alt.sci.physics.acoustics Google Group

Re: Helmholtz absorber size question

2009-11-30T21:18:26Z

Ethan Winer <blow_...@hotmail.com> wrote in
Sounds like gibberish to me. Perhaps something got lost in the
translation.
That is correct, but that lumped-element electrical equivalent network
model only accounts for the approximate resonant frequency of the Helmholtz
absorber. It has nothing whatsoever to do with the effective absorption

Re: Helmholtz absorber size question

2009-11-30T18:22:29Z

Groan. :->)
In the mean time, Angelo Campanella was nice enough to email me off
list with further information. As I understand his comments, the waves
travel into the slots, so the depth of the cavity behind increases the
apparent "surface area" exposed to the room. Angelo also described an
electrical equivalent - the slot opening is a series inductor and the

Re: Helmholtz absorber size question

2009-11-30T16:38:33Z

Ethan Winer <blow_...@hotmail.com> wrote in news:200e9718-1cb3-40cb-8287-
ea301d130...@g23g2000vbr.googl egroups.com:
It's not the size, it's the frequency that matters...that's what she said!

Re: MODELLING NOISE FROM BLASTING

2009-11-27T11:52:57Z

Hi,
I add one rather new paper:
C. Kuzu *, A. Fisne, S.G. Ercelebi, Operational and geological
parameters in the assessing blast
induced airblast-overpressure in quarries, Applied Acoustics 70 (2009)
404-411.
The list of references is worth browsing, too.
Kari Pesonen

Re: MODELLING NOISE FROM BLASTING

2009-11-21T18:11:22Z

Hi,
There are, for example, some military blasting noise prediction methods
(simple formulas to estimate peak or max levels as a function of
explosive
mass and distance). Methods expect open of buried explosive
blasting at soil surface.
One method used in estimating quarry noises is to measure first sound

MODELLING NOISE FROM BLASTING

2009-11-20T14:50:22Z

Hi All
I have recently been asked to model noise from blasting activities in
a quarry which has been mothballed. As far as I am aware, there is no
previously measured blasting noise data. It is my understanding that
this is impossible. Does anyone know differently?
It is my understanding that to do any sort of modelling of blast noise

Re: Helmholtz absorber size question

2009-11-17T21:00:35Z

Nothing, I'm afraid. He vanished.
d

Re: Helmholtz absorber size question

2009-11-17T20:45:54Z

s...@spam.com (Don Pearce) wrote in
You had several exchanges with Bob Cain in rec.audio.pro. He seems that
he's dropped off the face of the earth. What if anything do you know?

Re: Auditory masking.

2009-11-17T20:43:25Z

On Nov 17, 7:28 pm, Linda Strautzele <linda.strautz...@gmail.com>
wrote:
Auditory masking is modeled in IEC60268-16 for the calculation of
speech intelligibility (STI).
The amount of auditory masking is captured in tabular form for some
relevant octave band levels.
The standard refers to: "Zwicker, E. and Feltkeller, Das Ohr als

Re: Auditory masking.

2009-11-17T19:09:28Z

Linda Strautzele <linda.strautz...@gmail.com> wrote in news:dce55d36-0a05-
40f1-9be6-a13ea9a92...@x31g200 0yqx.googlegroups.com:
Auditory masking is stimului specific. There aren't any formulas.

Auditory masking.

2009-11-17T18:28:15Z

Im making a scientific work in physics about frequencies relations.
Now i`m studiying about simultaneous and temporal masking, but i can`t
find formulas how to calculte new thresholds. Could anybody help me?
Thanks!

music talent competition

2009-11-17T09:28:08Z

Music Contest 2010 – Imahollywoodstar - is a Great Hollywood Stars
Original Music Talent Song Competition live Song Contest is to open
for songwriters, lyricists and music composers.
[link]

Re: Helmholtz absorber size question

2009-11-17T09:27:18Z

"Ethan Winer" <blow_...@hotmail.com> wrote
absorb
But we have the three types of the traps: passive, reactive and active.
The passive convert the sound into the heat. The reactive and active no.
only half the job.
"The downside is that in some places in the room, for a given note,
compression meets compression, amplifying that frequency (constructive

Re: Helmholtz absorber size question

2009-11-17T09:04:48Z

"Kari Pesonen" <Kari.Peso...@rem.welho.com> wrote
Each resonator need the external power. The power is from the wave emmited
by the primary source. The energy is very small so it takes time to achive
the full amplitude.
S*

Re: Helmholtz absorber size question

2009-11-16T21:31:32Z

s...@spam.com (Don Pearce) wrote in
Page 108, equation (4.2).