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.  

Added 4 Deck select using standard DECK+A/B/C/D deck selector feature which ALSO changes Deck Focus so that the EQ's change target to the Active/Focused Deck selected.

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.