A DI Box, abbreviated from direct injection box, is an extremely significant piece of audio recording equipment. They can, however, be a bit puzzling for many people. DI boxes convert unbalanced, high-impedance instrument or line-level signals to balanced, low-impedance mic-level signals. But what exactly does that mean, and when and why would you need to do this? We will dismantle the nitty-gritty aspects in this article, taking a look at the various functions of a DI box.
The Significance of A DI Box
First, it’s vital to understand that various devices (mics, guitars, keyboards, etc.) produce different signals with varying signal intensity and output impedance. When connecting a device to an audio system or mixing desk, you have to be sure that it is connected to an input built to handle that particular signal.
Dedicated inputs for ‘Mic,’ ‘Instrument,’ and ‘Line’ type devices are becoming more frequent on current interfaces. You can attach just about any device to your interface if you have these three inputs.
The ‘Mic’ input is for receiving audio from a microphone. The ‘Instrument’ input accepts signals from electric guitars, electric basses, and electro-acoustic guitars. The ‘Line’ input is for receiving signals from electric pianos and drum machines.
But what if an instrument input isn’t available when you want to attach an instrument, such as an electric guitar, to your interface? And what if you don’t have access to the type of information that you require?
This is where a DI box comes in handy.
The Purpose of A DI Box
While not all interfaces and combining desks have all three types of inputs, almost all will have mic inputs. An XLR input is the most common of this type of input, intended to accept a mic-level signal with a low impedance.
Now you may want to link the signal from your guitar to your mic input. And a DI box is what will turn these signals into low impedance, mic level signals. As a result, you can utilize a DI box to transform your electric guitar’s high impedance, instrument-level signal to a low impedance, mic-level signal.
You can also use a DI box to connect any other devices that would not ordinarily be acceptable for attachment to a low impedance, mic level input (for example, an electric piano) to make them perfectly suitable for connection to a mic input.
Being able to transform a signal into a low-impedance, mic-level signal is incredibly useful because it is not uncommon to find yourself in a situation where you only have mic inputs available.
Sound engineers frequently use a stage box during live performances. That is where signals from the stage are sent to the mixing desk. In this case, the stage box will typically only feature low impedance, mic level inputs in the form of XLR inputs.
In a studio setting, the same is typically true, where a stage box may be utilized to send signals from the performance room to the control room in this case. Once again, low impedance and mic level inputs are likely to be your only option.