A breath controller device originally invented by Nyle Steiner in the early 1970s. The EVI, which stands for Electronic Valve Instrument, is a controller designed to duplicate the fingering of a trumpet, allowing trumpet and other brass players to play a synth using an interface familiar to them. Steiner had been a professional trumpet player, and was interested in designing a controller that he could use with his existing skills.

The EVI has, over its history, been offered by three different manufacturers, plus examples being built and sold by Steiner himself at various times. The original version was made by Steiner-Parker, the company that Steiner founded with Dick Parker in 1974. The first versions were basic, with three pushbutton switches that the performer fingered like the valves on a trumpet, and a breath sensor that sent a gate signal when the performer blew into the mouthpiece. At the front end of the device, hanging underneath the slim rectangular body, was the "canister", which served two purposes. First, it gave the performer a place to hold the device up with the left hand. However, with a turn of the wrist, the player could rotate it to expose a series of metal rollers through a window cut into the side of the canister. This allowed the performer to select which octave to play in; the octave was determined by the left thumb being placed in the "crotch" between two rollers, and changed by rotating the canister to move the thumb to a different pair of rollers. The EVI's mouthpiece could not sense vibrations of the lips (unlike a real trumped, the EVI does not rely on the player's lips being "buzzed", nor does it sense such), so the canister served as an alternate means of selecting the octave. This, combined with the combination of "valve" switches pressed, determined the note to be played.

Most of the Steiner-Parker EVIs were packaged with a modified version of a small synth called the Micrcon, a singe-VCO monophonic analog synth with a single VCF, VCA, LFO and envelope generator. A CV/Gate interface made it possible to control an external synth. As the EVI evolved, it gained additional control mechanisms; the wind pressure sensor became proportional rather than just on-off; a bite sensor was added (usually used to control portamento), and "trill" keys were added to shift the fingering in various ways to enable playing of runs in keys atypical for a trumpet.

Steiner-Parker folded in 1979, and Steiner took the EVI to Crumar, which began manufacturing it. This was essentially the same as the Steiner-Parker version, with a dedicated synth of Crumar's design being substituted for the Microcon. During the early 1980s, while Crumar sold this version, Steiner worked on a further improved version. Steiner worked with Jim Cooper to develop a MIDI interface for the device, and then continued to improve it, building and selling small quantities of this new design, plus adding the MIDI interface on a custom basis to Crumar-built units. Crumar folded in 1987, once again leaving the EVI without a manufacturer.

At this point, Steiner took his latest design to Akai. They combined the controller with a synth of a new design, having two layers with two VCOs each, and a variety of control options on the device. This became the EVI1000, the first Akai model. At the same time, Steiner finally decided to respond to the requests of woodwind players who wanted access to the EVI's capabilities, and he designed another controller with clarinet-like fingering. This was the Electronic Wind Instrument, or EWI, and Akai put into production an EWI1000 which used the same synth model as the EVI1000. Several later models followed; the 1400 and 1500 models became the first to achieve the goal of incorporating the synth circuits into the controller itself, eliminating the separate box with the proprietary interface to the controller.

As of 2017, Akai currently does not produce an EVI, but it produces three models of the EWI -- the 4000, 5000, and USB. The 4000 includes a virtual analog synth circuit, while the 5000 includes a sample playback synth unit; both models offer battery-powered operation with wireless connectivity for both audio and MIDI outputs. The USB model is strictly a controller, designed to interface with a soft synth running on a computer. All have several choices of fingering modes, including an "EVI mode" that duplicates the right-hand fingering of the traditional EVI (and hence a trumpet); although the EWIs do not include the canister, the octave selection mechanism is somewhat similar, consisting of a line of rollers underneath the unit which are selected by the left thumb.

Steiner himself continues to build EVI models as custom orders, in addition to offering various modifications for existing Steiner-Parker and Crumar units.

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