DIY - Room Acoustics..

[Naturelover]

Great job.
Please confirm the dimensions

 

[elangoas]

Great job.Please confirm the dimensions

It is 57 inches (W) x 24 inches (D) x 11 inches (H)..

 

[Naturelover]

It is 57 inches (W) x 24 inches (D) x 11 inches (H)..

Thanks. I thought there was some error there.
What's the thought process of putting it under the seat?

 

[elangoas]

Thanks. I thought there was some error there.

Ha ha..Nope..

What's the thought process of putting it under the seat?

My listening position is against the back wall.. From the earlier measurements i had from my room, it was clear that my listening position has some peaks between 100 - 250Hz, with a lot of variance.. The most damaging ones were the height mode & length mode resonance that build up against the back wall..

I have a 3 seater sofa against the back wall.. Though the space below the couch is unused, thought of stacking an absorber in that space, which can effectively absorb more in the lower range, from 100Hz on wards.. Hence the dimensions of 5 ft x 2 ft x 1ft approx..

Got the absorber and slid it under the couch..

 

[elangoas]

Per the frequency wavelength chart, to absorb a 100Hz fully, the absorber has to be 34 inch thick.. Though am no way near it, the DIY absorber is 24 inches deep and should be able to do atleast 50% absorption there.. Also uncompressed rockwool has more absorption lower down the range..

Hopefully it reduces the peaks and brings the freq range > 90hz with little, but acceptable variance..

 

[elangoas]

The addition of DIY absorber under the couch, made some improvement to the listening for good, am now considering to treat front wall and back wall in the living room with uncompressed mineral wool..

- Can't do side wall absorption as it is the most accessed space..
- All absoprtion will be mounted to wall, with 0.5 inch airgap (or) without airgap..
- Also planned to move all the 4 subs to ceiling, have a 5.4.2 set-up..

I have done some rough room layout and where i intend (possibilities) to add absorption in the room..

L-C-R speakers are mounted to wall.. There is a window behind the Acoustic transparent screen & center channel, which i thought to make use of absorption there, on either sides of center speaker..

The surrounds are to either sides of listening position..

My listening position is against back wall, so can't add / do rockwool there.. Thought of low density acoustic foams, and can do abt 2 inch foams behind my listening position, fixed to walls and door directly opposite L-C-R..

Above 6.5 ~ 7 ft from the floor, i can do more thickness on front wall & rear wall, which is the most unused space in the living room, so thought of more thickness.. I can do upto 15 - 18 inch thickness of absorption, high on front wall & rear wall.. Is this too thick?.. Would it deaden the room?..

Appreciate your inputs..

 

[mpw]

Please buy only Flame Retardant material

Regards

 

[sound_cycle]

so thought of more thickness.. I can do upto 15 - 18 inch thickness of absorption, high on front wall & rear wall.. Is this too thick?.. Would it deaden the room?..

Highly likely.

What are you aiming to do ?

Why do you want to place thick absorption where it is sub optimal ?

Ciao
GR

 

[elangoas]

Highly likely.

Hmm.. So reduced thickness should work?..

What are you aiming to do ?

Apart from the recent DIY absorption, i don't have absorption at all in the room.. Trying to bring down the room resonance to the extent possible..

Why do you want to place thick absorption where it is sub optimal ?

I can't place absoprtion in ideal locations of wall behind my listening position, so thought to make use of the least accessed space in the room with thicker ones..

But, wouldn't i benefit taming (or) reducing the intensity of the modes between 90Hz - room transition freq?..

 

[sound_cycle]

So reduced thickness should work?..
Apart from the recent DIY absorption
I can't place absoprtion in ideal locations of wall behind my listening position

But, wouldn't i benefit taming (or) reducing the intensity of the modes between 90Hz - room transition freq?..

I think that you should benefit from some careful reading, understanding and thinking about the issues you are addressing before rushing to get things cut and installed. But hey it's your time and money.

If you room is so lively that some absorption placed at floor level makes a audible difference it would seem like you are addressing the wrong (set of) issues. I am guessing of course from what you just wrote.

But then I might have missed reading the post where you listed them.

Dirac beta is on trial. It does a fantastic job with low bass. Trying to fight 90 hz with BBA at the wrong place is unlikely to get anywhere so I am just putting that info out.

Ciao
GR

 

[elangoas]

I think that you should benefit from some careful reading, understanding and thinking about the issues you are addressing before rushing to get things cut and installed. But hey it's your time and money.

