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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Interference of sound: how to calculate the sound intensity at each point?

I need help with the following question: Two speakers are sending out sound in phase with the frequency 2,13 kHz. The sound from the speakers is registered in three points A, B and C. See figure. ...
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20 views

How does resonance store vibrational energy?

In the wiki article, it is written that in resonance, maximum amplitude is possible as vibrational energy is stored. What does that statement mean? How is energy stored so that max. amplitude ...
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151 views

Why doesn't amplitude affect the speed of sound?

I understand why amplitude doesn't affect the speed of the sound AFTER the 'leading compression'. The extra force provided on one stage of the cycle is countered on the other stage. But shouldn't the ...
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16 views

Loud, low-frequency “booming” sound in car [duplicate]

I drive a Scion XD, and I've noticed that whenever I drive at about 40mi/hr or so with just the back windows rolled down, I get a loud "booming" effect at roughly 10Hz. What causes this? I assume it ...
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44 views

Using physics in music?

If stereo speakers are connected to the amplifier "out of phase," one speaker is moving outwards when the other is moving inwards.This results in a weakness in bass notes, which can be corrected by ...
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2answers
32 views

For creating beats how small the difference should be between the two frequencies

It is said that to create beats we need two "slightly" different frequencies, and subtract it. 1- My question is why do we need slightly different frequencies? Why not large difference? 2- Also ...
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126 views

Questions related to resonance/standing-waves and sound

I understand resonance for a simple harmonic oscillator but not for more complex systems like standing waves. How can I be in resonance with the normal mode in an organ pipe? I understand that the ...
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20 views

Good references for mathematics of sound attenuation? [closed]

I am looking for recommendations for good references for mathematical modeling of sound attenuation.
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170 views

Can a sound like a sonic boom change a object like a wall? And how the light on the walls will be changed after a sound like this? [closed]

Can a sound like a sonic boom change a object like a wall? And how the light on the walls will be changed after a sound like this? .
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What properties of sound make music sound “better” when it is loud? [closed]

Yes, I realize there may be some cultural interaction at work here, if you've ever seen the classic image of 1950's parents criticizing their kid's "loud music." However, to me -and my hearing is ...
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4answers
2k views

Polarization of sound

Sound can't be polarized because the vibration of such type can't be polarized i.e, it can't be limited or controlled by any barriers and so polarization is not possible in them. This is what my ...
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Why do bass tones travel through walls?

I was in the shower while my roommate was listening to music and got to thinking about the fact that I could only hear the bass and lower drums through the walls. Why is this? The two possibilities I ...
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4answers
149 views

Why Light isn't like an Acoustic wave?

I just wanted to know why light isn't an Acoustic wave.Is it because light wave doesn't obey acoustic properties?
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13 views

What is the best shape for passive sound amplification [closed]

I'm asking this to make a passive sound amplifiyer. In the web they usually do a HORN shape that looks like exponential function mirrored about 'x' axes. But I wonder is there a better shape for ...
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1answer
75 views

Help me understand resonance

I don't fully understand how resonant chambers work. My confusion stems from the fact that they are passive elements or "filters", yet somehow are able to "amplify" the sound. Questions: How can I ...
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0answers
44 views

Can we hear on Mercury, since the atmosphere is so thin? [duplicate]

Since the atmosphere of Mercury is very thin, and only contains negligible amount of Oxygen, Hydrogen, and Helium, can we hear the sound over there? can the sound be transmitted by some mean?
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23 views

How do sound wave interact with a bubble?

When a sound wave propagates in a medium consist of liquid with a bubble, what cause oscillation of the bubble? Negative pressure of sound cause drop of pressure in both liquid and bubble ...
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2answers
109 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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3answers
873 views

Why can't echoes be heard inside a room?

If I go camping and shout anywhere, in the forest or on a cliff, I usually hear the echo of my voice. Why when I shout in my room I do not hear any echoes?
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1answer
38 views

Why can someone in a noisy room not hear others outside, yet they can hear him clearly?

If I'm in a noisy room (radio on, babies splashing in bath, etc.) I struggle to hear someone shouting to me from outside the room. Yet to them, my voice comes through quite clearly. What causes this ...
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1answer
141 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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1answer
2k views

Does the absence of a sound particle indicate that there are no photons?

Sound is usually referred to as just "sound waves" - we do not talk about a "sound particle" and only as a wave or "matter wave." Could something similar apply to light i.e. that there really is no ...
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727 views

Why is a whistle sound emitted when air is pushed through a tight space?

Seems like a simple enough question: Why is a whistle sound emitted when air is pushed through a tight space?
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1answer
35 views

How does an acoustic guitar amplify its sound?

An essential part of a guitar is its hollow body. Without it, the strings wouldn't be very loud; as far as I know, the purpose of the body is to set up some sort of resonance and make the sound ...
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1answer
79 views

Oscillation of air particles and speed of sound wave

A sound wave is essentially air particles oscillating parallel to the direction of travel of the wave. We learnt that $v = f\lambda$, where $v$ is the speed of the wave, $f$ is the frequency of the ...
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2answers
52 views

Is there a relation between music chords and visible light palette [closed]

Ok I have no idea if this is the right stackexchange so if you know who would know please tell me :) In music there are groups of notes that, when played togheter, are basis to harmony. Since both ...
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1answer
22 views

Air Presure and Air Velocity from speaker

How do I determine/calculate the air pressure emitted from a speaker ? And how to determine the velocity of air from the sound air pressure ?
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1answer
128 views

Giant Wind Chimes

I am building large wind chimes out of ALUMINUM TUBES with a D2 at 73.41 hertz as the lowest and two other higher frequencies of A2 at 110 hertz and E3 at 164.8 hertz. I know how to find each length ...
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How much air needs to be displaced to generate an audible sound?

