here's the deal; a Herzan is 500x stiffer than any passive device since it can 'stop' in 10-20ms.....passive devices have no ability to stop, they resonate....the Herzan's have 'essentially' no resonance. so while a passive footer is always a matter of whether it's compatible and complimentary, the active device is never adding resonance. it's merely reducing feedback and noise.
the Herzan AVI Series can be configured up to 9000 pounds. it uses at least 2 separate modules and one control unit with a 'stiff' shelf on top. not sure I want a tall heavy speaker (my MM7' s are 750 pounds-7 feet tall each) sitting on a shelf on two modules. and the whole 'look' would likely be a deal stopper for me.
the TS-300 stand alone table can handle up to 660 pounds. and it also has self leveling....whereas the AVI series does not.
so sitting on a concrete floor it would be the ultimate.
in the back of my mind I've always considered trying one under speakers. my problem is that both my MM7 towers are 750 pounds, and the AVI direction is not quite as elegant in use as the all-in-one TS series.
but there are lots of under 660 pound speakers in rooms with concrete floors that are candidates.
Great stuff!! I suppose at 575lbs each, the X1s qualify for sub-660lbs. I will look the TS-300 up. Thanks!