I think Oofda makes a good point here. As long as you go low on the crossover frequency, most subs will end up integrating well. I use a Velodyne ULD18 crossed over at 50hz with the Maggie 3.3s running full range. I don't run my signal through the Velodyne Controller as I'm sure much will be lost...and my system is all balanced anyway. And I have also learned the link between preamp and amp is so critical so I don't want to add another cable to this either. I will soon solder capacitors on the input of my amp (ARC VT130) to create a first-order high-pass at 50 hz for the Maggies. This no doubt will clean up the Maggies significantly and give the amp more headroom for the upper frequencies without degrading the main speaker signal (except for another capacitor in series).
John
John