I'm reading a book where in one scene a wizard/alchemist teleports a scroll after reading. He folded the parchment carefully and muttered a single cantrip. The note vanished with a small plop of ...
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Ray tracing a three-way intersection

I've been studying ray tracing in media with linear velocity-depth functions. One of the key concepts I've come across is the ray parameter, and in particular the idea that the ray parameter is ...
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1answer
5k views

Sound - what happens with the particles when a wave passes

I'm having some problems in understanding the principles of sound propagation. The wave propagates though air (for example) exerts compression, which is followed by rarefaction. I think I got than ...
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2answers
60 views

Why need for 96kHz, 192kHz audio? [closed]

Human can hear 20-20,000 Hz waves, so by Nyquist theorem it's sufficient to sample audio with 40 kHz. Indeed, 44.1 kHz widely used. But what do we need higher sample rates for? 96 kHz, 192 kHz are ...
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Bell vs. diaphragm of stethoscope for low frequency sounds

Why is the bell of the stethoscope used to hear lower frequencies if it has a smaller diameter than the diaphragm? I would have thought that a bigger diameter diaphragm could pick up lower frequency ...
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1answer
58 views

How does underwater sound sound?

I have been thinking about underwater sounds (i.e. sounds produced and recorded underwater), what exactly the water does, and how to emulate this effect. Imagine a sound played underwater (e.g. from ...
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46 views

Sound power radiation of two monopole sources

For a fixed given electrical power to two monopole sources, producing the same frequency. Which mode, either in-phase or out of phase, will radiate the most sound power into the far-field?
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120 views

What is the physical meaning of complex eigenvalues?

I understand the mathematical origin of complex eigenvalues, and that complex eigenvalues come in pairs. But what is the meaning of the imaginary part? In particular I refer to an acoustic problem ...
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1answer
40 views

Why do empty vessels make more sound?

Why do we hear a roaring or humming sound when an empty bottle is held close to our ear ? When I hold a flask close to my ears, I hear like a sound which coming from its interior.
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3answers
111 views

If a tree falls in the forest [closed]

The question of whether or not a tree that falls in the forest makes a sound - if there is nothing or no one around to hear it - comes up frequently at my house. So, my question is: is there any way ...
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3answers
64 views

How does ultrasonic horn produce a convection current in the water?

When I was using ultrasonic horn in a beaker, I notice that there are convection currents in the beaker and stir up my substance. I don't understand why it produce water current, I thought that it ...
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1answer
68 views

Sound Wave interference Experiment

I was wondering, can we use two sound sources so as to create a destructive interference at the position of a recorder at home? If possible, what is the easiest way?
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2answers
189 views

At what speed would you die upon impact with water?

If we hit the water at great speeds, we die. This is because the water has no time to "move out of the way" and acts as a "solid" surface. At what falling speed can we consider the water as a ...
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Do low frequency sounds really carry longer distances?

It is a common belief that low frequencies travel longer distances. Indeed, the bass is really what you hear when the neighbor plays his HiFi loud (Woom Woom). Try asking people around, a lot of them ...
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1answer
51 views

how does air pressure affect the speed of sound

How does air pressure affect the speed of sound in relation to its kinetic theory etc? I have tried searching this but i have not found a suitable answer as other websites simply related to air ...
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1answer
40 views

How to create a barrier for sound waves?

Is there a way to create a barrier so that sound waves cannot pass through? Does laser light have this ability to act as a barrier or bounce sound waves back? This came to my mind when I was ...
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16 views

What's responsible for dull or sharp sounds in a struck sintered rods?

I've sintered a number of rods from powdered oxide materials, and some of them ring clearly after being struck (not as clear as, say, a metal tube, but clear enough to hear a definite pitch), while ...
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Will a sodium bell ring clearly after being submerged in liquid nitrogen?

Lead is fairly soft at room temperature but rings clearly when cooled to liquid nitrogen temperatures. Sodium is even softer. If cooled to liquid nitrogen temperature, could it also ring?
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4answers
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Is it theoretically possible to have a universe where sound travels faster than light $c$? [closed]

We all "know" nothing can travel faster than light. However, if we're allowed to tweak the fundamental constants of nature, is it theoretically possible that such an universe might exist? Update: I ...
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2answers
46 views

Resonance of a tube of air in case of more complex shapes

I've been thinking about posting this question on Music Performance stack, but finally I think it fits more here since I'm interrested in technical details. The subject of resonance of a tube of air ...
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1answer
49 views

How much of the chemical energy in a burning log is released as sound?

Firewood has energy content of about 15 MJ/kg for hardwoods. You throw one of these hardwood logs onto a fire hot enough that it burns with, say, 50% efficiency. How much of that energy will be ...
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44 views

Why does the pitch of a container being filled with water increase? [duplicate]

I wonder about this. If you pour water in a closed tank, it makes a noise. I have noticed that as the container becomes more and more full, the pitch of this noise also increases. Why is that? I do ...