Natural Science Forum / Physics / Acoustics / November 2004

hello, maybe somebody knows where i can find the final product of
active muffler . on the web i found only description , technology ,
articles about principles etc. but i'm interesting actually for final
product , i mean the ready box that i can connect to my machine , i.e.

For an impedance tube setup, I would like to use 1/8" measurement
microphones. I found exactly two:
- G.R.A.S 40DP, price with amplifier and adapter: ~2300,- Euro
- B+K type 4138, price: I didn't ask...

It would be appreciated if anyone could let me know if there is any
Spectrum Analyser Software available that can be used on a laptop
computer.
I would like to measure the frequencies of sounds in a room caused by

Here's the problem on a off-shore platform: at a certain wind speed
and direction the air intake louvers start to behave like organ pipes
producing a pure tone. The pure tone is so loud that is causes problem
to workers.

someome have a trial copy of software norxfer for norsonic SA 110.
I've a old DOS program to transfer data and don't work with XP.
I want to try the software somone could help me? Thanks
Hello Folks

I am doing a project in which I am constructing
a home theater, I need to know the shape,style that would provide the
best acoustics, along with the physics behind it.  I have heard a
sphereical room would not be best because of echoing, is this true?  I

Why is it that I always see sound waves plotted in two dimensions when
in practice they're always three dimensional?  Does the brain simply
average a three-dimensional sound wave so that we can always model it
as if it was a 2D wave?

What mathematics is involved in modeling 3D sound waves?  If anyone
could point to some books on the subject I'd greatly appreciate it!
Chuck

           Survey by The Scientist magazine finds scientists love working
in
           Canada
           TORONTO (CP) - The University of Toronto is one of the most

I attached a steel, standard size slinky to a metal plate.  I then
held the assembly about 6 feet high and turned it upside down so that
the free end of the slinky rapidly fell and struck the hard floor.
The result was a high-frequency transient sound with spectral peaks

I have some information that provides different sound level dBA
ratings for a particular engine at different frequencies.  How would I
take these values and combine them into an equivalent dBA rating?  I
am looking for the equation(s) required to do this with variable

I was wondering if anyone could tell me what the STC ratings would be on a
house constructed of codeboard, insulation, drywall and either wood siding
or vinyl siding on the outside??
Thanks in advance!

What is the Ontario Building Code's STC rating requirement for a single
detached home?  What is the minimum rating allowed?
Thanks!

-------- Original Message --------
Subject: Re: Experimental Evidence for Dynamic Doppler Shift
Date: 23 Aug 2004 16:32:06 -0700
From: the_ghostbuster@netzero.com (The Ghost)