ADDAC System ADDAC805. VS2 VC Signal Router Module
The Mono Sum output always mix Left and Right outputs together allowing the possibility to use the module as a peculiar 6 channel mono mixer. 4 quadrant mixing is achieved by using the stereo Master as a X-fader between left and right channels, this way you can plug 4 audio sources and sweep/crossfade between each and any of them using the 3 x-faders.