At 8:12 PM +0000 1/16/07, jpbeale wrote:
>Posted by: "Eric Benjamin"
>> Commercially available sound booths usually give about 40 dB of
>> attenuation in the mid-band (500Hz)...
>
>If performance is critical, and you have the space and the money, then
>you can built a second larger isolation booth entirely enclosing the
>first booth. To enter you would pass through two separate doors. That
>would double the attenuation from 40 dB to 80 dB, which is enough
>attenuation to push the large majority of background noises completely
>below the threshold of hearing.
>
One would hope so, yet energy is energy and the lowest octaves really
possess it. I would be surprised if four, free-standing walls of the
type I described could knock down the energy below 30Hz close to 0dB.
A windowless basement sound studio I once worked in had ~20" thick
Indiana Limestone exterior walls. When we searched the magnetic tape
at ~8X normal speed, we could distinguish every car pass on the
street about 60 yards away. Less than of the basement's exterior
wall was exposed to air, the other part was below grade in clay.
Helped me realize that everything has capacity as a membrane. Rob D.
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