John Sayers' Recording Studio Design Forum Archive

After long hour of research and emails with some known guys in this field I decided to build my own instead of buying ready made. I have questions.

1. My frames are 3" thick the glass board(Manvill 6#pcf) is 2" thick. Should I mount the glass up front or to the rear?

2. Should I use filling or some foam to fill the 1" space. (front or rear)?

I want to keep the frames exposed due the aesthetics of the room.

3. My frames are tight (2'x4') how do I get the material to stay in the frame?
a. liqid nails, spay adhesive. gorilla glue

4. I found speaker grill material at a local fabric store can I use it to cover my material?

Thanks for your respose.

1. My frames are 3" thick the glass board(Manvill 6#pcf) is 2" thick. Should I mount the glass up front or to the rear?

Mount it to the front; that effectively makes it 3" thick for better absorption at lower frequencies.

2. Should I use filling or some foam to fill the 1" space. (front or rear)?

I want to keep the frames exposed due the aesthetics of the room.

I wouldn't worry about that; especially don't use FOAM - most of these are closed cell, which will hurt absorption of the panels.

3. My frames are tight (2'x4') how do I get the material to stay in the frame?
a. liqid nails, spay adhesive. gorilla glue

All three have been used, with no reported problems.

4. I found speaker grill material at a local fabric store can I use it to cover my material?

Perfect; if it's designed as speaker cloth, you KNOW it will breathe enough to work for absorbers... Steve

Thank you. I will post some pics if allowed.

Pix - no prob; please resize so they're no wider than 750 pixels, plus there's a size limit of 150k each.

Also, it would be nice if you can edit your profile to include a general location... Steve

I did my first one to see how it will look. Here are some pics. Thanks for the help.

I have never done the photo thing so here is another. I was trying to put multi photos on one post. Oh well.

A few more

did you route the edges with a 45degree router. That looks good. So do you actually have a frame around the inner frame that holds the insulation?

Knightly. Do you mean that placing foam infront of insulation will hurt the properties of the traps he's making. Will that be the same as using polyester baffling on top of bass traps or traps in general. I am making bass traps, that I place fibreglass insulation on one version and rockwool on the other then I place 50mm polyester baffling on top of the insulation to absorb the high frequencies as well as hold the insulation fibres from going out of the traps. Will the polyester baffling prevent the bass traps from functioning properly and if so, what type of effects or damage is it causing. So making a bass trap and placing acoustic foam on top of it, will it affect the bass traps as well, in what way?

No I just cut the ID 2' top/bottom and 4' both sides and cut the angles with a compound miter saw. I got it at the hardware store for 99.00 US. I do trim work in my house with that saw. Its really good to have and it make jobs really easy.

As far as a frame in a frame......there is nothong hold the fiberglass except the wooden frame you see in the photo. That fiberglass is really stiff and the frames are exactly 2'x4' I.D. so when i put the speaker grill material on it with contact spray cement glue it is a tight fit.

Rigid Fiberglass

Sorry about the foam confusion; when I re-read that part, I realized I didn't state that the foam to stay AWAY from is the typical EPS, closed cell, BUILDING foams - what was being referred to is ACOUSTIC foam, which is OPEN celled. That type won't hurt anything, and could help the heavier density stuff when placed in FRONT of it; by "help" I mean enhance higher frequency absorption, if that's what you need... Steve

How do you identify open cell and closed cell foam. Are mattress foam closed cell and acoustic foam such as aurelex and sonex open cell. Do breathing tests identify if it's closed cell or open cell. Is the texture different, or is there a particular look between the two types of cell foams.

Also, knightly, my use of polyester baffling question. Can you please answer.

Hey Phunkeman - they look great.

Are you using them exclusively for corner bass traps?
How are you mounting them?

Ever bought an electronic component that came in a box with stiff white stuff pre-formed as packing? That's closed cell, usually EPS (Encapsulated Poly Styrene) - Mattress foam is usually open celled, but not always; and yes, the "blow test" is the most reliable to be sure. Textures vary depending on the material, rigid fiberglass just looks/feels like somebody "squished" regular fiberglass house insulation down to about 1/5 its original thickness (in fact, that's what's done) - rockwool/slag wool/mineral wools are still fairly rigid boards, but more greenish in color and rougher to the touch. Type "bob golds" into the search engine here, you should come up with a link to his absorber page; 'way more info than anyone else on the planet has collected in any one place... Steve

Thank You.

I will be hanging them in the corners for bass traps and on the wall as well.

I haven't discovered a cool way to hang them to get the most out of them yet. I hope some of you guys may have some cool way to hang and the look good too.

I believe if you hang them off the wall by an inch or two it will help get a little more low freq absorpsion...I have a couple ideas but i'm still looking.