Violin typically are lower in pitch than the G-string; these strings are usually tuned to C, F, and B. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than , then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed
Electric violin to an independent MIDI channel. Most recently, Keith McMillen of Keith McMillen Instruments, a founder of Zeta Music, announced the StringPort polyphonic string-to-USB 2.0 converter for the Zeta polyphonic pickup and other modern polyphonic violin systems. Whilst no other dedicated violin-to-MIDI systems have been manufactured, more generic pitch-to-MIDI systems like those from Roland, and Yamaha can be adapted to use standard electric violin output. Most systems allow only monophonic operation—only one pitch can be detected and digitised at a time—but through the use of proprietary pickups, some limited MIDI polyphony can be achieved. Some pitch to MIDI interfaces from Axon/TerraTec