Originally Posted by stevekale
How much power is really needed? I feel you've really got to have a huge room to need much, if anything, over 200W (8R) unless you have grossly inefficient speakers. The distortion specs on the amp aren't spectacular but they've done a nice job keeping SNR high given 5 channels are packed into the same chassis.
Over the years I have found that within any single line of amp, for example Classe or Krell, etc., the more powerful amp will yield some consistent findings:
deeper bass and smoother high end, and a seductive "ease" to the sound presentation
wider and deeper soundstage with more defined layers within the soundstage.
I actually have rather intimate experience with the amp you own Krell FPB 200, or rather its big brother, FPB 300. Switching from FPB 300 to 600 in my system was a revelation, to put mildly. And this was no unreliable quick AB switching, I owned both amps for a long time.
This is NOT to say my findings will apply to all situations (as you've mentioned speaker efficiency and impedance, room, listeners' taste all come into play); one has to let his own listening test be the judge. So the answer is -- it depends: in my system, with main LCR running full range, it is AS MUCH AS my budget and the law of diminishing return deem appropriate.
Interestingly enough, I've found film mixers to become increasingly more "evil"
with low bass in movies, A LOT more, both quantity and quality, than we are familiar to in music. That silly movie with the guy running around with a hammer hitting people, Thor something, causes the second story foundation of my home theater to shake seemingly sideways, and I've read that when the housing structure feels like it is shaking, you might be in *loud* 15-25 hz territory (!). So if anything I am even more thirsty for power with movie sound. BTW, most if not all ultra high end speaker manufacturers (Wilson, Magico, etc.) would likely tell you similar story about more power never hurts.