[LAD] sound dissipation in air - formulas and filters?

[Jörn Nettingsmeier]

victor, fons, thanks for your replies.

Fons Adriaensen wrote:

> This will show you that a simple 2nd order
> lowpass will do the job - it's not a perfect
> match but good enough. It's not critical at
> all - for small distances you can even use
> a standard shelf or parametric.

true, for this particular case it would do (and that's what i'm using
atm). but i have this idea for a plugin that takes actual mic distance,
temperature, humidity and desired distance as parameters and will do
something that is reasonably correct (not taking into account sound
diffraction or reflection at temperature boundary layers, obviously).
would be kind of cool, but i need to get a deeper understanding of the
physics involved... especially the dependance on humidity is a very
tricky and quite non-linear issue.

fons is probably right that it doesn't make all that much of a
difference, but since such a plugin could be a nice learning tool for
sound engineers, i'd want it to be as precise as reasonably possible.

google books has one interesting paper, but it's part of a rather
expensive book:
http://books.google.de/books?hl=de&lr=&id=1x_RvffW-hcC&oi=fnd&pg=PA305&dq="Sutherland"+"Atmospheric+sound+propagation"+&ots=-_5OK7SyHS&sig=XvBWOH8X-1W-CTszwGpkfeomO8Y#PPA306,M1
there is a graph on page 307 that is quite frightening (and that's for a
constant temperature :)
i think i'll go digging in the library first.

best,

jörn