Date: Sat, 12 Oct 2002 01:22:19 +0200

Author: "Simcha Segev"

Subject: RE: FW: Physics and Music demo's

Post:

Dick,

Great stuff, lot of work and experience that you put in your web site.
Cheers.

About reverberation, I did not find any description in your catalog.

Demo 8.3, REVERBERATION TIME OF LECTURE HALL, is exactly the demo that I
would like to perform but you didnít edit this demo yet.

In your answer concerning this demo, you mentioned some Apple program.
First, I do not have an Apple and I use, like most of the computer users
in Israel, Microsoft Windows based software. I'm sure that there is lot
of software that has been written for Windows.

Second, please specify what kind of equipment you use. Is this demo
required special kind of loudspeaker or horn? Perhaps a directional
microphone? In what frequency you get the best results.


Thanks and kind regards, Simcha



Simcha Segev - Demo Lab
School of Physics and Astronomy
Tel Aviv University - ISRAEL
Tel. 972-3-6408077 Fax. 972-3-6429306
E-mail: simcha@post.tau.ac.il
http://minerva.tau.ac.il/physics/demolab


-----Original Message-----
From: owner-tap-l@listproc.appstate.edu
[mailto:owner-tap-l@listproc.appstate.edu] On Behalf Of Richard Berg
Sent: Friday, October 11, 2002 2:12 AM
To: Simcha Segev
Cc: Tap-L
Subject: Re: FW: Physics and Music demo's

Simcha,

We have a large number of acoustics demonstrations catalogued by chapter
and section in the physics of sound book that I co-authored and is now
being used in our Physics of Sound class. Try:

http://www.physics.umd.edu/lecdem/services/demouse/phys102sugg.htm

We had a really neat program on an old Apple II+ that used 1/3 octave
pass
band filters covering the entire audio spectrum to measure the response
of
rooms. It made very nice measurements of the reverberation time at any
frequency band or for the sound as a whole. Since our old coomputer
went
south on us I have not been able to find another to replace it and we
have
not been able to measure the reverberation time of our lecture hall.

Best wishes,

Dick Berg

On Wed, 9 Oct 2002, Simcha Segev wrote:

> Hi All and good morning,
>
> One of the distinguished professors here sent me this mail. I will
> appreciate your ideas for nice demo's in acoustics and physics of
> musical instruments.
>
> Thanks, Simcha
>
> -----Original Message-----
> From: Abraham Katzir [mailto:katzir@post.tau.ac.il]
> Sent: Wednesday, October 09, 2002 1:58 PM
> To: simcha@post.tau.ac.il
> Subject: RE: Physics and Music
>
> Dear Simcha,
>
> As part of my course WAVES, I plan to teach a few hours on PHYSICS and
> MUSIC. I will include ACOUSTICS and the physics of musical
> instruments.
> I would love to have few demonstrations. In particular I have two
> demonstrations in mind:
>
> 1. Reflection and Absorption of acoustical waves:
> I thought of using a directional loudspeaker, which can send sound
waves
> onto some surface. A sound level meter can be used for measuring the
> intensity of the incident waves and the reflected waves. The ratio
can
> give the absorption of the surface. I thought that we can use some
> concrete wall as an example of a surface that reflects well sound
waves,
> and some heavy carpet as a surface that absorbs well sound waves.
> Alternatively, we can possibly place a thin layer of material between
> the sound source and the sound level meter and measure directly the
> absorption coefficient. These experiments can obviously be carried
> out at different frequencies, so that a plot of the absorption as a
> function of frequency can be obtained.
>
> 2. Reverberation time in an auditorium
> The reverberation time could be calculated, knowing the absorption
> coefficient of the wall materials and the volume. We can possibly
> measure the reverberation time of the Lev Auditorium where I teach. I
> thought of using again a loudspeaker for generating sound at some
> frequency. We can use a microphone to measure the sound waves at some
> location in the auditorium. You can, for example, generate a very
long
> pulse of sound. We can measure the time it takes to reach steady
state,
> and the time it takes the sound to decay. The rise time or decay time
> can be used to determine the reverberation time.
>
> I would be most grateful if you could check for me what has been done
> elsewhere, and how we can carry out these demonstrations. Also, you
> may find on the INTERNET other beautiful experiments in acoustics. I
> would gladly adapt them in my course
>
> Best Regards
>
> Abraham Katzir
>
>

***********************************************************************
Dr. Richard E. Berg, Director Phone: (301) 405-5994
Lecture-Demonstration Facility FAX: (301) 314-9525
Department of Physics e-mail reberg@physics.umd.edu
University of Maryland www.physics.umd.edu/lecdem
College Park, MD 20742-4111
***********************************************************************
Eschew obfuscation.
-Joseph A. Ecclesine
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