Sound synthesis is the process of producing sound. There are a lot of techniques to do so, analog or digital, and many subcategories such as subtractive and additive synthesis or granular and software synthesis. Many synthesizers consist of specific components and by manipulating them, one can transform the initial signal of a synth into something completely different. These components are oscillators, filters, ADSR envelopes and LFOs.
Oscillators are the source of sound. They create raw sounds with a timbre that depends upon the waveform generated.
Common waveforms: sine wave, triangle wave, square wave, sawtooth wave
Filters allow some frequency regions to pass or increase them while significantly reduce others
Common types of frequency response curve are low-pass, band-pass, high-pass, notch
ADSR envelope is the overall ‘shape’ of the volume of a sound that is produced by envelope generators and consist of four basic segments attack, decay, sustain, release.
- Attack timeis the time taken for initial run-up of level from nil to peak, beginning when the key is first pressed
- Decay timeis the time taken for the subsequent run down from the attack level to the designated sustain level
- Sustain levelis the level during the main sequence of the sound’s duration, until the key is released
- Release timeis the time taken for the level to decay from the sustain level to zero after the key is released
LFO (Low-frequency oscillator) generates an electronic signal which is usually below 20 Hz and creates a rhythmic pulse or sweep. This pulse or sweep is often used to modulate synthesizers and to create effects used in the production of electronic music.