How Do Microphones Accurately Capture Sounds?

[austinv]

I suppose this question really has to do with how multiple sound waves can combine into one, while that new sound wave still sounds like a collection of all the sounds that made it up.

But I'm really curious, how does a microphone accurately capture multiple sounds at once? Let's say a guitar chord is strummed near a microphone, and that microphone is driven by the sound waves, but of course it can only respond to one frequency at any given time because it can only move in one way at any given moment, and yet numerous sound frequencies are striking it. So how does the microphone accurately capture all of those sounds rather than distorting them because it can't vibrate to match every single one at once?

(I'd just like to note that I understand how this works in the ear, because the ear works much like a waveguide and so it can parse out the individual frequencies that enter the ear and then specific hair cells in different regions respond to specific frequencies. But a microphone does not, and can not, work like this.)

Thanks so much for your answers!

 

[HallsofIvy]

All of those many different frequencies sum to one wave. The microphone responds to that single wave.

 

[AlephZero]

A microphone doesn't "vibrate" in the way that a pendulum vibrates. Or to be more accurate, a good microphone doesn't vibrate like that at any frequencies in the audio range. It just moves to follow either the air pressure that hits it, or the air velocity, depending what type of microphone it is.

If you get a flexible plastic ruler, fix one end, and push on the other end slowly with your finger, the ruler doesn't "vibrate", it just moves to follow the movement of your finger. That's what a microphone does, though of course the mic moves much faster and with much smaller amplitude.

 

[chrisbaird]

The microphone does not respond to a single frequency. It responds to a single waveform, which is the sum of many frequencies.