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DIY Room treatment

Holmz

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We have a multi use lounge room (living room) which is 4.1m x 5.8m x3.35m high. (13.5’ x 19’ x 11’ ceilings)
It is an old house (~100 years old) with plaster walls and ceilings on a wood floor.

There is a dining room which is open to this room, and a door way to the hall from both rooms, and another doorway from the lounge room open to an entry room.
So whether these doors are open or closed likely affects the bass (??).
The dining room is 4.1 x 3.6m x 3.35m (13.5’ x 12’ x 11’ ceilings), so efffectively the room might looks more like 31’ long x 13.5 wide.

There is a TV connected to an AVP, currently in 5.0.0, eventually 5.3.2
The 2 channel goes (or will go) to the L/R front speakers.

The TV will be moving to a table under the window with a TV-lift mechanism to retract it during the day.

I’ll blame the general mess on a new puppy.

View looking down the room:
128D6DFA-7C05-43B6-92E5-F3C290687A9B.jpeg


View from the sofa:
F09579CC-B99A-4947-A1A7-7A737F6D9660.jpeg


As I Fly-In/Fly-Out (FIFO) and we are in the middle of an extended move it is taking a while.

I guess I’ll start with REW measurements and get a subwoofer into the mix.

My Plan:
  1. Do REW measurements
    1. RT60 decay
    2. and room modes
  2. Get the subwoofer put together and place it on the sofa seats
    1. Take measurements around the front and back wall for subwoofer placement giving decent response
    2. And to determine if the corners can be used for bass traps
Bass Traps:
As mentioned I can probably do some bass trapping in the corners, once I move the surrounds up the wall.
Any diffusers and absorbers will need to meet some WAF approval.

Absorber:
I have some WAF blessing for where the big IKEA light is in the middle of the room, so be some ~4’ square x 8” thick hanging elements with lights. These can house absorber and 2 of the surrounds which can be Atmos speakers. These are the two speakers in the front parading as LF and RF currently.
(Ignore the speaker on the stand in the foreground.)
Those panels would hang about a 12-18” off of the ceiling.

I can make a mock up panel and put in about 14 square feet of absorber in 6-8” thick on each of these absorber/Atmos panels

Diffuser(s):
We also have some agreement on diffuser or absorber panel behind the sofa.
It would be easier to do diffuser scheme there from a decor perspective, and I am not sure if a 2-3” thick absorber there would do anything good.
(I guess the measurements might infor me?)
and also a diffuse for the front is possible.


The LR surround is on the floor (next to the didgeridoo), which will move up wall when I get the bracket installed.


I should be able to get some more work done on it during the XMAS break. Just getting the AVP running was a big step for me, as it was my first jump into HT.
Basically I am trying for some optimization of the room without going to the point of making it dedicated room, which is a non starter.
So any idea for approaching the problem is welcome, in a step by step sense.

@sarumbear said he would be willing to comment as I go, so hopefully the endeavour can aid someone else in the future.
 

sarumbear

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We have a multi use lounge room (living room) which is 4.1m x 5.8m x3.35m high. (13.5’ x 19’ x 11’ ceilings)
It is an old house (~100 years old) with plaster walls and ceilings on a wood floor.

View looking down the room:
View attachment 242557

@sarumbear said he would be willing to comment as I go, so hopefully the endeavour can aid someone else in the future.
These are the issues I see in order of importance:
  1. I do not know the actual layout of the room but the positioning of the speakers in the room is a major problem. If it was my room I will place the speakers on the wall opposite to the window. No acoustic treatment will eliminate the issues you are having with that asymmetrical layout.
  2. Speakers will sound infinitely better if they are stand mounted.
If the relocation of the speakers is acceptable then please post the layout of the room with any connecting rooms and the doors if any. An RT60 response chart of the room below 500Hz is the next to make a decision on what acoustic treatment is required, if any.
 

Curvature

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Be careful with diffusers. The requirement that the listening distance is at least three times as long as the lowest operational wavelength to avoid issues. A few diffusers in a room is also fairly ineffective compared to using absorbers.

I personally would never put an absorber behind my head unless it was mostly reflective and had absorption focused on LF. The effect is very negative otherwise. In general I find the closer your head is to the back wall the less pleasant listening becomes, so treatment thickness also becomes a balancing act.
 

sarumbear

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Be careful with diffusers. The requirement that the listening distance is at least three times as long as the lowest operational wavelength to avoid issues. A few diffusers in a room is also fairly ineffective compared to using absorbers.
True but you should not rely on a diffuser for taming the acoustics above around 400-500Hz anyway. Diffusers are not low frequency management devices.
 

Curvature

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True but you should not rely on a diffuser for taming the acoustics above around 400-500Hz anyway. Diffusers are not low frequency management devices.
It was more of an FYI for the OP and anyone with small living or listening rooms. At 500Hz 3x the wavelength is just over 2m.
 
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Holmz

Holmz

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It was more of an FYI for the OP and anyone with small living or listening rooms. At 500Hz 3x the wavelength is just over 2m.

OK, but what is the factor of 3 for?

in my mind, one ideally one sucks the wall reflection to zero for the wall behind the listener.
Certainly lower is better for those early reflections which are ~2 feet away.

We have two feet to the wall and 2 feet back.so that is about 250Hz to be in phase, and a 125 Hz it about an 8’ wavelength, which would make for a null.
(using 1000 feet per second to make the math easy)

It is absorber to be used in a panel behind the listener, with a print on canvas covering it.
 

kemmler3D

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OK, but what is the factor of 3 for?
Diffusers scatter the sound evenly within a certain band using cleverly selected ratios of wavelengths. However, if you're closer than 3x the wavelength in question, you can experience uneven frequency response, because up close the even scattering is actually compromised by lobing. The diffuser works by causing self-interference via cleverly timed reflections (this is also why they are absorptive at certain frequencies) so you need enough space to let those interferences actually happen before the wave comes back to your ear again.
 

Curvature

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in my mind, one ideally one sucks the wall reflection to zero for the wall behind the listener.
Certainly lower is better for those early reflections which are ~2 feet away.

We have two feet to the wall and 2 feet back.so that is about 250Hz to be in phase, and a 125 Hz it about an 8’ wavelength, which would make for a null.
(using 1000 feet per second to make the math easy)

It is absorber to be used in a panel behind the listener, with a print on canvas covering it.
You can try this right now without a proper absorber and see if you like it. I uniformly have not, and dislike seats with headrests for the same reason.

All you need to do is to bundle some blankets or pillows behind your head while listening to music. Preferably something decently porous and fuzzy, but it doesn't really matter. You're aiming for an approximation. I like the envelopment caused by even a little extra space behind the head. Nearby rear absorption removes a lot of that.
 
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Holmz

Holmz

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You can try this right now without a proper absorber and see if you like it. I uniformly have not, and dislike seats with headrests for the same reason.

All you need to do is to bundle some blankets or pillows behind your head while listening to music. Preferably something decently porous and fuzzy, but it doesn't really matter. You're aiming for an approximation. I like the envelopment caused by even a little extra space behind the head. Nearby rear absorption removes a lot of that.

I totally agree, but the house is nearing 100 years old, and the walls are where they are.
 
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