Contents overview
1. Competitors  (shure 940, denon d2/5/7k, akg k271, beyer dt770 (80/600) dt150, beyer t5p, ultrasone ed8, htf600, shure 840) 
2. Isolation
3. Leakage
4. Build  (looks, materials, portability)
5. Fit  (clamp, earcup+earpads, overall comfort)
6. Amplification and sources
7. Sound  (sub bass+bass, midrange, highs, soundstage, the akg sound, overall sound)
8. Conclusion
[size=10pt]* Note: I've put in a few possible Q&A's in this color. You may find them helpful.[/size]
 
 
I must say that this is a good headphone. But it takes a bit of time to appreciate it.
 
After a decent amount of time with the k550, I know what I think of it. First though i'll mention my experiences with some of it's 'competitors,' so you know a bit about my tastes.
 
 
 
 
1. Competitors
1.1 Shure 940
Reminds me a lot of the ath ck10 iems. Both sound great but to me are the only two headphones i've come across that I can't listen to. That 9khz treble peak induces a sibilance that I simply cannot cope with. And so I haven't really used this heaphone much, although I liked the crispness and air present around notes in the midrange (upper midrange). Crisp, punchy notes.
 
Anyway, the lacking bass was another problem along with the quite bad comfort. Them bumps on the headphone band are only meant to touch your scalp as the earpad clamp of this 330g+ headphone is what's meant to hold it in place. Oh, and them pads aren't the cushiest either. A bit too thin, and surprisingly heat trapping. 
 
 
1.2 Denon d2k/d5k/d7k
Smooth, relaxing and perfect for movies. Dynamic soundstage full of energy, with a satisfying sub bass. You feel real grumbles, and sometimes with other headphones i'm talking about here, this can be missed. But given bass heavy tracks and these can get a bit over excited and give me a headache. 
 
Nice spicy high end that for me borders on sibilant, but doesn't cross it. I'm just going to talk on the d2k out of the denons here, as the d5k-d7k just extend on it's all round character. 
 
 
1.3 Akg k271
My long time personal favourite of the closed headphone. But not the best sounding. Awesome vocals. Brilliant highs. With this I really get the feeling of i'm hearing all that's within the song (although it is 'missing' a bit on the sub bass, i've got to admit). But this brings me to highlight an interesting point. 
 
In all the a-b'ing (sometimes extremely extensive) i've done with all these headphones I can't really come to a comparison on the detailing each headphone is capable of. They're all the 'same' to me in this regard. Seriously. It's just different headphones emphasise different notes. 
 
Anyway, what really lifts these to my number 1 spot is truly unrivaled comfort. 240g with a leather, fully flexible large headband. No stupid bumps. Great amount of clamp, with thin, smooth and rather cool pleather pads. And there's plenty of ear room. I could go on and on, but I'll stop as I know you get the idea.
 
 
1.4 Beyer dt770-600/ dt770-pro80/ dt150 
The 'new' 600ohm's sounds like the dt770 pro80. They have such a sucked out midrange, it's unbelievable. Man, not an audiophile can for me. 
 
Even the dt150 were more to my liking than these. It just had a more uniform bass extension, tamer highs and a general more realistic tone/timber. Include in the fact that the midrange was present and it made for a better can than the dt770's. Wait- I'm not saying I really liked them. An extensively hyped bass left me feeling gloomy after listening in it's constricted headstage space.
 
 
1.5 Beyer T5p
The t5p sucked. Like a sour candy, that's past it's sell by date. I only had it for a very short while, before I wiped it clean and sent it back. So no real impressions, except that it's ugly in it's sound. Almost like a poor mans shure 940, except that it's four times the price.
 
 
1.6 Ultrasone ed8
The edition 8 is what i'd call the best closed headphone i've tried. It performs well all the way across the frequency spectrum and is unique in doing this. It's soundstage isn't small but it's not as large as the d5/7k (maybe with different amps?). All instruments are portrayed with a brilliant realistic energy that is simply hard to find elsewhere. Interestingly, on my first listen of this headphone, it overwhelmed me with dissapointment.
 
The comfort is slightly ear-size dependant but the stock rigid earpads do soften eventually, increasing comfort and sounstage. Oh, and if you happen to, by any chance, live around humans or anything else that makes noise you'll notice that it isolates remarkably well for a non iem.
 
