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What is the best route to go with insulation for the theater ceiling? I don't want to break the bank, but i want something that will reduce noise. Mineral wool is somewhat expensive, but if it's the best route then i guess i will do it. If i go with fiberglass what R value should i use? Paper faced or not?
 

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What 'noise' are you trying to stop? If it's just mid and high frequency and things coming INTO the theater, filling the cavity full of standard insulation will help a good bit. If you're trying to stop low frequencies, you need that plus additional mass - like another whole layer of drywall. You'll also need to pay attention to any openings for things like can lights, HVAC, etc.

Bryan
 

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Discussion Starter #3
yes, mids and highs. The bass shakin' thing should be ok, because i really do not want to do a second layer of drywall. I have 5/8 going up and that's all I can handle. So what R value do you think I should use?
 

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The R value has no bearing on your choice of insulation as a means to burn off frequency. What does is the depth of cavity or area you are trying to install it in.

As a rule of thumb, my thumb anyway, whatever the depth is of the lumber, get the r-rated equivalent.

4" depth, get r 11.
6 inch depth, get r 19

The main thing is to not compress the insulation, too much.
 

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Correct. Fill the cavity full even if you have to (and you will) use multiple layers. There is no need to compress it - though it won't hurt anything much from an acoustical standpoint if you do. That'll only impact it's heat insulation properties which we really don't care about.

Bryan
 

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The posters question/situation is un-clear to me as it is written. If the r value is under question then by way of simple error it should be noted that over-compression of this material can create a bridge and diminish isolation.
 

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I think people usually refer to R value as that's how it's sold rather than by thickness. You're correct that if it was severely compressed (like 3.5" down to 1") then there could be some transmission.

Bryan
 

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Not sure what thickness that is but if it's close to 12" then yes.

Bryan
 

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flash, As a sound reducer, insulation is often not thought of in this capacity. Not alone, anyway. As part of a system it is used to damp panels from vibration and stop high frequency.

Maybe if you explained more about your situation you would get better clarity.

Bryan Pape is a noted professional in this field, he can help.


Mass is what stops sound, it has no equal. In whatever form you get it, mass is the way to beat sound from moving between panels in a wall or ceiling system.

Please share more if you have time.


Brien
 

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Absolutely - mass is always your friend. As has been said, the cavity still needs to be filled or we just get a drum that's tuned lower.

Bryan
 

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Discussion Starter #12
I bought r30 and r11 both stacked i believe gives me the 12 inches i need. The only problem is my joists are about 17.5 inches wide and the insulation is 15". Should i just cut and stuff some insulation in the 2 inch gap? I bought un:yay2:faced. I figured faced was not needed.
 

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Unfaced is just fine. You might be OK with out stuffing but if you have extra, I would.

Bryan
 

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As a side note, while filling a 12" cavity you can use R38, but there are little benefits gained in STC and IIC beyond R19. Hard data, not opinion, there.

Also, it makes no difference where the insulation is placed withing the cavity. Up by the floor, down by the ceiling or in the middle. Again, all based on actual lab tests.
 

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Mass is what stops sound, it has no equal. In whatever form you get it, mass is the way to beat sound from moving between panels in a wall or ceiling system.
Mass is one of 4 elements of soundproofing. I would not characterize it as having no equal. A system primarily dependent on mass will still resonate and conduct. In the real world, you'll never get enough mass to depend on it exclusively.

Rather, you would prefer to attack a sound containment system using multiple elements. Decoupling, mass, absorption and damping.
 

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Good to see ya again Ted ;)

Space said:
"As part of a system it is used to damp panels from vibration and stop high frequency."

It's been covered, but thanks for watching out for me.

BTW, would you have access to the lab data you mention?


Good luck,

Brien
 

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The link you want is here:
http://irc.nrc-cnrc.gc.ca/pubs/ir/ir766/

The data will also show(top of actual page: 88) that there is a point difference in STC and/or IIC depending on placement of absorption material. :) If points matter...

Thing is, this is a good document, maybe not for this specific topic as it was written based on data produced by many different assemblies of many different materials in many configurations. So a broad statement taken out of context cannot be made with this document as support.

Page 25 will disagree with you. A thickness of 90mm to 456mm(3 - 1/2" to 18") shows an increase in overall performance in both STC and IIC.

But it only applies to the 457mm depth wood I-beam with 15mm OSB attached on top, 610mm O.C. RC with 1 layer of 15.9 gypsum ;)

It also will prove my statements incorrect about "bridging" from over stuffing! Whadaya do?

I appreciate what your doing. I love this stuff too!

Brien
 

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Thanks for that URL Correction... not sure what happened to the old link.

The link you want is here:
http://irc.nrc-cnrc.gc.ca/pubs/ir/ir766/

The data will also show(top of actual page: 88) that there is a point difference in STC and/or IIC depending on placement of absorption material. :) If points matter...

The data becomes clearer as you perform many tests. Comparing one isolated test vs. another may simply be comparing anomolies. I look at the quote from AA Warnock:

Position of sound absorbing material in the floor cavity:

To test the effect of moving the sound absorbing material inside the floor cavity, 152 mm thick glass fiber batts were placed at the bottom (against the ceiling), in the middle and at the top (against the subfloor) of the 235 mm deep cavity of the reference floor. As expected, changing the position did not change the results.

Thing is, this is a good document, maybe not for this specific topic as it was written based on data produced by many different assemblies of many different materials in many configurations. So a broad statement taken out of context cannot be made with this document as support.

Page 25 will disagree with you. A thickness of 90mm to 456mm(3 - 1/2" to 18") shows an increase in overall performance in both STC and IIC.

No disagreement. I wasn't comparing R13 in the floor. What I stated was that there was little difference between an R19 filled cavity (152mm) and a full cavity, in this case 456mm. The majority of the work is done with 6" of fiberglass. This is especially true when we look at a heavier system where the added mass would alleviate more of that STC difference. Lastly, you're looking at I-Joist data which they identified as being wildly anomolous. Better to look at the data on page 17, which is solid wood joists which are far more consistent.

It also will prove my statements incorrect about "bridging" from over stuffing! Whadaya do? No, you're right. Overstufing will most certainly couple the surfaces. More of a risk when you start with demser insulation.
I appreciate what your doing. I love this stuff too! Thanks for the comments. I always pick up something new when looking at data again

Brien
 

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On a side note I like to talk in terms of "practical" improvements rather than "technical" improvements.

Doubling up on a material to get a point of improvement may technically be better, but considering the cost, it is not practically better.

Green Glue for instance is technically better at 3 tubes per sheet, but we never recommend more than 2 for the practicality.
 
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