Auralex Mineral Wool??

Earle Mankey · Post by **Earle Mankey** » Tue Apr 05, 2005 7:48 pm

Universally, everyone seems to equate "Auralex" to "foam" and "expensive"

It looks to me like Auralex sells 6 pound mineral wool for the same price as everyone else, and it's available almost everywhere. (Guitar Center, etc, although it must be ordered)

Am I overlooking something? Will I be sorry if I buy this stuff? Is it rigid enough to stand up on its own? Has anyone used it?

Earle · Post by **Earle** » Wed Apr 06, 2005 3:51 am

http://truesoundcontrol.com/products/1MFINS12.html
http://truesoundcontrol.com/products/2MFINS6.html
http://truesoundcontrol.com/products/4MFINS3.html

The first of many sources I found, $80 is the price in some places.

BTW, where is this forum's "edit" button?

Oh, I guess you just can't edit a topic starter....

Sword9 · Post by **Sword9** » Wed Apr 06, 2005 6:39 am

you can only edit as a registered member, i believe.

gdgross · Post by **gdgross** » Thu Apr 07, 2005 4:04 am

Earle, as I remember, the mineral wool available from auralex/guitar center was very expensive. Check out Roxul products for chepaer rockwool. I dont know if the auralex mineral wool is any better, but everyone around here seems to be happy with 'normal' rockwool/mineral wool insulation.

I see you are also in southern california. I bought my insulation from Insulation Wholesalers in Pomona. I think it was around $0.30 per square foot.

Earle · Post by **Earle** » Thu Apr 07, 2005 7:38 am

Yes, Insulation Wholesalers in Pomona was one of the many that I priced in SoCal, most are in the same price range.

They sell Roxul AFB (which is 2.5 lb. BATTING) for $.30/sq ft

They sell Knauf 2 inch 6 lb. RIGID FIBERGLASS for $1.85/sq ft

That Aurelex MINERAL WOOL that I mentioned in the 2 inch 8 lb. size is $80/48 sq ft, which works out to $1.66/sq ft !!!

And I can buy it at the guitar center down the street instead of driving to Pomona or OC.

I hope it's rigid enough.

gdgross · Post by **gdgross** » Thu Apr 07, 2005 7:43 am

How much are you buying? For my small (10 x 14) studio, that would be a $830 for the auralex vs. $150 for the roxul. Saving $700 isn't worth a drive out to pomona? You must not be buying very much...

Earle · Post by **Earle** » Fri Apr 08, 2005 5:44 am

You might be missing the point:
2.5 lb/cu ft batting is not the same as 8 lb/cu ft rigid insulation.

If you study the absorption charts, it takes a heavy, compacted material to affect the frequencies under 150Hz. Plus, the lighter materials take up lots of room space to get similar results.

Roughly, it seems like the insulation prices are linearly incremental- twice the weight/cu.ft. or twice the thickness at that same weight costs about twice as much.

Note that when we compare apples to apples, (if this Auralex is an apple) the Pomona price for 6lb Knauf is $1.85/ sq ft, while Guitar Center's price for 8lb Auralex is $1.66/ sq ft.

Remember though, I'm here to ask the question: "Am I missing something obvious?"

I havent tried to order it yet from Guitar center.
Maybe they'll boost the price for this one item when they find out how heavy it is.
Or maybe I'll find out it isn't as rigid as I thought it was from the pictures, so it will fall apart when I try to mount it, or sag too easily.

How stiff/sturdy is your Roxul AFB? I would certainly rather pay $.30 /sq ft if I thought it would do the job!

I'm posting here hoping to find someone who has tried it out.....

BTW, here are the Roxul AFB coefficients (It looks like the thickest they sell is 4")
http://www.roxul.com/graphics/rx-na/can ... t_info.pdf

And here are the Auralex values for mineral wool ( 4 inch looks good at 125 Hz)
http://www.auralex.com/testdata/test/mastertable.pdf

Earle · Post by **Earle** » Wed May 04, 2005 3:08 am

UPDATE:

Apparently no one had a clue about the Auralex mineral wool question, since it remained unanswered for a month.

But while searching, I found 12 Pound/CuFt mineral wool Armstrong Acoustic Ceiling Panels (#942B) at my local Home Depot for .$91/SqFt (figuring a 2" thickness)!

They sell it in 2' x 4' x 5/8" panels, so I would have to combine 4 panels to get 2" thick.

