I'm using the Rolls Mini mix Pro-MX122
My vocals go into a Voice tone harmony-M unit,
the output of the harmony-M into one of 5 channels on the Rolls. The Ketron SD1 feeds into two channels of the stereo Rolls mixer.
Once in a while someone will ask me for a mike-to make an announcement or whatever-so the Rolls has one XLR input for a mike that I use for this purpose. My Barbetta powered speakers have tone controls -if I want to change the eq. The balance between voice and keyboard is set at home -so I just have to adjust the Master Volume on the Rolls for correct level when I'm out. The Rolls also has a phone/aux level control-so I plug my ear plugs into the 1/8 front panel jack for monitoring -and use the 1/4 front panel jack for recording with my Zoom H4. The Harmony-M unit is attached by Velcro to the Rolls unit along with a single power supply-also velcro attached to the rolls that feeds both units.
The mixer, Harmony -M unit and power supply -with short SD1 cables and Midi cable/pwr supply cable all fit into one plastic box for transport.