How does a computer find the ?

Music technology · signals · beginner friendly · about 18 minutes

A computer does not hear a flute or a violin. A computer only sees numbers: a long list of quick measurements of the sound. So how does a computer turn that list of numbers into a spectrum?

A digital sound is a list of samples. Part 2 shows, step by step, how those samples become a frequency recipe.

The five steps ahead:

  1. Sample dots
  2. Test wave
  3. Multiply
  4. Add
  5. Spectrum bar

The whole method is simpler than the formula looks:

  • Choose a frequency, and make a test wave.
  • Multiply sample by sample, then add the results.
  • See if the total is big or small.

By the end of Part 2, you will be able to:

  • See where digital samples come from.
  • Run the frequency test: multiply sample by sample, then add.
  • Interpret the main pieces of the DFT formula.
  • Calculate one small frequency result by hand.

Where this sits in the series:

  1. 1. See the recipe
  2. 2. Find the recipe
  3. 3. Use it, and prove it
Quick check
Before any frequency test, what does the computer actually have to work with?

An interactive lesson by Chalece DeLaCoudray

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