Acoustic Treatment for Bedroom

[Josh784]

I'm setting up a stereo in my bedroom, which is 12' x 12' x 12'. The speakers will be against the far wall on either side of the window on stands. The floor is carpet, and there is an open (no door) closet to on the right side of the room. The acoustics in here are pretty bad and I'd like to do something to improve how the stereo sounds when I set it up.

I was thinking about doing something along the lines of what is outlined here:

http://mywebpages.comcast.net/kidder/Audio/Room/PANEL/Panels.htm

Problem is I can't find fiberglass duct board anywhere in town.

Are the panels outlined in the above article a good way to go? What other options do I have? I'd like to keep it under a couple hundred dollars.

Thanks!
Josh

 

[highfihoney]

Hi josh, contact your local "industrial construction supply house" & buy owens corning rigid fiberglass insulation panels,they are made from woven fiberglass fibers & are denser than duct panels,the cost wont be bad at all.

Be aware though that fiberglass by design is very much like asbestos & dangerous to a point, if you plan on using it in your living area all 4 sides should be encapsulated so as not to release airborn fibers in your home,fiberglass is much like asbestos & all the related diseases that came with asbestos, be carefull with it & treat it like asbestos.

 

[Josh784]

I assume that is the same material that can be found on atsacoustics.com?

What is the best way to encapsulate all 4 sides?

 

[Josh784]

Also what is the difference between the 703 and 705 board?

What are the advantages of the fiberglass board over mineral wool?

 

[sploo]

Hi Josh,

It looks like the atsacoustics.com panels are Owens-Corning 703 and 705.

The two products are different densities; Lower densities are generally better for high frequency absorption (i.e. at first reflection points), and higher densities, especially with some form of membrane, are better for bass traps.

Lots of info here: http://www.ethanwiner.com/acoustics.html

You can see details of some panels I made here: http://spikyfish.com/acoustics/ and here: http://spikyfish.com/acoustics/panels.html

The above pages include wrapping the panels in batting/wadding to seal in fibres.

I found a source of panels by contacting various manufacturers and asking if they had local distributors. BTW I've just found my Knauf link on the second page is now dead... looks like the whole URL may be down .

 

[highfihoney]

Also what is the difference between the 703 and 705 board?

Im not familuar with these numbers but i'd guess that the difference would be produce density & R factor.

What are the advantages of the fiberglass board over mineral wool?

I wouldnt have a clue as to which product is superior over the other.

Im just a contractor who works with fiberglass & have used it for various applications for my work including sound deadening & sound dampening of school gymnasiums ,im also very aware of the serious dangers with fiberglass especially with children thats why i pointed it out,the government & OSHA are very slow to act on this material but it is a carcinogen & the dangers are real.

I would recomend looking into another non fiberglass product for your panels but if you chose to use fiberglass you can seal if with clear coat spray in a can to minimumize the danger.

 

[Josh784]

Cool, thanks for the tips

 

[Josh784]

Is the mineral wool easy enough to work with? Obviously it isn't rigid, but I'm assuming it wouldn't be too difficult to attach it to a rigid backing. The reason I ask is that it's half the price of OC fiberglass panels, and would save me a few hundred dollars.

Would 4" panels made using either material (via layering) be effective low frequency control if made into triangles and placed in the upper corners of the room? I was thinking of doing this, and hanging some 1" or 2" panels on the walls for middle and upper frequency control. I am unsure of where the best place for these wall panels would be however.

Am I on the right track here or should I be moving in a different direction?

Thanks

 

[Scott R. Foster]

Hi Josh:

Rockwool works fine... look for something +/- 60 Kg/m3. If that material is cheaper in your area than fiberglass than it its may make sense. But rockwool is floppier than an equivilent fiberglass board and a bit harder to work with as a result. Also, the lack of stiffness make getiing a sharp looking panel problematic. Don't build a solid back panel... a simple open frame sufficient for stapling fabric is all you want/need.

Changing from a 3 lbs. density fiberglass board to higher densities [such as going from 703 to a 6 lbs. board such as 705] will not make a material change in absorptive properties given you make your panels a rational thickness to begin with [4" for a broadband panel is the efficiancy "sweet spot" for fiberglass boards]. A 4" thick 703 panel will weight half as much as a 4" thick 705 panel, have about half the material cost, and work just as well.

