Pink fluffv vs. Rigid cost vs. Performance question....

[amishsixstringe]

There is no real simple answer, but I will try.

703 is glass fiber. So is R30. 703 is compressed to right about 3lbs per cubic foot. I believe most "fluffy" stuff is about 1.5lbs/ft^3. So, about half the density.

You need to know what you are trying to do. What frequency band you are trying to trap. It is a good idea to find out what you want to do, then decide how you want to do it. You don't just start treating all willy nilly and expect to solve unknown problems.

If you want to get r30, it is 9" thick. If you stack it up and squish it down to about 4-1/2" thick per slice, then you are getting close to making your own 703. It's just not rigid. You could simply, squish it into a frame, and then stretch some GOM over it and be set.

Probably what I would do.

Neil

[rms8]

Originally Posted by amishsixstringe

There is no real simple answer, but I will try.

703 is glass fiber. So is R30. 703 is compressed to right about 3lbs per cubic foot. I believe most "fluffy" stuff is about 1.5lbs/ft^3. So, about half the density.

You need to know what you are trying to do. What frequency band you are trying to trap. It is a good idea to find out what you want to do, then decide how you want to do it. You don't just start treating all willy nilly and expect to solve unknown problems.

If you want to get r30, it is 9" thick. If you stack it up and squish it down to about 4-1/2" thick per slice, then you are getting close to making your own 703. It's just not rigid. You could simply, squish it into a frame, and then stretch some GOM over it and be set.

Probably what I would do.

Neil

Thanks Neil!

You answered my question 100% !

By "GOM" I assume that means "Guilford of Maine" ?

[avare]

Originally Posted by rms8

Thanks Neil!

You answered my question 100% !

By "GOM" I assume that means "Guilford of Maine" ?

Did he? You did not clarify what your goals are. If it is low frequency absorption, R30 uncompressed is better than 4" 0f 703.

Andre

[rms8]

Originally Posted by avare

Did he? You did not clarify what your goals are. If it is low frequency absorption, R30 uncompressed is better than 4" 0f 703.

Andre

Thank you too Andre.
So leaving R30 fluffy stuff uncompressed is better than compressing it? I wanted to use something less $$ for rear corner bass traps than the OC703. The fluffy stuff is vastly lower in price but I was concerned how much a difference (if any at all) in performance it would be.

BTW, Neils build thread is amazing!!!!!!

[kasmira]

Originally Posted by rms8

Thank you too Andre.
So leaving R30 fluffy stuff uncompressed is better than compressing it? I wanted to use something less $$ for rear corner bass traps than the OC703. The fluffy stuff is vastly lower in price but I was concerned how much a difference (if any at all) in performance it would be.

BTW, Neils build thread is amazing!!!!!!

R30 fluffy vs rigid fiberglass isn't better or worse. It depends on your situation. Andre said R30 uncompressed is better at absorbing lower frequencies. Rigid fiberglass is nice to use because its thin, easy to mount, and has similar properties to its uncompressed brethren. But lower density insulation with a lot of depth is usually recommended for low end problems over rigid boards.

What exactly are you looking to do in the room? What problems are you having? Have you measured your room at all? We don't know enough to evaluate what would be best for your room.

[rms8]

Thanks for all your answers/advice.

We'll be building a new home next spring and I will be building a HT once the house is complete. I am just on a data gathering mission at the moment. From the last few rooms I have had, I know that the bass tends to be pretty heavy and overpowering for the rear row of seats. I'm assuming that rear corner traps would help this out.

[boggy]

Originally Posted by rms8

Thank you too Andre.
So leaving R30 fluffy stuff uncompressed is better than compressing it?....

I'm not Andre, but ... yes, that's true, fluffy stuff is better than compressed rockwool for low frequencies, because lower gas flow resistance, and I believe that low frequencies problems is what you need to solve, if you build corner traps...

[7thbass]

Should I use Rigid or Fluffy for superchunk bass trap?

[avare]

Originally Posted by 7thbass

Should I use Rigid or Fluffy for superchunk bass trap?

Fluffy.

Fluffy soft,
Andre

[avare]

Originally Posted by rms8

Thank you too Andre.

You are welcome.

So leaving R30 fluffy stuff uncompressed is better than compressing it?

Yes. IT is not material specific. At the full range absorber depths, any material less dense is better than the same material compressed. The material density goes up AND the material is less distant from the partition, where the sound velocity component is greater.

Andre

[localhost127]

Originally Posted by avare

Fluffy.

