Natural Science Forum / Physics / Acoustics / October 2004

I am still using the original MLSSA - after all it still works and I am used
to it.  However on a Windows XP PC, it is impossible to copy a MLSSA graph
into another program.  The "Print Screen" key, which worked in earlier
"home" versions of Windows, doesn't work in XP, and ...

I would like to ask about methods that are used to convert measured
SPL of a large plant item to a SWL for that item. For eg a generator
or chiller.
In a perfect world the manufacturer would be nice enough to give you

First off, I have absolutely no knowledge when it comes to firearms.
So I was hoping you guys might be able to help me with the following.
I don't know if the following two questions are both so elementary
that they are "slam dunks" or if they actually could be harder to

Physics newbie question here: what does a laser sound like?  Some sources
I've read claim that a sufficiently powerful laser would ionise the air
along its path and produce a "crackle" or "pop" noise, while others claim
that regardless of power, a laser has to be of a particular ...

A guy who I suppose ought to know (he spent 30 years in the industrial
plastics industry) told me that expanded polyesterene or polystyrene
foam sheets...IOW, those foam insulation boards made out of the same
stuff as beer coolers, like Styrofoam...make an effective sound

Is it true that sound wave propagation is not affected by wind (in terms of
a perfect wind at perfect speed).
My idea was that it would be carried faster in the wind direction, and
slower against the wind - actually returning without notice if it was

Does anybody know which institutions can carry out pattern evaluation tests
of sound level meters, according to IEC 1672-2 standard. I guess this would
be NIST(USA), NPL(UK), DANAK(Denmark), PTB(Germany)..., though I only found
on PTB site that they clearly state, that they perform ...

Microphone spiking 450Hz?
Hi,
I'm planning to do measurements with microphone in the frequency range of
380-510 Hz.  Sound, in the question, is low amplitude sine wave and is

I have following vibration related question.
In a system under forced vibration,if the frequency of the excitation
matches with the *natural frequency* of the system , the *resonance*
occures and the systems starts vibrating with continuously increasing

Hello to everyone,
as a part of my masters thesis in Technical Acoustics I want to built a
modern impedance tube for absorption measurements, using the
two-microphone-technique described in ASTM E 1050-90 and EN ISO 10534

I have following vibration related question.
In a system under forced vibration,if the frequency of the excitation
matches with the *natural frequency* of the system , the *resonance*
occures and the systems starts vibrating with continuously increasing