Questions tagged [acoustics]

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. Applications of acoustics are for instance the audio and noise control industries.

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51 views

Can sound be recovered? [duplicate]

An interesting thought struck me today, can sound be recovered? I mean sounds from the past, maybe a year or a millennium back.
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How does particle acceleration amplitude relate to particle resonant frequency? (ULTRASOUND)

In diagnostic ultrasound the acoustic pulse propagates in a non-linear fashion (Duck 2002). I have been taught that: The increase in wave velocity in the compressive phase increases particle ...
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Why are ultrasound devices using ultrasound?

I wonder why ultrasound devices are using ultrasound. Is it a biological reason due to our human audible range? Or is there a physical reason for that?
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What causes the noise when you get an electric shock?

When we get a minor static electric shock, we often hear a noise associated with the shock. Or for example, when you swat a fly with a zapper, you can hear a noise from the electric transfer. What ...
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The travel of soundwaves

As we are waiting in the subway station, we will hear the rail screeching when the train is arriving. Is it because soundwaves travels faster in a solid substance than in air? or is it a compartment ...
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What is the relationship between pressure and displacement of a sound wave in a tube?

I am currently studying out of Vibrations and Waves by AP French. I have been trying to solve this problem but seem to be having trouble deriving mathematical equations for it: I have a qualitative ...
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Materials that behave as “metals” for sound waves?

Probably the most well known property of metals are that they are shiny. Ultimately arising from the high density of conduction electrons capable of carrying current, this shinyness is means that ...
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Variation of Intensity when a source moves

When a sound source moves, frequency perceived by the observer is changed due to the doppler shift. Does this apply to intensity too? If yes then how. Thanks!
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Velocity of Sound with an Increase in Pressure

Why does the velocity of sound not increase with an increase in pressure? Let me take an example. Suppose there exists a gas at some pressure. With an increase in pressure, it would turn into a liquid....
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Data for experiments of Doppler effect

I am a high school student that has attempted to carry out the experiment for the Doppler effect using an RC car going at constant speed, a sound source at constant frequency and phyphox app to ...
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Generate a sonic boom from a stationary device

Is it possible to create a sonic boom using a specially designed audio device for this purpose?
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Why the frequency of sound can vibrate the object if the frequency of both is the same (resonance)?

I mean what actually happens so that sound can vibrate an object? If both frequencies are subjected to constructive interference then resonance, why doesn't the sound only increase in amplitude rather ...
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Lattice vibration and sound waves

In general, the acoustic branches of a crystalline solid has a nonlinear dispersion relation. For small values of the wavenumber $k$ or wavelengths large compared to the equilibrium lattice separation,...
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Phase difference of a standing wave

Before starting the actual question: I do not want any typical answer that anybody might have thought of or criticism and downvote without even reading the question properly. I have been googling and ...
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Potential error in a physics exercise [closed]

My physics textbook has the following exercise: My grasp on the problem is that the situation is similar to than of an organ pipe closed at one end. As such, standing waves would be set up in the ...
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Why don't we hear sonic booms because of gas molecules?

I was running some calculations of ideal gas molecules in a box for $O_2$ molecules at $T=300K$ and $V = 100 cc$, and I saw that $v = 445 m/s$. My question is, why don't we hear sonic booms all the ...
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Why is the sound produced by a sonic boom low pitched?

According to Doppler's effect $$f'=\frac{v+v_0}{v-v_s}f$$ where $f'$ is the observed frequency, $f$ is the actual frequency, $v$ is the velocity of sound waves, $v_0$ is the velocity of the observer ...
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Does a object always ring at resonant frequency?

I'm trying to find the resonant frequency of glass panes and how the resonant frequency is affected by the thickness of the glass pane. I set up the glass pane with the ends of the glass pane fixed. (...
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Working principle of echo sounder

An echo sounder is simply a device that is used to help sailors determine the depth of water at different locations in the sea. There is a transducer that is attached to the hull of the ship that ...
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Why doesn't the acousto-optic frequency shift depend solely on the velocity of sound in the medium, if it is a form of Doppler shift?

Many optics books make the statement that the frequency shift of a laser beam from the acousto-optic effect can be thought of as a Doppler shift from a traveling index of refraction grating (pressure ...
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Physical amplitude of sound

So, as far as I understand, sounds are ripples through a material. If you strike a rock, then (ignoring thermal motion, if we may) the molecules in the rock start off stationary, then wiggle back and ...
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How does a drum's membrane oscillate?

I was thinking about a problem with a simple wooden drum , constructed but just a membrane and a wooden circular part .Let's say the mebrane is streched by a constant tension $T$ and it has a density ...
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What is the mass of the Goldstone boson sound wave?

Wolfe and N.H. Fletcher in the “Interactions between wind instruments and their players say that, in a flute “…after a few periods of the fundamental, the overtones become locked into exact harmonic ...
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Properties of an Echo Relative to the Original Sound

If we have a sound wave that hits a surface and is observed after it has done so, have its frequency and amplitude changed?
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Identifying centre of rarefaction and compression of a graph in a st graph

We know that for a sound wave traveling to the right, the centre of compression occurs at $s = 0$ and $\frac{ds}{dt} > 0$ (take right direction as positve i.e. traveling to the right too!). And ...
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Will sound wave travel faster if we are traveling while speaking?

