Chris, what you report will undoubtedly startle some readers. Both the Axiom speakers and the Yamaha receivers are allegedly "bright" and overemphasize the highs(both claims are nonsense), so in combination the highs would really be overbearing. It's difficult from your description to analyze what the problem in the setup would be, but neither the Axioms nor the Yamaha are in any way deficient in highs if they're operating as designed. Are you certain that the connecting links on the M60 terminals are tight so that the tweeters are actually operating? In the past this was the cause a couple times of "muffled" M60s.
