As far as impressions after only ~45hrs burn-in is that the treble is still very prominent and noticable. Comparing to my reference highly-modded JVC DX1000's, detail is a touch better on the JVC still, despite the
appearance of more detail due to the brighter nature of the HE-5 -- the way I am judging clarity is how clear and easy it is to understand various difficult to understand lyrics.
Despite good prat for an open can, the JVC is far better, especially since it extends to all frequencies as opposed to being limited to the lower half of the bass register on the HE-5. The HE-5's openness sounds great, but despite the JVC sounding more closed-in, the JVC still sounds much more natural, both in tone and in recording venue - e.g. studio recordings sound like they're in a studio and live recordings sound like they're in the open.
The biggest problem I have with the HE-5 at this early point (besides the crack), is that the JVC conveys increable emotion to the music and I get hardly any from the HE-5 -- (and I'm not talking about prat, but I guess 'musicality'.) The music sounds very good, but it's just
there, and doesn't pull me in.
Of course these are just initial impressions and will most likely change significantly with more break-in, and especially tailoring my configuration to these cans (eq settings, asio4all and foobar settings, tubes, etc.) I've owned the MAD HD-250 amp for four months now and have been trying different things the whole time, and only recently feel I've tweeked my system to the point where it can't get any better -- and I would expect something similar with this new headphone and amp.
BTW, I do like the EF5 amp - I'm using an Amperex tube in it right now. It's not nearly as good as the MAD, but I still like it. The HE-5's sound good out of the EF5; has bad bass distortion out of the Extreme; but sounds far better out of the MAD than the other two amps. I haven't done enough comparisons to describe the differences yet.
