In Austria we have a standard for noise pollution. I learned about it when
I did my post-grad on environmental sciences. They evaluate sound first
according to the A-curve which associates a perceived dB value according to
the frequency. Certain frequencies are percieved much louder than others.
In additon there are correction values that are added to this if the sound
has certain characteristics. Like a very rhythmical sound adds 3 dB, speech
adds 5, music adds dunno how much.
These values are all based on empirical studies. I don't have access to
them here but next time I am back in Vienna I can look them up - that may
be months in the future though.
In any case it means that a noise that is repetitive or that has 'high
information content' (I think that is the wording of the standard document)
is perceived as much more disturbing than a singular event or a steady
ongoing hum. This is also the reason why there are very different noise
pollution regulations for propeller aircraft and helicopters than for jets.
Just as an example.
Cheers,
Andreas
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Andreas Dieberger
Emory University / Multimedia Communications
550 Asbury Circle -- Atlanta, GA 30322
phone 404 727 1025 -- fax 404 727 2257
Leopold-Ristergasse 5/97 -- A-1050 Vienna, Austria
phone +43-1 544 11 47 -- fax +43-1 544 11 474
adieber@emory.edu (Contact by email preferred)
andreas.dieberger@acm.org -- andreas@ebweb.tuwien.ac.at
http://www.lcc.gatech.edu/faculty/dieberger/Home.html
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The last good thing written in C
was Franz Schubert's Ninth Symphony
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