Dunlavy SC-IVa how best driven

I had a friend drive a pair of IV's with a pair of B&K M200's. He then added a second pair of B&K M200's (all amps sent back to the factory for calibration). The differnece was startling. I know these speakers are 91 db efficent. I know these speakers don't vary much in impedance. I know the manufacturer claims 150 watts max. I know the manufacturer doesn't think bi-wiring or bi-amping helps these speakers. I also know what we heard. The soundstage became enormous particularly in height and depth. There was an effortless quality to micro and macro dynamics that was both staggering and elegant. Vocalist became more coherent and dare I say human. Why such a difference? I don't know. Maybe we wanted to hear the differnce? Maybe the amps were running in class A longer? I don't know. I do know that it happend consistently, time and time again, even in different rooms.

Evo845 I believe the 150 watts max that I applied to the Dunlavy IV's came from Dunlavy's old web site. It was in context of recommended power not short term power capability. Yes the soundstage of the Dunlavys when set up right is huge. But my friend and I were not expecting this already huge soudstage to expand even more and with more dimensionality when doubling the amps/power from over 400 available watts to over 800 available watts per channel. The Dunlavy's don't necessiarlly seem to need a lot of power. But, obviously we agree, that the Dunlavys seem to enjoy the extra power. I only wish that we could have tried doing the same with amplifiers having a better "pedigree". BTW, the rest of the system included a CAL CD player, Sonic Frontiers Line 3, identical Wire World eclipse (balanced) interconnects and identical Wire World Polaris speaker cables.