Sine Wave
The purest waveform — a single frequency with no harmonics. The building block of all periodic sound via Fourier synthesis.
Triangle Wave
Contains only odd harmonics, diminishing as 1/n². Softer than a square wave; sounds hollow and flute-like at low frequencies.
Sawtooth Wave
Contains all integer harmonics at 1/n amplitude. The richest standard waveform — ideal as a starting point for subtractive synthesis.
Square Wave
Contains only odd harmonics at 1/n amplitude. Sounds hollow and reedy. A 50% duty-cycle pulse wave.
Pulse Width
The ratio of high time to total period in a pulse wave. Deviating from 50% introduces even harmonics and changes timbre dramatically.
White Noise
Equal energy per frequency — all frequencies simultaneously with random phase. Useful for percussive attacks and wind/sea textures.
Harmonic
A frequency component that is an integer multiple of the fundamental. Harmonics above the first are also called overtones.
Overtone
Any partial above the fundamental. Harmonic overtones are integer multiples; inharmonic overtones are not. Bells and strings differ here.
Fundamental
The lowest, usually dominant frequency in a tone. Determines the perceived pitch. All harmonics are integer multiples of this frequency.
Timbre
The perceptual quality of sound that distinguishes instruments at the same pitch and loudness. Determined by harmonic content and envelope shape.
VCO
Voltage-Controlled Oscillator. Analog circuit whose output frequency is proportional to an input voltage. The heart of subtractive synthesis.
DCO
Digitally-Controlled Oscillator. Uses digital clock division for rock-solid tuning stability while retaining analog waveform generation.
Wavetable
A stored single-cycle waveform. Scanning through a table of waveforms during playback creates evolving, animated timbres impossible with static oscillators.
FM Synthesis
Frequency Modulation synthesis. A modulator oscillator varies a carrier's frequency at audio rate, creating complex sideband spectra from simple sine waves.
Carrier
In FM synthesis, the oscillator whose frequency is modulated. Its base frequency determines the perceived pitch of the output tone.
Modulator
In FM synthesis, the oscillator that modulates the carrier's frequency. Its ratio to the carrier and its amplitude (index) shape the spectrum.
Modulation Index
In FM, the peak frequency deviation divided by the modulating frequency. Higher index = more sidebands = richer, denser spectrum.
Sideband
Spectral components created by FM modulation, appearing at carrier ± (n × modulator) frequencies. Their relative amplitudes follow Bessel functions.
Aliasing
Artifacts that appear when a signal contains frequencies above the Nyquist limit. In synthesis, deliberate aliasing can create lo-fi texture effects.
Nyquist
The maximum representable frequency in a digital system — half the sample rate. At 44.1 kHz, the Nyquist limit is 22.05 kHz.
Karplus-Strong
Physical modeling algorithm: a noise burst through a delay line with a lowpass filter in feedback. Simulates a plucked string with minimal computation.
Physical Modeling
Synthesis that simulates the physics of a vibrating body — string, tube, membrane — rather than recording or approximating its sound with oscillators.
Oscillator Sync
Forcing a slave oscillator to restart its cycle whenever the master completes one. Creates harsh, cutting timbres where the slave frequency sweeps against the locked reset.
Ring Modulation
Multiplying two audio signals together. Produces sum and difference frequencies — no carrier fundamentals survive. Extreme, metallic, robotic timbres result.