Hi redo,
If by "thicker" you mean "fuller", i.e. male vocals will sound a bit more resonant, even a bit "fat" at times, then the M3 is the speaker to choose. It has a built-in slight bass hump around 100 Hz so when it's compared to the M22, which is more linear in the bass, then the M3 does sound fuller.
If you want a more detailed midrange, then the M22 is the one to choose. The M3's mids are a little recessed by comparison to the M22's, although these differences are really only immediately noticeable when you do instantaneous switching between the two speakers.
Regards,
