Modular synthesizer

The modular synthesizer is a type of synthesizer, which exists in both physical and virtual forms, consisting of separate specialized modules. The modules are not hardwired together but are connected together with patch cords, a matrix patching system, or switches to create a patch. The voltages from the modules may function as (audio) signals, control voltages, or logic conditions.

There are two basic kinds of modules: source and processor. The basic modular functions are: signal, control, logic/timing. Outputs are an electric voltage.

There exist many different types of modules. There are basic modules, and compound modules, a compound module being a single module made up of several basic modules internally wired together. Examples of compound modules include the envelope follower, sequencer, and vocoder. Modules with the same basic functions may have different inputs, outputs and controls, depending on their degree of complexity. Some examples include the VCO, which may have options for sync (hard or soft), linear or exponential frequency modulation, and variable waveshape; the VCF that may have both resonance and bandwidth controls; and the envelope follower which may provide outputs at each stage of the process. There are some standards which manufacturers followed for their range of physical synthesizers, such as 1V/oct control voltages, and gate / trigger thresholds providing general compatibility; however, connecting synthesizers from different manufacturers may require cables with different kinds of plugs.

Some standard modules found on almost any modular synth are:

Sources - characterized by an output, but no signal input; it may have control inputs:

Processors - characterized by a signal input and an output; it may have control inputs.

Modular synthesizers can be bulky and expensive. Due to the continuously variable nature of knobs and sliders, reproducing an exact patch can be difficult or next to impossible. In the late 1970s, modular synthesizers started to be largely supplanted in pop music by highly integrated keyboard synthesizers, racks of MIDI-connected gear, and samplers. However, there continues to be a loyal following of musicians who prefer the physically patched approach, the flexibility and the sound of traditional modulars. Since the late 1990s, there has been a resurgence in the popularity of analog synthesizers aided by physical standardization practices, an increase in 'retro' gear and interest, decreased production costs and increased electronic reliability and stability, the rediscovered ability of modules to control things other than sound, and a generally heightened education through the development of virtual synthesis systems such as MAX/MSP, Pd and Reaktor etc.

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