Modular synthesizer

Modular synthesizers are electronic musical instruments composed of separate synthesizer modules that represent different functions. The modules can be connected together by the user to create a patch. The outputs from the modules may include audio signals, analog control voltages, or digital signals for logic or timing conditions. Typical modules are voltage-controlled oscillators, voltage-controlled filters, voltage-controlled amplifiers and envelope generators. A modular synth is made up of individual modules which are combined into an instrument. A semi-modular synth allows patching within a fixed set of circuits and fixed user interface.