SF Cremonas with BAT VK 75SE

Effeciency as in 90 db is only a small item, the big thing is impedence. How much does it fluctuate? It is different all accross the sound spectrum and some speakers are better then others at this being constant, whatever it is. If in the bass notes it is 2 and 4 in the highs, or a difference of 50% it can be a rough load for an amp. However, size of room, volume, music played all mean something as well. It is far easier to drive speakers then a lot of people think. I drive QUAD 988s with 50 wpc. A little more power will, I would think, drive them a bit more easily, but I never feel like I am missing something. The VK-75se is an excellent amp and, for my money, beats VTL hands down. If you want the definitive answer however, contact Victor at BAT and the speaker manufacturer. They can tell you more then we can.