It doesn’t matter if you just bought your first hardware synth or you’re dabbling in soft synths like Native Instruments Massive or Xfer Serum. A general understanding of the principles of sound synthesis goes a long way, if you don’t want to stick to the factory presets or spend money commercial preset packs. Below we’ll take you through the building blocks which you’ll find in just about any synthesizer out there.
The basic components of a synthesizer are sound sources (oscillators) and modifiers (filters, envelopes etc), which make these simple sounds more complex.
An Oscillator or VCO produces the basic waveforms of sine, square, and sawtooth, each with its own distinctive synth sound. These waveforms can have different frequencies, usually from 0 to 20,000Hz (Hz = oscillations per second). Having two or more oscillators playing waveforms on top of each other is called “additive synthesis.”
Unison is a kind of additive synthesis, where the synth generates multiples of the same wave form, all slightly out of tune with each other, to create a broader, richer sound.
Filters modify a synth sound by taking away certain frequencies and adding emphasis to others. A low pass filter (LPF) takes out certain high frequencies. A high pass lter (HPF) does the opposite. A band pass cuts out low and high frequencies around a certain middle band. The “cutoff ” of a filter determines the frequency where the modification begins. The “resonance” affects the sharpness of the modification.
Envelopes shape sounds over time. They usually control either the volume of a sound or the amount it is affected by the filter, from the time a note starts to the time it stops. The basic parameters of an envelope are: attack, decay, and release, together are often referred to as ADR. Sometimes an envelope will have a sustain parameter (this is an ADSR envelope). Sustain determines how long a sound holds at a given volume after it has decayed.
LFO (low frequency modulation) and Cross Modulation occurs when one waveform alters a parameter of another — either the pitch, the volume, or the action of the lter. This can produce tremolo-type effects (waveforms altering volume), vibrato (altering pitch), or sweeping sounds (altering the lter). If the modulation is happening at a rate of about 20hz or lower, it’s considered LFO.