The first generation EVI (Electronic Valve Instrument) is for wind players to play and control synthesizers. The early models also came with their own case with a dedicated synthesizer module with 4 switches and 5 knobs.
The original unit only sent one cv signal by blowing through the mouthpiece. The gate was triggered by the pressure of the player's air through a sensor in the mouthpiece.
The mouth piece measured the air being blown through which did not actually flow through the instrument. A nice feature was the unit offered the same expression as a Trumpet the harder you blew the more dynamic the instrument was.
The EVI had keys and switches like a real Trumpet with thumb rollers and a canister on one end. The player could adjust and play the key and octave of a connected synthesizer by rotating the cannister in combination.
In 1998, Nyle Steiner completed and made available the world's first MIDI EVI! The MIDI EVI is a totally self-contained, trumpet-style MIDI controller which outputs MIDI directly from the controller thus eliminating the need for an additional interface box.
After he did some improvements/fixes on AKAIs EWI instruments, in early 2004 Nyle Steiner traveled to Japan and delivered a new EWI prototype to the Akai Japan engineers. Nyle consulted with Akai on this project. This resulted in what became the new Akai EWI4000s which was based on his prototype.