Here are some thoughts after almost two straight days of burn-in:
wearability - these feel like large pillows. I have a rather narrow, pointy head, and the single bump problem on my AKG 701 was a concern after some reports in this thread. But, I've flattened the headband a bit and they are really easy to wear. They do slip, though, with lots of head movement. And, I'm pretty sure they look dopey on me. I don't care.
Isolation - very good, but not like an IEM. My gf has already noticed how she can call my name from upstairs and I won't hear her. Thanks, shure.
Build quality - excellent, except for the cord. They just feel very durable, very business-like. But, the cord is a problem, not so much because of the coil ( though I'd prefer without ) but because the jack into the headphone is HUGE and not at all what I am looking for into an iPhone or my Macbook. I like the locking feature but I had that it's proprietary. My #1 wish for these phones is that Shure will make a locking mini to 2.5 adapter, and allow us to replace the cord easily.
Sound Q - really coming into its own. At first listen, impressions were really positive, except for some really woolly, distorted bass. For ex, on "Song for Charley" off of Nick Cave's OST to "The Assassination of Jesse James...." I heard some distortion on low notes in the right driver that had me thinking i'd need to return them. I tried, but could not replicate the buzzing in any of my other headphones ( none high end at all ). Now, however, that distortion has disappeared, and the bass is starting to tighten up. Songs with a big, snappy drum ( say, Ants Marching by DMB ) are a real pleasure.
I've also been impressed with the dynamics. I've been burning in with my entire music collection, but also Pandora set to classical. Although not a high-end source by any stretch, some of the Pandora tracks have had such swings that I've been really, really moved. Very cool.
Clarity, however, is not up to the same level as my 701s. Looking back ( mine were lost in a move ) the 701 really didn't smear ANYTHING that you sent its way. A really beautiful, "dont know what you got til its gone" type of presentation. Now, that said, I dont think these are muddy at all - just not up to the high level of the 701s in that regard. Also, with the 701s, I would use the tone controls on my vintage Marantz integrated to apply some tube-like bass boost, but nothing of that sort is necessary. In fact, Im not sure these are a great match for tubes or warm electronics. They already have enough bass to make me happy without EQ.
I'm skeptical of major differences between amps, but so far these seem relatively easy to drive. I usually listen to them at less than three clicks on my Macbook and its loud enough. And, as they've burned it, I haven't heard any distortion when I really crank them.
.gif)
