Again, those NRC graphs are plotted on logarithmic scale and are rather small to look at.
Those graphs are ANYTHING but flat and they certainly are NOT identical.
Talking about the frequency response of 2 receivers that ARE identical on these graphs would mean they both look EXACTLY the same and just as flat as this:
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until they trail off at the lower or upper end of the spectrum.
The brightness perceived in the Axiom speaker could be due to any number of varying peaks shown in those NRC measurements.
