So I bought a pair of these after spending a while looking for something to replace my B&W P5s. I've had a number of headphones in recent years (the most high-end of which was Grado's GS1000) but I picked up the P5s because I was looking for something smaller & lighter, with good isolation. I'm going to compare it with these because, here at least, they have the same recommended price. (though I did get the AKGs at a discount)
The P5s appealed to me due to their construction: mostly metal & leather with little plastic, a replaceable cable, and their premium styling. In less than a year though, the memory foam pads had worn thin, and combined with the tight clamping force of the headphones, they became painful to wear for more than an hour or two. The right headphone started "clicking" every so often (I think it was something to do with the hinge construction) the cable that runs down the outside of the left driver had come loose (there's actually nothing to hold it in place) and the main cable came apart—I will never understand why anyone puts a straight connector on a 3.5mm jack, 90 degree connectors have never given me a problem. Sure, the cable is replaceable, but put a 90 degree connector on there and you shouldn't have to.
I did like the isolation that I got from the P5s though, and the sound signature was great for film & games, which is more of a priority than music for me these days, and they're one of the first closed headphones I could stand to listen to. I've never liked the sound of most closed headphones, but I don't have the luxury of a quiet enough environment to wear open headphones any more.
So on to the AKG K550.
First impressions are almost the exact opposite of what I had with the B&W P5s. When you open up the P5s, you immediately smell the leather used on the earpads, which is incredibly soft when you pick them up, and the construction looks & feels great.
The AKG K550 looks cheap & plasticky in its box, is held down with twist-ties, and absolutely stinks of the off-gassing of the cheap pleather used for the padding. (at least that seems to be what it is) It's probably just my particular pair, but while I like the idea of the screw-on jack adapter, it's poorly threaded and doesn't screw on/off easily. As I am often changing between sources, I'll have to leave it off and use a standard 3.5mm adapter anyway. Oh, I should point out that due to the construction of the connector, I can't see it falling apart the way the B&W one did despite being a straight connector. (it's pretty chunky)
Once you actually get them out the box, they do look better when you see the profile and the design of the cups with the metal accents. They styling is good, it's the materials I object to.
The fit of the headphones seems pretty good for me. I think I must have quite a wide, but short head, because I often find that with most headphones, I don't have them extended very much, if at all, but I do usually need to stretch out the headband quite a bit to reduce the clamping force. (something I could never quite get right with the P5s, exacerbated once the foam wore thin)
I have both sides set to 3/13 (they're marked to 12, but have a notch below that) which puts my ears right in the middle of the cups, and I haven't had to do anything to the headband to reduce the clamping force, as I normally would. This seems to give me a pretty good seal, as pressing on the sides of the headphones doesn't really change the sound of them as some people here seem to have mentioned. Another thing about the construction: the right side works as intended, but I really have to pull hard on the left-hand-side to adjust them.
I was somewhat concerned by how thin the top of the headband looked, but I've had these on for four or five hours now, and it seems fine. The size of the cups, combined with the width of the band, and the overall design doesn't seem to put much force on the top of your head, unlike some of the other large headphones I've owned in the past.
While they are a comfortable fit though, they're still very big. Not as big as the GS1000 I had before, but they definitely shift around a bit on your head when you move, simply due to the size of them (though the pleather helps them stick in place more than real leather might have) After having them on for this length of time, I'm definitely starting to notice the weight of them—which was part of the reason I moved to the P5s in the first place. There don't seem to be any specific pressure points though; the GS1000 pads had a small contact area which could leave ring imprints on my head after having them on for a long time, and the top of my head would get sore due to the thin headband.
While the pleather pads are fairly soft, I'm not sure that they're soft [i]enough[/i] that I can wear these headphones with my glasses on for long periods of time—that's one of the other reasons I had shifted over to using on-ear heaadphones rather than circumaural ones. That's something I'll only find out after trying them for a few more days.
Isolation seems good, but maybe not quite as good as the P5s, to my surprise. Because it's a circumaural design, I was expecting them to isolate better than the on-ear P5s. Perhaps because it's pleather rather than leather, and there isn't such a tight clamping force?
So enough about that, how do they sound?
Keep in mind that I haven't spent a huge amount of time with them yet, but they're definitely the most "open" sounding sealed headphones I've ever tried. There seems to be a fairly good soundstage and positioning, certainly a lot better than the P5s in this regard.
The overall sound signature is actually very similar to the P5s they replaced, but with a bit more bass extension and treble. Bass doesn't seem quite as "tight" as the P5s though, it doesn't seem to hit quite as hard. They do seem quite sensitive and detailed headphones though, I'm noticing details on tracks such as subtle reverb/room echos that I hadn't heard before, even after playing them with many other headphones, and when driving them from my TV, you actually hear pops & clicks when it's changing resolution (as it temporarily cuts off the sound) which I hadn't noticed before. On a positive note. they're not so sensitive that there's background noise (hiss) which has been a problem with other headphones when using certain sources.
With clarity in the trebles, there's potential for sibilance though, and I'm certainly noticing a bit more "sparkle" in the upper end, but I don't know if I would call the headphones sibilant in the way that my GS1000s were, definitely not as sharp and piercing as those could get at times. I need to spend more time listening before I find out whether or not it would be an issue for me.
Overall, it seems like quite a well-rounded sound signature that is probably quite well suited for extended listening.
So I'm a bit torn about these. From what I've heard so far, I'm happy with how they sound, they're a good fit, and seem pretty comfortable.
At this price-point, I'm very disappointed with the construction though. They're solidly put together, but I would happily pay a premium for the same design if they used better materials; get rid of the plastic, and use real leather. Pleather only gets worse with time, leather gets softer and fits better as it ages. I can't see any way of removing the pads to replace them either. The ear cups are only attached to the headband at one side, which is another potential point of failure. (it seems fairly sturdy though)
I didn't realise that these actually had a fixed cable though; I thought a mini-XLR cable was a standard feature of all but the cheapest AKG headphones. (I must admit, I hadn't paid too much attention to AKG in the past, as most descriptions of them seemed like they wouldn't suit me)
I'm a bit unsure about the size of them as well. They're very big headphones, which is probably why they're so comfortable, but you couldn't get away with using these as portable headphones due to that, and the length of the cable, and I don't know how the weight will be for me, as I've definitely noticed neck & shoulder pain from wearing other large headphones and sitting at a desk using a computer all day. Probably not an issue for most people that have other large headphones though.