A MIDI controller is any hardware or software that generates and transmits Musical Instrument Digital Interface (MIDI) data to MIDI-enabled devices, typically to trigger sounds and control parameters of an electronic music performance. MIDI data includes instructions related to pitch, velocity, and timing of notes played on a keyboard, as well as general transport controls for a project such as play, record, and stop. MIDI controllers are used to control other MIDI-compatible devices, such as synthesizers, digital audio mixers, and complex guitar effects units.

The most commonly used MIDI controller is the electronic musical keyboard MIDI controller. When the keys are played, the MIDI controller sends MIDI data about the pitch of the note, how hard the note was played, and its duration. Other common MIDI controllers include wind controllers, which a musician blows into and presses keys to transmit MIDI data, and electronic drums. MIDI controllers can be populated with any number of sliders, knobs, buttons, pedals, and other sensors, and may or may not include a piano keyboard.

It is important to note that a MIDI controller generates no sound on its own. Instead, it sends MIDI data to a computer or other hardware, which then produces the sound. MIDI controllers are used to play other sound sources by wiring the controller’s MIDI output to the input of another instrument. MIDI controllers are the first piece of kit for many budding producers, owing to their flexibility, affordability, and tactile response.