D2 Standalone Deck and Mixer Control
Description and Instructions
Since TP3.1 the Performance controls (buttons, faders, encoders) on the D2 and S8 allowed for Override Factor Map option.
This map is for using the D2 to control Decks A & C as well as mixer functions for A&C Channel Gain, Volume, Filter, 4-Band EQ, and Cue, Cue Volume, and Master Volume.
The idea is you can use your computer audio out for sound and control it with the D2 Performance controls.
I actually use my Duet Firewire for Mains and my 2017 MBP headphone port for Monitor out.