3 6.5 inch drivers. What kind of output are they capable of at 20hz?

 

[sarumbear]

Always intrigued by the possibility of in wall subs… It looks like 3 6.5 inch drivers. What kind of output are they capable of at 20hz?

95dBSPL at 20Hz. I am planning to use six of them, which calculates as 110dBSPL. Enough to cause bowel movements

 

[Dj7675]

95dBSPL at 20Hz. I am planning to use six of them, which calculates as 110dBSPL. Enough to cause bowel movements

With some on front wall/back wall for room mode cancellation purposes, would it be that predictable as a calculator. It would seem if all were on the front wall that would be the case but on front/back would that necessarily be the case (not saying it won’t be enough, but just curious)?
Edit: Does KEF sell backer boxes for their in wall subs?

 

[sarumbear]

With some on front wall/back wall for room mode cancellation purposes, would it be that predictable as a calculator. It would seem if all were on the front wall that would be the case but on front/back would that necessarily be the case (not saying it won’t be enough, but just curious)?
Edit: Does KEF sell backer boxes for their in wall subs?

I’m planning to put all six on the front wall. They will replace the also in-wall JBLs which have 2x 10” drivers each.

The rear wall will have 4x KEFs as it will be narrower than the front wall due to space constraints. Besides, the rear wall doesn’t add any SPL capacity to the system. They operate out of phase to cancel the standing waves.

 

[Dj7675]

I’m planning to put all six on the front wall. They will replace the also in-wall JBLs which have 2x 10” drivers each.

The rear wall will have 4x KEFs as it will be narrower than the front wall due to space constraints. Besides, the rear wall doesn’t add any SPL capacity to the system. They operate out of phase to cancel the standing waves.

Sorry misunderstood all 6 were going on the front wall. That was my thought regarding if they were split front wall/rear wall. Be sure to post how it goes. Does KEF selling backer boxes for them?

 

[sarumbear]

Does KEF selling backer boxes for them?

I don’t know, haven’t enquired as I have a false wall that acts as a very large enclosure.

 

[mczx]

There are five bass resonators hidden inside the false ceiling. These suck the five main room resonances (room modes) caused by the standing waves. Each is a tuned Helmholtz resonator made from 20cm (8”) diametre plastic water pipe. Their length set the frequency range they will operate at and the opening is adjustable for precise tuning. Once the room modes are reduced to near elimination the room frequency response became pretty flat. Only a very small amount of equalisation is required, which is done by Trinnov.

Do you have the before and after measurements regarding bass modes?

How can a small tube volume correct a large rooms volume?

 

[mczx]

Do you have the before and after measurements regarding bass modes?

How can a small tube volume correct a large rooms volume?

It turns out the handbook of acoustics claims they are great for tackling modes, also mentions partial fill with absorbent.

 

[mczx]

I create a rectangle opening (port) and over it slide a flap to change the port area. Once the required frequency is reached I tighten the screws (that are acting like a guide to the flap) to fix the flap in place.

I see adjustable length vents on the market but I don’t use long vents on my resonators.

How do do this on long pipes like you have?

 

[Dj7675]

@sac

Most recent update is here.

I have been posting about benefits of acoustic treatment of a room, especially in larger rooms. I believe that if done right it is a better, and if you have basic carpentry skills, a much cheaper option then using multiple subwoofer setups. I have the degree to do it right and thankfully the means to hire a carpenter. Here on I will present you my Home Theatre (HT) system where I applied my knowledge (and money!). As you may guess from the layout the room it is not visually a purpose built HT. it is our main living place that combines, sitting & dining rooms and the kitchen! It is light and bright as it use an HDR TV.

Acoustics​

Other than the specifically designed shape and layout of the room I only use five Helmholtz resonators to tame the major room modes (standing waves). Three are in the ceiling and two are on the ends of the false wall where the TV, and in-wall LCR and main subwoofers located. The resonators are inside the false ceiling. They are made of 5m long 25cm diameter plastic water pipes. Ends are blocked and there are variable area opening on one end to tune the resonator. Each one cancels one room mode. The remaining two are at the sides of the false wall and use the otherwise unused volume.

The first image is the room response to pink noise measured at three sitting location separated by colour. Measuring locations are shown on the room layout image that follows as 1-3. Individual position FRs are also provided. Chart resolutions are 1/6 octave.

No EQ is used.

View attachment 221277View attachment 221279View attachment 221281View attachment 221282

Note: I could have adjusted the resonators so that they don’t over-compensate in the 30-60Hz octave but it required a change to the front resonators in the false wall, which was already build twice! However, as the dip is within 3dB I decided Trinnov to supply a small lift.

Layout​

View attachment 221286

​

Speakers​

LCR: 3x KEF Ci5160REF-TH as Left, Centre & Right speakers, in-wall
SB: 2x JBL Synthesis SSW-3 as main subwoofers, in-wall
SS & SR: 4x JBL CBT70J-1 as side & rear surrounds, on custom stands
SP: 2x KEF Ci200RS-THX as spatial speakers on the ceiling
LFE: JBL Synthesis SSW-2 as unmanaged LFE channel
Not shown: 2x KEF Ci200RS-THX as height speakers above the L&R flush to the ceiling, in-wall

Equipment​

Apple TV
Sky Q
Fire TV
Trinnov Altitude 16
JBL Synthesis 2x SDA-4600 & 1x SDA 8300

Connection diagram​

View attachment 221284


Please feel free to ask questions or let me hear your comments. However, due to personal reasons I am not willing to post photographs.

I believe you originally had JBL (C211 I think) and switched the the KEF 5160REF-THX. Did you notice any difference in dynamics with the switch? I am thinking of going a similar route to KEF in walls (probably CI5160RLM) and was curious what you thought of the dynamics between KEF/JBL if any.

 

[Dj7675]

@sarumbear couple of follow up questions if I may…
-Did you end up using the KEF KASA500 amp for your CI3160RLB-THX subs?
-What kind of volume did you use in the false wall space?
I ask because in my new space (living room) it looks like this is the direction I am going to be going as well.
Thanks