You can view the manufacturer's specs for these two materials [and many others] here:

http://www.bobgolds.com/AbsorptionCoefficients.htm

Note the lack of any indication of superiority in 705 versus 703 [in fact the opposite is the case].

Adding membranes and such to broadband absorpers is generally a bad idea, as it yields a peak in the absorption curve - if you have reason to feel this is desirable you should validate the effectibeness of the membrane you add to suit your needs with measurements post installation.

 

[Glenn Kuras]

Im just a contractor who works with fiberglass & have used it for various applications for my work including sound deadening & sound dampening of school gymnasiums ,im also very aware of the serious dangers with fiberglass especially with children thats why i pointed it out,the government & OSHA are very slow to act on this material but it is a carcinogen & the dangers are real.
.

You may want to take a read here.
http://www.recording.org/ftopict-21013.html

Glenn

 

[Josh784]

Ok, Owens Corning 703 shall be the material of choice...Now on to what I should make from it.

I am thinking some 4" thick triangles to place in the 4 top corners, and then some 2" panels.

Where should I hang the panels? I'm pretty new to all this and don't understand reflection points and all that. I think some reading may be in order.

 

[Glenn Kuras]

Cutting the 703 to triangles then stacking floor to ceiling will work GREAT!!

Building the 2" panels for the first reflections is the right way to go. For panel placement you would want to run a mirror down the left, right, and ceiling to find the reflections. Where ever you can see a speaker from the sitting location (some one else will need to run the mirror down the wall while you sit in listening location) is where you want a panel. Remember if you have more then one setting spot you may want to cover for those areas also. It all depends if you want the other people in your room to benefit from reflection panels or not.

Glenn

 

[Josh784]

I'd love to stack floor to ceiling, but I'm not sure that I can afford that much material at this point. What I was referring to was making a single triangle and placing it in the top corners so one edge was against the ceiling, and one edge against each of the two walls forming the corner.

Thanks for the mirror trick, I will definitely do that!

 

[Glenn Kuras]

I'd love to stack floor to ceiling, but I'm not sure that I can afford that much material at this point. What I was referring to was making a single triangle and placing it in the top corners so one edge was against the ceiling, and one edge against each of the two walls forming the corner.

Thanks for the mirror trick, I will definitely do that!

Oh making the triangle thing will help, but not solve the problems. If nothing else build the panels 4" thick and straddle corners.

Glenn

 

[Josh784]

How long should I make them? I doubt I can afford enough material to do all 4 corners down to the floor. The other issue is with installation as there is a 1.5" wide, .75" thick strip of wood running around the room about 18 inches from the ceiling.

 

[Glenn Kuras]

How long should I make them? I doubt I can afford enough material to do all 4 corners down to the floor. The other issue is with installation as there is a 1.5" wide, .75" thick strip of wood running around the room about 18 inches from the ceiling.

Start with an 2'x4' panel in each corner and see how that goes. Most rooms need more then 4 bass traps but 4 is much better then none!!
If you get a moment take a look at this study case about adding bass trapping to the room. It gives samples of 4 vs 8 traps and set up of them.
http://www.sbrjournal.net/journalsite/archives/acoustics/Acoustics.htm

Glenn

 

[Nick250]

The acoustics in here are pretty bad and I'd like to do something to improve how the stereo sounds when I set it up.
Thanks!
Josh

Don't forget to keep in mind the acoustical impact of the big mirror on the ceiling over the bed! That seems to have been overlooked. As usual I am just doing my best to help out.

Nick

 

[Scott R. Foster]

I'd love to stack floor to ceiling, but I'm not sure that I can afford that much material at this point. What I was referring to was making a single triangle and placing it in the top corners so one edge was against the ceiling, and one edge against each of the two walls forming the corner.

Thanks for the mirror trick, I will definitely do that!

Just Use 4" panels across the corners... in fact use 4" panels throughout.

 

[majorloser]

Don't forget to keep in mind the acoustical impact of the big mirror on the ceiling over the bed! That seems to have been overlooked. As usual I am just doing my best to help out.

Nick

So satin sheets and a mirrored ceiling isn't accoustic treatment?

(Maybe sound proofing ain't such a bad idea )