[linux-audio-user] measuring sound volume

[davidrclark at earthlink.net]

Regarding the inverse square law: Be careful! 

This law applies to idealized situations such as point sources in isotropic,
homogeneous media.  For a speaker in a  tunnel, for example, it does not hold
true.  Speakers have radiation patterns as do electromagnetic devices such as
antennae.  Boundaries are also important.  You will also have interference
effects, etc.  I would anticipate that the inverse square law to be quite
inaccurate, but being  outside will help.  I love theory myself, but this
situation calls for the voice of experience.  (Now if that voice says,
"Always use the inverse square law," please let me know.)  The best thing
I can think of from a theoretical perspective (sort of) is to obtain the
speaker patterns if you can.