Editing DI unit (section)

===Instrument amplifiers===
Some [[instrument amplifier]]s, particularly [[bass amplifier]]s, contain built-in DI units, and can be connected to a mixing console directly without needing an external direct box. This would be a typical setup for a bassist who wanted to connect their instrument through a [[public address system]] (PA system) or [[sound reinforcement system]] at a live show, while keeping the unique sound of the amplifier's [[preamplifier]] and [[Equalization (audio)|equalizer]] circuitry and the custom settings. In comparison, if an external DI box is used, with the bassist plugging their bass into the DI box and sending the signal to their bass amp, the DI box signal would be the direct signal from the bass' pickups. With the external DI box approach, the sound shaping added to the bass' signal on the amplifier (e.g. boosting the preamplifier, adding [[distortion (music)|overdrive]], or adjusting the equalization to change the tone) would not be present in the external DI box signal. Some instrument amplifiers have the ability to turn off the amplifier's equalizer (EQ) through a pre-eq/post-eq switch. This can be used if a "clean" direct output from the amplifier is desired, which does not contain the tone shaping created by the bassist's adjustment of the EQ controls.

It is common to use both a DI signal and a microphone in front of the speaker cabinet or combo amp, in both live sound and recording settings. One method is to connect a bass guitar amplifier's speaker level output (via a pad, to attenuate the signal) to a DI and then run it to one channel of the mixing console, and run a miked guitar speaker cabinet signal into another channel of the mixing console. Another method is to connect a DI between the guitar and the amplifier. The DI signal and mic'd guitar speaker can then be selectively blended, with the DI providing a more immediate, present, bright, un-equalized sound, and the microphone providing a more 'live' sound, with instrument amplifier and [[speaker enclosure]] characteristics and some room ambience (natural [[reverb]]).