# Tagged Questions

57 views

### Does timbre consist in pitch and volume?

I read that the physical properties of a sound wave correspond to its audible qualities: pitch, volume, and timbre. However, an oscilloscope uses only two-dimensions to accurately depict the physical ...
66 views

### Why are two voices singing the same note louder than one?

Let's say for example: Two people sing the same note (frequency) and volume (amplitude) together. Why is it that the two persons sound louder than they would ...
25 views

### Number of wave modes in a cavity

I'm trying to calculate the number of acoustic modes that can exist in a room in a certain range of frequencies. I thought of using the Rayleigh-Jeans formula for the electromagnetic standing wave ...
107 views

### Are small speakers inherently limited to higher frequencies?

I am hoping to build a subwoofer using multiple smaller speakers (165mm) instead of a single larger speaker (380mm). My theory is that the displaced air volume is what matters, not the individual ...
60 views

### What is sound in terms of acoustic sources?

Sound is nothing more than small amplitude, unsteady pressure perturbations that propagate as a longitudinal wave from a region in space which created it (called the source region) into a quiescent ...
32 views

### What is the longest distance over which echolocation is effective?

Some animals, most notably bats, use echolocation in order to navigate and detect the location and size of objects and prey. This usually takes place over short distances. What are the theoretical ...
33 views

### Standing sound wave tube

If there was a standing sound wave tube and a flammable gas was introduced then ignited, would the combustion be more forceful and more efficient since its following a standing wave, than just a gas ...
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### Why is sound intensity proportional to the square of sound pressure not to sound pressure alone?

I am trying to understand the physical principles behind the sound intensity and sound pressure. As far as i know, sound intensity is proportionate to the squared sound pressure. Can someone explain ...
32 views

### Math formula for crystal glass resonance [duplicate]

For a music therapy experiment, I have to use several crystal glasses with water and different cylindrical shapes, and make them vibrate and produce different sounds. Is there a math formula that ...
180 views

### The shape of speaker cones

This is related to another question I just asked, but they are different enough I thought it deserved its own spot. Speaker elements seem to always be shaped like a cone with a portion of a sphere at ...
84 views

### The physics of sound boards

As a kid I was bemused at why soundboards worked. A small sound could be demonstrably amplified simply by attaching the source to a surface that is rigid and not too thick. How could the volume ...
3k views

### Speed of sound at temperatures below 0 °C

How can the speed of sound be calculated for temperatures below 0 °C (down to -40 °C)? Does the calculation $v=331\ \frac{m}{s} + 0.6 \frac{m}{s°C} \times T$ still hold (where T's unit is ...
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### How can one calculate the distance a particular sound will travel?

What do you need and how to calculate a distance traveled by sound? For example if you hit a bell with a specific amount of power how far will it travel?
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### How far do air particles move when a sound wave passes through them?

How far do air particles move when a sound wave passes through them? I know that they don't actually travel, the question is how far do they oscillate or what is the physical amplitude of the ...
98 views

### 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?
141 views

### Is it possible to estimate the speed of wind by the sound emitted by a cable of an overhead power line?

I was near ($\approx40m$) an overhead power line and I heard a sound coming from the cables of the power line; I think the sound was made by the vibrations of the power cables due to the wind but I am ...
75 views

### Diffraction of sound

The sound waves, by the virtue of it being a wave, shows diffraction and interference. But in diffraction, I learnt that if the wave is allowed to enter through a small aperture, there is a central ...
41 views

### Rijke tube: Why Sound is maximum when heated 1/4th length from bottom of tube

Why is it that the maximum sound coming from a Rijke tube happens only when heated wire gauze is placed at 1/4th the length of the tube from the bottom. According to Rayleigh: If heat be ...
79 views

### Frequency shift without affecting signal length

Non-physicist here. From what I've learned in university and what common sense says, a shift in frequency of a signal results in a change in its length in time. For example, if a sinusoid signal of ...
246 views

### Are pure mechanical evanescent waves possible?

Consider a lattice of massive points connected by harmonic springs, with zero or periodic boundary conditions. If we make a repeating pattern of $N$ varying masses, the system will have $N$ bands of ...
201 views

### Theory behind patterns formed on Chladni plates?

In this video of vibrating Chladni plates we can see small sand particles align themselves into different interesting patterns (also shown in the image below) which correspond to some particular ...
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### Differences of waves in water and air

When one drops a pebble in a body of water, one can observe multiple waves emanating from the point the pebble came in contact with water. Be it because the water "jumps" up and comes back down, ...
84 views

### Modeling sound resonance in an arbitrary cavity

I am trying to solve a challenging problem, and I'm hoping for some advice on how to proceed. I want to model sound waves in a cavity for the purpose of determining resonance. The plan is to answer ...
121 views

### Numerical simulation of sound propagation in air

How does one go about accurately modeling sound propagation in a room (with reflections, absorption, and diffusion characteristics) from the motion of a loud speaker? More specifically what are the ...
87 views

### Can sound be propagated without initial mechanical interference?

I have researched up a little on sound, and it seems that sound is a mechanical wave that propagates through the air as energy, and that is how we hear it through our ears. Depending on the medium's ...
240 views

### Is it possible for a sound to be louder as you move away from it?

I was asked a puzzling question/thought experiment: Given the source of a sound in a wide open field so acoustics do not play a role, is it possible for a sound to be louder as you move away from it. ...
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### Does sound cancel itself out?

