Just wondering if the following is true, not having seen any plots on this speaker.
SHL5s have a certain
relaxation in the region between
2kHz and 4kHz, with a return to
level above that, whereas the M
series are essentially ruler-flat
across this region. This dip in the
region of maximum hearing
sensitivity tempers aggressive
recordings, and arguably makes the
speaker more agreeable over a
wider range of material, though I
personally prefer the M40's behavior
in this regard. I n any case, the dip
gives the SHL5's sound a certain
character in the treble.