You’ve just discovered Axiom’s most underrated speaker, despite what the reviews say, congratulations.
Maybe Axiom could make an pseudo M80 upgrade module for the M22s, say a cabinet about the height of the M22 with 2 woofers and a crossover. Connect it at the binding posts and set it under or even next to your M22s. You’d be missing the extra tweeter but could theoretically get close to an M80 in the height of an M22. I wonder if you’d need a different crossover if placed next to the M22s rather than under it to account for the different driver orientation. Now that would be a Franken-speaker.