 
1.7 Panasonic hft 600
Very comfortable hft 600. The k550 obviously beats these in SQ from top to bottom. And so by simple deduction it beats easily anything from beats, bose, bower & wilkins. End of this argument, if ever there was one or is to be one. 
 
 
1.8 Shure 840
Although I've never purchased these headphones, i've demoed them quite extensively. I'm only putting them in as I feel as they're really quite good competition to the k550's. Closed and isolating, and not far from the price of the k550, these share similarities in a lot more areas to the akg than the 940's do.
 
 
 
 
2. Isolation
(less than) < ultrasone ed8, t5p, dt770 pro80, dt150
(more than) > k271, shure 940, denons, dt770 600.
This isn't as impressive as it is important. I mean considering that this headphone grips the head quite lightly, isolation levels are pretty good.
 
Important?
It passes the main test in my book to distinguish a closed headphone from a non closed- Enough isolation. It provides more than satisfactory levels isolation for normal usage unlike say the shure 940. 
 
 
 
 
3. Leakage.
> ed8, dt770 80
< k271 (pleather/velour), denons, shure 940, dt770/600
 
My initial impression was mislead somewhat- coming from the ed8 it's easy to make that mistake. Yes, at normal listening volume for me, it's inaudable to the person next me. Well done here AKG.
 
 
 
 
4. Build
4.1 Looks.
An impressive all slick and slim black theme employed by the upper part of the headphone is rather spoiled by the elephant ear like earcups. I reckon it'll look a bit weird to strangers of headfi, but to us guys it looks good. Err, what doesn't. Audio technica alien cans anyone?
 
 
4.2 Materials.
- Impressive: refined metal headband and nice enough feel to the earcups and supports. 
- Not so impressive: Headband padding and earpad material. The padding is a bit too rigid making it feel as if it isn't actually there. It may loosen up a bit, but at the moment i'm not that impressed, as this headband is important for the earcups don't grip the head that much. I don't know- maybe i'm a bit too fussy. 
Anyway, the earpads, for me are plush and soft BUT they heat up a bit too much. I'm not fully sure but it feels like quite an inexpensive pleather really, but not anything as bad as ath a900's. Unlike the denons, this plushness whilst being very comfortable really does create sweat problems for me. To tell the truth, impressions after two/three days on headphone materials can be rather raw- I'll update after a week or two.
Fast forward 2 weeks and err yes, i'm too fussy. The headband causes no real problems and the pads' pleather is actually quite good. More comfortable, less sweat provoking than most other types of pleather i've come across (shure 840, a900, dt150 and cheaper headphones). I definitely prefer this material to velours on the beyer dt770/ akg k271 
 
[size=10pt]Q1. These have a weird smell out of the box. Is this meant to be?[/size]
[size=10pt]Well mine didn't at all. That's not to say I actively sniffed them, but I would have realised if such a smell existed. I mean, I have ears that are quite close to my nose.[/size]
 
 
4.3 Portability
I like the earcups swivel function designed to make them lie flat on the table; a nice touch making it much easier to put in your rucksack to transport to and fro the library for instance. Their overall build seems a tough one, so no initial concerns there. Extra points go to the k550 for the ruley and flexible left terminating cable that noticably has less microphonics than the k271's cable.
 
 
 
 
5. Fit
5.1 Clamp
The second least in my list. Denons have the least followed by these. Or is it.......
 
[size=10pt]Q2. These are way too loose for my head. Only for big heads is it?[/size]
The following paragraph may be the most important thing for you in this entire review, so please read it carefully:
Out of all of these headphones, the k550 is very unique in one aspect. The clamp is adjustable. Yes, I'll say that again. Without any mods at all, the completely new out of the box akg k550 allows, by design, for us to adjust the clamping force the headphone exerts on our heads.
 
How and why?
This is simple. You see the actual earcups can be moved in both the up/down and right/left directions (read below) BUT each 'change' you make to the inclination of the pads require application of actual force- using your hands. This is especially true for the up/down movement. Unlike other headphones where the cups are attached to a loose swivel hinges, these won't change shape once on your head as the force required to make this change, to make the earcups move, is far greater than the outward (normal) force that your head can provide- so there is no movement.
All this is largely independant of how you use the headphones left and right size meter (how big your head is!). 3 clicks on either side or 5, you can still change the clamp of the headphone by moving the earcups.
 
