Rigid vs. Fluffy

  • Thread starter Thread starter sizzlemeister
  • Start date Start date
This has all been interesting, but I'm still not getting the answers on rigid versus fluffy.

Actually, the OC QZ adds into this. At 3.5" the QZ has a R-value of 13, while rigid, I can't remember, but isn't it 3.5 at 1"? It's comparable at equal thickness I believe. So, what is Owens Corning doing to rigid and QZ that they're NOT doing to standard insulation to make it absorb more sound?
 
sizzlemeister said:
This has all been interesting, but I'm still not getting the answers on rigid versus fluffy.

Actually, the OC QZ adds into this. At 3.5" the QZ has a R-value of 13, while rigid, I can't remember, but isn't it 3.5 at 1"? It's comparable at equal thickness I believe. So, what is Owens Corning doing to rigid and QZ that they're NOT doing to standard insulation to make it absorb more sound?
Click to expand...

The R value is not related to acoustic performance.
 
apl said:
The R value is not related to acoustic performance.
Click to expand...

I UNDERSTAND THAT.

Let's not continue to go in circles, shall we? Think outside the box for a moment and consider the question again. I even said it's about equal between QZ and rigid in terms of R-value, so that's a wash. BUT BOTH ARE SAID TO RESTRICT SOUND MORE THAN EVEN THICKER REGULAR FLUFF. WHY? What is done to the material to make it have that property?
 
If R values applied to Sound absorption, styrofoam insulation would have sound absorption characteristics, but since it does not, well.....it does not. The reason is very simple. RESISTANCE to air molecule movement. Rigid fiberglass RESISTS when it is at the right density, does NOT resist as well when it has batt insulation density, and resists TOO MUCH like stryofoam when too dense because stryofoam is CLOSED CELL. Simple.
fitZ :)
 
RICK FITZPATRICK said:
If R values applied to Sound absorption, styrofoam insulation would have sound absorption characteristics, but since it does not, well.....it does not. The reason is very simple. RESISTANCE to air molecule movement. Rigid fiberglass RESISTS when it is at the right density, does NOT resist as well when it has batt insulation density, and resists TOO MUCH like stryofoam when too dense because stryofoam is CLOSED CELL. Simple.
fitZ :)
Click to expand...

Well put, Rick. Balancing the resistance is the trick. Actually, the resistance is an impedance and is complex (as in a real + imaginary mathematical function). Too much resistance and it reflects, not enough and the sound goes through, bounces off the next hard thing and comes back.

I very seriously doubt there would be any measurable difference between a wall built with regular pink and the QZ stuff.
 
RICK FITZPATRICK said:
:eek: You mean I actually said something correct for once? :D Thanks apl. You made my day :p
fitZ
Click to expand...

Most of the time you do, it seems.
 
Well, thank you one and all. I consider myself edumacated on the matter. My next thread will be a question about quantum mechanics and paint colors...stay tuned!
 
apl said:
I very seriously doubt there would be any measurable difference between a wall built with regular pink and the QZ stuff.
Click to expand...

QZ comes precut to 93" length to drop right in. I think it's mostly convenience.
 
mshilarious said:
QZ comes precut to 93" length to drop right in. I think it's mostly convenience.
Click to expand...

Ah-ha! That makes sense. Not having to cut is big $ for builders.
 
sizzlemeister said:
A greater R-value means there's a greater density of air pockets which resist cold or heat. According the definitions of r-value here: http://ceramicadditive.com/facts.html and http://www.ibpteam.com/about/faq.asp among other places. Clearly they're talking about conventional forms of insulation, but then again so are we.

And isn't the principle, as APL noted, to stop, retard, dampen the transfer of energy? And, mass aside, isn't this accomplished effectively by using air pockets of some form or another (remember, I said HELP in sound proofing, not be the all-be-it-end-all-solution).
Click to expand...

Sorry, but the principles are different.

I hope you don't mind my jumping in here - but I am a pro.

We don't use 703 or 705 in wall construction for sound isolation.

Quite often we will use rock wool (mineral wool fiber) instead of standard fiberglass. But not the high density glass boards.

