A synth which is constructed from discrete functional modules (such as VCOs, VCAs, envelope generators, mixers, etc.), which the performer can purchase and install individually as needed to construct any desired configuration. The first practical synthesizers as we know them today, beginning with the work of Donald Buchla and Bob Moog in the early 1960s, were modular in construction.In a typical modular synth, all inputs and output within each module are accessible via jacks on the front panel, and are routed by the use of patch cords; there is no pre-defined routing. (If no patch cords are plugged in, the modular makes no sound.)
Because of this, modular synths are considered by many to be the ultimate in complex-sound creativity, as the number of possible signal routings in any non-trivial configuration is nearly infinite, and the system is fully open to interconnection with external devices at any point in the signal chain. However, this flexibility and lack of pre-wired connections makes this type of synth difficult to learn and to play.Also, the modular method of construction is relatively space- and cost-inefficient, meaning that a large configuration will require a substantial amount of time, space, and money to set up. (Among other things, this means that as a practical matter most modular synths are monophonic, as a polyphonic setup requires multiple copies of everything.)All current modular synths employ analog signal routing and most of the module circuitry is analog, although there are some digital processing modules available. Modular synths disappeared from the market in the 1980s, but since about 1997 have made a significant comeback, with over a dozen manufacturers currently active in the market.