Some very early impressions. Keep in mind that I don't believe in burn-in beyond psychological acclimatization. So for those of you who do believe in burn-in, these are still "un burnt."
Packaging on these is really nice. The box is thick and sturdy, with a plastic window in front showing off the headphones. Similar to the K701 / Q701 but more heavy duty. You get a single cable, which enters into one earcup rather than a dual entry with a Y splitter. The jack is a 1/8 that has a 1/4 inch adapter that screws on over it seamlessly. The cable is similar to the Q701's, but the plug is nicer with a soft powder metal finish.
The headphones themselves are built much nicer than I expected. They're definitely more robust compared to the Q701. Instead of plastic, you get metal and a sort of rubbery material coating various parts. Very classy given the price point. The headband is metal and a solid band rather than the wire arc assembly of the Q701. The headpad is a thin rubbery leather piece directly on the band rather than the leather strap in the Q701 assembly. It's neither here nor there in terms of comfort for me. If these were heavier cans, then it might put too much pressure on the head. But the cans are lightweight so it's not too noticeable. Pretty sure the earpads are synthetic leather. They're cushy though, and provide a comfortable seal that does a fairly decent job at isolating. Rather than the self adjusting arc assembly of the Q701, you get a manual adjustment mechanism on the K550. However there's a handy ruler on the headband that looks pretty cool as you adjust them, and the clicking mechanism is satisfying to work and tactilely responsive. Overall the Q701 are slightly more comfortable to me. They're lighter and seem to float on my head. The K550 is still comfortable enough to not be problematic however, and the slightly weightier feeling due to the better quality construction is welcome. The K550 definitely looks and feels like a classier headphone.
So how do they sound? Straight out of a MacBook Pro, they're a bit too bright. They're not painfully bright, but having listened to the Audez'e LCD-3 and Ultrasone Signature Pro all weekend it's definitely noticeable right off the bat. The sound is a little thin and brittle. Soundstage is impressive for closed headphones, perhaps smaller than the Q701's but not by much. It still has a nice dimensional feel to it. Mids are forward and sound rich, but not colored. Some of the delicacy of the Q701 seems lost, replaced by a more energetic presentation on the K550. One of the more noticeable issues is that the bass presence is rather lacking in impact and fullness, especially considering these are closed headphones. I'd say it's about the same as the Q701. Overall detail level is impressive at this price point, and from an analytic standpoint these are definitely capturing everything there in the music. Out of the Zana Deux SE the K550 gains some body and resolution, sounding more detailed and fuller, less thin. They seem less bright up top as well. Unfortunately the bass remains a touch anemic. Soundstage is is still impressive, gaining more dimensionality when amped, and while lacking some of the airiness of the Q701 it is still immersive.