As my last assignment for IMPMOOC at Coursera I am going to explain the five most important synthesis modules very briefly.
All synthesizers, no matter if hard- or software, make use of the same five basic modules that are outlined in Loudon Stearns overview.Those modules are the Voltage Controlled Oscillator, Voltage Controlled Filter, Voltage Controlled Amplifier, Low Frequency Oscillator and Envelope.
The primary modulation section consists of those modules that produce directly audible effects.
The first one is the VCO, that creates the actual sound by generating a signal using simple waveforms such as sine, triangle, sawtooth and square waves or even noise.
In the next step the VCF shapes the spectrum of those often very agressive sounds to make them more pleasing to listen to. On the other hand it’s also able bring out resonances or use comb filtering to shape the sound.
The final module in the primary section is the VCA. It simply shapes the volume of the generated sound.
Those three primary modulation modules are again modulated by the secondary modulation modules.
Here the LFO is a cyclic modulation module that usually runs at frequencies below the range of human hearing, i.e., 0 – 20Hz and often modulates the VCO. This can for example be used to simulate vibrato, which ranges somewhere between 3 and 6 Hz. It employs the same wave shapes as the VCO.The Envelope finally most often modulates the VCA giving the user the possibility to modulate the amplitude over time to create sounds ranging from percussive to violin-like or even swelling sounds among many more. It consists of the main blocks Attack time, Decay time, Sustain level and Release time, which are depicted in the overview. When the synth receives a note on command the attack phase begins and the envelope is processed until a note off command is received, which starts the release phase.
This was my very brief overview of the most important synthesis modules. Thank you for taking the time to read my posts.
All the best,