But they come in a 2' x 4' x 6" cardboard edge container, and all I have to do to get a 2' x 4' x 6" , 12 Pound/CuFt absorber is to remove the plastic wrap and leave the cardboard! This package costs $22.

They even have a white facing (not vinyl) to contain the mineral wool fibers, so I don't have to cover them with cloth. (This facing is designed to absorb, not to reflect)

BTW, after all this searching for absorber materials, I have now realized that the true specs of interest are the Lb/CuFt and the price per CuFt.
Since the materials come in all shapes and sizes, these are common denominators that let me compare value per dollar.

These 12 Lb/CuFt ceiling tiles are $5.50/CuFt , or $.46/Lb

$.30/SqFT Roxul AFB 3" 2.5Lb batting is $.48/Lb (takes up 5 times as much space)

The 8Lb Aralex was $1.25/Lb

The 6Lb Knauf was $1.85/Lb

Sword9 · Post by **Sword9** » Wed May 04, 2005 7:54 am

You got a link to that stuff? Because I can't find it on Armstrong's site. They don't seem to have anything that dense.

Earle · Post by **Earle** » Wed May 04, 2005 12:13 pm

Yeah, the density is not easy to figure out, from their site, but it turns out that almost all their panels are that dense!

The 942B box has a second "commercial" number on it, #755.
This is it:

http://www.armstrong.com/commceilingsna ... m_id=45018

I weighed my box of panels (2' x 4' x 6" = 4 CuFt) and it was 48 Lb.

48Lb/4CuFt= 12 Lb/Cu Ft.

This works out the same as the spec sheet:

.60 Lb/SqFt of panel x 20 panels per foot of depth = 12 Lb/CuFt

The surprise is, these 942B/#755 panels have an NRC of .55 listed on the box.

That's average for all the Armstrong absorbing panels, though they have some higher values for more money. That means to me that any non-vinyl faced mineral wool Armstrong panel would work great. The Vinyl faced ones are for blocking the sound better- bad for my absorber needs.

These 942B/#755 panels are in the lowest budget group. They have no vinyl facing, and the only "added feature" is a Class A flame retardent "flame spread" of 25- whatever that means.

Sword9 · Post by **Sword9** » Wed May 04, 2005 10:22 pm

that seems like it would be more reflective than absorbative, since the wool is compressed so much.

Earle · Post by **Earle** » Thu May 05, 2005 4:19 am

But they're selling it as acoustic absorptive ceiling panel, and I think they are selling more than any other company.

I think that the defining point about absorbers is that air can pass through them, especially at the frequencies of interest.

While I don't care to breathe through these panels, I'm pretty sure I could if I had the nerve!

Sword9 · Post by **Sword9** » Thu May 05, 2005 5:05 am

I think you're misinterpreting the density values on this stuff. On top of that, it's coated in a vinyl latex paint. I'll wait for an actual expert opinion from somebody that knows more than me, but I can't see this doing much better than normal ceiling tiles.

AVare · Post by **AVare** » Thu May 05, 2005 6:55 am

Earle wrote:But they're selling it as acoustic absorptive ceiling panel, and I think they are selling more than any other company.

I think that the defining point about absorbers is that air can pass through them, especially at the frequencies of interest.

While I don't care to breathe through these panels, I'm pretty sure I could if I had the nerve!

The average absorption in a diffuse field is good, but for normal incident waves it is poor, and there are bumps in the low fequency range where the material uses the cavity effect to obtain lf absorption.

Note the mounting method used in the testing. A 16" gap betwent he material and the hard surface.

Andre

Earle · Post by **Earle** » Tue May 10, 2005 7:10 pm

AVare wrote:
The average absorption in a diffuse field is good, but for normal incident waves it is poor, and there are bumps in the low fequency range where the material uses the cavity effect to obtain lf absorption.

Note the mounting method used in the testing. A 16" gap betwent he material and the hard surface.

Andre

That is all true, if you hang one single tile 16' from the roof, using a ceiling frame. It would also be the case using any other rigid 5/8" insulation.

But that's not what I'm doing. I'm using multiple thicknesses to build the same dimensions of absorbers/traps as the others on this forum.

BTW- does anyone know a better way to compute density, besides weight/volume? I'm open to suggestions. I hope no one thinks I have an attitude - I'm just trying to find the most insulation for the least money.