Importance?
Getting a good tight fit is crucial for good sound. When I first got these I thought they sounded awful. I had them ready to send back to amazon. The next day however, I couldn't believe my eyes when the earpads moved up and down after I pushed them. THEN I had the fit. THEN I realised what headphones these are. Gone were the tinny mids and highs, the bass deficiency and the grating highs. A few experienced headfiers I suspect haven't really played with the fit- as their final impression of the k550 is exactly what I thought of it when I first tried it out. 
Look at my profile and see the closed headphones I've owned. I'm not embarressed to say that I got fooled at first with the k550, as it's just so unique in this regard. You know what- I doubt that there is another full size headphone that functions like this...
 
Conclusion?
For a standard fitting akg k550 (the way i first wore it):
clamp strength:
>denon d7000 (maybe)
<all others
 
For how I wear it now (complete seal around me ears)
clamp strength:
> akg k271, beyer dt770/600, denon d2k, denon d7/5k, beyer t5p, shure 940 (maybe)
< shure 940 (maybe), shure 840, ed8, beyer dt770 80, dt150
 
 
5.2 Earcup + earpads
My ears just touch the driver cover. It's only slightly and isn't a problem at all, as is it with me with the dt770. The space for you ears is nice, but there seems to be too much of the padding coming in contact with the skin, exasperating the sweat/heat problem. I guess the extra ear space makes up for it in the end; I easily go beyond 3 hour listening in a room temp of 24 celsius without needing to take the headphone off.
 
An interesting point is that the earcups can be adjusted along both the x and y axis. You have the above mentioned swivel function allowing for around a 120 degree rotation in the horizontal plane. The outer hinges allow each cup to be rotated around 40 degrees in the verticle plane, up and down. Importantly, as i've said before, unlike anything I've seen before, you have to put a bit of force to achieve any rotation. Each movement feels rigid and holds it place- you literally need both hands free to adjust them, especially for verticle movement. I'm saying all this as I think it's important to realize that such rotations of the cups are possible, in the name of achieving a perfect fit in seal and comfort.  
 
 
5.3 Overall comfort
Very good. No. Extremely good, except for the minor sweat/ heat issue. The headband I feel I can get used to, but the slight problem with the padding material is probably here to stay. Maybe i've been spoilt by ed8's ethiopian sheepskin leather. Mind you, with the k271 the pleathers are thin and have a cold to the touch feel so I find the k271 to stay cooler. Obviously in comfort the k550 easily beats the raw, uncivilised, beyer dt150's/dt770's and anything shure can throw at it.
 
Combine with the large pads a very light clamp, an inoffensive headband and a very ruley cable- the k550 feels truley delicate to the touch. I must add that the weight of the k550 reveals a nice relief from the denons and the t5p's. At around 40-70 grams lighter, this can certainly be felt, and appreciated.  
 
These are true a comfort king.
 
 
 
 
6. Amplification and sources.
I tested with the nfb 12, samsung galaxy i9000 voodoo sound, pc-fiio e10. Nothing here feels as though they are underpowering or starving the k550.
Good, bad or inconclusive news? 
You decide.
 
 
[size=10pt]Q3. Hey! So do I need an amp for these or is it okay straight out of an ipod/ipad?[/size]
[size=10pt]This is a headphone of true sound quality- so it's going to show improvements when you use it with vaster systems than an ipod. I mainly tested this with the similarly priced nfb12, and for example I can hear an improvement switching to it from the samsung i9000. More horizontal soundstage extension. More controlled and extended bass, with tamer highs. Also notable when switching from mp3 players to desktop rigs, i've noticed that the presentation becomes slightly less forward (a good effect).[/size][size=10pt][/size]
[size=10pt] [/size][size=10pt][/size]
[size=10pt]What I still insist though is that the k550 is different from many acclaimed 'easy to drive' headphones in that it doesn't dissapoint when you downgrade your listening from say a mediocre desktop rig to straight out of an mp3 player. The denon d2k feel depleated to me from a cowon s9/sansa fuze/samsung i9000 and so does the ed8 to a large extent. The k550 are great in this apect.[/size]
 
 
 
 
7. Sound
7.1 Sub bass + bass
 quantity:
> k271, shure 940, t5p 
<ed8, denons, shure 840, dt770,dt150
 
No midbass hump. No sub bass hump. I think it's a level quality and volume on both ranges, making it better bass than the k271 and the 940. 
Simple. 
 
