[hubert]

Yep, there it is... and it has been there since 2006?  At least januar 2007.

I have thought about an active bass system, but there is another issue present that remains fairly significant in my opinion.  The input impedance for plate amps is terrible - about 10k ohms.   This requires a very robust preamp that would add at least $1500 to any decent system.  And the preamp would have to have output cables for the plate amp. 

I tried an okay quality (Tweaked Foreplay) preamp several years ago and ran the cables through the plate amp and used the high-pass for the monitors.  It completely ruined the midrange quality.  It became very gritty and grainy - with no dynamics.

I really don't think there is a clear "winner" in this situation - unless there is a high quality plate amplifier with a high input impedance and very high quality active crossover circuit for the high-pass.  This would necessitate mono-block amps, or more RCA cable, but this is a minor concern in the grand scheme of things.  Do you know of a plate amp having at least 50k ohms of input impedance AND some degree of quality discrete components (i.e. no op amps) for a high pass? I use my sub without high passing the monitors, no need for me; but I do understand your wish in this matter (reducing the VC/cone displacement and therefore related distortions...IMHO overstated distortion type on 99% of the music types and in domestic environment). My Callisto1 from Sitronik Industrie has an input impedance of 47Kohms on the line input but I own an SKA integated amp without preamp for the monitors , thus I use the high power input of the Callisto (300 ohms) running cables to the speakers output of the SKA:
http://www.sitronik-industrie.de/frontend/dyn,pmode/eshop/shop.php?rub=h7&sub=subbooster&shopy=692cebdcca03e6be30dd37d7c904ffd5