As far as R-Value and TL Value goes - it's very diffrent things.

The pockets that exist in standard (fluffy) insulation cause the air molecules to travel a great distance to make it through that 6" thickness of material. They have to weave their way back and forth before they ever make it out. Sort of like a maze.

Low frequencies (on the other hand) are very much like a wave - and pass straight through the material - in this case the density of the 703/705 helps to cause more of the wave to become heat during the process.

This makes the 703/705 much more attractive for sound attenuation within the studio - but as far as sound isolation goes - we can (for a whole lot less money) add mass to the wall through the use of more drywall layers than we could ever do with rigid fiberglass, so why waste the money when it's won't get us where we want to go anyway.

Please post links to the posts you're refering to - I would be interested in seeing what "pros" are advocating the use of rigid fibergall within wall cavities for sound proofing purposes.

Rod
 
Rod Gervais said:
Please post links to the posts you're refering to - I would be interested in seeing what "pros" are advocating the use of rigid fibergall within wall cavities for sound proofing purposes.

Rod
Click to expand...

Oh no, I never said pros were advocating it. However I've seen rigid mentioned nearly everytime sound proofing comes up in threads on the various boards.
 
sizzlemeister said:
Oh no, I never said pros were advocating it. However I've seen rigid mentioned nearly everytime sound proofing comes up in threads on the various boards.
Click to expand...

Well, again a lot of people say soundproofing when they really mean treatment, and most of us are conditioned to ignore the error, so that could be a source of confusion.
 
sizzlemeister said:
Oh no, I never said pros were advocating it. However I've seen rigid mentioned nearly everytime sound proofing comes up in threads on the various boards.
Click to expand...

Correct - you never used the word "pros" - however you did say things like this:

Now we're getting somewhere; why, though, is the rigid stuff recommended over fluffy stuff for sound absorption IN SOUNDPROOFING applications? This is what I want to know. What makes the rigid better than the fluffy given that the fluffy technically can absorb more energy (hence the mention of R-value)?
Click to expand...

A statement like that tends to suggest that there are people out there who actually have some validity in the field reccomending this.

If (by that statement) you mean that people who know little to nothing about construction techniques make suggestions that you take to heart as being valid - then I would not catagorize that as being seriously worth considering.

You post suggests that this is something seriously recomended in the industry....... I consider this akin to some people suggesting that the use of egg flats is great for isolation and sound attenuation within a room.

Maybe it could elicit a comment from me about how people continue to talk about things they know nothing of - but never a serious conversation about the recomendations to use egg flats in sound isolation construction.


I visit over a 1/2 dozen sites on a regular basis - and if I were to encounter comments like that I would dispell them the minute I view them.

I have not seen anything to the extent of your comment "However I've seen rigid mentioned nearly everytime sound proofing comes up in threads on the various boards."

I would like to visit the various boards you refer to........ which ones are they?

Sincerely,

Rod
 
Let me see if my own perspective on this might help.

Sound is the coherent vibration of air.

For absorbtion to work the surface must be porous enough for the vibrations to be let in (otherwise sound is reflected away) and then it must be dense and twisted enough for the vibrations to lose there coherency. the problem with very loose materials is that the waves have too easy a path through without having their coherency disrupted. Now a very thick panel of a somewhat less dense material might still cause the waves to lose their coherency, but there is a practical limitation as to how thick you want a bass trap to be.
 
SOOOOOOOOOOOOOOOoooooooooooooooooooooooooooooooooooo!


I suppose it would not be a good idea to build a panels out of R-13 to put in the corners. It would be kinda like a bass trap but not really.. Or something..


I guess it would absorb the high and mids but do nothing for the bass. Because in order to affect the bass you need something with more density.
 
Forget batt type insulation for absorption purposes. EVEN in rolls. Bite the bullet and make superchunk corner absorbers floor to ceiling at wall intercections and even wall/ceiling corners for bass traps. It really is the best DIY choice for PROVEN bass traps. Either 703 or rockwool, the choice is yours.
Look at it here.

http://forum.studiotips.com/viewtopic.php?t=535
fitZ
 
You must log in or register to reply here.
Back
Top