John Mansville R-30 vs Roxul Safe 'n' Sound for Superchunk Bass Traps (and other ?'s)

Z

Zaubereixmc1

New member
Hello all!
Recently, I have been trying to figure out what insulation material is best to use for my first room treatment. After browsing/drooling over HomeRecording, Gearslutz, etc., I see that many use OC703, Roxul Safe 'n' Sound, or simply pink fluffy fiberglass insulation for larger bass traps. The room I'm going to be using is --you guessed it!-- my bedroom, which is 101.5" W x 159.5" L x 98" H (2.58m x 4.05m x 2.49m).
Since I cannot find OC703 in my area (called all the building-supplies stores around Bloomington, IN), I have narrowed my choices down to Roxul Safe 'n' Sound or John Mansville R-30 fiberglass insulation. I will be using the Safe 'n' Sound for first reflection points/bass traps/clouds, whereas the JM R-30 will be used for the superchunks. My current plan is as follows:
(4) Superchunks in each corner, using JM R-30
(2) Absorbers at first reflection points on L/R walls, using the SnS
(1-2) 6" acoustic clouds, one above mix position, the other in the back of the room
(4-6) 6" bass trap panels in wall-ceiling corners -- two in the L/R corners of mix position (hereinafter MP), one in corner in front of MP, possibly three in the rear wall-ceiling corners
Since it's a hard floor, I will probably through a rug under the mixing chair, to tame any highs if necessary.

Reasoning for my choices are 1) budget (the usual; the JM is much cheaper), and 2) because of the rough correlation between a material's density and its gas flow resistivity, which I believe affects an absorber's range of well... absorbtion.

Quoting Andre:
For BIG Bass Traps: (i.e. significant corner trapping)-- Use LESS DENSE material, i.e. Roxul 40 or Safe N Sound. 17" corner superchunks (24" facing) or 12" soffets -- or larger. Fully pack -- leave no airspace. The air already moves through the less dense material.
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Density of the Roxul: 2.5 pcf (40kg/m3)
Density of the JM R-30: 0.5 to 0.8 pcf (8.01 to 12.8 kg/m3)

So will using the R-30 negatively affect the trap's performance in regard to using the SnS instead?
Maybe I should I just wait until getting a measurement microphone?
For some of you, these are probably some of the most redundant questions you get! :p But hey, I'm only in high school, and it's late here, so you just KNOW that I'm going to forget things! I also tend to overthink things... :facepalm:

Anyway, thanks for the help! Hope to hear from you!
-Joseph
 
mjbphotos said:
R-30 (the 'fluffy' fiberglass) is no good as bass/sound traps. You need compressed fibreglass.
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Not true. The pnk, fluffy stuff is good for bass traps, and might ven be considered better for bass traps. It might have to be a minimum thickness (like 8" for superchunks), but it's actually very good for bass traps.
 
Really? Bass, but no good for other frequencies? Curious about your statement that 'it might have to be a minimum thickness' - I've got 3/4 of a roll of 8" (yellow, not pink) insulation in my basement left over from blanketing my attic. I've always read that the 'fluffy' insulation is no good for sound traps. Period.
If I could use this (I could compress it into 4" thick frame with a few lath strips and cloth) my hunt for a small amount of compressed fibreglass/rockwool would be over!
 
GIK indicates it needs to be 18" thick. :facepalm: I want some portable 4" thick 2 ft x 3 ft traps. I doubt I can compress two layers of the fluffy stuff into that 4" space.
 
mjbphotos said:
GIK indicates it needs to be 18" thick.
Click to expand...

Yeah, he's talking about Superchunks. But I have read that the pink stuff is fine for, and maybe even better, for bass traps elsewhere. I wish I kept some of those websites. Anyway, might be worth doing a little research on, because I don't think they have to be 18" thick to be effective.
 
I've seen a few times even some of the acoustics gurus (not sure if it was Ethan, or one of the others over at TapeOp) say that if you get rolls of the pink stuff, leave them all rolled up, and stack them in the corners it works as well as anything else.

Also, consider this: What happens if you compress the pink fiberglass insulation?

