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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Why do I hear beats through headphones only at low frequencies?

I was recently playing with this Wolfram Demonstrations applet, which demonstrates beats. At first I thought the app didn't work because I couldn't hear any beats. Then I realized that the applet ...
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Could submarine SONAR kill a diver?

Could a diver swimming next to a submarine be killed or seriously injured by its SONAR? What physical aspect of SONAR affects the human body in a potential harmful way?
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What happens to sound at speeds greater than mach 1?

So what we know about the Doppler effect is that if the origin of a sound is moving, the sound waves will be closer together in-front of the origin, and farther apart behind it. This creates a ...
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4answers
272 views

Resultant frequency if 3 harmonic notes (a chord) is played

If I know the frequency of individual notes being played (let's assume D, F# and A), how do I determine the final frequency if they are played (nearly) simultaneously as a chord. To put the problem ...
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7answers
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Why don't two musical instruments sometimes generate destructive interference?

I'm an electrical engineer, and I understand wave propagation, interference patterns, and so on. But I'm missing something basic, so perhaps my understanding isn't as good as I believe. I'll show my ...
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Are there limits for the speed of sound? A maximum or a minimum only?

The speed of sound in materials of various states of matter differs a lot. But does it have fundamental limits? Is there a maximal possible speed of sound? Is there a minimal possible speed of ...
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163 views

different liquid in a container produce different sound

Does the type of liquid in a container affect the sound it produces? example like milk, water and coffee produce a minute different sound
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91 views

What physical properties of silver would contribute to the sound of a musical instrument? [on hold]

A question was recently asked on Musical Practice & Performance, asking what physical properties of silver would contribute to the sound of percussion instruments. It is likely to be off-topic ...
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90 views

How do phase carries structural information about the function? [closed]

Suppose you are on a railway platform and you hear the sound of train coming towards you. Now, Using Fourier transformation we can convert the time domain function (here take sound as a function) ...
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82 views

Why can microphone be much smaller than wavelength of sound?

For sound from 20Hz to 20kHz, wavelength is 17m to 17mm, for sound at 2kHz, wavelength is 17cm. And I saw tiny microphone which is much smaller than that. In electromagnetic, there is a smallest size ...
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175 views

How quickly should a fluid come to hydrostatic equilibrium?

Let's say I'm holding a one-liter water bottle, full of water, which I then drop. Before dropping the water bottle, the equilibrium is for there to be a pressure gradient in the water canceling the ...
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23 views

How much energy is contained in a human yell? [closed]

How much energy is contained in the pressure wave caused by a human yell? Assume the yell lasts for one second.
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1answer
176 views

Sound Propagation using Finite-Difference Time-Domain (FDTD) considering wind effects

I am trying to plot the propagation of sound from a fixed source in a 2D environment using Finite-Difference Time-Domain (FDTD) Method taking into account the effects of the wind velocity. I came ...
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2answers
393 views

Sonic boom and resonance

Can the damage caused by sonic booms be seen as an example of resonance? that is, when the driving frequency (be the sound wave) is equal to the natural frequency of the glass being damaged?
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1answer
86 views

Significance of higher harmonics

I am analyzing a noise signal and have identified the fundamental frequency of a tone and it's higher harmonics. Say for example given the signal below, The fundamental frequency has a sound ...
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1answer
35 views

How sound waves are graphed

I asked a basic question about sounds waves recently and got really helpful answers. I have another question (from the same youtube video) about how different sound graphs are used in real world ...
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1answer
30 views

Does a ceiling fan sound louder when humidity is higher?

It seemed to me the ceiling fan is making louder noise(of cutting through the air) when the day is a bit damp/humid, especially after a rainy day/hour. Is this a valid observation? Can the increased ...
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2answers
51 views

Why does the sound of my tea stirring go up in tone the faster I stir?

I've noticed that when stirring my tea, as I stir faster the tone generated by the stirring goes up. Why is that? Is it something to do with the Doppler Effect? EDIT -------------------------- ...
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1answer
30 views

How to calculate whistle parameters for given frequency? [closed]

I would like to build powerful and yet cheap whistle. So I was thinking about buying vuvuzela and turning it to high-pitch whistle. However I have to make a whistle for precisely given frequency -- ...
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1answer
126 views

How does a sonic black hole (or dumb hole) work?

I came across this term and I heard they used sonic black holes to detect something analogous to hawking radiation, but I have failed to find sources which explain how exactly they work and how they ...
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1answer
387 views

Relation between pressure and particle displacement in an acoustic wave

Consider an acoustic wave in some medium, expressed as particle displacement: $$s(t,x) = e^{j(-\omega t + kx)} $$ I understand that pressure must be at its maximum when the particle displacement is ...
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3answers
433 views

Do particles in a sound wave ever move vertically?

I'm trying to visualize how sound waves work and I was curious about something. So sound moves in longitudinal waves, which I think I understand. There is a really good khanacademy video explaining ...
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2answers
159 views

What is the exact physics behind sonic levitation

Me and a group of friends decided to choose sonic levitation as our research topic. However, after looking up the theoretical background, we hit a roadblock: (Here is an image of a standing sound ...
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2answers
280 views

Sound source not in a straight line with the sound receiver - does that make a difference?

