Subtractive synthesis is a method of
sound synthesis in which partials of an audio signal (often one rich in
harmonics) are attenuated by a
filter to alter the
timbre of the sound. While subtractive synthesis can be applied to any source audio signal, the sound most commonly associated with the technique is that of analog synthesizers of the 1960s and 1970s, in which the harmonics of simple waveforms such as
sawtooth,
pulse or
square waves are attenuated with a
voltage-controlled resonant
low-pass filter. Many
digital,
virtual analog and
software synthesizers utilise subtractive synthesis, sometimes in conjunction with other methods of sound synthesis.