Originally Posted by Harish Gangidi
I'm new to AVS forms. I'm building a new home and a dedicated home theatre(15.10 by 19.6). I am interested about sound proofing my theatre. When inquired about the pricing he said its 400 but i don't know what kind of material is he using to do it. Do you guys know if this is typically the price? will it do any better ?
A lot of contractors don't fully understand soundprooing principles. They usually just throw insulation in the wall and call it soundproofed.
You'll want to start reading some articles over at soundproofingcompany.com http://www.soundproofingcompany.com/soundproofing101/
Once you've done that you'll need to determine how important it is to you to soundproof. Keep in mind, your weakest link will effect your result. Weakest link such as a door, stairs, vents, etc. Think of it like a fish bowl. If the tank (theater) has a hole, water (sound) is going to leak.
Make sure you do all walls, ceiling and floor. If it's a basement on a concrete slab then the floor can be skipped. If you don't do the walls, sound will flank through the walls and go up or down to the other floors.
The two most important factors are decoupling and mass. When you decouple you build double stud walls with floating joists or use metal channels
attached to clips which are attached to the wall studs and ceiling joists. Here's an example of the clips: http://www.soundproofingcompany.com/...solation-clip/
The drywall then attaches to the channel. You want to use 5/8" type x drywall. The more mass, the better. It's recommended to double the 5/8" drywall with staggered seams. If room height is a concern with the clips, you can install the clips/channel to where the ceiling would only be 1/2" inch below the ceiling joists.
To help with cavity resonance you can use pink fiberglass insulation.
If you want to do more, you would than use green glue or something similar between the two pieces of drywall. Keep in mind it's not actually glue. It doesn't harden which allows the drywall to flex.
There is also the issue of ceiling lights. Any lights need to have backer boxes. If you don't use backer boxes than you'll have created a swiss cheese ceiling for sound to travel through. You may also want to treat any supply/return vent that opens into the room. If you have done all this than you should do the outlets as well by using puddy pads or duct seal.
You can read more in depth about these principles at soundproofingcompany.com.
...therefore $400 is more than likely not enough.