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Re: Digest Number 1820

Subject: Re: Digest Number 1820
From: Michael Dalton <>
Date: Thu, 4 Aug 2005 15:18:53 -0700 (PDT)


RE:Message: 1=20=20=20=20=20=20=20=20
Date: Wed, 3 Aug 2005 10:06:38 EDT
From: 
Subject: Re: distance vs. strength

Ah yes, I had to go back and refresh my memory of basic geometry
formulas.
Thanks to math.com:

Volume of a sphere is 4/3 pi r cubed, but surface area of a sphere is 4
pi r--squared.

So I retract the suggestion of a cubed relationship for distance and
strength."

***
Gentlemen:

Regarding sound pressure level; not all sounds follow the "inverse square l=
aw." The idea depends upon the assumption that the source is very small or =
is located a very great distance from the observer. Additionally, some sour=
ces are what are know as "extended sources," an automobile on a nearby stre=
et, for example. The result is that the sound field falls off much more slo=
wly, such as 1/R, where R is the distance to the source.

The above situation is precisely one that I have to deal with in my speech =
research. The sounds generated by the car (noise) is extraordinarily diffic=
ult to remove precisely because it does not abate according to the "inverse=
 square law."

Recordists should at least be aware of this phenomenon, because you may nee=
d to deal with such extended noise sources from time-to-time. I surely need=
 a good amount of help dealing with my difficulties with such noise sources=
.

Mike


=09=09
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