I agree with everything Dan said. Your EP500 should blend well with the M80s no matter the crossover, it is then a matter of taste. I have mine crosses at 40Hz for 2ch stereo and 60Hz for multichannel to relieve the M80s a bit from the heavy bass found on movies.

Bruno
M80s/VP180/QS8s/EP600/AVR-890
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"The problem is choice..."