I’ve had Monoliths for 6 years now, and when the prodigies came out I seriously considered them. However, I just did not hear enough of a difference to convince me they were worth the coin.
Instead, I spent effort in getting the most out of the Monoliths.
First step, as you note is to ensure sufficient power, therefore I used a pair of 400w channels from the Sunfire Cinema grand signature amp just for the panels and another 200w channels from a Sunfire stereo amp for the woofers. Each going through the respective half of the Crossover.
Next step was to replace passive x-over with an Active system. After some iteration, I wound up with the DBX DriveRack 260. This allowed incredible control of the speaker and associated environment and totally transformed the Monolith. With this, it was head and shoulders above a stock prodigy.
Somewhere in there, I also found that the Woofer in my III’s were a bit flabby, so in went a new woofer. Currently recommend either of these two as the upgrade:
The
Peerless 830669 12". Ideal for 3 cu.ft., Dead flat out to 1.7K, 91+ db/watt (really) +/- 8mm xmax and a Faraday ring. A bargin at $75.00.
http://www.madisound.com/cgi-bin/index.cgi?cart_id=1916198.29527&pid=1946
Also recommended is the
Flexunits 12 B 77 25 10
With the woofer tightened up, the active Crossover and enough juice, these speakers can really rock. High SPL is no problem for these now. I even had to upgrade the Sub to keep up.