I don't know if this is a stupid question or not, please tell me if it is. I will use an example to illustrate my doubt. Suppose I am moving to the right with a speed of $30ms^{-1}$. And sound wave ...
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What is the role of sound in string theory?

Densely packed strings (perhaps in a fuzzball scenario) should impact one another frequently and transmit sound. If they're densely packed enough, the sounds produced might be affected by the fact ...
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Helmholtz Resonator: What are some factors that might affect the resonance frequency in a glass bottle?

I'm trying to understand what are some factors that may positively/negatively influence the resonance frequency in a glass bottle, if we wish to compute this frequency with Helmholtz's resonator ...
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Why do airplanes make a humming sound when airborne while the engines (when on the ground) make a steady sound?

I know experience-based questions are a bit tricky on this site but isn't every theory based on common experience? Every time I hear an air jetliner flying over at a high altitude it seems the engines ...
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1answer
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Ultrasonic vs x-ray (for medical applications)

What are the differences between using x-rays and ultrasounds for medical diagnosis? From a physical point of view I am aware that x-rays are able to reach deeper into the material - but I think this ...
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How does air flow within a melodica when two key are pressed?

I'm trying to understand the air flow within a melodica. A melodica is a wind instrument that has a piano-like keyboard. Pressing on a key opens an airway so that air entering the melodica's air ...
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Does an overcast sky alter the sound waves coming from above it (like the sound of an airplane)?

This morning, in our little backyard, I heard an airplane that was flying above the clouds, which were completely and uniformly covering the blue sky, as if they formed one big homogeneous grey mass. ...
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Can the $Q$ factor of a system exceed unity ($Q>1$) while the maximum gain is 1?

when calculating the quality factor of an acoustic system using FWHM definition I get 39. the maximum gain is approximately (see the attached figure ). when I calculate $Q$ in time domain using the ...
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Amplitude of a spherical wave very close to its source

The amplitude of a spherical wave can be shown to be $$A \propto \frac{1}{r},$$ where $A$ is the amplitude and $r$ is the distance from the (isotropic) source. This seems to imply that $A$ tends to ...
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Is it possible that a tall bush could actually severely block nearby sounds/noises?

I live (against my will) on the bottom floor of an apartment building, with a car road nearby. I made this text illustration to help you see the situation: ...
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How to kill an insect without touching it? [closed]

Apart from the interception by a sufficiently powerful laser, what would be the means to neutralize (kill/repel) an insect in full flight and indoors (so no water, pepper, etc), and without touching ...
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How would I go about finding the resonant frequency of a glass pane?

I've done some research, and found some videos and articles on how I could find the resonant frequency of normal objects - By hitting them, and then finding the frequency using a software. But the ...
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Will non-radially radiating sound plane wave propagate forever without losing intensity?(assuming no dissipative forces)

I have encountered on a textbook that established the relationship that intensity is proportional to the square of displacement amplitude and the square of angular frequency. However, the equation ...
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Standing wave and energy conservation

Consider a one-dimensional standing wave formed on the interval $0 \leq x \leq L$. Let's say that this is an ideal model motivated by a string as a medium with both ends closed. Assume that there is ...
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Doppler effect when source and observer are in different media

According to what I learnt about Doppler effect, on moving the source and/or the observer relative to medium, there is a change of frequency heard by the observer. f(new) = f(old)(v(sound)+v(observer)...
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Frequency of human body - EM vs vibrational?

Apologies for the noob question. I have seen people calculate the wavelength of the human body based on weins law as follows: 0.002898/310 = 0.00000934838 m ...
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Derive shape of sound wave from vibrating string simulation

I have a physical simulation of a vibrating string (made with matter.js). From this, how can I derive the sound wave / air pressure over time, that would result from such a string? I had considered ...
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Sound reverberation in a completely flat environnement

I don't know much about physics but I have a question. Let's say you were lost in a completely flat desert, with seemingly nothing else surrounding it, and you screamed at the top of your lungs: would ...
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Compering an acoustic modeling RIR method with the best realistic method

I have implemented a method for simulating a point source located outside of a shew-box room in vacant space and I wish to compare the resulted impulse response (IR) with a more accurate one. Is there ...
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Diffraction of sound waves vs EM waves

How does the diffraction of sound waves differ from the diffraction of EM waves? EM waves have their electric field vector point in a direction perpendicular to the direction of travel and sound waves ...
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Does it make sense to talk about the speed of sound at some pressure?

Physically speaking, does it make sense to talk about the "speed of sound at some pressure"? Is this a coherent concept?
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Is it possible to register the effects of sound interference in everyday settings? [closed]

For example, sound interference could lead to a loud room feeling louder simply because of sound waves colliding. Or an orchestra which is perfectly synchronized could create loud and quiet spots in ...
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Help understanding sound wave interference from two sources as a function of distance and frequency

I am trying to optimize the acoustics of a room in my house for music listening. I use a computer that runs a free app called, REW (room Equalization Wizard) . This app can play a test noise through ...
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Can physics help in choosing watermelons? [closed]

Just a lighthearted question for the summer :) I was at the supermarket the other day, and I wanted to buy a watermelon; great straight out of the fridge, to chill and rehydrate in this sweltering hot ...
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Attenuation of acoustic waves in fluid media

Have spent quite a lot of time looking for some data on the attenuation of acoustic waves in fluids (preferably water or hydrocarbons) with little success. I figured this would be a good place to look ...

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