West Coast synthesis adds harmonics to simple waves; East Coast synthesis filters them from complex waves

Two synthesis philosophies invert each other. The East Coast lineage (Moog, ARP) starts with harmonically rich waveforms (sawtooth, square) from basic function-generator oscillators and uses resonant low-pass filters — classically a 24 dB slope — to subtract harmonics, sculpting timbre downward. The West Coast lineage (Buchla, Serge) instead starts from simple waveforms (sine, triangle) and adds harmonic content through frequency modulation, amplitude modulation, and dynamic waveshaping / wavefolding. A wavefolder folds the waveform back on itself, so pushing more signal (more drive) through it produces progressively more overtones. West Coast rigs also favor low-pass gates (LPGs), which combine amplitude and timbre control in one unit, producing a natural swell-and-decay like a plucked string dying away — more “acoustic” than a bare VCA. Neither approach is superior: they yield different timbral qualities and suggest different patching workflows, and modern systems routinely mix both in one rack. The distinction is a conceptual map of adding-vs-subtracting spectral content, not a rigid hardware category.

Examples

East Coast: sawtooth VCO into a resonant low-pass filter cutoff sweep into a VCA — classic subtractive voice. West Coast: sine oscillator (optionally FM’d by a second oscillator) into a wavefolder (adds harmonics as drive rises) into a low-pass gate struck by a trigger — organic, percussive timbre. The Buchla Music Easel (and Arturia’s 2017 Buchla Easel V emulation) is the portable West Coast reference.

Assessment

Given the patch ‘sine VCO -> wavefolder -> low-pass gate’, name the philosophy it follows and state what each module contributes, then sketch an East Coast voice aiming at a superficially similar result. Explain what a wavefolder does to a sine wave as input level increases, and why an LPG sounds more acoustic than a VCA alone.