Just did a head to head comparison between the M15 and M20 with my a18Ts on some bass-heavy tracks (Brian Wood: Cantalope Island and Kevin Mahogany; Teach Me Tonight). I found the M20 to be overkill on the bass and a tiny bit muddy. The M15 has plenty of bass for me, and more clarity. Thanks for the great review of these great ciems. I am getting even more enjoyment from them now thanks to your review.

You are welcome! I am truly glad I could help.