Show dictionary · Audio
DI Box
Also: direct box · DI
A DI box (direct injection, or direct box) converts an unbalanced, high-impedance instrument or line signal into a balanced, low-impedance mic-level signal that survives long cable runs to the console. Most also isolate grounds and provide a ground-lift switch.
In practice
The DI solves the physics of plugging a bass, keyboard, or laptop into a snake: instrument outputs cannot drive 100 meters of cable, and unbalanced lines collect hum along the way. The DI’s transformer or active circuit fixes both, and its ground lift breaks the loop when a hum appears anyway.
Passive DIs (transformer only) are bulletproof and love hot sources like keyboards; active DIs need power (battery or phantom) and suit weak sources like passive basses and piezo pickups. Every stage box position on a corporate show grows a stereo DI eventually, because every presenter has a laptop.
How you’ll hear it
"Keys are stereo DIs on channels 11 and 12; lift the ground on 12, it is humming."
Related resources
Part of the eventools.io Show Dictionary, a free glossary of live event production terminology.