A DI box is a device that allows musicians to connect their instruments to an audio mixing board without adding undesired noise in the process. Most electronic musical instruments send out unbalanced high-impedance audio (i.e., the electric current faces high resistance, measured in Ohms), but audio signals travel better through wires that are balanced with low impedance (i.e., low resistance, as is the case with microphones using XLR cables). To prevent an audio signal from becoming too noisy on its way to the mixing board, we need a way to convert the unbalanced signal from an instrument cable into a balanced signal that can run to a mixer's microphone input via XLR. This is where a DI box comes in.

Watch the video (right) to find out more about DI Boxes.

There are two types of DI boxes on the market: passive direct boxes and active direct boxes. Active DI boxes need a power source, whereas passive DI boxes do not require power. Although they perform the same function—converting unbalanced high-impedance signals to a balanced XLR output—they operate differently and pair with different kinds of instruments.

Watch the vido (left) to find out more.

Summary

• Passive DI boxes increase saturation.

• Passive DI boxes have ground lift.

• Passive DI boxes pair well with active instruments.

• Active DI boxes serve as preamplifiers.

• Active DI boxes pair best with passive instruments.

With many DI boxes on the market, there are two main considerations to take into account when choosing one:

1. Figure out what kind of inputs you will be using. If you're working with a bass or a guitar, you'll only need a single-channel DI. If you're working with a keyboard, you'll benefit from a stereo DI, since most keyboards provide stereo output.

2. Choose a passive or active DI box. This choice comes down to the kind of instruments you'll be amplifying. Passive audio sources like vintage pickups and acoustic instruments go well with active DI boxes, and active audio sources like electric keyboards and powered guitar pickups go well with passive DI boxes.