How are headphones with single drivers able to make sounds that are “multiple sounds at the same time?´´

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So from what I know, the drivers vibrate at a given wavelength and that makes a sound. That makes sense to me of how you can create voice for example. But how does multiple instruments + voice in one driver work? You hear all them seperately but at the same time?

To me this sounds like a monitor pixel making more than 1 pixel at once.

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16 Answers

Anonymous 0 Comments

the simplified way I was told is that you can play a higher frequency sound inbetween the lower frequencies.

Anonymous 0 Comments

All sounds can be broken down into a sum of sine waves. You can then add those sine waves together again in your operating system, and play them through your speakers.

Anonymous 0 Comments

Any speakers can only play 1 wave at a time. And the air can actually only carry 1 wave at a time.

What happens is that all the sounds from different sources merge together and become a wave that is a combination of all the waves playing together.

A speaker generates that wave.

Your ears hear that wave and then your brain sorts it out so you hear all the different individual sounds.

Anonymous 0 Comments

Inside your ear, there is a membrane. This membrane is vibrated by the air moving against it. This single membrane (per ear) transfers the information that your brain can interpret to understand as any number of sounds happening at once, because what is actually hitting your ear is all the different frequencies of different sources of sound hitting your ear at once creating a single line over time. The ability of our brains to interpret all those frequencies stacked on top of each other is really impressive.

Speakers are just the exact same principle done in reverse.

Anonymous 0 Comments

You can simply add two sinus waves together. Or three. Or a million. It still results in a single new wave, containing all the information. That’s what sound is. At a given point in space there can always be just a single wave. Same thing with sound drivers. They don’t output a sinus wave, they output a really complicated wave that contains thousands of different sinus waves

Anonymous 0 Comments

You know how your eardrum is just a single membrane reacting to air pressure, but you can hear all kinds of simultaneous noises? Well, that but backwards. A single speaker driver can move in the pattern that matches the sum of all the waveforms it is being asked to replicate.

Anonymous 0 Comments

I know this one! You can *add* sound waves together.

Basically, sound is when the air pressure in your ear goes up and down repeatedly. However, there can only be one value for air pressure at a time. You can’t have 5 pressure and 10 pressure at the same time. Instead, you have 15 pressure.

At any given time, each sound wave increases or decreases the pressure in the air. You can add up all the changes from each sound wave, and you get a new wave which combines all of them. Your speaker plays this combined wave from its single driver.

[Here’s a graph which shows what it looks like when you add two sound waves.](https://www.desmos.com/calculator/pjn6ru9uyr)

Anonymous 0 Comments

Aside from the top comments.. what is a “driver” in your mind? It’s not a word often used to describe sound.

Some pixels for example have RGB LEDs in them. SO the Purple you are seeing is blue and red LEDs switched on, green off. It’s the same with sound. Personally i find it a bit tricky to visually imagine multiple waves at different frequencies superimposing.

Anonymous 0 Comments

How does sound work?, how do speakers work?, how can the sound of an orchestra be contained in a single waveform? how can one vinyl record groove have so many sounds? … Variations of your question are asked here every week or two, and usually are removed with a “search first” admonition.

[This animated explanation of how sound & speakers work](https://youtu.be/RxdFP31QYAg?t=156) is probably is all you need. It’s a video companion to the [explanation on the Animagraffs website](https://animagraffs.com/loudspeaker/).

Anyway, since a top-level comment has to be an answer:

Everything you hear is just vibrations of the air molecules at your eardrum (plus some vibrations conducted through your skull & jaw). The sounds of different instruments are combinations of relatively simple vibrations, and they all merge into one very complex vibration as they arrive at the same time in your ears. Your eardrum converts the sounds to electrical signals for your brain, which eventually learns to identify separate sound sources and roughly where they are coming from.

To envision two frequencies combining into one complex motion, wave your hand slowly moving back and forth, mimicking the motion of the air as it transmits a low bass tone. Keep doing that, and add a fast tremor to your hand, mimicking a higher-pitched tone “riding on top of” the lower tone. That’s all there is to it; it’s what the instrument, the speaker, the air, and your eardrum are doing: making unique combinations of simple vibrations.

How far your hand moves back and forth, relative to a neutral center position, is the amplitude, and it correlates with sound intensity, which we perceive as “volume” or “loudness”. How fast your hand moves back and forth is the frequency (expressed in Hertz, e.g. 20 Hz means 20 times per second), and it correlates with pitch. Actual sound sources just vibrate the air much faster and with much less amplitude than your hand ever could, and they normally contain many pitches combined.

A speaker only has to make the air at your ears vibrate like that, and most full-range speakers can do a pretty good job. Your brain is what recognizes and distinguishes between instruments and other consistent sources of sound. How *that* works in the inner ear and brain is more difficult to explain, but is not really what you asked.

Anonymous 0 Comments

they generate a composite of multiple soundwaves. this composite wave is then decoded in the ear into multiple “base” waves again. you can see the soundwave it generates here: https://meettechniek.info/additional/additive-synthesis.html