Hi axiom_man,
As others have explained in this thread, when you set the M80s to "Small" and use a crossover frequency of 80 Hz or 60 Hz, it's a very gradual transition from the lower bass octaves to the subwoofer.
If you go up to the M80s when they are set to Small and play music with bass content, lightly touch the M80s woofers and you'll find that they are still producing bass output. But they don't have to "work" nearly as hard--the back-and-forth excursion of the woofer cones is much less--as the subwoofer takes up the slack and does all the bass heavy lifting, so to speak.
Set to Small, I find that the M80s used with a sub still have more lower bass "authority" than do the M22s used with a sub. I have both on a comparator in my living room and use 80 Hz as the crossover frequency when I make the comparisons.
Regards,
