The BBE DI-400 4-Channel Direct Box is a professional-grade four-channel active Direct Input ("DI") box with a built-in Sonic Maximizer processor on each channel, the DI-400 employs the BBE 4th-generation processing engine. An "active" direct box, the DI-400's design is completely transformerless. Nothing to color the sound, its transparency reveals the free expression of the instrument's voice.