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terrible_buddhi
New member
trying to find out what kind of rockwool I need...seems there are a lot of different products they make...anyone?
knightfly
GrouchyOldFartOnBatteries
For which part - kinda depends on what you're using it for... Steve
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terrible_buddhi
New member
well, I was going to use it as insulation between the wall of the studio and the control room and the vocal room...I was also going to use it in the bass traps you suggested.
dobro
Well-known member
I'm looking at the stuff to kill bass frquencies. What I'm reading says that the denser it is, the better.
knightfly
GrouchyOldFartOnBatteries
Actually, that depends partially on the angle the sound hits the material from - for straight-on, 90 degree incidence, that's true up to a point, then the material gets so dense that it acts more like a solid board.
For normal bass trapping AND for in-wall insulation, 2.5 pounds per cubic foot (48 kG/m^3) is optimum, that's why USG has decided on that density for their Sound Attenuating Fire Blankets - heavier density for in-wall insulation and you start degrading bass Transmission Loss, lighter and you start degrading high freq Transmission Loss. Since you get best results with BALANCED losses, stick to the 2.5-3 PCF stuff for inwall insulation.
Traps rarely see all head-on incidence, so the same would apply there - some people have gotten satisfactory results with 6 PCF stuff, like Owens Corning 705 - but for more broadband absorption the 703 series, or 3 PCF Rockwool gives the most uniform results.
HTH... Steve
For normal bass trapping AND for in-wall insulation, 2.5 pounds per cubic foot (48 kG/m^3) is optimum, that's why USG has decided on that density for their Sound Attenuating Fire Blankets - heavier density for in-wall insulation and you start degrading bass Transmission Loss, lighter and you start degrading high freq Transmission Loss. Since you get best results with BALANCED losses, stick to the 2.5-3 PCF stuff for inwall insulation.
Traps rarely see all head-on incidence, so the same would apply there - some people have gotten satisfactory results with 6 PCF stuff, like Owens Corning 705 - but for more broadband absorption the 703 series, or 3 PCF Rockwool gives the most uniform results.
HTH... Steve
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terrible_buddhi
New member
so is this more like a roll, or rigid boards? Any pictures of it?
knightfly
GrouchyOldFartOnBatteries
Here's one pic, of the OC 700 series -
http://www.apidistribution.com/products/duct_board/fiberglas_board_oc.php
If you can't find the rigid stuff locally (yellow pages, commercial insulation/drywall contractors) for in-wall insulation it's almost as good to cram 6" soft fiberglas into a 4" wall cavity. For traps, though, you need either the mineral wool semi-rigid board or the fiberglas semi-rigid. Do a google search on rigid fiberglas and follow some links, it may help... Steve
http://www.apidistribution.com/products/duct_board/fiberglas_board_oc.php
If you can't find the rigid stuff locally (yellow pages, commercial insulation/drywall contractors) for in-wall insulation it's almost as good to cram 6" soft fiberglas into a 4" wall cavity. For traps, though, you need either the mineral wool semi-rigid board or the fiberglas semi-rigid. Do a google search on rigid fiberglas and follow some links, it may help... Steve
dobro
Well-known member
Damn, you know a lot about this stuff!
What's the advantage of the rigid stuff, aside from being easier to work with? And aside from the fact, of course, that 'rigid' is good news these days...
I've got a line on some free 40kg/m3. I'll think I'll go with that. It seems close enough to 48 to work.
What's the advantage of the rigid stuff, aside from being easier to work with? And aside from the fact, of course, that 'rigid' is good news these days...
I've got a line on some free 40kg/m3. I'll think I'll go with that. It seems close enough to 48 to work.
knightfly
GrouchyOldFartOnBatteries
40 is great for nearly everything - the advantage of "rigid" is that it's rigid because it's compressed. This puts more fibers in the way of sound passing through it, which (up to a point) makes it more absorbent. If I remember correctly, fluffy fiberglas insulation runs around 1/2 pound per cubic foot - the ideal for both in wall and trap applications is around 2.5-3 PCF (40-48 kG/m^3) -
What you get with the rigid stuff, is approximately equivalent to the same weight of the fluffy stuff, only in less space. So, with 3 PCF rigid, it would take about 12" of the "fluffy stuff" to keep up with 2" of the rigid.
In the case of bass traps, even that isn't a fair comparison - because of the physics of sound absorption, a sound wave has to be near its maximum velocity and minimum pressure when passing through an absorbent before it will do much absorbing. By using compressed absorbent, you have more of it at the right distance from a boundary (1/4 wavelength) so more of that frequency gets absorbed.
"Damn, you know a lot about this stuff!" - Gettin' there - made some MAJOR mistakes building my own rooms about 22 years ago, learned what they were, been putting up with most of them since, and don't plan on repeating them (or any OTHER ones I can avoid) next time... Steve
What you get with the rigid stuff, is approximately equivalent to the same weight of the fluffy stuff, only in less space. So, with 3 PCF rigid, it would take about 12" of the "fluffy stuff" to keep up with 2" of the rigid.
In the case of bass traps, even that isn't a fair comparison - because of the physics of sound absorption, a sound wave has to be near its maximum velocity and minimum pressure when passing through an absorbent before it will do much absorbing. By using compressed absorbent, you have more of it at the right distance from a boundary (1/4 wavelength) so more of that frequency gets absorbed.
"Damn, you know a lot about this stuff!" - Gettin' there - made some MAJOR mistakes building my own rooms about 22 years ago, learned what they were, been putting up with most of them since, and don't plan on repeating them (or any OTHER ones I can avoid) next time... Steve
c7sus
Disenfranchised Member
Rockwool and Rigid Fiberglass Soundbaord are two very different products.
The Rockwool costs about HALF as much as comparable RFS.
The Rockwool costs about HALF as much as comparable RFS.