Questions tagged [acoustics]

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4 votes
3 answers
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How to reduce resonance from livingroom table

Odd ting, the table surface echo/resonance sound when speaking, especially lower lower frequencies. It helped putting on a cloth, but it did not completely remove resonance. Putting a rug beneath did ...
Hallvard Haanes's user avatar
2 votes
0 answers
17 views

Does excitation matter in a time-domain simulation/computation of a transfer function of an LTI system?

Let's say I am running a FDTD simulation of a wave-equation to determine a transfer function of an LTI system: \begin{equation} H(f) = \dfrac{Y(f)}{X(f)}\ \end{equation} where $Y(f)$ and $X(f)$ are ...
tomi.lee.jones's user avatar
1 vote
1 answer
19 views

Designing a siren to vary pitch with port width/pattern. Advice needed

Background: I am trying to design a multi-pitch port siren with one central shaft at 3300 rpm. I've calculated the number of ports needed for each frequency to be n = f(60/rpm). This approach gives me ...
Jordan Iversen's user avatar
1 vote
0 answers
79 views

Help me find a material with low acoustic impedance but high wave velocity

I'm trying to find a material that would have two seemingly opposite qualities. I need something with low acoustic impedance, like a plastic, but also with high wave velocity like a metal. Here are ...
Arnaud Cayrol's user avatar
1 vote
0 answers
46 views

How loud can an induction hob be?

People that are cooking food with induction will occassionally encounter loud noises from the hob. There can occur a high-pitched whining sound when heating the pots and/or pan. As I searched the ...
kryomaxim's user avatar
  • 101
1 vote
0 answers
188 views

Modelling acoustic instruments — predicting frequencies, decays, levels, and phases of modes of a circular membrane (drum head)

I have been working on some acoustic synthesis software for modelling several acoustic instruments. I am using the principle of modal synthesis, where every mode of vibration is individually ...
mike's user avatar
  • 161
1 vote
0 answers
104 views

Did the pressure unit "bar" change definitions since the 1930s?

I don't see anything in Wikipedia about it, but (from this question) when I try to reproduce the equations in this 1933 paper, I get values 106 away from the values in the paper. When I reproduce ...
endolith's user avatar
  • 226
0 votes
0 answers
60 views

Shielding or jamming ultrasound waves using software

I've downloaded SoniControl and it works somewhat well as a jammer, but I am looking for more options. I'm trying to shield from or jam Ultrasonic Cross-Device Tracking (uxDT). (See "data over ...
user40996's user avatar
0 votes
1 answer
95 views

Troubleshooting clipping

I am collecting data for a project, where I am measuring the room impulse response by playing a sine sweep from a speaker (QSC K8 1KW Active Loudspeaker) and measuring it from the other side of the ...
Mason Wang's user avatar
0 votes
0 answers
33 views

Which is the better magnetic arrangement for a voice coil to give a larger amplitude of movement all else being equal?

Given everything else equal (e.g. same overall amount of magnetic material, same strength magnetic material, same coil, same power supplied, etc. etc.) which of these two magnetic configurations of a ...
Oliver Walters's user avatar
0 votes
3 answers
102 views

Respirator mask that transmits sound waves

If one had to design a respirator that would have the minimal sound distortion, and allow to communicate normally (one-on-one at least), how would one do it? I wear powered respirators (PAPR) and ...
runcyclexcski's user avatar
0 votes
0 answers
42 views

How to read this UAV Muffler Sound Test Charts?

Just downloaded this UAV Muffler Sound Test Charts (PDF) file from here. e.g. here is an image of the table in the file: I have several questions on it: Why is there written a constant number next ...
Roh's user avatar
  • 113
0 votes
0 answers
43 views

Why are there no mufflers for water plumbing?

People who live in multi-unit apartment buildings often need to be careful not to bathe late at night, because their neighbors will be able to hear the sound of the water going through the pipes. As I ...
Metamorphic's user avatar
0 votes
0 answers
71 views

Custom cavity for speaker system?

Typical acoustic speakers come mounted in boxes. The shape of the boxes is important because the speaker throws pressure both forwards and backwards, so the back pressure goes into the box and ...
Wallace Park's user avatar
  • 1,625
-1 votes
1 answer
82 views

Roskam assumptions in order to calculate speed of sound formula, need explanation

As you can see inside this following link: https://books.google.it/books?id=bSq-cEf0EWsC&pg=PA19&lpg=PA19&dq=Aerodynamic+2.3.2+The+speed+of+sound&source=bl&ots=iFRByWKpwG&sig=...
p.pensopositivo's user avatar
-1 votes
1 answer
55 views

Roskam book uses Eulero motion eq. and mass continuity eq. to find speed of sound but (in my opinion) not in a coherent use (about density variation)

As you can see inside this following link: $$$$ https://books.google.it/books?id=bSq-cEf0EWsC&pg=PA19&lpg=PA19&dq=Aerodynamic+2.3.2+The+speed+of+sound&source=bl&ots=iFRByWKpwG&...
p.pensopositivo's user avatar