How is audio represented with numbers in computers?

Question

I like thinking about how everything can be and is represented by numbers. For example, plaintext is represented by a code like ASCII, and images are represented by RGB valu

Answer 1

I think a good way to start playing with audio would be with Processing and Minim. This program will draw the frequency spectrum of sound from your microphone!

import ddf.minim.*;
import ddf.minim.analysis.*;

AudioInput in;
FFT fft;

void setup()
{
  size(1024, 600);
  noSmooth();
  Minim.start(this);
  in = Minim.getLineIn();
  fft = new FFT(in.bufferSize(), in.sampleRate());
}

void draw()
{
  background(0);
  fft.forward(in.mix);
  stroke(255);
  for(int i = 0; i < fft.specSize(); i++)
    line(i*2+1, height, i*2+1, height - fft.getBand(i)*10);
}

void stop()
{
  in.close();
  Minim.stop();
  super.stop();
}