In the very near future I'm going to make some treatments involve stapling a batt of kraft-faced pink stuff on either side of a 2 x 4 frame, so that the two get squished together in the middle. I have a bit of a question as to what frequencies will be reflected by the paper, but if it becomes an issue I'll find some thrift store quilt or shag carpet or some such thing...
 
Yeah, GIK corrected me on pink fluffy a few weeks ago, but it takes considerable space. A studio or bedroom like the one in question might not have that luxury.

To the OP, Johns Manville does offer a rigid fibreboard product very similar to OC703. I have some panels and I find it easier to work with than OC703.
 
mjbphotos said:
Really? Bass, but no good for other frequencies? Curious about your statement that 'it might have to be a minimum thickness' - I've got 3/4 of a roll of 8" (yellow, not pink) insulation in my basement left over from blanketing my attic. I've always read that the 'fluffy' insulation is no good for sound traps. Period.
If I could use this (I could compress it into 4" thick frame with a few lath strips and cloth) my hunt for a small amount of compressed fibreglass/rockwool would be over!
Click to expand...

Fluffy insulation is good for very thick traps (typically minimum of 8" but really >12" for good results, >17" for good control down to 50 Hz). It does not work the same at all when compressed. Rigid/semi-rigid fiberglass is basically that (compressed fiberglass) but with extra binders in it to make it more stiff. The problem with compression is though while it /may/ work well with certain types of insulation, there really is no way to tell for sure. And in either case, not compressed works best anyways.

Safe n' Sound works a little better than pink fluffy in most situations. Especially for thinner traps (6" is thin when you're talking about very porous materials like these). Large traps at 16" or something (like soffit traps) there isn't a huge difference between the two.
To the OP - your plan will work well, post some pics of the build when you get them going!
You've
 
Oh My god! GIK is like some kind of Superhero!!!! Right in the middle of a post, he got whisked off to an emergency bass trap disaster!!!!!
 
Rachael Ba-Baby had peaks right around the 400hz range. Twin Peaks if I heard correctly. They needed to be attended to...
 
GIK Acoustics said:
Fluffy insulation is good for very thick traps (typically minimum of 8" but really >12" for good results, >17" for good control down to 50 Hz). It does not work the same at all when compressed. Rigid/semi-rigid fiberglass is basically that (compressed fiberglass) but with extra binders in it to make it more stiff. The problem with compression is though while it /may/ work well with certain types of insulation, there really is no way to tell for sure. And in either case, not compressed works best anyways.

Safe n' Sound works a little better than pink fluffy in most situations. Especially for thinner traps (6" is thin when you're talking about very porous materials like these). Large traps at 16" or something (like soffit traps) there isn't a huge difference between the two.
To the OP - your plan will work well, post some pics of the build when you get them going!
You've
Click to expand...

EMPHASIS ADDED
++1 :thumbs up:

Cheers,
John
 
RAMI said:
Oh My god! GIK is like some kind of Superhero!!!! Right in the middle of a post, he got whisked off to an emergency bass trap disaster!!!!!
Click to expand...

These really do happen much too often! I'm not even sure how, but we get calls about it all the time!
Really, it should I think i'm just going to hide stuff like this in my posts all the time
 
Thank you to everybody for the great responses! It's greatly appreciated! Especially considering that Glenn and John offer services for payment, but are willing to guide those who seek to pursue recording/acoustics. I will commence building my panels/traps as soon as possible, along with a studio desk at some point. For the superchunks, I plan on making them either a) 21" on the "leg" sides, 15" deep, with a ~30" face OR b) use twice the amount of insulation to make 30" for the "legs", ~21" deep, with a ~40" face. Either can work according to my Sketchup plan, since I wouldn't have enough space behind my desk due to my setup. If I went with the deeper traps, I would keep the traps at the rear of the room 15", although I think I will just make them all 15" deep and make deeper traps if the need arises.
Either way, birthday in a few days = money = LET'S BUILD THESE SUCKAS! :) Will post pictures as the process continues!

Thanks!
-Joseph
 
I also enjoyed finding out that GIK is not-so-secretly Superchunk, the superhero who uses his brain to bring the evil Brotherhood of Bass to justice!
 
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