It has just enough bite to make it okay for movie watching, but brilliant for gaming. I mean, repeated gunshots and explosions with the denons are just a bit too strong for me. Oh, there's no leaking of bass either- leaking into other frequencies I mean. The latter point is what is mighty impressive with the ultrasone edition 8. It can host a huge bassline, yet absolutely to no detriment of the other frequencies. 
 
The k550 doesn't suffer from bass bleeds, and so isn't a dark headphone by a real measure. Interestingly, It isn't a bright headphone either. You'll see why I think this is interesting later
 
 
Q4. Is this a bass light phone?
What's bass heavy!? For most people i'll say it is a slightly bass light headphone BUT it's performance down here is stellar.
The denon's and the ed8/pro 900 have simply a too strong of a level of bass. The k271 doesn't emit sub bass to the desired level of many listeners. And the shure 940/t5p's are flawed in many ways here, with holes in the freqency coupled with an altogether weak presentation. A quite strong performer happens to be imo the shure 840 as it's bass quantity is at the level that shouldn't dissapoint the basshead or the more tender sorts of headfiers!
K550's bass is of a brilliant strength, very even from 40khz+ with no holes anywhere in the range of bass. With this all blended nicely with the lower midrange, the k550 gives a light but very satisfying bass experience.
 
 
 
7.2 Midrange
This is quite a weird one. 
 
Okay as we progress from the bass frequencies to the midrange, we have a midrange that's definately slightly 'laid back,'  but not recessed as it is in the dt770 (distractingly distant) or the denon's. Not really upfront or in the backround. Notes are not meaty, but not overly thin, sharp and metallic either. Just very smooth. It feels like there is a genuine lack of energy, but not a lack of resolution. Repeat: not even a 1% lack of resolution. I've switched over to other 'resolving' cans and haven't noticed anything other than improvements. But there's no doubting that this slightly un-dynamic midrange may make the headphone sometimes sound somewhat 'muddy' when it isn't. 
 
More about this lack of energy. Maybe this is a result of the forgiving and smooth, rather subdued, high range. And if it isn't it's probably coming from the position in the soundstage that notes take. It's like there is an in-built crossfeed effect going on as the blend between the left and right headphone channels is very impressive. Seriously, very impressive. 
 
Imaging is great, and you never feel lost in the large soundtage it has. Not better than the edition 8, but still good.
 
I'm in no way among the most experienced of closed headphone enthusiasts, but I've heard a fair share. I simply haven't heard anything quite like this midrange. Probably closest to the k271, but please don't interpret that as 'an improvement on the k271.' No, this entirely is a different beast.
 
 
Q5. Does the k550 have a recessed midrange?
No way. Well, you see, closed phones that have a large soundstage always face this question of whether or not their midrange is recessed. I'm talking about quality audiophile level phones here, as it's easier (or more common at least) for a phone that has a recessed midrange to support a large soundstage as opposed to a small one.
 
Recessed for me is defined by the dt770 range. Our ears have to squint to obtain information about what's going on in our listening sessions!  The denons are way better in that they present the details very satisfactorily, sometimes even emphatically, whilst endeavouring to remind us that things have been pushed back on purpose for the sake of a better musical presentation, not because of incompetence (the dt770 range).
 
Then there's the shouty headphones with an upfront middle presentation. Akg k271, Ultrasone ed8. The shure 940 is also friendly with this crowd sponsoring a very edgy presentation with a high level of attack, penetration, in the midrange through to the high ranges.
 
The k550 tries to take the middle ground. Quite like the shure 840's it offers more of a blend of notes rather than a series of distinct individual ones. In pure placement of the sound spectrum within the soundstage the k550 to me comes across as not recessed and not too upfront.  Balanced. Maybe a bit too uninvolving for some of you? A bit boring?
 