Hope the graphics will help me explaining my question better. Let's say the box would be a room in the fourth floor, and the sound source would come from cars in the street. It is clear that in ...
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0answers
34 views

Why do certain types of sound seem to fade faster? [duplicate]

I noticed that if I'm playing music in a room and I go into another room or walk further and further, then at some point I can only hear the percussion and the melody to a lesser extent. All the ...
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31 views

As the speed of sound varies in different mediums, what's the density of a theoretical material that allows it to go at the speed of light? [duplicate]

Viewing a list of the speeds of sound in various mediums, I note that none of them come even close to 300,000,000 m/s. It appears that as the speed of sound goes up, the object's density more or less ...
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Is it possible to create an audible sound source in mid air by intersecting ultrasonic sound beams?

In the book Daemon by Daniel Suarez a technique gets described, that enables a device to create an acoustical illusion of a moving person inside a house. Just then a voice called out clearly from ...
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3answers
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What is the relation of sound propagation to air pressure?

I am wondering, air makes sound propagate. So in a vacuum there is no sound, but what is the relation of pressure to sound volume? Is it linear? If I have a source of sound and let's say I am in a ...
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7answers
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Physics of how the cochlea isolates frequencies along its length?

Can anyone explain the separation of frequencies along the basilar membrane of the cochlea please? (equations would be nice) I understand it being related to the resistance caused by fluid in the ...
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33 views

Experiment to find Velocity of sound

Please read the question and feel me the experiment we can perform to find the velocity of sound! Thank you
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1answer
78 views

Do neutron stars produce sound?

I've watched a video on youtube about neutron stars as called (pulsar) and it claims that pulsars produce this sound. then i found that they produce radio waves which can be converted to sound. Radio ...
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2answers
47 views

Other frequencies and breaking glass

I know an individual can use the natural frequency of glass to break it, but is it possible to break glass with a frequency other than the natural frequency? Will the glass still vibrate if the ...
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3answers
79 views

Can sound be used to deviate objects?

I'm doing a fictional history, where there is a very advanced army but i like to keep things real, and my knowledge of physics is very limited...but i know sound has been used to levitate objects ...
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21 views

Acoustic sound box simulator

I'm looking for a simulator (2 or 3 dimensional + time) of an acoustic box. I'm trying to see where the high/low pressure areas would be depending on where I tap the box on the outside. PS. Not sure ...
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240 views

Hearing sound around corners

I've been taught that diffraction is the reason why we can hear around corners, since the wavelength of sound is approximately 10 cm (smaller than a door or a window). I wonder how can this be ...
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55 views

Why do I hear a squeak in my pipes when my neighbour runs his water?

I just installed a new water-heater in my apartment. Now, I hear a distinct squeak from some rooms some times when I or some neighbour run the water. Could not hear this before, and the pipes are all ...
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2answers
59 views

How do vinyl records work? [duplicate]

I know that vinyl records save the sound as ups and downs on the record plate surface. Let's say two people with different voice timbers say "I like vinyl records" with the same level of voice. It ...
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4answers
2k views

Why does sound need air in order to travel?

I know that in space, because of vacuum that we can't hear voices or sound to be specific, why is that? Why does sound need a medium to go through?
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Sonoluminescence spectrum

During cavitation created by sound in a liquid the collapse of the bubbles can lead to very high temperatures and pressures resulting in the emission of light - sonoluminescence. Can the spectrum of ...
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3answers
49 views

How does any vibrating object generate sound?

We all know that vibration is the cause of sound generation. But here my question is, Internally what happens in vibrating object which creates sound? I guess, generation of sound will be some where ...
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4answers
217 views

Where do sound waves go after being heard?

I honestly can't come up with anything that makes sense, because obviously, energy cannot be created nor destroyed. I think the question is pretty self-explanatory, so there isn't much to say here.
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Cigarette butt sound wave

What happens when I extinguish a cigarette in a recipient with some water in it ? It goes like pshhh, but what creates the sound wave ? Is it the water evaporating ?
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Resource on history of acoustics

Shortly: I am looking for a good resource (article, book, chapter in a book, introduction in an article...) about history of acoustics, I will be glad for any recommendations. By acoustics I mean the ...
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1answer
63 views

How is possible to hear mechanical sounds in space?

In the footage taken by U.S. astronaut Terry Virts during spacewalk (EVA) on the International Space Station on 25.02.2015, sounds can be heard while in space. I can understand "shaking" sounds while ...
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1answer
49 views

How to get the pressure amplitude at any spatial point?

Working on the pressure equation from the linearized euler equations, I stumble across a very simple problem : How, from the pressure solution of the specific equation (see ...
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1answer
88 views

Why does a double-slit experiment with sound waves never result in complete destructive interference?

Today, I find a question that if the speakers are set in parallel towards the wall. It has no complete destructive interference due to difference in distance from the point to each speakers, which ...
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2answers
60 views

How can I easily measure the distance between well head and water surface continuously

Reprhasing the question is a more open ended manner: Method 1: Use a pipe and measure it's resonance. Given a closed pipe from 10 to 300 feet in length, and roughly 5/8" in diameter, made of 1/16" ...
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1answer
133 views

Positions and corresponding terminology of “acoustics energy”?

From limited knowledge, decades ago, dating back to the nineteenth century: Ohm's law of specific acoustic energies was the first biological application of Fourier's theorem. Actually, it was ...
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1answer
107 views

Physical intuition for quadrupole source

In his Theory of Vortex Sound M. S. Howe defines sources "mathematically" (i.e. dipole is a source that could be described as a vector and than there is proved that it's equivalent to a two point ...
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Relationship Between Acoustics and Gravity?

I have studied some physics in college, but not enough to know the answer. My motivation: sound (or acoustics in general) does not exist in a vacuum, which means that acoustic waves are only present ...