What is a DI Box and what does it do?
A Direct Injection (DI) unit converts unbalanced, high-impedance signals into balanced, low-impedance signals. This allows you to insert an instrument signal directly into a preamp, mixer, or recorder at the right impedance for cleaner sounds and less noise.
Do you need a DI Box?
DI boxes are used to convert an unbalanced, high impedance, instrument or line level signal to a balanced, low impedance, mic level signal suitable for connecting to a mixing desk or interface microphone XLR input. Essential for connecting your instruments such as guitars, keyboards or playback devices for recording or live applications.
Available in active or passive versions as a general rule of thumb an active DI box is best suited to passive instruments such as an acoustic guitar and a passive DI box best suited to connecting active or electronic inputs such as a keyboard. But either option can work with a high impedance input.
Which DI Box do you need?
The advanced signal routing capabilities and higher headroom make Active DI boxes excellent choices for electric guitars, keyboards, and instruments with active pickups. If you have a passive instrument, with no preamp inside it, an Active DI box should be utilized.
DI boxes can be used to take a line in from an electric guitar and won’t pick up the background noise that a microphone will.
What is a Passive DI Box?
Passive DI boxes such as the Dual Passive DI Box by Lambden Audio mostly use a balun audio transformer to convert impedance, electrically separate windings in the input and output stages isolate ground-level voltages and eliminate ground loops.
Simple, durable, and reliable, they only contain a transformer and a few resistors and remove the existing static from your sound. The simple circuitry easily isolates the signal from your instrument and converts it into XLR, with no noise added. The longevity of Passive DI boxes is incredible, and you can guarantee that they won’t let you down when you need them like the Radial JDI Passive DI Box.
You’ll never have to worry about battery life as they use the power from your instrument, no matter the length of your cord. As they don’t require power to operate, they attenuate signals instead of amplifying them.
What is an Active DI Box?
Active DI Boxes such as the ADI1 Active DI Box by Lambden Audio require a power source, some have a built-in preamplifier, some use 9V batteries and some have an AC power supply, but they all produce a stronger signal than a passive DI box without the signal level dropping.
They provide a direct injection of electricity into the audio signal and are normally best paired with passive instruments with low output and high impedance to boost higher frequencies. The lower the instrument’s output the more effective an active DI box will be.
The most common application for them is in the studio for instruments such as an electric bass with a passive pickup or a guitar with passive pickups, an acoustic guitar that does not have a battery powered output and can even be used with condenser microphones such as the Warm Audio DI Box Active.