Found this on another forum:

In Reply to: Just purchased Axiom M50's - My God do I need a new amp? posted
by scottilad on July 26, 2002 at 12:56:23:

IMHO, you are using a bright speaker, and unless you turn up the volume to compensate for the fletcher-munson effect of low frequency loss at low volumes, this is what you get.

Also, the lack of a proper crossover on the midrange driver, An Axiom trademark, can cause some untideyness in the midrange.

A NAD amp may do the trick, they are rolled off and muffled sounding, but I would recommend and amp that is both rolled off and a generous in the bottom end.

A Jolida 1703 hybrid will do the trick. Jolida recommends this hybrid for bright speakers.

It has a big bottom end, and is rolled off on top, just what you need.

It is a TUBE mosfet hybrid,, cheers