# Help with acoustics (12' x 18' x 9' room)



## blued888

*Help with acoustics (12' x 15' x 8.75' room)*

Room size is 12' x 15' x 8.75'.

It is pretty much all bare walls, thin curtains hanging over the windows.

What materials are good as acoustic panels? I've found Rockwool by searching and it is also what's available locally to me. I live in the Philippines.

These are the available Rockwool stuff I can get:

*- Triangular corner bass traps (4', 5' or 6' in height)
- Pillar bass trap stands (2', 3' or 4' in height)
- Acoustic paneling (2' x 4' x 2")*

These are being made by a local HT forum member but I was thinking of doing it myself if I would be needing a lot of it. I'm initially looking to get two 4-ft pillar bass trap stands and four 6-ft triangular corner bass traps. I don't know how much acoustic paneling I actually need. I was told that only the first reflections are crucial (position to be placed can be found through the mirror method)? 

*Some questions:*

Do I need *ALL* these in tandem with each other for the best sound experience?
Does acoustic paneling *HAVE* to be mounted on the wall/stuck onto the wall? I just plan to lean the boards on the walls. They'll be slightly angular to the walls and not totally flat. (Can't make any major modifications to the room obviously.)

I know I definitely need acoustic materials for this room because the speaker system sounds so much better in a room almost three times as large. I can barely feel and hear the bass unlike in other rooms where the bass was really tight and loud.


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## bpape

Welcome to the Shack.

First of all - be realistic. No matter how much you treat a room, you're not going to get things to sound the same in a small room as you will in a large room.

Second, your room dimensions have some overlap (L=2xH, 2xW=3xL AND 4xH) so there will be more modal buildup. 

You will need a combination of broadband bass control and reflection control. You don't necessarily need the triangular ones and the tall ones (sorry, Pillar is our product name but I understand what you mean). Before saying which would be better, I'd need to know the sizes of the triangels and the taller ones.

You might also need some thicker panels on the rear wall if you end up with nulls off the back which I suspect you will.

Bryan


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## blued888

bpape said:


> Welcome to the Shack.


Thank you. I actually registered January 30th but only got the e-mail fixed today.



bpape said:


> First of all - be realistic. No matter how much you treat a room, you're not going to get things to sound the same in a small room as you will in a large room.


So a bigger room is indeed better for HT? Don't know much about how room size affects HT performance. The other room I tried putting it into was around 3700 cubic feet.



bpape said:


> Second, your room dimensions have some overlap (L=2xH, 2xW=3xL AND 4xH) so there will be more modal buildup.


It's not entirely rectangular shaped, there's a set of cabinets on the left side of the room. Will provide a visual top view model of the room when I get to 5 posts.

What's meant by modal buildup?



bpape said:


> You will need a combination of broadband bass control and reflection control. You don't necessarily need the triangular ones and the tall ones (sorry, Pillar is our product name but I understand what you mean). Before saying which would be better, I'd need to know the sizes of the triangels and the taller ones.
> 
> You might also need some thicker panels on the rear wall if you end up with nulls off the back which I suspect you will.
> 
> Bryan


Reflection control is done by acoustic paneling, right? While broadband bass control is done by bass traps? Wasn't sure as to how else properly term those "Pillar" stands. Sorry about that. :bigsmile:

I was thinking of getting the stands because they could double as speaker stands for my surrounds. Base dimension would be 8" x 8" or 12" x 12", height I'm planning to get is 4-ft. 

For the triangular corner bass traps, base dimensions are 11.8" x 11.8" x 16.5", height I'm planning to get is 6-ft. It's constructed by stacking up triangular rockwool boards and putting them into a triangular wooden frame.

The acoustic paneling is a normal 2-ft by 4-ft by 2-inch rockwool board that is supported by a wooden frame.

Btw is it okay to cover the rockwool board with wool batting in order to prevent any particles from going around? Burlap fabric will be the outer cover of everything.

By thicker you mean the 4-inch variant? I think that's the thickest I can purchase, other than stacking them up.

Thank you Bryan for helping.


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## bpape

A bigger room certainly has advantages. Your room is not small though. My point was that you have dimensions that are multiples of each other which causes frequency response peaks and dips (room mode issues)to occur in the same places in the spectrum - so they tend to build up and be more pronounced than if they were occurring in different places.

For the bass absorbers, both are a bit small IMO. The 12"x12" will work OK. 16"x16" would be better. For the triangles, 17x17x24" will reach deeper into the subwoofer range.

Batting on top of the mineral wool will be fine.

Bryan


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## blued888

I Google'd broadband bass absorbers and saw images of panels with 24" x 48" x 8" dimensions. Is that what you were talking about? What would be your minimum recommended dimensions for the triangular bass traps?

And are diffusors a necessity?

How would you rank acoustic paneling, bass absorbers and diffusors/diffusers based on importance? 1 being the most important.


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## bpape

The trianges are equilateral with 2 17" sides and a 24" hypoteneus. That will require double the internal material to a 12x12x17". 24x48x8" could be a good treatment in the right application.

Do you need diffusers? Hard to say. I'd want to know more about the room but overall, no, they're not absolutely necessary but they're a nice addition in the rear half of the room or behind speakers like Magnepans, Martin Logans, etc. to minimize comb filtering from the rear wave.

As for ranking, there really isn't any ranking to it. They all do different things and are part of the solution. If I could only do one, I'd do the broadband bass control.

Bryan


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## blued888

bpape said:


> The trianges are equilateral with 2 17" sides and a 24" hypoteneus. That will require double the internal material to a 12x12x17". 24x48x8" could be a good treatment in the right application.


You mean 17" x 17" x 24" triangles, right? Equilateral would be three identical sides of 17" or 24".



bpape said:


> Do you need diffusers? Hard to say. I'd want to know more about the room but overall, no, they're not absolutely necessary but they're a nice addition in the rear half of the room or behind speakers like Magnepans, Martin Logans, etc. to minimize comb filtering from the rear wave.
> 
> As for ranking, there really isn't any ranking to it. They all do different things and are part of the solution. If I could only do one, I'd do the broadband bass control.
> 
> Bryan


Thanks. I'm actually thinking if I should just move the equipment to the other room. Will have to weigh in on things I guess.


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## bpape

Sorry. You're correct on the term. I meant Right Isosceles triangles. 2 sides the same and a right angle.

Bryan


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## blued888

bpape said:


> Sorry. You're correct on the term. I meant Right Isosceles triangles. 2 sides the same and a right angle.
> 
> Bryan


No problem at all. 

I'll post a better idea/visual of the room later.


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## blued888

*Re: Help with acoustics (12' x 15' x 8.75' room)*

Room dimensions corrected: 12' x 15' x 8.75'


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## bpape

Looks like any kind of symmetry in treatment in the front or rear of the room is pretty much out - at least down low. How tall is the big cabinet on the left wall?

Bryan


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## blued888

*Re: Help with acoustics (12' x 15' x 8.75' room)*

The cabinets are integrated into the room, from the floor to the ceiling. The stand/shelf on which the TV is on is about 6.5-ft. The center sits on the top of the shelf and is pointed down towards the listening spot.

Attached is a photo of what the room actually looks like.


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## bpape

Can you trap in front of the cabinet in the 'corner'?

Bryan


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## blued888

Possibly. Are the bass traps going to be really heavy? Will they be easily movable just in case the cabinets need to be opened from time to time?


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## bpape

They don't need to be depending on how they're constructed. Our Tri Traps for example, only weigh about 20lbs each, don't have to mount, and would easily slide across the wood floor. Add 'furniture sliders' to the bottom and it's a piece of cake.

Bryan


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