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Sound Acoustics
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Author:  djd_oz [ Sun Dec 08, 2013 8:27 pm ]
Post subject:  Sound Acoustics

Anyone used products from these guys before? http://soundacoustics.com.au/

Any comments or feedback would be appreciated.

Author:  Martha Bern [ Mon Sep 04, 2017 9:41 pm ]
Post subject:  Re: Sound Acoustics

I'm also interested in the best soundproofing materials. A friend of mine is going to build a vocal booth for his band rehearsals and he's currently looking for this info. I'd really like to help him with a nice piece of advice. Thanks!

Author:  Soundman2020 [ Mon Sep 04, 2017 11:15 pm ]
Post subject:  Re: Sound Acoustics

Quote:
Anyone used products from these guys before?
No. Why? Do you work for them?

Quote:
Any comments or feedback would be appreciated.
My comment is that we don't like spammers here on the forum, and my feedback is that spammers get banned pretty fast...

Martha Bern wrote:
I'm also interested in the best soundproofing materials. A friend of mine is going to build a vocal booth for his band rehearsals and he's currently looking for this info. I'd really like to help him with a nice piece of advice. Thanks!
If your friend wants to "soundproof" something, then he's out of luck.

It is impossible to "soundproof" a room. Any sufficiently loud sound will easily penetrate any conceivable barrier. The loudest sound ever recorded on planet Earth was loud enough to crack concrete 300 miles away, and was heard around the world.

Also "soundproofing" means different things to different people. Some use it to mean "stopping sound from getting in and out of a room". Others us it to mean "making the room sound nicer inside". Neither is correct.

If you are referring to the former, what acousticians more commonly refer to as "acoustic isolation", then the best materials are massive and air-tight. BUt according to mass law, they still aren't much good. To get really good isolation for a studio, you need a fully-decoupled two-leaf MSM isolation system, consisting of two massive air-tight leaves separated by sufficiently large air gap that is fulled with suitable acoustic damping material. That system is then tuned to the correct resonant frequency.

So the best piece of nice advice you can give him is this set of equations:

TL = 14.5 log (M * 0.205) + 23 dB

Where: M = Surface density in kg/m2

(That's the empirical form of the Mass Law equation)


f0 = C [ (m1 + m2) / (m1 x m2 x d)]^0.5

Where:
C=constant (60 if the cavity is empty, 43 if you fill it with suitable damping material)
m1=mass of first leaf (kg/m^2)
m2 mass of second leaf (kg/m^2)
d=depth of cavity (m)

(That's the 2-leaf MSM equation)


R = 20log(f (m1 + m2)) - 47 ...[for the region where f < f0]
R = R1 + R2 + 20log(f x d) - 29 ...[for the region where f0 < f < f1]
R = R1 + R2 + 6 ...[for the region where f > f1]

Where:
f0 is the resonant frequency from the MSM resonant equation,
f1 is 55/d Hz
R1 and R2 are the transmission loss numbers you calculated first, using the mass law equation

And that's it! Nothing complex.



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