On the treble side, I found something interesting with the Energy C3. The "listening window" curve for the C3 was reasonably flat up to 20 KHz while the corresponding curve for the Axioms dropped a fair amount between 15 and 20. The listening window is several curves averaged together so I took a look at the individual curves. Aha -- the C3 spikes UP fairly sharply between 15 and 20 KHz on axis, is flat slightly off axis and rolls off sharply further off axis. The result is a flat curve when you average together at the cost of pumped up high treble when listening on axis (which IMO is what matters).
M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
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