Yes I've read all of them.
But I am a long-time Audio-Technica loyalist, so this I'll be interesting (I won't be biased against K550; I am just interested to see how either of these cans compare against the traditional AT presentation, which IMO is defined by the likes of A9X and EW9)
I opened my A900X and am currently burning them in. Personally, I can assure you that many criticisms concerning the build quality of these cans is overly harsh and unwarranted. The craftsmanship is definitely there, and although I would have liked to see more metal than plastic on the frames, the housings are sturdy and well-made. The plastic bits are also high quality plastic, not "cheap" looking (the A900X is miles better than the A900 when it comes to construction quality and aesthetics, IMO - though I wished the appearance had a bit more punch like my A9X).
As for the biggest complaint most people had, which is the Audio-Technica "wing-support" design - I had
absolutely no issues in the comfort department with the A900X. They are comfortable, and doesn't slip off or press down on my ears due to weight. May be I just have a wide head. I've never had any issues with AT's "wings" in any previous models.
Chances are, if you had issues with previous AT "winged" models, you will with this one. If you didn't, then you won't.
Originally when I saw all the complaints regarding the A900X's wings, I thought may be they reduced the downforce of the springs to reduce pressure on the top of the head, thus causing the headphones to slip down. But I compared A900X's wings directly against my A9X's wings, and the downforce is exactly the same. So this is definitely not the issue.
The other complaint was how "flimsy" the wings are and they just kinda flop around. Katun's review especially tore it apart saying it's a step backward compared to previous wing designs. I examined the design of the wings carefully and determined the cause: It's a new implementation of the "3D Wing" design, likely done to make the manufacturing process easier. Let me explain:
- On the old, old model like the A9X, the wings only pivot in one direction (let's call it the Y-axis), which is up and down.
- On the A900, AT implemented the "3D Wings" which pivot in two directions (X- and Y-). The way they achieved this is by making the wings themselves into a 2-piece design - there's an "outer ring" that pivots around the Y-axis (like the old wings), and an "inner piece" that pivots back and forth (X-axis). This is actually a fairly intricate design and I imagine, harder to manufacture.
- On the A900X, AT simplified the "3D Wings" to ease manufacturing process while still retain pivots in both directions. The wings themselves are now back to a 1-piece design and pivots up and down (like the old wings on A9X), but the T-shaped joint where the wings are clipped onto the arms now pivots back and forth (in the older models, the joint is fixed).
The new design seems to be a bit more loose in the X-axis, which is why they wobble/flop around a bit, lending the impression that they are flimsy and not well-made. But I really don't find this to be the case - durability remains to be seen I suppose, but this really doesn't bother me.
Anyway, will report back with sound quality once they are burnt in.