If there are two 10 x 2 x 1 foot rectangles in space and they are lined up so if they hit each other there will be no spots that are not hit in the front of the rectangle. Then they are pushed forward ...
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### Why are waves, the means, of information transfer over long distances, excluding difusion or contact of info stored in matter

Practical long distance communication, which does not rely on the movement of encoded configurations of matter, from source to destination(odor,books,DNA,floppy disk), always involves waves (EM, ...
125 views

### The Mysterious Reverb in a Jar of Hair Gel

I have a small jar filled with hair styling gel (or, as it calls itself: Ultra Gel-Wax). The jar is cylindrical(with the height being less than the width), has an unscreweable lid and is made of ...
161 views

### How to determine the positions of two points in a radial line by an intensity level dB?

The following is the question from my school. A source emits sound uniformly in all directions. A radial line is drawn from this source. On this line, determine the positions of two points, 1.00m ...
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### Relative velocity of sound

Relative velocity of sound. As I know that speed of sound in medium is property of medium. And independent of source motion but depend on motion of audience or observer and motion of medium. But it ...
310 views

### FFT distortion, harmonics (singing wine glass)

I'm doing a school assignment on Singing Wine glasses (you rub the rim of the wine glass with a wet finger and it produces a pure tone). I have recorded $30\,\text{ms}$ of the "singing" at a sampling ...
174 views

### Is sound relative?

Is sound relative? For example, if I and my friend are having a ride at 1000 mph and I shout towards him (speed of sound 700 mph). What would happen? Will the speed of the sound relative to the ...
111 views

### physical difference between A and B

We all know that when we say A it sounds different than when we say B. I was wondering what exactly can be the difference between saying A and B in terms of physics. I first thought that it may due ...
39 views

### is it possible to load a transversal wave with a longitudinal wave

like in communication engineering for sending information what we do, we take a high frequency carrier and modulate it with the message signal so can we do the same thing like take a high ...
55 views

### Relationship between tones made by a piano

If a piano were to be tuned perfectly with the equal temperament system, what would be the relationship between standing waves from one note to the next? How would the frequency and wavelength of ...
67 views

### Energy in a wind instrument?

My physics teacher said that he saw a guy playing a very large wind instrument on TV, and the guy apparently calculated that the total energy present in the instrument when he was playing was almost ...
38 views

### Bass and Treble-Car Steroes

In a car which phenomenon, diffraction or the resonant frequency of the car, lends itself more to the ability of bass to go farther? Related Answer: Why do bass tones travel through walls?
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### Varying the amplitude of a driven wave

I' d like to know whether varying the amplitude of a system at resonance is possible or not and if it is, how? I've calculated the resonance frequency of a material and I'd like to know the ...
1k views

### A Doppler Effect problem with a moving medium

I tried solving the following question and started having multiple doubts: Two cars A and B are moving towards each other with some speed $25$ m/s. Wind is blowing with speed $5$ m/s in the ...
2k views

### A Musical Pathway

Using a small number of sound emitters, could you create a room where certain nodes emitted particular tones, but no meaningful sound was heard anywhere else. So, for example, by walking down a ...
158 views

### Can random constructive interference with sound waves cause damage?

Any two sound waves have a random chance to constructively interfere with each other at a given spot and this will cause an increase or decrease in pressure. So is it possible that a large number of ...
521 views

### Why do sound waves travel at the same speed moleculewise? (Same medium)

I don't understand what happens in reality (outside of wave theories). If I clap my hands I invest energy in the nearby air molecules, which move and transfer their energy to nearby molecules which ...
326 views

### Slinky reverb: the origin of the iconic Star Wars blaster sound

This is a fun problem that I came across recently, which I'm posting here for your delectation. We all love a good slinky: they can be used for all sorts of fun demos in physics. One example is the ...
170 views

### Lethality of sounds and extreme “loudness”

In theory, could pure sound be lethal? How loud would it have to be? Also, which events are the loudest in the universe, and how loud are they? I'm confining attention to events which occur regularly, ...
150 views

### In terms of the Doppler effect, what happens when the source is moving faster than the wave?

I'm just trying to understand this problem from a qualitative perspective. The Doppler effect is commonly explained in terms of how a siren sounds higher in pitch as it is approaching a particular ...
166 views

### Waveguides (in the ocean?)

The speed of sound in the ocean is given by $$c_s(\theta,z) = 1450 + 4.6\theta - 0.055\theta^2 + 0.016z$$ $\theta$ is the temperature in degrees celcius, and $z$ is the depth. In a simplified model, ...
183 views

### How does one find the wave velocity and the phase speed?

While I was studying beats, I tried to find a displacement function of any particle in the most generalized form. I ended up with $$y=2A\sin(\pi(t-x/v)(f_1+f_2))\cos(\pi(t-x/v)(f_1-f_2)).$$ Now, ...