We’re rewarding the question askers & reputations are being recalculated! Read more.

Questions tagged [acoustics]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
0answers
10 views

Who was the ANSI certifying authority for Titus CSE ear muffs?

Titus CSE claims to have achieved certain NRR ratings with ANSI for some Titus ear muffs. How can we verify their claims? I looked into this, but I cannot find the ANSI certifying authority for ...
1
vote
1answer
50 views

Why is the Cape Elizabeth Fog Signal shaped like this?

On a recent trip to Cape Elizabeth, Maine, I came across this fog signal: It appears to have an electromagnetic diaphragm in the middle, surrounded by concrete and some very curiously shaped steel ...
1
vote
1answer
19 views

Sound level emissions (IEC 60704-1) spectrum?

I have a very noisy air conditioner that have a 10kHz peak at 75 dB, the rest (fan/compressor/pump) are under the regulation limit. I would like to understand what is the measurement spectrum. I ...
1
vote
3answers
28 views

Grate that does not cause air rush noise?

I have an air supply grate that is making a roaring noise. It has rectangular slats. I know the sound is coming from the grate, not the duct, because when I remove the grate, the duct is silent. It ...
1
vote
1answer
50 views

What is tonal masking?

I have checked the definition of tonal masking on Wikipedia and google but I saw the definition of sound masking and auditory masking. Auditory masking Sound masking But I want to know what ...
2
votes
2answers
65 views

Will a 3-wall acoustic barrier work or will sound go around?

I have two heat pumps directly outside my house and they are noisy so I am considering the viability of using a sound barrier to block the sound. The acoustic barrier itself will definitely absorb and ...
1
vote
0answers
36 views

What is the principle behind controlling thermoacoustic combustion instability with a speaker?

From "ThermoAcoustics and the Rijke Tube: Experiments, Identification, and Modeling", thermoacoustic instability can be subsided using an amplifier and a speaker. It says in page 4, The microphone ...
3
votes
2answers
104 views

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 ...
1
vote
1answer
108 views

Does the stress on exhaust hanger amplify sound transmission into the vehicle chassis?

I have an exhaust that drones with the vehicle. However, outside, it's not a loud exhaust. So my assumption is the vibrations are transmitted into vehicle interior via the points of contact - in this ...
0
votes
1answer
33 views

Acoustics resonance question

I have a complicated cylindrical geometry with a speaker mounted on somewhere middle of the rig. The one end is closed, the other is open. Sweeping the speaker frequency from 0 to 1000 Hz, I tried to ...
0
votes
2answers
154 views

Microspeaker enclosure design for headphones

I want to embark on an acoustic project of designing an enclosure for some 40mm microspeakers, identical to ones found in a typical on-ear headphone solution. Are microspeaker enclosures treated in ...
0
votes
1answer
32 views

How can I calculate headphone driver excursion?

I'm a headphone enthusiast, and once I tried to open up my headphones to see how much they move when I play my music. However, I was really surprised to see that the sounds that I could "feel" ...
1
vote
1answer
67 views

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 ...
1
vote
0answers
12 views

How do I convert coefficient values from 1/3 octave band to 1/1 octave band?

I have some coefficient values i.e. 74.9, 81.3, and 80.5 at frequency centers ...
0
votes
1answer
69 views

Why aren't these kind of drivers used in loudspeakers?

This is a driver in a headphone. These can produce every sound and beyond that humans can hear. I understand that there are full range speakers that are sometimes used, but they work in a very ...
1
vote
2answers
97 views

Sudden increase in noise levels - subway noise -happend overnight [closed]

This is real life issue I am having currently and I am puzzled as to why it happened. I have lived over the subway lines (two actually each going in the opposite direction, two sets of tracks) for ...
3
votes
0answers
63 views

Optimal size and shape for a steel target?

Problem I'm building a steel target for long-range rifle shooting. For those unfamiliar, the purpose of the steel is to produce a loud "PING" when the bullet strikes the target. It's very fun. Since ...
0
votes
1answer
37 views

How well would viscoelastic damping work between isogrid- or honeycomb-faced constraining layers?

I'm considering doing some experiments with 3D-printed surfaces and sound transmission with constrained layer damping. I've also been thinking about using isogrid or honeycomb interior surfaces, ...
1
vote
0answers
94 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 ...
2
votes
2answers
41 views

Are there general-purpose acoustic FFT sensors for plant diagnostics?

For the purpose of detecting a defect or failure in a machine, it is often practical to physically listen to any abnormal noises that a machine might be making, and even use a simple stopwatch to ...
1
vote
1answer
70 views

Which Whistle Type works with the lowest PSI?

I'm working on a project where we are trying to prototype a whistle that works at the lowest possible air pressure and still produce an audible sound. Any suggestions on whistle type? and any ...
1
vote
0answers
52 views

How much does a wall stop sound?

So I have this problem, every Sunday we have about 200 kids come over to our house in town, and they make a LOT of noise. We also have mildly nice neighbors that do not like noise Sunday afternoon ...
1
vote
0answers
14 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 ...
0
votes
0answers
21 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 ...
1
vote
1answer
158 views

Audio frequency sweep spectrogram artifacts… hints?

I'm wondering how to interpret artifacts on spectrograms like the following which shows the recording of a linear frequency sweep. In this case: The recording is done with a cheap microphone and ...
4
votes
1answer
267 views

How much noise does a road noise barrier block?

I am from The Netherlands, where noise barriers like these are commonly built along motorways: Now I live in England, where such structures are almost non-existent. In The Netherlands, living 200 ...
1
vote
1answer
43 views

Reed played by the wind [closed]

I am trying to build a reed instrument played by the wind (kind of like these aeolian instruments: Eerie musical instruments played by the wind from around the world but using reeds rather than ...
2
votes
1answer
49 views

Acoustic transmission through houseboat hulls

The short version is: should I be worried about bass transmission through water into my neighbors' hulls? I am renovating a small houseboat (12x30 ft) to live on. It is one large room, and I plan on ...
-1
votes
1answer
50 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=...
-1
votes
1answer
45 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&...
1
vote
1answer
107 views

Acoustic absorption of different materials? (gypsum board versus plaster)

I would assume that different materials absorb sound differently (maybe not?) What is this called? How can I compare the sound absorbent properties of different materials with the same surface ...
2
votes
1answer
148 views

Determining frequency of an ultrasonic transducer

Ultrasonic transducers emit sound at a frequency greater that 20 KHz. What are the ways the frequency of sound emitted by such a transducer can be verified?
3
votes
1answer
508 views

Piezoelectric matching/backing layer materials

To maximize the piezoelectric transducer reception/transmission power we must choose the correct backing/matching layer materials, I'm working on a project to measure a steel tank liquid level (non ...
-1
votes
3answers
330 views

Measuring the distance to a sound [closed]

Do you know if there is some sort of equipment that can measure the distance to a sound? What practical application can such an equipment have? The reason I'm asking is because I just got an idea of ...
1
vote
1answer
168 views

How can I determine the overall acoustic impedance of a string with different core and winding materials?

Violin strings are either single core materials or of the wound variety with a single core of one material wound with a helix of another (usually heavier) material to give the string a lower resonant ...