Natural Science Forum / Physics / Acoustics / August 2006

Another one paying with my head. I know there is rules of thumb for
wavelength much larger than radius etc but does anyone know of a
reference that is slightly more detailed? I am interestd to know what
the upper and lower frequency for reasonable diffusion from a semi or

Another one paying with my head. I know there is rules of thumb for
wavelength much larger than radius etc but does anyone know of a
reference that is slightly more detailed? I am interestd to know what
the upper and lower frequency for reasonable diffusion from a semi or

Can anyone direct me to a reference that describes the effect of adding
absorption inside an enclosure (like a pump room) on sound transmission
outside of the enclosure?
thanks

SAE will be holding its Noise & Vibration Conference May 14-17, 2007,
in St. Charles, IL.  Abstracts due September 5, 2006.  Look at
www.sae.org/events/nvc for more details if you like.
Steve

I have two fm instruments with slightly different modulation indices. I
have both instruments playing the same notes at the same time with the
same asdr. I have one of the fm instruments hard panned to the left and
the other to the right. In other words, each instrument has its own

Here..
http://membres.lycos.fr/plasmapropulsion/Basic%20course_&_models/Corona_Acoustic
_theory.html
From: "Radium" <glucegen1@excite.com>
Subject: Cold Plasma Speakers

The speed of sound in a porous absorbing material is lower as in air,
AFAIK.
Is there anybody who knows if this effect is frequency dependent?
Or knows a paper or something about this?

Where can I find info on cold plasma speakers?
Thanks,
Radium

Newbe here
What is the iPod or defacto standard for earbud acoustic THD+N. Seems
like 1% -5% is the target But I'm looking for what do most people want
Vs what they get in a typical consumer portable audio player?You know

I wonder if a diaphragm-less loudspeaker could use a mechanism similar
to a stun gun. The spark from a stun gun does not produce any
perceptible heat in close proximity because -- despite being a 100,000
volts -- the power is not enough to raise temperature sufficiently to

I have a question about attenuation of sound. From several sources,
I've found the following formula for the acoustic intensity of a plane
wave:
I(x) = I(0) exp [-2 alpha x]

I realized that earbuds may be bad but look at what's comming next in
the popular consumer playback delivery accessories.. the latest
alternative is a Bluetooth stereo A2DP headphone set:) Now we have
a lossy coder sending WMA MP3 etc over Bluetooth lossy compression RF

Magnetic field -- electrical , machinery1ststatic magnetic field1) the
direct current machine, namely has work -- commutator the Edison classics
direct current machine. The commutator has its birthLives at the beginning
of the magnificence and arrogant, also has it to receive the ...

Sick Bob Cain has been stalking, harassing and posting defamatory comments
about me on the usenet for the past six years.  
Sick Bob Cain's latest tactic is to impersonate me on the usenet using
my name and falsified headers.

A recent book by an experienced consultant advocates the use of a technique
called "stepped blocking" to stiffen wood-frame floors to reduce the
low-frequency thump in such floors.  The method is as follows.  Suppose you
have 2 by 10 joists.  You use pieces of 2 by 8 for the ...