Hello alm129,
I couldn't have said it better than JohnK's response, although you should remember that most of all male singing voices fall into the region of "upper bass"--from 100 Hz to 800 Hz or so--as do lower female vocals (altos, contralto, etc.).
This is a very important region and the M22ti's response through the upper bass is very smooth. Moreover, the M3ti has a noticeable dip in its on- and off-axis frequency response between 1 kHz and 2 kHz, which is audible, as is the M3's lesser output between 2 kHz and 5 kHz. This gives the M3ti a softer, more "laid-back" quality on a lot of instruments. The M22ti is very linear and smooth through these regions, which adds great detail and clarity, although pop CDs with aggressive treble will be mercilessly revealed. Even vocal mikes with sibilance peaks will be evident. But on smooth recordings, the M22ti's yield a fine presence and sense of realism.
Regards,
