Natural Science Forum / Physics / Acoustics / September 2005

Since I added a few things on echolocation, this might be of interested
to this group:
The latest edition of the free Motion Mountain physics text can be
downloaded at

Anyone,
Is Lep,d the same as TWA? or is it different.
(Assuming the d is 8 hours?)
Knowing my sample time, Leq and d how can I

        I am looking for the vibration environment criteria for surgical
equipment for a new hospital. The building will be deigned within a
year, and I need to know what maximum allowable floor vibrations from
other building mechanical equipment we should allow.

    In recent years, the installation of vibration sensitive equipment in
multi-story buildings has become commonplace. We all know that placing
such equipment on the ground floor, on terra firma, is the best choice,
But that is not the way that humans act and think. As a result ...

Looking for a software package for a PC that will take a digital audio
signal (WAV file) and do LEQ measurement in bands filtered with IEC standard
octave or 1/3 octave band filters.  Not FFT.  Real time not necessary.  Is
there such a thing?  I'm looking for a supported product, ...

As it says in the title, I'm trying to source in-ear microphones for
use under a motorcycle helmet. Bruel and Kjaer make a set but I would
like to know if there are any others available which I could consider.
Thanks.

Aside from the clarinet and oboe having single and double reed respectively,
the main difference in construction is that the clarinet has a uniform bore
while the oboe has a conical bore. Supposedly, the clarinet will not
generate strong even harmonics. The clarinet forms an closed ...

1.I am considering doing a simple midi file generator for my
 4th year project in B.SC.
2.I would do it using c language, but i'm not sure how
 difficult it would be.

Search Ebay for seller "accordlogic", or use the item numbers at left.
7546139339    Ivie IE-30A Spectrum Analyzer RTA Complete System    $199.99
7545446292    B&K Bruel & Kjaer 2031 Narrow Band Spectrum Analyzer    $99.99
Other Stuff:

Bats make ultrasonic sounds. Different species of bat can be identified by
their sounds. There are different types of bat sound detectors. Heterodyne
seems to be most common. Time division and time expansion are other methods
used in detectors. All detectors convert ultrasound to ...

Can anyone reccomend a manufacturer/supplier of Air Coupled
Transducers? I am looking for an air coupled transducer that operates
in the range of 50kHz - 1 MHz.
Thanks

Dear Readers,
I am a university instructor recently commisioned to look after
acosutics and lighting in the school. Browsing for resources available
on the internet, i found nothing useful to cite as a reference for