Wind controller are replacements for wind instruments. They do not contain an air column like any real wind instrument. Thus the players air stream cannot excite an oszillation. Instead the air pressure is measured inside the controllers mouthpiece. The fingering is determined using switches or touch sensors. Additional sensors may be used to characterize the embouchure of the player. All this information is sent to a synthesizer module where it is available to create extremely versatile and expressive sounds.

The Akai Professional EWI 4000s is a newly designed wind controller. It incorporates touch sensor keys (no moving parts, no wearout) which enable very precise and fast playing. The breath and byte sensors encourage expressive playing. Unlike its predecessor models, the key sensor signals are processed digitally. Thereby it is possible to switch between different fingering modes. Using the current firmware operating system (version 2.3), the player can choose between four different fingering modes: The standard fingering mode of its predecessor model, two different modes for brass players, and a newly designed fingering mode for saxophone player. Operating system updates are simply installed via midi connection.