 
Q6. How good is the detail?
As good as you can hope for. I'm talking about the sensation of 'discovering' completely new sounds in your music, not changing the presentation of the notes you can already hear. Detail is obviously fantastic- but so to is resolution. The way it portrays this detail is impressive, especially considering it does this without being overly edgy or bumped up in the high range.
 
 
Q7. Uugh, a thin and metallic presentation. Yuck !!?
It's a thin (lacking in body) presentation, definitely. Timber and tone come into question and this is where I find the main faults of this headphone. Please don't confuse this thin, unextending, portrayal as something that makes the phone bright (i'll explain why later). Well, with the k550 for example it's sometimes tough to get a true sense of the emotion of a pianoist performing an immersive piece on a grand piano. It's just that the correct, or natural tone isn't quite there on a few occasions, giving this appearance of a genuine lack of energy. A half-hearted presentation almost.
 
 
 
7.3 Highs
sibilance quantity:
> dt150, ed8
<dt770, shure 940, t5p, k271, denon d2k
 
I don't know what to make of this. To me it sounds like akg here were trying to achieve the opposite effect shure were with their 940's. So much of modern music is unlistenable with the shure's, as with the t5p's.... 
 
Akg's k550's are smooth on the top end. No sparkle. If you like the crash of cymbals and the slish of tamborines, then these may dissapoint. Take for example when a singer breathes in. On the denon it may come across with a gust like force, on the shures it comes across very crisply. But here it may feel a bit too soft. Mind you, by the same token they can really impress.
 
I think I may have detected one or two weird resonances at first, but no.
 
 
Q8. K550 is a very bright and screeching headphone. What have you been listening to CantScareMe?
In my opinion it's doesn't classify as being truly bright. A bright headphone has an emphasised high range, a bumped up treble. K550 doesn't so it's not bright. It's high range sounds rather flat and purely because the entire headphone is highly resolving at every freqency level, rough parts (like sibilance) of the music will come through with this headphone. They'll come through BUT NOT EMPHASISED as they would with the shure 940, dt770 and the denon's even. That's why I call it a relaxing and smooth treble- nothing is exaggerated.
 
In all that I can detect, I've come across no real treble rolloff. So don't think by smooth, I mean it only because the headphone couldn't reach that high!
 
Ignoring possible problems with fit, I can only assume that it's the thin all-round presentation that gives it a bright appearance. I understand where you come from with that, as this will in many instances give us the impression of the k550 focussing too much on the higher frequency sounds.
 
 
 
7.4 Soundstage
size (estimate):
> shure 940, shure 840, t5p, k271, dt770's, dt150
< denon d2k, ultrasone ed8 (soft pads)
 
Very Very impressive for a true closed headphone that isolates and doesn't leak. Clean but not clinical. Okay, it's not larger than the denon d2k, but very close. Actually, it may be, as this soundstage is filled more densely with sound than the denon d2k's. I must from the outset say I like the denon's one better as it's more dynamic and energetic. Just more impressive and wowing. Akg's K550 fails to offer a truly immersive experience with real lushness as the notes are a tad too thin- opposite of the denon's which are still the sounstage king for me at this price. They really do it right, although at times I prefer the k550's as it sometimes sounds less left and right. Less separated. 
 
For me the shure 940 creates a fatiguing artificial soundstage present with far too much sparkle and crispy, crunchy, overemphasised notes.
You may say the shure exhibits these traits in the genres where badly recorded music prospers, but if we move to tame ambient or classical pieces, still for me the k550 wins, although not by such a large degree as before. I don't know how to say it. Actually I do! With the shure it feels like windows SRS WOW settings has been applied! There seems to be an echo everywhere, in pieces where there shouldn't be one. And as with SRS WOW, the highs are overpresent and just unbearable. It's almost like the bass AND the mids are recessed- as they are compared to the highs.
 
Needless to say, I much prefer the larger, more mature, akg's headstage to the 940 and the shure 840. I mean now I listen to mainly the k550, d7k or the ed8 and it's just too difficult to accept the constricted space the 840's offer to sound. 
 
