What does a DI box do? Why use one?
A direct injection (DI) box converts unbalanced instrument level signals with high impedance (electrical resistance) into balanced microphone-level signals with low impedance.
The pick-ups on instruments such as electric guitars and bass produce a signal with high impedance, but we need to decrease the resistance via a DI box so we can run these signals through a mixing desk.
- What does a DI Box do?
- Do I need a DI Box for home recording?
- But in a professional studio…
- How does a DI Box work?
- What does a passive di box do?
- What does an active DI box do?
- What’s the difference between active and passive DI boxes?
- Common features you’ll find on a DI Box
You’ll usually find DI boxes on stage during a performance, though you can use them in your home recording studio. However, the reason you’ll see them on stages more than in studios is due to how unbalanced signals pick up noise over longer distances.
The point of a direct injection box is to convert an unbalanced signal to a balanced one while it travels through a long cable. So converting that unbalanced signal into a balanced one via a DI box eliminates the noise problem. As a result, DI boxes come in handy in larger venues on big stages with big PA systems. In fact, one DI box allows the signal to travel a distance of 100 meters (300 feet) without picking up noise! And a live mixing console is usually positioned 50 to 100 meters away from the performers. So a DI Box is a critical tool that sits between them that keeps the signal from bass and electric guitars and keyboards/synths clean as it travels to the mixing desk.
audio interface will have at least one microphone preamp built-in. This means you do not need a DI box to record with a microphone in your home studio as your audio interface does the same job.
As for instrument-level signals, audio interfaces have dedicated instrument inputs in the form of 1/4″ inputs that have a high impedance to match. Hypothetically, if you were to connect a high impedance instrument signal to a low impedance input you’ll chop off some high-frequency content which isn’t very desirable. But thanks to the manufacturers of audio interfaces, this won’t happen!
So no, you do not need a DI box for home recording if you have an audio interface.
But in a professional studio…
In contrast, you may find DI boxes in high-end recording studios. This is because instrumentalists record in an isolation booth which allows the microphone to capture the direct sound from the instrument with no background noise.
What are the different types of microphones? How do they work?