The vocals on the IM50 seem to be a touch grittier than the 70. I auditioned both for a while, and that was the biggest point of comparison between the 2 IEMS: Vocal reproduction on the 70 was better. Also, it's been mentioned before, but these certainly aren't basshead IEMS, even though the bass hits hard. Bass decay is a little quick, and after some time I find sub-bass reproduction (which is more important for basshead gear IMO) to be pretty neutral. The great thing though is that the bass does not bleed into the other frequencies, after owning a bunch of bassy IEMs I just wanted something that sounded clear, and while it does look like the IM-02 and up are the clarity champs, the 50 and 70 can't be very far behind.
An IM-02 purchase is definitely on the cards for me, the 70s were a bit of an impulse buy and they were cheaper lol. Don't regret the IM70 purchase one bit though.
Edited by bedlamite - 3/5/14 at 2:29am