Acceptable Density of Rockwool for Basstraps?

[teknosmoker]

I just picked up a pallate of 20 sheets of 2' x 4' (120cm. x 60cm.) Rockwool out here in Spain to make my own bass traps (I can't afford to buy pre-made ones).

The only information on the outside label of the pallate is the following (I'd post a picture, but GS attachments aren't working right now):

ROCKWOOL
ROCKSOL 501 000 096
20mm (thickness of each panel)
120cm x 60cm (side of the sheets)
14.4 m2 (cubic meters of material)
R = 0.60 m2K/W (thermal resistance)
Quality Control: 3140231 04:04:07


Can anybody tell me how many of them I should be using per trap? I have no idea what the numbers on the label mean with regard to absoption coefficients. Each sheet is 2 cm. thick. I'm guessing that I should use about 5 sheets per trap, for a total of 4 traps. That would make each one 10 cm thick (or about 4 inches).

Or would it be better to make 5 traps containing 4 sheets each (8 cm. / 3.15 in.)?

-T

[bpape]

For bass control, you'll want at least 10cm thickness. If the density is low, then more like 15cm is recommended.

Bryan

[teknosmoker]

Thanks for the reply Bryan.

I have had difficulty determining the density of the stuff I purchased. I've gone to Rockwool's spanish website and searched for products named "ROCKSOL". There are only 2 listed items by that name on the website, neither of which matched the thermal resistance (the only specs I have on my purchase) specifications on the palate I have. I've also emailed Rockwool, but have gotten no response.

The material I purchased is fairly rigid, but ceratinly does give in a bit when I squeeze it (kind of "crunches"). It's softer than styrofoam, but more firm than fiberglass bat. I guess it's safe to assume that I should use 5 sheets for each trap then?



I just moved from the US to Spain (into a new house) and the room I'm using as my studio/control room sounds horrible. The bass is boxy and way off, highs are hyped (very reflective room) and there is no definition in the mids! The room is about 11' 4" wide x 13' 10" long. It has plaster walls, tile floors and there is a window on one side of the room. The one saving grace is that the ceiling slopes upwards from the front (7' 10") to the back (12' 5") of the room. Also, there is a 8.5"' high x 7" 10" wide x 2' 3" deep hardwood sofit closet covering most of the back of the room (which makes the actual dimentions of the room closer to 11' 4" wide x 11' 7" long).

I need to make this room useable....

[bpape]

Will come back later and take a closer look at the room stuff. For now, if you want the density numbers, simply weigh it and extrapolate out to kg/m3 or lb/cu ft. For instance, a piece of 2'x4'x4" = 8 sq ft x 1/3 ft for a total of 2 2/3 cu ft. (as long as my less than one cup of coffee math is wrong... ) Divide the weight of that piece by 2.6667 and you'll get the density number.

Bryan

[teknosmoker]

Excellent! Thanks very much for the formula Bryan. thumbsup

I look forward to any advice you can offer with regard to how I can make the room usable on a budget.


-T