CV/gate

This method was widely used in the epoch of analog modular synthesizers and CV/Gate music sequencers, since the introduction of the Roland MC-8 Microcomposer in 1977 through to the 1980s,[1] when it was eventually superseded by the MIDI protocol (introduced in 1983), which is more feature-rich, easier to configure reliably, and more readily supports polyphony.

[4] However, numerous companies – including Doepfer, who designed a modular system for Kraftwerk in 1992,[5] Buchla, MOTM, Analogue Systems, and others continue to manufacture modular synthesizers that are increasingly popular and rely primarily on analog CV/gate signals for communication.

Many modern studios use a hybrid of MIDI and CV/gate to allow synchronization of older and newer equipment.

They are represented on the front panel of many synthesizers as knobs, but often a patch bay allows the input or output of the related CV to synchronize multiple modules together.

Trigger also has two implementations: Depending on the voltage level, connecting an incompatible triggering system will either yield no sound at all or reverse all keypress events (i.e. sound will be produced with no keys pressed and muted on keypress).

Since the publishing of the MIDI standard in 1983, usage of CV/gate to control synthesizers has decreased dramatically.

In order to facilitate synchronization between these older instruments and newer MIDI-enabled equipment, some companies produced several models of CV/gate-MIDI interfaces.

CV/gate is also very easy to implement and it remains an easier alternative for homemade and modern modular synthesizers.

There is less likelihood of hearing the zipper effect or noticeable steps in resolution over large parameter sweeps.

CV control is based on the audio interface line level outputs, and as such only supports a limited number of synthesizers.

Implementations vary widely and are not compatible with one another so it is critical to understand how a manufacturer is producing the CV before attempting to use multiple processors in a system.

Moog has facilitated this by producing two interfaces designed to receive and transmit CV in a system, the MP-201 (which includes MIDI) and the CP-251.

Examples of effects allowing the use of CV include delays (Electroharmonix DMB and DMTT, Toneczar Echoczar, Line6, Strymon and others), tremolo (Goatkeeper), Flange (Foxrox Paradox), envelope generators/lowpass filters/ring modulators (Big Briar, WMD) and distortion (WMD).