# Sound Synthesis Theory/Subtractive Synthesis

The oscillator will typically produce a waveform with a wide frequency spectrum (square wave, noise) at a frequency, ${\displaystyle f_{1}}$ and an amplitude ${\displaystyle a_{1}}$, although there can be two or perhaps even three oscillators in the design; any more begin to distract from the purpose of a subtractive synthesis technique although there are designs which exist. The filter block, which can be comprised out of many different types of filter (lowpass, bandpass), changes the character of the oscillator by controlling the balance of the frequency spectrum, before being modified further by additional effect modules built into the system. These elements can be user specified or automated using other oscillators or value envelopes. The subtractive approach is favoured by many musicians due to the fact that it is comparatively imprecise and therefore requires tweaking and experimentation of control parameters to get a desired sound.