Robb, as John B. has indicated, any reports that you may have read about the bass response of the M22s may not be well-informed. The M3s certainly don't have greater bass extension; the slightly bumped-up M3 response in the upper bass lends what some consider to be more "fullness" in the bass, but it results from slightly overemphasizing fundamentals in the 100-150Hz area and likewise making 50-75Hz tones sound more prominant by emphasizing their 2nd harmonics at 100-150Hz.
My M22s, with room reinforcement, measure very flat with test tones down to about 60Hz, still very strong at 50Hz, and greatly reduced, but still usable, at 40Hz. I'd think that they'd serve very well as studio monitors.
