The FX speakers mount flush onto the walls. And they are pretty flexi about their positions…
ok here now see what happens when you put the left speakers into the room
Depending on how you place the MA speakers and MLP, the first early reflection point changes. but notice it is always at the 4 corners, left right front back. Also noticed that whether or not if it is the left or right speakers, they both benefit with a velocity absorption panel behind MLP, ie the yellow circle on your right in this picture.
but since i cant do 3d modelling, i cant show u what happens to ceiling floor reflections
what the above means is that, the first reflections are arriving 1.5ms later after the direct sound. Now if we dont weaken/absorb or scatter this reflection into tiny bits, our brains will interprete this as a second source of sound
now see again below what happens when you dont kill off the first reflections points and you have the 2nd reflections to deal with
pretty scary all over the place, the sound is bouncing off all the walls, no control. So its very important we kill off the first reflection points. Ill teach you how to solve it when we meet up. so i can show you what is happening at my place
How to know by measurements if the reflections are kills off? We can use REW ETC plot to tell. That way we will know we have effectively killed off the nasty reflections.
But notice one thing, the more surface area you cover to kill off sound velocity, the more effective it becomes. Because as it bounces around in the room, it is bound to come across one of the rockwool panels hanging in lateral positions around the room, that way the energy dies down eventually.
This is why it is important that the effective absorption area/abroption panels, are placed 60cm from ground.
Also notice one thing in common, the back wall centre location, is where it always hits. Notice that it doesnt really hit the corners of the room ?
So when i look at it, you can place some nice panels there. If your room door is there, then you may have some headache. because its gonna be difficult to treat that area. So the door at the right, is not a bad thing afterall.
Overall i think your room will be ok.
Here is where I shared previously
On why we need to have the acoustic absorption panels right in the middle behind MLP. No matter where u place the LR speakers along the front row, the “ sound velocity “ is always higher at the back of MLP. Hence we need to use absorption right in the dead centre behind MLP. (Very important ) remember this
On the platform, it’s easy to build, you can use plywood, that works well as a “pressure membrane” . Just need it zig zag with air gap. Make sure it is able to support the weight of the RS2 JTR
Here is one DIY’ed by another member for his speakers to be elevated before going behind the AT screen… unfortunately he had to scrap the project
They followed the same method. This has more to do with vibration control and absorbing sound pressure.
Remember the diagram above? You see sound velocity is not at corners of the room ? That’s because sound pressure is concentrated at that area. This panel, now works at reducing sound pressure moving downwards.
The above is how I did it at my place, 26cm height. Below that DIY pressure plate, I used granite. Granite’s resonant frequency is 7khz range. So we are not concerned with “ringing” from the subwoofers because they don’t play that high up in the frequency. The granite 4cm thick , now works as a mass to absorb all the energy moving downwards . Beneath that granite place cork + sorbothane.
Next you just need to have 25kg of steel shots on the top cabinet of the JTR RS2. The steel shots now works to dissipate energy moving upwards towards ceiling . U can get it from pan abrasive
S460 will work
You are now done with subwoofers all 4 JTR isolated, with top cabinet having steel shots. It is now ready for integration. This integration part is where I will need to come into the picture. So u can first go ahead with the above and get it ready.
I’ll come down more on acoustics and why we shouldn’t go full range… they are all inter related…
Now that you can understand the difference between sound velocity and sound pressure, I’ll dive in to the room acoustics
“are placed 60cm from ground.”
Normally I DIY 2.4m tall panels and let them rest on floor but secured to the wall. Is that ok?
plywood, that works well as a “pressure membrane”
Plywood not too thick so that it can flex a bit?
“Just need it zig zag with air gap”
Paiseh, does not understand this
“are placed 60cm from ground.”
Normally I DIY 2.4m tall panels and let them rest on floor but secured to the wall. Is that ok? Yes that is ok. Ideally the panels are velocity absorbers. Noticed that at the bottom or corners, pressure builds up. So ideally I would want to place pressure type of absorption devices at those areas. Because your can only place either one. It you decide to absorb velocity, u can’t absorb pressure and vice versa. Something must give way
plywood, that works well as a “pressure membrane”
Plywood not too thick so that it can flex a bit? 20mm ply is good
“Just need it zig zag with air gap”
Paiseh, does not understand this. As in one on top of another like the below , front look
Back
Bro , if the JTR is a no go and at any point in time Econav is involved in any of the activities or u get the Rythmik F18s, I don’t want to get involved. I have been through one round previously, and I don’t wanna be involved in any drama. I’m just into it as a hobbyist. And the main reason I’m helping is because I want to return the favour to our local Singapore community. That is the main reason why I’m here at this forum and not at stereonet. But you will understand the story here on why I would not want to get involved.
Because I won’t know who u approach. But if you do wanna get from Econav and his products, I would prefer to stay away. This I have to make it absolutely clear up front.
I will help you all the way… to make sure you are really satisfied and happy with the system. But must let me know upfront if this dealer is involved
If you decide for JL, seatons, psa subs, svs, or even DIY from synthesis, I’m more than happy to work with synthesis to discuss how we can execute it at your place.
The best is do a quick round of demo at my place when u pop by, if you love what u are hearing, then just need to Mimic what I have done .
