Stephane, there's doesn't appear to be any good reason for the M3 to have an actual bass advantage over the M22. The real capabilities appear to be nearly identical, but the M3 has a bit of a hump in the 100-150Hz area which gives an impression of more bass, even much farther down, by making the second harmonic of those lower frequencies louder.

-----------------------------------

Enjoy the music, not the equipment.