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AKG K 550


Pros: Looks, Build Quality, Decent tonality and fairly flat FR from midrange down to bass, no treble emphasis, decent soundstage for a closed headphone

Cons: Serious peak and resonance in one spot in the upper mids ruins an otherwise decent headphone


First Impression


When I first listened to these headphones, my initial two thoughts in this order were:

1. Wow these sound pretty fast and also fairly even

- 15 seconds later -

2. Wow something is wrong with the upper mids



who cares


Build Quality/Aesthetics

These headphones feel very well built.  I can't speak to their longevity or durability, but they are nice to hold, feel sturdy, the movements are tensioned well and feel solid, there's no creaking of cheap plastic.  The finish feels durable and well made.  One of the better headphones out there IMO for it's apparent build quality and finish. 


They look very nice when sitting on your desk, and in pictures.  A good design, but they are one of those headphones whose looks don't entirely translate to looking good when worn.  They have all the right shapes and dimensions relative to each of the parts, but the whole thing is just too big to look very good.  For their size, I'd say they don't look too bad as they are slim, so they don't stick out horizontally very much and give you the alien mind probe look that grados and many closed headphones do.  The headband is slim too since it comes together at the top of the cups, so it doesn't have that gigantic and unnatractive arc that the older AKG's have like the K240.  The headband hugs the sides of your head well.  Still, the cups are huge even on my big noggin.



Very good except that the earpads just aren't thick/deep enough.  Huge design flaw IMO because everything else was done very well for an extremely comfortable headphone.  The cups swivel in a really nice way since they have a good amount of friction in the movement, so you can place them at the right angle for your head, and they stay there.  Headband is comfy and is the right shape.  But the earpads aren't thick enough to keep the grill over the drivers from hitting your ears.  With such huge, soft earpads this is a pretty big fail IMO.  I tried putting the foam donut shaped inserts that Hifiman has in their earpads into the K550 earpads, increasing the thickness, and it had no effect on the sound and made them supremely comfortable by simply increasing pad thickness.  So as long as you don't have huge ears they should be fine.  Or if you don't mind a little pressure from the grills.  it doesn't hurt too bad on my big ears, but it just would have been so easy to avoid this situation.  I get the feeling they didn't do much real world testing on these and got carried away with computer modeling. 





They overall have a flat, balanced sound from bass to midrange with good tonality, and with a treble presence that is in balance with that part of the spectrum, which is very rare for headphones.  But there is a serious problem spot in the upper mids that ruins this headphone.  A resonant peak in a small part of the upper mids.  I would describe their overall sound as a slight rainbow shape FR, though leaning upwards towards the upper mids for enhanced sense of clarity.  They also can sound kind of fast for a closed dynamic.  Not ortho or stat fast by any means, and not Grado fast, but maybe 6/10 for speed.  Not bad. 



Good not great.  It extends down plenty low, it seems flat, there's no apparent midbass hump, bass does not bleed into the midrange or vocals in the slightest but is also well integrated with the midrange.  There's no "bass + mids"  or subwoofer effect where the midrange and bass feel separated by gaps in the spectrum.  They have a cohesive transition from bass to mids, likely from a fairly flat FR.  But bass is a bit low in quantity despite what the FR measurements suggest.  The bass is in the background on these phones, with emphasis on the midrange.  Not for bassheads at all.  Bass is not bad quality, but it sounds kind of dry and a bit soft, whereas better headphones have more definition and dynamics and detail in the bass.  Not bothersome, especially since it's in the background.  I'd describe the bass as being just enough to provide a foundation and not sound too lite, but too low to sound totally neutral- it keeps your attention on the midrange.  It gets out of the way so to speak, for better or worse.