Notably though the soundstage arena is where it leaves the k271 behind. After intensive A-Bing The k550 is clearly better than the k271 for music listening. It's just not this extension in the horizontal soundstage and new 3d sound space, but the main difference lies in the bass; a complete and great bass that the k550 houses really leaves the k271 and even the shure 940 wanting. Anyway, with the k271 we have vocals quite upfront giving the feeling they 'hog' the limelight- many times to great effect. This is slighly similar to the k550, although it's obviously less on the latter. I feel that sometimes though, on some albums, this can project an unnatural musical presentation, certainly bettered by the denon's that keep vocals firmly but happily 'lost' in the 3d soundstage. 
 
 
 
7.5 The akg sound  
Well, you can tell it's part of the akg family if you're familiar with the k271. Remember, this is their current reference closed can, but  they clearly are reluctant to make the k271/k272 extinct. 
 
Anyway, if it can be said that in many areas they share the same tonality of sound as the k271, then let it be. That's how I feel anyway. 
 
 
 
7.6 Overall Sound
This is one real relaxing can. A relaxing can that for once isn't bass heavy (denons), lowly resolving and overly dark. And no, this relaxing feeling isn't achieved by a hollow, recessed midrange either. Man, you can really pump the volume up without feeling the effects of an intolerable bass thump or a screetch in the highs. I don't like to use this word that much, but if there's ever a time I should, it's now; Neutral is how to describe the k550.
 
I love the way the large soundstage houses smooth highs and keeps everything at a great distance within itself. I've talked about the lack of energy in many areas, but this is special. It's on the opposite scale to the ultrasone ed8 in this sense, which sometimes can fatigue after long listening because of its thorough projection all the way across the spectrum. You will here it no matter what. Not like the k550 which employs a stance more like  'you'll hear it only if you want to.'
 
It's definately up there with the big boys, and I have no reason to give it bias. I've been trying to think of headphone groupings, if it were, like the {shure 940, t5p} as they have a similar presentation. I just can't think of anything to group the K550 with. 
 
 
 
 
 
8. Conclusion
So how does it rank in the closed headphone world? 
 
For me, It's definately one of the better headphones. Well, as a new years resolution I want to 'stop,' or partially stop this habit with getting new headphones. Okay, maybe for 6 months. 
 
But i've got to say, writing this review makes me question beyerdynamic. The over over priced t5p, dt770 80 and dt770 600 were massive dissapointments. Surely they can do better.............Maybe the T70p. That has to be good............Oh, and I've always wanted a set of custom earphones. It'll be the t70p or customs. 
 
 
Im not going to be drawn into ranking this with the others. I just can't see how I can do that. I can't predict your response either when you first listen to these. If you do have a listen- bear in mind one thing. Give it time. 
 
Your first impression shouldn't be your final one.
 
 
 
 
 
 
 
 
 
 
p.s I'm not sorry for the lack of pictures! guess where the £ for a camera went..
 

Nice work CSM.  So far I've used the K550 for jazz and acoustic blues music and they sound very nice.

I've been on the fence about these things since it's been announced, they look so nice and durable but it seems that they wouldn't do well on mids with such a laid-back mids would they?

Thanks
 
I proof read the review and made a few language tweaks. Sorry, I should have done that before posting.
 
A weak midrange is not what they have. Easily stronger in presence than the denon d2000. But it's not very lively and bursting with energy either. 

 
Quote:

they look so nice and durable but it seems that they wouldn't do well on mids with such a laid-back mids would they?

Click to expand...

 
Mids are the best thing from K550

Do they run loud enough straight from an iPod?

 
Quote:

Do they run loud enough straight from an iPod?

Click to expand...

 
Not enough for my taste.

When rapidly switching between the denon d2k, k271 and the k550 (using the audiogd nfb12), I'd only need to turn the volume up for the k271.
 
I've never had an ipod, but these are more than comfortably powered by the samsung galaxy s phone.

I think they loud enough strait from iPad/iPhone/iPod. I've compared them straight from i-device and via a amp...not that big of a difference in SQ to my ears...

Okay just a 'Last' update to my impressions of the K550. I think now they are fully formed, after having spent a week with them. Plus it seems like quite a bit of new folk are interested in this headphone, so I want to say a few basic things.
 
