Natural Science Forum / Physics / Acoustics / May 2007

(I posted this a few months ago, but only got a couple of replies, so
I'm trying again)
I'd welcome some advice on this noise problem.
The man in the flat above me has breathing problems and has to use

Below is an example of "parallel Hz"
http://img56.imageshack.us/img56/2427/clocksignalexample8is.gif
If each clock signal is 1 GHz, and you have a 4 of them, staggered
such that every 1ns part of the CPU can start, and finish, an

We had our monthly fire drill today, so I pulled out my B&K 2232 and
measured the (A-weighted) sound level to be 110dB at about 4 feet,
mike perpendicular to sound source in the hallway and 108dB just
outside my office.

I am involved in controlling the exposure to high sound levels of radio and
TV artistes. These people are listening on headphones to a mixture of
sounds, of which the loudest is their own voice.  The law on high sound
levels is of course the same for this type of sound as it is ...

A colleague asked me yesterday if I could explain why, at certain
frequencies, he got a sensation of resonance in his ear (in the region
of the ear drum as he explained it). He has done a little self-testing
and has found that middle C on his piano causes the effect. It is not

I'm looking for some lecture about detection of acoustic signal
patterns in environmental noise (or sth like near gaussian noise). Can
any of You help me with that... some titles, links? I wold be
grateful.

Anyone interested in buying some Green Glue.  I know someone with 9 cases
they need to get rid of.

I just found out : http://www.respa.de/en/start.htm. This is pretty
interesting. The panel is tuned somehow (reminds me to RPG's modex/
broadband panel) and I guess comb filtering will happen as well and
color the sound. Any thoughts on this product? I wonder if anyone here

Say I have a 3 DOF system and I find the eigenvalues of the 3x3
stiffness/mass matrix (no damping).  The eigenvalue solution gives me 3
complex numbers.  As I understand it the square root of the imaginary part
of the solution gives me the natural frequency (in radians/sec).  Do ...

I have a wave recoding of a guitar playing single notes which I'd like
to convert to MIDI format. I'm using a C++ program to process this
audio.
My first question is, how do I detext the attack points accurately? At