Paula,
To put some perspective on how the M3's relate to classical music, the bottom string on a double bass is 41 Hz (or on an acoustic or electric bass used in jazz/pop/rock). The M3s do a very nice job of reproducing that. In double-blind tests I've described the M3's bass as "quite good". The M2s I've rated "bass is decent but I want more--maybe a sub".
The bottom note on a grand piano is at 28 Hz. Those aren't played very often, but you will find them in some of Debussy and Ravel's piano pieces. (There is a special Bosendorfer grand, with an extra 8 keys, which go as low as 16 Hz, again seldom used). Even if the M3 doesn't go to 28 Hz, the higher harmonics will give you the impression that you are hearing a note that low.
Regards,
Alan