 
General discussion- Clarification of terms
- Portability
The k550 are 'portable' although they are not. Let me explain
 
Our definition, the working definition, of an open headphone is that it makes no effort to conceal sound or provide any isolation. So when music is playing, taking the headphone off would reveal the extent others at the same distance would hear the sound leakage. Now, this is exactly the same with 'semi opened' headphones, so what's the 'semi' all about? Well, it doesn't have anything to do with isolation and sound leakage, but only in a technicality about material dampening to enchance bass (or something similar). So in the technical definition semi-open and open are different, but to us in the working definition, they're the same.
 
To me, this portability thing suffers from a similar mixup of definition- between the technical and the working definintions. For us a headphone that is light, low profile, quite clamping, fixed on the head, isolating, easy to walk with.....  circumaural or supraural. But to me it seems as if the term portable to headphone manufacturers means to say a headphone that can be used on a long plane/train ride or say in the library. And for this it needs to satisfy two basic conditions:
a) Can be driven to a high standard by portable mp3/mp4 players.
b) Fit for private listening- isolating and non leaking
c) Transportable. It won't be damaged inside your rucksack. No ath wings. No fragile denon d2k cups.
 
 The akg k550 fits this definition comfortably. So does the t5p and actually quite a few other large bulky headphones.
 
 
- Closed
I still see people having come from open headphones, looking for closed cans (specifically that they can benefit from isolation and maybe a little sound escape) being recommended denons d2000. Even after all that has been said, this still happens today.
 
The denon range of d2/5/7k do not genuinley isolate people. Only slightly more than semi open headphones. They leak a lot less than open headphones, but at any ones normal listening volume, in a quiet room other people will be able to hear your music. At any standard listening volume, you'll be able to hear a cpu fan or air conditioning. 
 
My point is, by, again, the working definition of a closed headphone, the denon's (+ a few audio technicas) are not closed. Something like the akg k550 is a true example of a closed headphone. And another important point is that for manufacturers to achieve this closed stature, much sacrifice to sound quality has to be taken. The beyer T1's are among the best headphones out there. Just by closing this off (giving it isolation and no sound leakage) the qualities are ruined. Yet this closed T1 sells at the same price in the guise of the bitterly dissapointing t5p's. 
 
The only advantage the t5p's over the t1 is really in it's isolation and leakage property i.e it's closed. So make sure when buying closed headphone, this advantage appeals to you. If not- then look at open headphones.
 
 
- Initial impressions
I've never believed in burn in of headphone drivers. Haven't really experienced it. I've only included this section so that I can proclaim I've definitely experienced 'burn in of fit!' And this is why initial impressions, including my own of this k550, can be immature (I therefore, following the lead of many senior headfiers, normally listen to something over a couple of days before I judge it).
 
When you insert an iem in your ear on two different occasions, strictly speaking you haven't put them in the same way. So by function they shouldn't sound identical. That's the physical aspect, but you also have the need to experiement with different ear tips, which as you know greatly change the sound. Some of these tips change over time, like the comply ones, and this also changes the sound of your iem's.
 
It's a similar story with full size. You have to find the ideal placement of the pads around the ears, making sure that the seal is correct. The greatest way i've ever been able to change the sound i hear from on of my headphones is use different pads- the alteration is massive. This actually is an important point, because there exist a few headphones where the pads themselves change drastically over time and so have a quite significant effect on the SQ. The ultrasone ed8 springs to mind straight away- and maybe this is why in the headphone meets no one's been impressed by it. Hear one worn for 2000 hours on a sweaty head- then i'm sure you'll see its true colours.
 
This isn't true for all headphones though. Like the k271 pleather pads are rigid and don't realy change over time and velour pads, from beyers to shures to akg, I haven't experienced a noteworthy  SQ adjustment. Anyway, I can't see much happening with the k550 pads, but I only found a correct fit on my second day of listening.
 