I'd say the treble on these is very similar to the bass.  Good not great.  There's no emphasis in the cymbal range as far as I can tell.  If anything it sounds a bit recessed in the upper treble.  Nothing sticks out at you here or is glaringly bad.  But the treble is not that clean or precise sounding.  It is a bit rough/textured or papery sounding.  Like the bass, I'd say it's a backdrop for the mids.  Not a treblehead headphone either.  Yet despite this lack of apparent brightness, these phones have a strong sense of clarity about them.  I think this is what people like in this phone.  They don't sound dull or rolled off or warm at all.  Likely because of the slight lowering of bass volume, along with the emphasis in the upper midrange, the "clarity" range in the FR.



Here's the problem.  Both the bass and treble on these are both presented as a backdrop for the midrange but there's a serious problem in this area, so these phones wind up failling short for bassheads, and treble heads, and then have issues in the midrange.  First the good part.


The heart of the midrange and the lower midrange is done pretty well.  Vocals have both the proper richness for a male voice like Tom Waits or Chis Isaak, which is surprisingly rare- they don't make vocals sound thin despite the lack of bass emphasis.  They also don't sound overly rich at all.  Chris Isaak's voice sounds very good.  Vocals also give the proper air and breadth to female vocals like Emmylou Harris or the Audiophile favorite Allision Krauss.  But sometimes vocals reach up into the problem spot and sound off. 


Upper Midrange Issues
There is a spot in the upper midrange that has a pretty bothersome resonant peak.  I kept wanting to call it "glare".  The upper midrange glare isn't the most peircing or painful I've heard in a headphone but it is very bothersome and might be described as severely "jarring".  It doesn't seem to cause me to reach for the volume knob as feverishly as some phones have, but it does keep me from turning them up and leaves me in a state of fear wondering when something is going to hit this problematic range and if it is going to hurt, since it seems to be right on the threshold.  Any instrument in that range sticks out way too loud, and looses proper tonality as the sound in that range gets mangled by resonance and takes on a plastic tonality. You can clearly hear the coloration being added to what should be the original signal.  This is partly because it's such a specific problem spot.  You can sometimes hear an instrument or voice go up in the range and suddenly jab at you by suddenly increasing in volume while taking on this plasticky resonant glare.  The decency of the lower part of the spectrum gives it a "surprise attack" quality which is what generates the fear and hesitancy when listening.  If there was an instrument that existed only in this range, I am doubtful you would be able to hear what instrument it was.  Some recordings play well with this problem spot and it's not grossly apparent because of the frequencies being excited by that recording and the particular balance of the recording (if the recording has a peak in that spot too, it's clearly going to be worse).  But even on these recordings, this spot gives the whole spectrum a cheap plastic headphone feel kind of layed over the sound, as if you are listening to some very good throw away headphones.  I kept thinking of them as the best airline headphones ever.  Much better extension, tonality, more flat, but still plastick-y. 



Overall good size for a closed headpone, has a spaciousness about it, but there's something strange about it as well.  It's almost like there are 2 soundstages happening at once, the lower part of the spectrum sounds more spacious to me than the upper mids/treble, which sounds more constricted.  This gives them a lack of coherency, or a kind of bad crossover effect, where the sound is a bit disjointed.  I think this is because the resonance artifact in the upper mids destroys soundstage by getting in the way of the "trick" the headphones are playing on your perception.  Soundstage is also destroyed by a "driver dildo" that was installed on the back of the driver creating a tiny chamber behind the driver rather than the comparatively larger size of the earcup.  I'm guessing it was placed there in an ill conceived attempt to control the bass, but I have modded a pair of these by removing this dongle, and correctly damping the cups, and the soundstage becomes more coherent. 



Good looking, sturdy closed headphone that is fairly comfortable and has a mostly well balanced, even sound except for a very problematic part of the upper mids that sticks out sorely and ruins them. However, this part may not bother everyone.  If it doesn't bother you ie if you're not sensitive to resonance or FR irregularities, and you are looking for a well balanced headphone erring on the side of being a bit basslite for the sake of clarity, and you want good soundstage these may be a good choice for you.  If you are not bothered by Grados you may not be bothered by this resonant peak.  however, Grados have much more natural tonality, for example vocals sound more life like.  I recently had an MS1 here and despite their colored signature they sound better than the K550 in every way except may soundstage width.  There's no plastic tonality in the MS1's signature. 


