Subtractive Synthesis The technique of arriving at a desired tone color by filtering waveforms rich in harmonics. Subtractive synthesis is the type generally used by analog synthesizers. Oscillator An electronic device which generates a periodic signal of a particular frequency, usually a sine wave, but sometimes a square wave or other waveform. In an analog synthesizer, oscillators typically produce regularly repeating fluctuations in voltage - that is, they oscillate. In digital synthesis, an