Natural Science Forum / Physics / Acoustics / June 2005

Does any one know where or how I could find a graph or table with the
attenuation of sound by air for different frequencies (and distances)?
I found this equation:
        I*exp{-2E-13*(f^3)*r}

I'm quite green at this, and I'm not even sure if I'm in the right group.
Any help is appreciated.
I'd like to sound proof a basement room.  Walls and ceiling.  Wooden studs
are in place on all the walls and the ceiling.  I'm going to eventually put

Hello gurus - I have a home office in a wood frame house and want to
separate it (read: block the screams of a 18 month old) from the rest of
the house.  I plan to have a partition wall built out of 2x material.
Can anyone give me practical suggestions as to feasible (I know a

any body aware of any interesting papers on this subject?

It's related to a parking project for trucks / vans along a high way. I
got to calculate whether noise from cooling units on refrigerated
trailers would be a problem for the houses nearby when the parking will
be built.

i just got the latest issue of the JAES and i'm a little bit disgusted.  so
i thought i might ask for a straw poll.
given a quasi-periodic musical tone:
           N

I already use ear soft insert (SNR=36)   WITH  muffler Peltor Optime 3
(SNR=35),to protect from strong sudden impact noise come from upstairs.
What better to do for sleeping at least?
What about a insulated box?

The rush of return air flow through my a/c blower is very
noisy. This is not 'mechanical' noise, but the 'wind rush' noise.
The return opening is at floor level and the air makes an
upward turn to enter the fan suction which is about 27 inches

Does the EU (or individual European countries) have a railroad whistle
blowing policy similar to the U.S.'s upcoming whistle blowing rule
(i.e., trains must blow horns at grade crossings unless said crossings
have installed supplementary safety devices)?

Seems to me it's a whole lot easier finding technical specs for a nuclear weapon
than it is finding the formula to determine the resonant frequency of unimorphs.
For brief moment I was happy when I found the two formulas here at
http://www.americanpiezo ...

I am curious about the difference between PSD(power spectral density)
and ESD(energy spectral density).
Why does we use these values?
Waiting for proper explanation...

Dear Colleagues,
I am a sound engineering student at the Frederic Chopin Conservatory in
Warsaw, Poland.
I am preparing to write an MA thesis on reverbaration time in acoustic

Hi, this is a question about UK railways.
Does anyone remember the situation where a railway operator has been
prosecuted for locomotive noise affecting residences whilst parked in a
siding?

if you know the far - field SPL, can you calculate the intensity using
characteristic impedance?
yours
Richard

I found a patent for a piezo-bimorph that has no center vane and is
supposedly capable of producing more acoustic energy than the current
design. The new design is tricky, but doable. I was wondering though,
for frequencies between 10 -50 kHz