The biggest benefits are they have been proven to be effective. I for one, advocate superior timing, maximum headroom and articulated bass. This is what I work towards and I will share this with your detail by detail when we catch up
Since I DIY, I can make the bottom 60cm pressure type and above velocity absorbers. With a lot of kids monkeys around, I prefer to rest big items on the floor and secured to the wall.
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No brand loyalty. Not even for MA after they discontinued the GX.
Looking forward for the demo session.
Ok no worries, hang on to any purchases for the moment. Have some ideas. I’ll break down all the details. Then once u have the idea, u will know which and what u like and you can then proceed to execute
I’ll also show u how full range sounds vs non full range. We have the same speakers and room size is about same. Yours is bigger. So it will be good experience, no second guessing. Just let the system do the talking. You can share with us from your neutral point of view, which one u prefer. Full range or non full range (speakers small +subs) . Don’t worry just shoot and be frank if u prefer A or B, so we can have a neutral second opinion
We will also do a quick 5 mins test
Playing physchoacoustic bass
Playing hard hitting bass
Playing air movement articulated type of bass
All sorts of different types of bass and we will run mostly 50-100hz range, I’ll randomly on off the subs and u can be the judge if u can pin point exactly which subwoofers are playing , whether it’s front corner, left back or right front
Once u have established all the facts and u possess the knowledge, u will understand what u need to do in your room. Then u can slowly plan which and what goes where and how to work with WAF factor at the same time
Catch up soon again.
Sometimes odd shape rooms like this has their own advantages . May not need to treat the side wall that much . Just need to treat the rear wall. The only thing is front stage must be at the smaller surface area side. Even for ceiling , low(front stage height) to high also good.
Here is an example of pressure absorbing devices, from SMT. It is known as the SMT Varitune V4. These are effective from 40-110hz type of range
Quote from SMT
V4 is part of the Varitune family and works as an adjustable Helmholtz resonator in the range 45-110 Hz. It is adjustable to all rooms and obtains a high absorption co-efficient. The module can easily be integrated above and below the different MA-modules to adapt the bass absorption to the diffusers lower limit. The setting of the V4 module is done with a test toner that generates the resonance of the room at the same time as the front shutter is adjusted to optional frequency within 45-110 Hz. Optimal placing is corners or floor-ceiling angles
Advantages with V4
The most flexible and effective bass absorbent in the range below 100Hz on the market Adjustable to fit all rooms High Absorption co-efficient due to the Helmholtz principle in combination with high Q-value Integrates with the rest of the SMT acoustic modules Available as standard in white, Oak and Birch
Notice it says corner ? That’s because at the corners, they are pressure zones. All the pressure gets accumulated at corners .
Whilst you can use bass traps (rockwool) with air gap at corners, the tuned traps targets pressure zones . The rockwool with air gap, is probably good from above 120hz, unless you have very huge bass traps
Base on your room layout, it looks like u can have traps at corner sections. Unlike my place, I can’t have this because one corner to my living room is to the kitchen, another corner is to the common room and master bedroom.
So on one side I’m using the active bass trap from psi. Because i don’t have the luxury to place any panels at these pressure zones
So remember, space is a luxury, it makes a difference what panels u choose to put there. If u r going to have something, make sure it’s really worth putting it there. (As in really working well)
So if you place an absorber like this in the room like the ones below
It not only doesn’t do anything down lower frequencies, it sucks away the useful energy upper frequencies going into the room. The sound becomes dull
But if you place this high quality effective diffusor, like the SMT below , you yield the full benefits taking advantage of the space u have
So remember, once u place those black foam absorbers, u no longer have the place to place the SMT diffusors . U can only choose 1. U cannot place both at the same location.
So this is important, what I’m trying to convey is when you do up your room, use quality effective diffusors or absorption panels. Diffusors made of solid softwood. Don’t use any styrofoam type, paper diffusors, cardboard diffusors etc. The same for bass traps
Imho, I prefer mixture of materials . Also depends on your placement of speakers and speakers characteristc . One type of material throughout will lean to one type of sound only (if it suit your taste) .
Bigger room maybe sounds ok . But if smaller room like me, mixture is still better .
Alamah. I got half of the advantage. my front is 4m and my back is 6m. And the half of the disadvantage, my front height is 5m and the back height is 1.6m.
The SMT and V4 look DIYable with solid soft wood board.
Are the plans available?
Also can use plywood or OSB?
To be frank, i myself have not experience front small, rear big room before. Just happened to read an article in the past when i started playing with acoustic treatment where some studios designed in such a way. Take note is for 2 channels so i also cannot confirm if it is good for ht. But i believe more or less has the benefit on reducing first reflection. U might want to try place 2speakers to try out first if u like it. I suspect front stage smaller will have better diffusing effect on surround ambience feel. Front stage bigger will have heavy front stage sound.
Density of materials does matter. Different materials vibrate at different frequencies. So u can copy the design to have similar effect but probably different sound signature.
If sound control room is one of your objectives, think u should do the basic first before move in the furniture n equipments.
Really envy u have a big room to start with. No matter how u cut it, still bigger than our regular hdb room 
If i have your ceiling height, most likely i will make a raise up platform on the floor.
I asked the archi to lower the floor of the HT room by 180mm. I will DIY Raise floor to 0 so that same level outside.
But now I able to do a 2nd row. not sure to keep row 1 or row 2 at zero.