Fluffy soft,
Andre

+1

if you're cutting and stacking layers of pink fluffy vertically, make sure to build horizontal supports every few ft such that the upper layers do not compress the layers at the bottom.

[boggy]

Originally Posted by localhost127

+1

if you're cutting and stacking layers of pink fluffy vertically, make sure to build horizontal supports every few ft such that the upper layers do not compress the layers at the bottom.

+1
Excellent advice!

[avare]

Originally Posted by boggy

+1
Excellent advice!

+2 to Boggy's +1 of localhost127s posts content regarding suport. Not +2 to the +1 of my post which would make it +3. that is +3 from me to me. That is I will stop trying to count hypothetically.

Andre

[7thbass]

Originally Posted by avare

Fluffy.

Fluffy soft,
Andre

Looks like building a superchunk may be cheaper than I thought.

[GoldenOne]

Would using the Ultratouch Cotton work for corner basstraps instead of Owens Corning R30 insulation?

This product:

2 cu. ft. R13 - R60 Nature Blend Cellulose Insulation-UTNB at The Home Depot

or this:

http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053

Instead of this product:

EcoTouch R-30 Unfaced 9 in. x 15 in. x 25 ft. Continuous Roll Insulation-RU70 at The Home Depot

[avare]

Originally Posted by GoldenOne

Would using the Ultratouch Cotton work for corner basstraps instead of Owens Corning R30 insulation?

This product:

2 cu. ft. R13 - R60 Nature Blend Cellulose Insulation-UTNB at The Home Depot

or this:

16 in. x 48 in. UltraTouch Denim Insulation Multi-Purpose Roll-60301-16482 at The Home Depot

Instead of this product:

EcoTouch R-30 Unfaced 9 in. x 15 in. x 25 ft. Continuous Roll Insulation-RU70 at The Home Depot

No. From all that we do know of them, the gas flow resistance is significantly greater than fibergalss. So much that low end absorption stopsnat significnt frequencies for thicker (> 4") materials.

Andre

[GoldenOne]

Thanks avare. From what i read about the ultratouch it seemed like it wouldnt be the best choice for taming low frequencies but i was curious if the r8 would have more favorable gas flow resistance. I know i need to read more but I'm assuming that density and the insulation material are factors which contribute to GFR.

[avare]

Originally Posted by GoldenOne

Thanks avare. From what i read about the ultratouch it seemed like it wouldnt be the best choice for taming low frequencies but i was curious if the r8 would have more favorable gas flow resistance. I know i need to read more but I'm assuming that density and the insulation material are factors which contribute to GFR.

Density in and of itself tells us very little about the GFR. Porous absorbers are made up of fibres, which the level at porous absorbers absorb sound.
There could be two materials identical in all othere characteristics except density, because one is made from an intrinsiclly heaveir material that the other. The absorption characteristics could be identical.

Similarly there could be two materials with all charcteristcs identical except for fibre lenght, and the one with shorter fibre length would have greater absorption.

Continuing on a roll, there could be two materials identical except t for the orientation of the fibres and, yes you guessed it, the absorption characteristics will be different.

We density as an indicator of the absorption characteristics of materials, because it is about the only descriptor we can get from makers. The closer a materials physical properties are to an absorption tested product, the better our extrapolation of the actual properties.

For more look a the Roxul Marine and Offshore Acoustics Manual, available off my Acoustics/Treatement Guide sticky suggested reading link.

Andre

[jacobq]

Originally Posted by avare

Fluffy.

Fluffy soft,
Andre

Avare
So it is ok to use the fluffy soft r30 in all bass trap corner locations? The reason I ask this is because I see so many being built using the stacked rigid 703. This seems like a waste of money to use 703 to me now.

In what case would you want to use the 703 rigid Fiberglass? I would asume the 703 is much better at high frequencies than the r30.. This could be another advantage to using the fluffy r30. The room would not be to dead I am assuming and it is controlling the low end better as a bonus ...

Thank You

[avare]

Originally Posted by jacobq

In what case would you want to use the 703 rigid Fiberglass? I would asume the 703 is much better at high frequencies than the r30.. This could be another advantage to using the fluffy r30. The room would not be to dead I am assuming and it is controlling the low end better as a bonus ...

The first factor is the available depth. For absorbers ~4" thick 703 like materials are just about ideal. For deeper absorbers, up to ~12", 4" of 70s 703 like material with the balance being an air gap, is great. Mineral and glass insulation of the R30 thickness and density is in the same class at thicknesses of ~8" and up. The deciding factors should include: ease of handling during construction, any additional mechanical support for softer material, surface durabiolity, and of course, cost.

