Author Topic: Roxul safe'n'sound in false av wall  (Read 4573 times)

Mike L

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Roxul safe'n'sound in false av wall
« on: September 23, 2012, 09:59:19 AM »
I built a wall in front of an external wall that is going to be my av wall.  I am planning on filling the cavities of this wall with Roxul safe'n'sound.  However, I am concerned that the wall will be too dead.  Can I do too much absorption behind the speakers?

Any thoughts would be appreciated.

Thanks,
Mike

Offline richidoo

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Re: Roxul safe'n'sound in false av wall
« Reply #1 on: September 23, 2012, 11:19:01 AM »
Hi Mike! If I understand you, there will be sheetrock between the Roxul and the speakers, so no, you can't put too much in the hidden cavity. You don't want sound in the cavity to echo.

Allow an inch of space between the sheetrock and the insulation to allow the sheetrock and wall to flex a little. The insulation will absorb the impulses and damp the movement of the wall, creating a bass trap. You can engineer a specific band of absorption by spacing the studs at particular distance, but the whole wall will still have some flex so it will work even without thinking about it. The compartment behind the fake wall and containing the insulation should be airtight, if possible, to maximize this bass trap effect.

Most acoustic experts would advise putting absorption between the wall and the speakers also, in order to lessen echo from the front wall cancelling direct sound from the speaker at low to mid frequencies. You have to balance it with how much "spaciousness" you lose by also absorbing the mid/high freq echos that sound good.

Roxul is rough on your skin, so be careful using it. An alternative is cotton bat. No itch and great sound absorbent. http://www.bondedlogic.com/
Have fun!

Mike L

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Re: Roxul safe'n'sound in false av wall
« Reply #2 on: September 23, 2012, 02:23:41 PM »
Thanks Rich.