[nst7]

If you are using a Clarett interface, there is no need to go into a separate controller like the Coleman. The Clarett can be configured for 5.1 monitoring by itself, in which you can use the main volume knob, mute and dim switches to control all 5 speakers and subwoofer.

For further surround control, you could get something like the Waves 360 surround bundle (on sale right now), which has plugins for bass management, and further specific control.