Multi-factorially,
Andre

[M.Brew]

I was just reading through some of these threads on super chunk traps and was wondering if putting a panel of 703 frk on the front of the trap while filling the rest with r30 would be more effective?

[avare]

Originally Posted by M.Brew

I was just reading through some of these threads on super chunk traps and was wondering if putting a panel of 703 frk on the front of the trap while filling the rest with r30 would be more effective?

Who knows? I would not do any guessing. Keep to the simple (and cheapest in this case).

Emphatically a great value,
Andre

[JulianFernandez]

So, what´s the smaller superchunks are worth building? (to work along with my 4" panels) Thanks Andre!

[M.Brew]

Originally Posted by avare

Who knows? I would not do any guessing. Keep to the simple (and cheapest in this case).

Emphatically a great value,
Andre

Ok thanks, for the advice. I've heard of people doing this before but Wanted to know if anyone had noticeable improvement.

[Tango4Cash]

So would we need to take this product and unwrap it, loosening it up so its "not compressed" and frame it with chicken wire or soemthing, or just leave it in the bag and stick it in the corner? At $70 bucks a pop, it seems MORE expensive than the panels.
EcoTouch R-30 Kraft 9-1/2 in. x 24 in. x 48 in. Batts in Bag Insulation-BF71 at The Home Depot


Also, what about this product? Its only 3 bucks a roll!!!
R-6.7 Unfaced 2 in. x 16 in. x 48 in. Multi Purpose Continuous Roll Insulation-A85P at The Home Depot

[anarchoic]

Originally Posted by avare

The first factor is the available depth. For absorbers ~4" thick 703 like materials are just about ideal. For deeper absorbers, up to ~12", 4" of 70s 703 like material with the balance being an air gap, is great. Mineral and glass insulation of the R30 thickness and density is in the same class at thicknesses of ~8" and up. The deciding factors should include: ease of handling during construction, any additional mechanical support for softer material, surface durabiolity, and of course, cost.

Multi-factorially,
Andre

Andre,

This is really the exact information I've been looking for, but I'd like to ask a more specific question, covered in my very lengthy first post in my recent thread, "Please Help pick correct insulation for my SuperChunk Build & Placing GIK 244 Panels" that hasn't, as of yet, provided a specific response to this question.

I have a large room, for HT use, at 20.4' x 26.66' x 8.66' wlh.

My front/screen wall is a poured concrete foundation (room is in basement) and my actual screen and front "wall" (nothing more than black thin curtains covering the width of the room to the left and right of the centered screen) is exactly 12" in front of the actual concrete wall.

This leaves me a 12" gap.

I was thinking of using this product, available from my local Lowe's, called, "Johns Manville 300"L x 15"W x 9-1/4"D R-30 Fiberglass Insulation Roll" at only $15.87 per roll.

I cannot find any specific gfr #'s/info on it though.

My plan is to use one layer, 9.25" deep, hung vertically from the ceiling to the floor, all across the entire width of the room (it's unfaced) at 20.4'.

In addition, I was thinking of making corner traps out of this, too.

I have the room to do 15" (the width of this stuff) x 18.5" (2 layers deep) which would simply be two pieces, hung vertically from the ceiling to the floor, so as not to have to use any netting or shelf support as it won't be able to compress on itself this way.

I could also pretty easily use four pieces, making a 30" x 18.5" rectangle trap, again, each of the four pieces hung vertically and this would be extremely cheap and easy.

The Question is, would using this material, in this configuration, be "effective?"

Would either/both sizes be as effective (looking for broadband bass absorption, don't care what it does to the highs since this is just for corners and room is so big) the way I plan to "hang" them as using Roxul or OC703 and building SuperChunks with a 34" face, triangles in corner?

That is what I really need to know. I've read about 200 threads over the last few weeks and just cannot seem to get a feel for whether this is a good idea.

I find it strange that I would be the first one to come up with this extremely simple and cheap way of making these, so I've been assuming it's probably just not an effective bass trap, but I'd like to call on your expertise and ask your direct opinion.

Thanks so much for all you offer here!

--Jason

[Gdupproductions]

Originally Posted by anarchoic

"Please Help pick correct insulation for my SuperChunk Build & Placing GIK 244 Panels" that hasn't, as of yet, provided a specific response to this question.

For chunks Fluffy insulation (the rolls, slabs are a mess to workwith im talkin out off expierience).

The 244 @ Reflection points (left and right off you).

[jim1961]

10" of Pink Stuff seems the clear winner when you have 10" of depth down to 80hz.

[Jens Eklund]

Low kg/m3 is worthless.