Roxul - just leave it in the bag and drop it in the corner?

[scoring4films]

A fellow engineer suggested I could "clean up the bottom end" in my control room by buying a few bags of Roxul Safe-and-Sound, cover each unopened bundle with fabric, and then drop one in each corner of the room. Crazy? I thought that the only way to "clean up the bottom end" was to identify the specific frequencies where you have build-up and then custom build bass traps to absorb only those frequencies.

Just the same, I'm tempted to try this unopened bags of Roxul trick, because it would be so cheap/easy. Plus if it doesn't work I can always return the unopened bags to the store and get my money back!

If it turns out that this can indeed reduce low end build up, does anyone know if it's better to just sit them on the floor, or raise/suspend them to ear/monitor level, or...?


thanks!

[Brainchild]

I don't buy the "leave it in the bag" line that crops up from time to time. You can try it, but you'll probably get better results by doing it right. As for the specific freuqencies, a porous medium like this insulation will absorb whatever frequency comes at it without discrimination (although of course it becomes gradually less effective as the wavelength gets greater and greater).

[DanDan]

I have used that technique on several occasions where it was not possible to interfere with the room. e.g Old building, rented. Here's a before and after in an old square room.
As you can see, it works very well, similar to the Studiotips SuperChunk. Go big though. A couple of the little bags will do little. Try to find wider bigger bags. Fill floor to ceiling in the four vertical corners.
DD

[scoring4films]

Originally Posted by Brainchild

I don't buy the "leave it in the bag" line that crops up from time to time. You can try it, but you'll probably get better results by doing it right. As for the specific freuqencies, a porous medium like this insulation will absorb whatever frequency comes at it without discrimination (although of course it becomes gradually less effective as the wavelength gets greater and greater).

Thanks for the advice. When you say "better results by doing it right", do you mean use it to build corner traps like this...

www.gearslutz.com/board/5418888-post10.html


...?

[scoring4films]

Originally Posted by DanDan

I have used that technique on several occasions where it was not possible to interfere with the room. e.g Old building, rented. Here's a before and after in an old square room. Attachment 174150
As you can see, it works very well, similar to the Studiotips SuperChunk. Go big though. A couple of the little bags will do little. Try to find wider bigger bags. Fill floor to ceiling in the four vertical corners.
DD

Hey thanks DD, that's awesome. I'm surprised to see so much attenuation in the top octaves. I thought that the plastic packaging would act like an LP filter and that the "traps" would soak up more lows than highs. I guess not. Thanks again for the plot. That really answers the question!

cheers,
t

[Brainchild]

Yeah exactly, open the pores directly to the air and reduce the impedance of the absorbent for better results.

[DanDan]

You are welcome t. I had doubts about the bag thing too, until I measured it. I sometimes wonder about how compressed the insulation is in those bags. Given a choice I would certainly chose a looser pack. I expect it would work better if allowed to fluff out a bit. Thick traps like low density fibre. In any case, measurement trumps notions, at least we can be sure of some effect.
The Bags were in a corner alcove behind the speakers. Little effect on HF I expect. The gradual slope downwards is a deliberate intervention on my part. I used the level and eq controls on these Gennies to do that. I use the curve from the old Bruel and Kjaer test Record, QR2011, I think. There is a post over at studiotips.com called Is the Earth Flat. That same site has great DIY and other info on the SuperChunk and other Corner Traps. If you do build SSC's, that corner brace thing is the key to an easy and successful build. As ever, bigger is better, i.e. the 34 inch wide version.
DD