What material to stuff inside drywall cavbity?

[allentx1]

I am about 2-3 weeks away from getting 4 walls worth of Quiet Rock installed and will be opening up the walls to insulate behind. Is there any reasonable (HomeDepot type) insulation I can add to those walls to help further the sound insulation? I am also considering adding a layer of carpet padding to help the floor which is over the garage.

[Robinson_A]

If absolute sound isolation is your goal you're going to want to jump on-line to check out what insulation brands R ratings are going to give you the most sound dampening for your money. That being said, be careful not to make your room to "dead" acoustically.

the thick padding might work well. Perhaps doubling up your subfloor would be better. You could even 'float' a subfloor.

good luck

[Brian]

The biggest effect the insulation is going to have in a typically framed wall is preventing wall cavity resonance. The cavity resonance will be affected more by the amount of fill rather than the "R" value of the fill itself which relates to thermal transmission, the higher the "R" value, the less transmission there is. Insulation will have little effect on sound transmission (assuming typical framing and no penetrations) other than any mass damping affect. For mass damping i would look to a Dynamat type product instead. Also make sure to seal all penetrations, preferably with a fire retardent material.

With respect to carpet pads for your floor, there are a few manufacturers of mass loaded pads that will reduce the noise somewhat, of course, the noise reduction would be greatly enhance if you also isolate the floor although that get expensive, especially for a floor over the garage. (assuming you are trying to keep your theater noise from escaping rather than keeping environmental noise out).

Good luck.

[JerryDelColliano]

When working on my theater's acoustics with acoustician Bob Hodas, Tim Duffy and Chris Hansen from Simply Home and a little with Kevin Voecks from Revel - I choked on getting the quiet rock.

It seemed like a REALLY good idea but my contractor had it bid out with all of the goodies at 3x the cost of standard drywall. Considering, my theater was going to be only really effecting the master bedroom - I went cheap (for once in my life!!!)

The effect is even with RPG treatments, plenty of "spun glass", Modex plates and other acoustic goodies - the system leaks a pretty good amount of audio energy into the rest of the house. For my wife and I - its no big deal.

If you are worried about being able to CRANK in your room - look into this quiet rock. Its pretty cool!!!

[JerryDelColliano]

Originally Posted by allentx1

I am about 2-3 weeks away from getting 4 walls worth of Quiet Rock installed and will be opening up the walls to insulate behind. Is there any reasonable (HomeDepot type) insulation I can add to those walls to help further the sound insulation? I am also considering adding a layer of carpet padding to help the floor which is over the garage.

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Tim Duffy from Simply Home Entertainment told me he used a product from recycled denim (a "green" product) for TV producer, Phil Rosenthal's new theater. That is something you could look into.

I used "spun glass" behind my RPG BAD pannels and in front of my fabric wall. That was a pretty effective solution that is also pretty cheap.

j

[Bob Hodas]

The recycled cotton insulation is made by Bonded Logic. The in wall home version is called Ultra Touch and is available at many hardware supply stores. The acoustic panel version is available through acousticalsurfaces.com.
BH