Sure.. The try, is only a calculation that it should work.. Will keep observing the changes that it brings at my listening position..

If you room is so lively that some absorption placed at floor level makes a audible difference it would seem like you are addressing the wrong (set of) issues. I am guessing of course from what you just wrote.

But then I might have missed reading the post where you listed them.

I don't know what is a lively room, nor have been to a place where i felt them.. The last time, i took measurements it was obvious that there are some peaks at my listening position and a variance of 15dB from 90Hz onwards upto 300Hz.. As mentioned earlier, i have limitation with placement of absorption in living room.. So tried to utilise the undercouch space to tame peaks at the listening position..

What the under-couch absorber has done is, made a good all round improvement from all the speakers, it has made L-C-R feel more prominent.. I don't know how much it has helped to absorbed, but it defently feels like a progressive improvement after adding multiple subs in the room.. Hence thought to try some more options..

Dirac beta is on trial. It does a fantastic job with low bass. Trying to fight 90 hz with BBA at the wrong place is unlikely to get anywhere so I am just putting that info out.

Thanks.. I already have an AVR with Audyssey XT32.. Am trying to move away from EQ, as soon as the bass variance at the listening position are within acceptable limit..

 

[sound_cycle]

I don't know what is a lively room, nor have been to a place where i felt them.. <snip>Am trying to move away from EQ, as soon as the bass variance at the listening position are within acceptable limit..

All the very best. Like I said it's your time and money.

GR

 

[elangoas]

All the very best. Like I said it's your time and money.

Thank you.. Sure it is.. Hope for the best..

 

[elangoas]

Got some material to build the enclosure for absorption..

- 4 ft wide x 10 ft long plastic coated metal mesh (green) for abt Rs 500..
- 4ft wide x 11ft long stainless steel mesh (Rs 1,000) to wrap the green mesh and hold the uncompressed mineral wool from the trap by not seeping out..
- Thinking of wrapping the whole absorber with chiffon saree material, as they seem to very closely knitted fabric (inexpensive) and a good amount of airflow through it..

Thought of a frame-less absorber, to absorb from all possible exposed sides of absorption..

Absorber dimensions - 36 inch (H) x 30 inch (W) x 15 inch (D)..

Planning to do an other one of the same dimension and place it above my listening position as a first step to try and observe the changes it brings to the room.. Planned to complete both the traps over the weekends..

If this works, will slowly add some more overtime..

 

[argentum246]

Great going elangoas.
With your efforts we all are learning new things. However i have some generic concerns here :
1. WAF or family using the same room. The dead sound (or anechoic ) might cause mild irritation that cannot be expressed in words. We humans cannot live until there is some noise around.
2. The extra sound absorbing material shall make home cleaning a tough task as dust and moisture shall creep no matter what, in India. This would then cause allergy / mold smell in diff seasons.
3. Room aesthetics would take a back seat unless all the materials you use are of same color / style and less obtrusive while you are watching / listening.
4. Diff materials have diff absorption / diffusion properties. Hope you had similar material through out.
5. A thick carpet and a good upholstery sofa (with inbuilt cushioning) add a lot to sound absorption without being eyesore in the room.

Let us know what specific issue , in terms of sound you feel, not the graphs, that are bothering you. That would also help us in finding if we unknowingly suffer the same but could not find words to express it the way you can do now.

 

[liverpool_for_life]

I don't know what is a lively room

Try and play a movie at reference, -10 dB and -20 dB, without room correction. If you find yourself looking for the remote because the highs are painfully loud, you're looking at a lively room. How lively depends on what levels the "painfully loud" occurs. FWIW, the vast majority of untreated rooms in India (and pretty much elsewhere) ought to be lively.

nor have been to a place where i felt them..

Come home! I'll be happy to demo without the diffusers in place

And (I know I've told you this before), please consider using EQ to fix your issues till 300 Hz. It is extremely likely that you're going to end up "deadening" your room too much with your current approach.

 

[elangoas]

Great going elangoas.
With your efforts we all are learning new things. However i have some generic concerns here :

Thank You

1. WAF or family using the same room. The dead sound (or anechoic ) might cause mild irritation that cannot be expressed in words. We humans cannot live until there is some noise around.

