All Acoustic. 600 watt head on bottom, 200 watt on top. The 200 powers the 4x10, the 600 powers both 1x15's. From my bass it plugs into the "active-in" on the 600, from the "passive-in" on the 600 I am using a 5" cable to the "active-in" on the 200 watt head. Is there a better way to do this? This way works and sounds pretty good, but I can imagine the possibility of signal/volume loss somewhere which is the one thing I really want to avoid.