how can lots of different sounds like a band be recorded onto a single sound wave? Or is it actually lots of different sound waves and then “generalized” into one wave?

Question

I understand how a single sound wave works, but I’m picturing the track on a vinyl record. How is a needle riding a single soundwave playing back all of those uniquely different sounds?

In: 4

Answer 1

It’s because any specific sound, of any shape, can be represented by some sum of all the different fundamental (perfect sine wave) frequencies. You are making one wave, but you can also decompose it into component sine waves. This is called the Fourier Transform, and it’s an underpinning of like half of all physics.

It’s not really a generalization, because it’s also true that only that specific combination of pure frequencies will create that specific wave.

For some intuition, you should find a “Fourier Transform animation”, where progressively small circles draw out whatever shape they want. Each circle represents the addition of another frequency to the sum, and the more frequencies you add, the more precisely you can approximate the shape.