DIBoxen

DI boxes, or direct injection boxes, are devices used in audio engineering to convert high-impedance, unbalanced instrument signals into low-impedance, balanced signals suitable for recording consoles, audio interfaces, and PA systems. By transforming impedance and providing galvanic isolation, they enable long cable runs with reduced noise and are standard in live sound and studio setups. In German-speaking contexts, DI boxes are commonly referred to as DI-Boxen.

DI boxes come in passive and active variants. Passive models use a transformer to provide impedance matching and isolation without external power, while active models rely on a powered circuit to achieve higher input impedance and often a wider usable signal range.

Key features typically include a high-impedance instrument input, a balanced XLR output, and sometimes a through or split signal to feed an amplifier. Many units include a ground lift switch to break ground loops, a pad to attenuate strong signals, and a choice of input/output connectors. Output is balanced to ride through long cables with minimal noise; the impedance and level matching help preserve tone from guitars, basses, synths, and other instruments.

Common uses are connecting electric guitars and basses to mixers, recording interfaces, or stage sound systems, feeding keyboards with line-level signals, and isolating sources during re-amping or direct recording. DI boxes also help prevent hum and RF interference and improve repeatable results across setups.

DI boxes are standard components of modern audio rigs and are referenced as direct boxes or DI units in both professional and home studios.