about 6 hours now. popped them in out of curiosity.
my ears are in a conundrum.
call me crazy but bass wise. i believe the m4's beat the m2s. that sub bass did the trick. (meaning they work for dubstep)
i think the m2's "forward-esque" midrange is what makes it seem like it has more bass.
but depending on the type of music i'm listening to, i find there can be much going on in this mid section that the m4's don't convey. (like a loootta guitars. minus bass guitar). when i say they don't convey these sounds i don't mean they are absent.
i can hear it clearly on the m4's but on the m2's it's "in your face you can't possible miss there's this sound here" obvious.
this makes me lean in favor of those who say the m4 midrange is a bit recessed.
but then again. this is compared to the m2.
though that doesn't seem to affect vocals in the least bit to my ears.
I agree about the recessed mids, it's strange though, sometimes the mids sound recessed but at other times they are not, it really depends on what you are listening to. Like yourself, the vocals sound fine to me.