I had the 6504's installed in a wall for several years as the rear channels for a 7.1 system. I then needed to replace my main speakers and not having much money laying around I decided to try converting the 6504's into main speakers. I wasn't expecting much but wow, what a nice set of speakers. Put in the right enclosure they can easily compete with more expensive mains after listening to several. I think the reason is because a lot of effort is put into providing deep bass for the mains. This is not easy to do and they compromise on the mid range and tweeter. But I read some articles touting that no matter what mains you have, you should always cross them over at 80 hz with the sub woofer to do all the heavy work. Providing of course you have a sub that can serve double duty. I have one of the Definitive Technology Trinity subs (no longer made), what a beast .. 2000 watts full power at 10Hz. So this sub can easily handle all of the LFE work and the mains. The 6504's are 4 ohms and when I first put them on my Integra amp, they really suffered to perform. I then purchased an Anthem MCA 225 and it easily drives 4 ohms with lots of reserve power for the 6504's. The best demonstration of this is to play a complex orchestral piece and at high volume listen to how clear and separate all of the instruments are during a crescendo .. it is amazing.