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703 mineral wool or 703 fiberglass?
Old 9th May 2006
Gear Addict
🎧 15 years
703 mineral wool or 703 fiberglass?

Hell fellow gearheads,
I'm getting ready to sound proof my home studio. I've gotten a lot of ideas from this site, and I plan on instituting a few. my question is, "Should I use 703 minerwal wool or 703 fiberglass for my broandband absorbers and bass traps?". I know that the fiberglass is more rigid, but is rigid better? Please provide some insight, as I plan to do this work soon.

BTW, my room is a 14 x 14 box (nightmare) but I plan on covering the entire rear wall with absorbers. I'm going to use the IKEA bookshelf idea I saw on this site a couple of months ago. If any olf you have suggestions, please fire away.

Old 9th May 2006
Lives for gear
HudHudson's Avatar
🎧 15 years
Whatever you do, you'll need substantial trapping in the corners to deal with the offending modes created by the square shape of your room. And by all means budget to included absorbers at the first reflection zone (even with your mix position) and possibly a couple clouds above the mix position. 2" 703 is only $1.50 a square foot, so spend a little more and make sure you hit all the problem areas. My last studio had a 20x20 control room with a 10' ceiling...half a cube, terrible bass response, so we ended up resizing the room to 20x17 and that little change (plus all the trapping we installed) made a world of difference in hearing what was going on in the low end. I prefer fiberglass to mineral wool because it's easier to work with, cut, and cover plus easy to glue together to make thicker panels for bass traps. Go check out Ethan Winer's site (, some great reference material there for treating any room.
Old 9th May 2006 | Show parent
Gear Addict
timmcallister's Avatar
🎧 15 years
703 is an owens corning product name for a rigid fiberglass product. Mineral wool (or rock wool) is a different type of product.

With that said, they are very similar in acoutical absorption properties.

I have used both extensively. Rigid fiberglass is much easier to work with but OC 703 s way more expensive than Rock Wool. Rock wool won't stand on its own, will droop if hung with out a frame, etc.

Specs can be quite misleading as the products are tested in different labs, years apart, using inconsistent methodologies. But not to worry... Use any rigid fiberglass or rockwool with 3-5lb density and you'll get good results.

And yes, you are going to need lots of bass treatment. Try superchunks in all the corners (rockwool works well for these). I did this in a similar sized room and was VERY pleased with the result.
Old 9th May 2006 | Show parent
Gear Addict
🎧 15 years
Thanks HH. I have a feeling that the entire room will be one big absorber before it's all said and done.
Old 9th May 2006 | Show parent
Gear Maniac
T9c's Avatar
🎧 15 years
Another alternative is "acoustic cotton" which is made up of various recycled cotton materials to about a 5.5" thickness. I think it is cheaper than 703, but I can't remember for sure. It was $135 /4 pieces in a bundle.

I used it in the corners and between wall & ceiling in my tiny control room (10.5 x 11). I covered it in burlap from Walmart. It looks like a bunch of pillows hanging all around my room. Instead of sewing the burlap, I used Ty-Raps to tie all the pieces together...real quick & easy.

The stuff comes in 2x8 ft peices. It is pretty easy to handle, as it doesn't fall apart. The easiest and fastest way I found to cut it was using a Skill saw with a plywood blade. You can cut it just about anyway you want to. I'll upload some pics if you want.

I bought it here:

Not affiliated with them, just a happy customer.

Anyway, hope this helps.

Old 9th May 2006 | Show parent
Gear Addict
cletus's Avatar
🎧 15 years
Mineral wool or "rock wool" is definitely cheaper and has a an 8 pound psi density. It's definitely not the easiest to work with but I much prefer the feeling of rock wool on my skin to shards of fiberglass! I'd say it matters very little in the end. They both absorb about the same (depending on the thickness and the density) it's more a matter of budget. I think I was $400 in the hole buying OC 703 and 705 when I realized I could get just as much rock wool for half the cost. I finished up the corners of my room with rock wool and have 703 on the walls. Did the job!
Old 9th May 2006 | Show parent
Gear Nut
🎧 15 years
does opening a window help?

i have a 8*10 room small. i know it probably got bad build ups
the room has two sets of windows on one wall facing the front of house and i happen to have my monitors infront of the windows on my table.
i notice if i stand in the corner the bass is so built up
but when i crack openthe windows behind the monitors the bass in the corner is not so bad.
if i open the windows more the bass decreases in the corner.

my question is with windows up do i still have to worry about mode problems and such. even tho alot fo the sound is escaping into infinity?
Old 9th May 2006 | Show parent
Gear Addict
cletus's Avatar
🎧 15 years
BTW you should check out ethan winer's acoustic forum. They definitely have all the answers in regards to individual room acoustics.
Old 9th May 2006 | Show parent
I just spent the weekend installing rockwool I got from:

about $40.00US a bail compaired to 703 @ $100.00 for the same sq.ft.

It was easy to work with.
What I did:
1. Cut a piece of ply/chip board to 4x6ish
2. Take 2 18" pieces of 2x4 and use them to frame a corner of the big board to 2'x2'.
3. Make a slit cutting diagonal through this 2'x2 square you made on the corner of the big sheet.
4. add 2 clamps, a serated kitchen knife and a 5" 1x4 and you have a mineral wool cutting machine.

Use the framed corner for slicing the panels into 2'x2', and the diagonal when you need it for the corner.

Use the clamps and 1"x4" to "rip" the widths you need and to create a square for cutting length.

God I hope this makes some sense......

BTW: If mineral wool is difficult to work with, you're not doing it right.

Good luck!


Last edited by dpasch; 10th May 2006 at 12:07 AM..
Old 10th May 2006 | Show parent
Gear Addict
timmcallister's Avatar
🎧 15 years
Originally Posted by cletus
Mineral wool or "rock wool" is definitely cheaper and has a an 8 pound psi density.

Rockwool can be obtained in various densities, depending on the manufacturer. Thermafiber (which I have used ) can be had in 3 and 4 lb densities

Heres a llink to plans and pics of my room, with before and after frequency graphs:

It also has pictures of the superchunks i made with rockwool

Last edited by timmcallister; 10th May 2006 at 05:50 PM..
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