It is a living room.. No luxury of dedicated room.. For a long time, i neglected / omitted the room treatment for i assumed it can't be accommodated in a living room.. But after consideration, i thought to do some in the room, which would improve the listening experience..

2. The extra sound absorbing material shall make home cleaning a tough task as dust and moisture shall creep no matter what, in India. This would then cause allergy / mold smell in diff seasons.

Ok.. I don't know much there as i haven't had an inch of absorption in the room, until recently i added an under-couch absorber..

I googled on the difference between rockwool & mineral wool, it seems the mineral wool / stone wool is made from stones, but not sure if it would have the same odour properties of "rockwool" (Which is made from volcanic rocks)..

3. Room aesthetics would take a back seat unless all the materials you use are of same color / style and less obtrusive while you are watching / listening.

Have carefully thought abt it, so not adding anything to walls in the living rooms, which are most accessed.. Planning to add absorption only in the unused space of libing room.. (Ceiling & high walls)..

4. Diff materials have diff absorption / diffusion properties. Hope you had similar material through out.

Yes, i will be using single material throughout the room, which is uncompressed mineral wool..

5. A thick carpet and a good upholstery sofa (with inbuilt cushioning) add a lot to sound absorption without being eyesore in the room.

Carpet (Fabric) & Cushion sofa (Polyester fiber) both have very little to no absorption properties below 300Hz, which also happens to be he most troublesome range to handle..

Let us know what specific issue , in terms of sound you feel, not the graphs, that are bothering you. That would also help us in finding if we unknowingly suffer the same but could not find words to express it the way you can do now.

Until i got the microphone, i fairly assumed that my room is good .. Post the measurements, it has become very obvious that the room needs some absorption to contain/bring down the resonance..

I sit against the back wall, (my ears are just 8 inch away from the wall) which seems like the worse place in the room, as most of room resonance build up against the wall / very strong.. All am trying to address is the bass issues in the room, below 300Hz ..

 

[elangoas]

Try and play a movie at reference, -10 dB and -20 dB, without room correction. If you find yourself looking for the remote because the highs are painfully loud, you're looking at a lively room. How lively depends on what levels the "painfully loud" occurs.

The highs are good, but not overtly bright even after prolonged listening sessions..

FWIW, the vast majority of untreated rooms in India (and pretty much elsewhere) ought to be lively.

Ok.. So mine is a lively room too

Come home! I'll be happy to demo without the diffusers in place

Thanks again.. For sure will drop in sooner..

And (I know I've told you this before), please consider using EQ to fix your issues till 300 Hz. It is extremely likely that you're going to end up "deadening" your room too much with your current approach.

Sure.. I will.. Probably i misimplied abt EQ.. I meant to correct the bass issues with absorption to the extent possible and then rely on EQ to do the rest..

There is a slight change in the approach now from the high wall absorption planned earlier, i will share details sooner with pics.. As a first step, i have thought to do the most room corners, joining the ceiling area, fully utilising the wooden structure which i have for subs & heights..

So, you as well as most other members have said my approach will deaden the room, which i guess happens only if the high freq in the room is absorbed right?..

 

[Dr.Lakshay]

Got some material to build the enclosure for absorption..

- 4 ft wide x 10 ft long plastic coated metal mesh (green) for abt Rs 500..
- 4ft wide x 11ft long stainless steel mesh (Rs 1,000) to wrap the green mesh and hold the uncompressed mineral wool from the trap by not seeping out..
- Thinking of wrapping the whole absorber with chiffon saree material, as they seem to very closely knitted fabric (inexpensive) and a good amount of airflow through it..

Thought of a frame-less absorber, to absorb from all possible exposed sides of absorption..

Absorber dimensions - 36 inch (H) x 30 inch (W) x 15 inch (D)..

Planning to do an other one of the same dimension and place it above my listening position as a first step to try and observe the changes it brings to the room.. Planned to complete both the traps over the weekends..

If this works, will slowly add some more overtime..

I think adding a wooden frame to it would be a good idea so that it doesn't deform easily and has better strength. Is it stable enough like this such that it doest not deform on pressure?

 

[elangoas]

I think adding a wooden frame to it would be a good idea so that it doesn't deform easily and has better strength. Is it stable enough like this such that it doest not deform on pressure?

Sure.. i understand.. It is fairly rigid.. Actually i have wooden frame on ceiling to hold subs.. So there will be back wall support and thought of mounting it to side walls using "L" clamps at the bottom of the absorber for that extra support..