The Blind Leading the Dumb

WeAreAs1 at aol.com WeAreAs1 at aol.com
Sat Jun 14 08:50:23 CEST 1997


>From Sweetwater Sound's "InSync" newsletter, 6/13/97:

<< Word For The Day:

"Inverse Square Law" - Useful when setting up a microphone or speaker, the
inverse square law states that, in a free field the intensity of sound drops
by 6 dB for each doubling of distance from the source.  Now, none of us ever
work in a truly free field (no reflective surfaces), but for most
applications
these numbers are accepted as workable.  In real world terms, this means that
for each time you double the distance between your sound source and a
listener
or microphone, the power of the audio drops by 75% - a fairly significant
amount! How much is this in terms of volume? Well, it depends on the source
you consult, we've seen both 6 dB and 10 dB convincingly listed as doubling
or
halving the volume (let's just say it's subjective and leave it at that...) -
regardless, 6 dB is a very noticeable drop in level! Consider this the next
time you place a microphone or speaker: Rather than just cranking up or
attenuating the mic preamp or amplifier level for gain control, look at the
distance to your source... >>

Wow!  Do these guys _really_ think that decibel ratios (as applied to
voltage, power, or SPL) are a "subjective" matter?  Remind me to not ever ask
*them* for any critical technical advice.  Sheesh....



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