As an owner of M50s, M22s, VP150, and Michaura M55s(Axiom made bookshelves similar to M22s in confiuration built for another retailer) used for surrounds, I believe that the timber matching comments regarding the M50s and other Axioms with the 5 1/4" midrange are generally overstated. I cannot recall a post making this comment that was based on actual experience rather than the hypothetical idea of the mismatch. While I don't listen to much true multichannel music I listen to music almost exclusively in a four channel DSP stereo mode that uses the 3/4" tweeter and 2 5 1/4" midrange/woofers in the Michaura surrounds with the M50 mains. I don't believe anyone would detect any timber difference between the mains and surrounds. There is a really a quite small difference in the midrange presentation of the M50s and the speakers using the 5 1/4" midrange judging from the graphs. I think the difference is less one of timber than of the volume of certain frequencies presented.
I posit that in listening tests the difference in using M60s or M50s for surrounds would be one of a subtly different sound of one compared to the other rather than of any sense of disharmony.
It would be helpful to us all to hear what your impressions are after you have them all set up and listen for a while. I believe that you will be the first to judge based on actual listening to this combination.
