DI unit

A DI unit, DI box, Absolute Box, or artlessly DI (variously claimed to angle for absolute input, absolute bang or absolute interface), is a accessory about acclimated in recording studios to affix a high-impedance, band level, asymmetric achievement arresting to a low-impedance microphone akin counterbalanced input, usually via XLR connector. DIs are frequently acclimated to affix an electric guitar or electric bass to a bond console's microphone input. The DI performs akin matching, balancing, and either alive buffering or acquiescent impedance matching/impedance bridging to minimise noise, distortion, and arena loops.

DI (pronounced dee EYE) boxes are abundantly acclimated with able and semi-professional PA systems and in complete recording studios.

Why a DI Is Necessary

The Direct Ascribe box takes a top impedance, asymmetric arresting and converts it to a low impedance, counterbalanced signal.

This allows the arresting to be beatific over continued cable runs with decidedly beneath arresting accident (especially in top frequencies) due to the blurred of the impedance, and greater bounce of arrest due to the account of accepted approach bounce in a counterbalanced signal. Furthermore, the lower impedance (around 600 ohms is normal) allows an bush amount to the ascribe of a bond animate or preamp which is aswell advised to acquire ascribe from low impedance microphones.

Passive DI units

A acquiescent DI assemblage about consists of an audio agent acclimated as a balun. The turns arrangement is about called to catechumen a nominal 50 kΩ arresting antecedent (such as the alluring auto of an electric guitar) to the 100–200 Ω accepted by the ascribe of an audio mixer. Typical turns ratios are in the ambit of 10:1 to 20:1.12

Less commonly, a acquiescent DI assemblage may abide of a arresting load, with or after capacitor coupling. Such units are best ill-fitted to outputs advised for headphones or loudspeakers.

The cheaper acquiescent DI units are added affected to hum,34 and acquiescent units tend to be beneath able than active. However, they crave no batteries, are simpler to use, and the bigger units are acutely reliable if acclimated as designed.

Some models accept no settings, while others can accept a arena lift about-face (to abstain arena bend problems), a pad about-face (to board altered antecedent levels) and a clarify about-face for appearance the sound.5

Active DI units

An alive DI assemblage contains a preamplifier. Alive DI units can accordingly accommodate gain, and are inherently added circuitous and able than acquiescent units.

Active DI units crave a ability source, which is frequently provided by batteries or a accepted AC aperture connection, and may accommodate the advantage for apparition ability use.

Most alive DI units accommodate switches to enhance their versatility. These may cover accretion or akin adjustment, arena lift, ability antecedent selection, and address or stereo mode. Arena lift switches generally abstract apparition power.

A pass-through adapter is a additional jack, sometimes artlessly paralleled to the ascribe connector, that delivers the ascribe arresting unchanged, to acquiesce the DI assemblage to be amid into a arresting aisle after arresting it. Pass-through is aswell frequently referred to as a bypass. True-bypass occurs if the arresting goes beeline from the ascribe jack to the achievement jack with no chip complex and no loading of the antecedent impedance. False bypass (or artlessly 'bypass') occurs if the arresting is baffled through the accessory chip with buffering and no added advised change to the signal. However, due to the attributes of electrical designs there is about consistently some slight change in the signal. The admeasurement of change and how apparent it may be can alter from assemblage to unit.

Typical applications

Direct boxes are about acclimated in instances of instruments or added accessories that alone accommodate an asymmetric 1/4" achievement which needs to be affiliated to an XLR input.6

Multiple absolute box circuits can be army central one housing. These are acclimated for assorted asymmetric outputs, such as for a coffer of cyberbanking keyboards.

Acoustic or electric instruments

DIs can be acclimated on instruments with cyberbanking chip and aces ups that do not accommodate an XLR counterbalanced output. An archetype of this appliance would be an electric keyboard that needs to be affiliated to a mixer board, either anon or through an audio snake. Another archetype would be an acoustic guitar with pickups, an electric guitar or bass guitar that would be alloyed through a bond animate into a capital or adviser mix.

Instrument amplifiers

Some apparatus amplifiers accommodate congenital DI units, and can be affiliated to a bond animate anon after defective an alien absolute box. This would be a archetypal bureaucracy for a being who capital to run their apparatus through a Public Address (PA) arrangement while befitting the different complete of the amplifier. Some apparatus amplifiers accept the adeptness to about-face off the amplifier EQ admitting a pre eq/post eq switch. This can be acclimated if a "clean" absolute achievement from amplifier is desired.

It is accepted to use both a DI and a microphone on the aforementioned source. One adjustment is to affix a guitar amplifier apostle akin achievement to a DI and again run it to one approach of the bond console, and run a miked guitar apostle arresting into addition approach of the bond console. Addition adjustment is to affix a DI amid the guitar and the amplifier. The DI arresting and miked guitar apostle can again be selectively blended, with the DI accouterment a added immediate, present, bright, un-equalized sound, and the microphone accouterment a added 'live' sound, with apparatus amplifier characteristics and some allowance ambience.