Oscillator Waveforms

The Four Basic Waveforms

Every tone you hear in subtractive synthesis starts with one of four fundamental wave shapes: sawtooth, square, triangle, or sine. Each shape has its own “personality” based on how its harmonics are arranged—bright and buzzy, hollow and woody, smooth and mellow. By choosing a waveform, you set the raw timbre you’ll later sculpt with filters and envelopes. In this lesson, we’ll listen to each waveform, see how its shape maps to its sound, and discover why it matters for creating everything from basses to pads to leads.

Sawtooth Wave (Saw)

  • Shape: A sharp ramp up or down.
  • Sound: Bright, buzzy, rich in harmonics.
  • Use: Great for strings, brass, bass, and aggressive leads.
  • Harmonics: Contains both even and odd harmonics.

Historical Note: One of the earliest and most important waveforms in analog synths due to its richness and versatility.

Square Wave

  • Shape: Alternates between high and low at a 50/50 duty cycle.
  • Sound: Hollow, woody, thinner than a saw.
  • Use: Good for woodwind-like tones, chiptune, and bass.
  • Harmonics: Contains only odd harmonics.

Variants like Pulse Waves adjust the duty cycle, making the tone narrower or more nasal.

Triangle Wave

  • Shape: Symmetrical upward and downward slopes.
  • Sound: Smooth and mellow.
  • Use: Soft pads, flutes, or blending with other waves.
  • Harmonics: Only odd harmonics, but much quieter than those in a square wave.

Sine Wave

  • Shape: A smooth, continuous wave.
  • Sound: Pure tone with no harmonics.
  • Use: Sub bass, pure tones, or for FM synthesis.
  • Harmonics: None (just the fundamental frequency).

Overview

Waveform Shape Sound Use Harmonics
Sawtooth Sharp ramp up or down Bright, buzzy, rich Strings, brass, bass, aggressive leads Even and odd
Square High/low switch (50/50 duty cycle) Hollow, woody, thinner than saw Woodwinds, chiptune, bass Odd only
Triangle Symmetrical slopes Smooth and mellow Soft pads, flutes, layering Odd only (quieter than square)
Sine Smooth, continuous wave Pure, clean tone Sub bass, pure tones, FM synthesis None (only the fundamental)

Why Saw and Pulse Came First?

Early analog synthesizers were designed with simple analog circuits. Saw and pulse waves are easy to produce using:

  • Ramp generators for saw waves.
  • Flip-flop circuits for square and pulse waves.

More complex waveforms like triangle and sine required additional filtering or integration stages. That’s why saw and square/pulse were foundational in early synth design.