 
 
 
 
Updates to k550 impression. More rankings included.
- Isolation and leakage
I've been able to give it much more of a long test, and I believe it performs better on the isolation front than I first thought. The headphone may feel loose in grip across your head, but this can be overcome to produce greater isolation, just by adjusting the tilts of the earcups. This can't be done on the denon's, k271 or the shure 940 for example. I'd rank them in isolation and leakage:
 
ultrasone edition 8
beyer t5p
dt770 pro 80 / k550, shure 840
dt 150
k271
dt770 600
ATH a900/ shure 940
denon d2/5/7k
 
 
- Comfort
These are ultra comfortable. I've got used to the headband, the padding is great and although the heat and sweat issue remains, it isn't a dealbreaker at all. A lot better than so many pads you get on sub £250 cans. Funny that whilst the pads do heat up your ears after time, sweat isn't as much of an issue at all. I don't find myself reaching for the cloth. Maybe its the creased & cushy nature of the pads surface absorbing sweat as it seeps out!
 
akg k271 / denon d7000
akg k550
denon d2000
beyer t5p
ultrasone edition 8 (softer than stock pads!)
dt770 600
shure 840
dt770 pro 80
shure 940
dt 150
ath a900 (unwearable- so loose and heavy. Nasty nasty pads.)
 
 
- Sound
I still think of them how I did in my first post. Remember this is a strictly competative world. Brilliant soundstage, or awesome imaging are only relative terms- relative to what else is out there. I mean if all monitor/media/pc speakers ceased to exist except the bose companion 2's, then i'm afraid they will be brilliant speakers. Because the next best thing is, errr, nothing!
 
 
Might as well give a rough ranking in terms of SQ.
 
1. Ultrasone ed8
2. Denon d7000
3.1 AKG k550
3.2 AKG k271
3.3 Denon d2000
4. Shure 940 (weaker bass than the k271)
5. t5p
6. dt 150
7. dt 770/ 600
8. dt 770/ pro 80
 
 
- Conclusion
Okay, that's my impression of the k550 done.
If it was a flop of a headphone- I wouldn't have bothered writing about it at all.
It isn't and in fact is a very capable headphone that i'm sure many of you will like. AND, of course, many will hate.
 

Thanks for your impression even if i m not agree with some points,lol.
 
For me, K550 isn't a portable headphone, but it must be a matter of head width imo and i don't find the K550 sound very good with just an ipod/iphone.
 
You find K271 more comfortable? The relatively small and circular pads (even if the K271 is an circum aural headphone) aren't very comfortable imo. I find K550 pads more comfortable but K271 headband is better,lol.
 
I never heard ED8, but i find many more headphones with better SQ than K550, but its of course, something subjective. I like K550 but there is better imo in SQ in this price range.

 
Quote:

dvdrey said:

 I like K550 but there is better imo in SQ in this price range.

Click to expand...

That's true. There obviously is.
 
But with this level of comfort and isolation (+ very little leakage), there isn't that much. I'm not sure if this is a strength of the k550 OR a general indication on the failings of headphone manufacturers to produce decent high end closed headphones. Sennheiser, audeze, hifiman, denon, haven't bothered. ATH's closed high end phones appeal to a unique head shape and don't have a headband. So it's really akg, beyer and ultrasone. Maybe a few other isolated examples (a sony or something).   
 
Anyway, I'm really averse to r shaped headphones. Some might say that rock is recorded like this and any true revealing headphone would output sound like the t5p or the srh 940. BUT, play these headphones with excellent recordings of live acoustic music, and calling on experience with loads of instruments myself, these headphones reveal to be simply not the real deal. The k550 is extremely well balanced across the frequency range. The notes themselves may appear to be thin, or some may hear some resonances and reverbs that make it sound tinny, but the good balance across the range is there to be seen. The midrange is also impressive.
 
 
And yea, the k271 I find the most comfortable. The headband is just too good. The clamp is light but not loose. And the weight is brilliant (like 240g. denon d5k is at 370g). 

 
Quote:

The k550 is extremely well balanced across the frequency range. The notes themselves may appear to be thin, or some may hear some resonances and reverbs that make it sound tinny, but the good balance across the range is there to be seen. The midrange is also impressive.

Click to expand...

 
Completely agree and more with your last sentence .

Thanks for the comparison thread!  One minor suggestion though - in commenting the direction in which beyer is headed in the end of your OP, you neglect to mention the well regarded dt1350's.  In my mind, these would seem to be the most direct competitor for the 550's.

 
Quote:

One minor suggestion though - in commenting the direction in which beyer is headed in the end of your OP, you neglect to mention the well regarded dt1350's.

Click to expand...

 
Imo, CantScareMe doesn't know the DT1350, we don't know all headphones,lol.
 
All mentioned headphones are circum aural (over ears), DT1350 is a supra aural (on ears) headphone.