# [ELI5] If sound is matter vibrating, and the speed it vibrates is pitch, what dictates volume? Is it the amount of matter vibrating, and if so, does that mean there’s a “max volume” for air?

213 views

[ELI5] If sound is matter vibrating, and the speed it vibrates is pitch, what dictates volume? Is it the amount of matter vibrating, and if so, does that mean there’s a “max volume” for air?

In: Other

Sound is low and high pressure waves in air. The difference between the low and high pressure waves is the amplitude or “loudness” you hear.

The energy it carries, which is apparent by the amount of space by which it displaces particles, known as amplitude. I’m not aware if there exists a max volume, but there’s definitely a threshold where it begins to cause damage to things.

Look at the speaker on a stereo system. The cone of the speaker vibrates, not up and down, but towards you and away from you. Sea waves go up and down, sound waves are usually bursts of compression and decompression.

So yes, the amount of air that’s vibrating is volume, but at loud concerts you can feel the sound vibrations in your chest, and if you keep increasing the volume it can start doing damage like an explosion shock-wave would.

So, as far as “max volume”, the atmosphere is certainly capable of transmitting shockwaves that are very damaging, and way beyond what you would call “sound”.

imagine that wave line. the number of times it goes up and down per second is the pitch and the height it goes up and down is volume.

now like ripples in a pond, small ripples will dissapear quicker than big ripples, and small rippled can be seen on a still pond, but not on a wavy pond.

There is at least a maximum volume in liquid; beyond a certain point the low pressure phase of the sound waves will flash vaporize the liquid.

It’s the amplitude, the maximum amount of oscillation from the point of equilibrium

The size of the vibrations – how far the matter moves. There is indeed a maximum possible volume, that’s pretty much what a sonic boom is.

ETA: The maximum is less about compression, more about decompression. Specifically, it’s the point that the pressure wave leaves a vacuum in its wake.

Sound is a pressure wave moving through matter. Higher pressure is higher volume. Rate of the waves is the pitch.

A blast from an explosive, repeating at 20hz is super loud bass. A butterfly flapping at 20hz is super quiet bass.

Imagine a pond. Throw a rock in the pond.

The rate at which ripples come out from where the rock lands is the speed of the vibration. The ripples will have a wavy shape. If you measure from the top of a wave to the bottom of a wave, you get the volume.

Air works just like the water rippling in the pond, and our ears turn that into “sounds”

The amount something vibrates is the volume. I’m guessing this is also why lower (slower vibrating) sounds tend to be louder, as a bigger distance to vibrate means it will take more time. But this could just be a misunderstanding on my part.

Sound is a pressure wave, and volume is basically the amount of pressure change it causes.

For a sustained sound, the maximum amplitude of this wave is equal to the ambient pressure, with the wave causing alternating regions of double pressure and vacuum. If you try to go higher, you break the wave form and your sound wave becomes a shockwave, since pressure can’t dip below vacuum levels.

At sea level averages, this limit works out to around ~194 decibels.

If you visualize sound as a 2D wave, the pitch is the distance between peaks and the volume is the height of the peaks.

In the real world, this translates to the speed at which things are vibrating and the distance it moves with each vibration.

You can see this in action by watching the cone of a speaker. If it is playing music quietly, it might only move a little bit, if it is playing loud, it will move a lot. But it is moving at the same speed either way.

This is also why speakers sometimes distort sounds at higher volumes- if it’s not able to move the distance needed to produce the sound quickly enough, it will change the pitch of the sound it produces.

the force of the sound wave, and therefore its pressure. you can imagine it as high peaks on a wave. to make things really loud you have to hit things really hard, for instance.

Amplitude, how *much* of the air is vibrating. Or how much force the sound has.

If you consider a mosquito’s wings, it’s a very high pitched note because the wings are flapping really fast, however the wings don’t push a lot of air so it’s quite faint.

Consider a thousand mosquitoes, now there’s a lot more wings pushing a lot more air! If all the mosquitoes were flapping in synch then the sound would be as high a frequency but *much* louder.

(It’s also amusing to imagine the scenario in which there are 500 mosquitoes flapping their wings precisely one half period out of synch with the other 500 mosquitoes, there might be a lot of air movement, but all the frequencies would cancel out meaning they’d likely be silent.)

the pitch of a sound wave is the frequency (how quickly a particle moves back and forth). the volume of a sound wave is the magnitude (how far the particle moves back and forth). the magnitude of the sound is dictated by how much ‘force’ the sound has, really. when you turn up the volume on your speaker and the noise gets louder, exactly the same amount of matter is vibrating (the speaker weighs the same and the air is the same), but since your speaker is vibrating harder, the air particle gets shaken back and forth harder, and the magnitude of the soundwaves are larger.

and to answer the last question, theres not really a max volume for air, as the sound wave can always have more force. the problem with answering this question meaningfully is that anything over like 200dB is, for all intents and purposes, an explosion.

pitch is how fast something vibrates for example 100 times per second (100 hz).

(“pitch” is mostly used for music though. For all other things, it’s called “frequency”).

Volume is how far the thing moves during this back and forth movement. So something can move 1mm back and forth, or 3mm back and forth. If they both move back and forth 100 times per second, then the one moving 3mm needs more energy, and this also gives it more volume.

I’ll start with the eli5 analogy. Imagine you were on the moon with it’s very low gravity, and you had a clear box full of ping pong balls, which will represent air molecules.

If you shake the box, the vibrations cause the balls to bounce off each other, trading energy, much like how sound waves move through a gas as energy, without moving the gas (think one of those desk top toys where the balls click off each other and only the ones at the end move).

But if you shake the box too hard, the balls will go flying out of it due to the low gravity of being on the moon. You can think of gravity as air pressure in this regard. Less gravity, the less tightly the balls are bound to each other and the more easily they can fly out of bounds without hitting each other. The higher the gravity, the more tightly compacted they are, and the faster the energy transfer, but also the more energy you can put in shaking the box, without the balls flying out.

So if you increase the amplitude (shaking) more than what the air (ping pong balls) can tolerate at a given pressure (gravity), the air flies apart and ceases to conduct sound. This is the amplitude limit.

But lets say you put a lid on the box of balls, and stuffed more in, now you can shake it much harder, and the balls have nowhere to go (they are in an enclosed space), now the amplitude limit is much higher.

Pitch is the wavelength, loudness is the amplitude, and the conductivity is how quickly sound waves travel through a medium. There is a maximum amplitude and frequency that sound waves can move through air. Above a certain point, the molecules just can’t move around any faster without heating up and knocking each other to far away to conduct sound (a huge fireball of plasma), and the same with amplitude where something too loud, would literally just shake the air to the point it flew apart and wasn’t conducting sound.

The maximum amount of sound energy that air could transmit would depend on the frequency of the sound, the air pressure and density, humidity, and whether that sound was open, or in a confined space.

The frequency of the sound wave is the pitch, the amplitude is what we commonly call “volume”. The speed at which the wave moves is fix, it’s the speed of sound. Speed of sound varies only based on the material it travels through and its density. Higher density gives higher speed of sound.

There is a maximum volume, it is called shockwave.

That sphere of vapor that you see moving away from an explosion faster than the explosion itself (the extreme compression forces the water to separate from the air).

Mind that the max volume is so high that it can be reached only with gigantic explosions (2000 kg of tnt and up) and volcanoes explosions.

Above max volume there is only silence, and a deadly wave that disintegrate you. Atomic bombs are silent at short distance.