A DI unit is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high output impedance unbalanced output signal to a low-impedance, microphone level, balanced input, usually via an XLR connector and XLR cable. DIs are frequently used to connect an electric guitar or electric bass to a mixing console's microphone input jack. The DI performs level matching, balancing, and either active buffering or passive impedance matching/impedance bridging. DI units are typically metal boxes with input and output jacks and, for more expensive units, “ground lift” and attenuator switches.
A professional passive DI box. It is passive because it does not need external power to operate. DI boxes which require a power source (batteries or phantom power) are called active DI boxes.
A vintage Wolfbox custom-made by audio engineer Ed Wolfrum in the 1960s.
A passive DI with "throughput" in addition to XLR output
An active stereo DI with pass-through in mono mode only
A recording studio is a specialized facility for recording and mixing of instrumental or vocal musical performances, spoken words, and other sounds. They range in size from a small in-home project studio large enough to record a single singer-guitarist, to a large building with space for a full orchestra of 100 or more musicians. Ideally, both the recording and monitoring spaces are specially designed by an acoustician or audio engineer to achieve optimum acoustic properties.
Control room at the Tec de Monterrey, Mexico City Campus
An audio production facility at An-Najah National University
A Mexican son jarocho singer recording tracks at the Tec de Monterrey studios
Neve VR60, a multitrack mixing console. Above the console are a range of studio monitor speakers.
