Timbral Evolution: Harmonic analysis of classic synth sounds

Since there is no seperate category dedicated to synthesis techniques…

Ever wondered about waveshape, harmonic spectra (and some math) in relation to classic synthesis techniques?

Look no further then this nice and concise summary by the Electric Druid.

It covers:

  • Pulse Width Modulation
  • Phase-shifted waveforms
    • Sum of phase-shifted waveforms
    • Difference of phase-shifted waveforms
    • PWM as a special case of phase-shifted waves
  • Oscillator Sync
  • Phase Distortion
    • Ramp-down/Triangle/Ramp-up
    • Sine Wave
    • The effect of source waveform phase on phase distortion
      • Phase-shifted triangle
      • Cosine Wave
  • Frequency Modulation

Timbral Evolution: Harmonic analysis of classic synth sounds

Posted on August 30, 2016

This post is a place to gather my thoughts about one of the most important parts of synthesizer design: the timbral evolution of sounds. It also presents the results of my analyses of some classic synth sounds.

There have been many methods developed over the years to achieve timbral evolution. The voltage-controlled filter is the first and most obvious. Pulse width modulation and oscillator synchronization are two more from the analogue era. Other later approaches include wavetables, vector synthesis, FM, phase distortion, and others.

The aim of all of these concepts is the same; to provide timbral evolution during the course of a sound. I would argue that many sounds have a richness and interest to the human ear because of the non-linear changes in their harmonic structures over time. Effective and efficient generation of these interesting non-linear changes is a fundamental challenge that synth designers must meet if their instruments are to make sounds that grab you.