Here is a picture of the inside of the K550's cups.  The lack of damping here contributes to the resonant peak, but after spending time with my modded pair which has damped cups, I have found that it is also being caused by the driver itself.  Damping the cups helps, but doesn't fix the problem.  The small rubber thing in the middle of the light gray circle around the driver, is the "driver condom".  This seals around the driver and makes a small enclosure size behind it.  The light gray area are vents, though they seem to be closed off with solid plastic.


AKG K550 inside the earcups- stock. The small rubber thing in the middle of the light gray area around the driver, is the "driver dildo". The light gray area are vents, though they seem to be closed off with solid plastic.


Pros: Linear, smooth bass with great extension. Manages to sound fairly neutral while still maintaining good musicality.

Cons: Multiple issues in treble region. Mids are thin and lack body or presence.

Comparison Review: ATH-A9X, ATH-A900X, AKG K550

Edition 2


I have decided to update this review, not only because I've spent some more time with both the K550 and the A900X, but because I found frequency response measurements for both of them on Golden Ears. I know not everyone likes the way they measure, but since there are no professional reviews of A900X other than on DigitalVersus, and since you shouldn't compare measurements taken by different websites/reviewers, I felt this was the best course of action to take.  I have also updated/adjusted several observations in the sound quality section, a lot of which I feel is much more quantifiable now that I have reliable graphs from the same source to look at.


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1. My Audio Preferences:


  • I listen to mostly new age and orchestral pieces, so natural/realistic instrument presentation and strong vocal performance is important to me (good timbre).
  • I like rich and lively sound presentation. So warm, pronounced mid-range; clear, sparkly, but unoffensive treble; and tight, controlled bass (that isn't overly loud).
  • I dislike over-abundance of bass. My ears are very sensitive to bass; headphones with bass-emphasis make my ears uncomfortable very quickly and gives me a headache after a while (to put things into perspective, the Superlux HD668b is considered bass-heavy by me).
  • I've been a long-time Audio-Technica owner, because their traditional sound signature is very much in-line with what I like: Rich, full-bodied, warm and engaging, with an emphasis on mids. The treble and bass presentation are typically pleasant and unoffensive on the AT's that I've tried. Aside from its narrow soundstage, my old ATH-A9X has always been my absolute favorite for music listening.


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2. Reason for Choices & Purchases:


While I love my ATH-A9X, I have been looking for a worthy upgrade that will improve upon its main weakness - the narrow soundstage (as well as having just a bit more substance in the bass region - the A9X is pretty bass-shy). After some research, I narrowed it down to two cans: The Audio-Technica's own ATH-A900X, and the AKG K550.  Both of these are hailed as having very expansive soundstage for closed-cans, and both supposedly have a warm, "musical" presentation. They are reported to sound fairly similar to one another, according to several Head-Fi'ers.


While professional reviews of the AKG K550 are abundant in the English-speaking side of the world, reviews for the ATH-A900X were unfortunately very hard to find. The only two good reviews I found were the one on DigitalVersus (an European site) and one by our fellow Head-Fier, Mysteek.  Impressed by the sound frequency measurements posted by DigitalVersus, I ordered a pair of A900X from a Japanese merchant on Amazon.


While waiting on the A900X to arrive, I noticed a few "comparison reviews" between it and the AKG K550 here on Head-Fi, most of which favored the K550. But opinions regarding K550's sound quality varies very drastically, and since sound is such a subjective experience, I decided the best way to determine for myself whether or not the K550 truly is superior in every way to the A900X is to listen to both of them.


So, having found a good deal for an used pair of K550 on Amazon, I placed my order.


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3. Objective of This Review:


The most detailed comparison review done for the A900X and K550 was written by Katun, whose neutrality I personally found questionable (not just the kind of word choices used in the review, but the attitude toward a few people who disagreed with his assessment).


That said, there's nothing more subjective than asking someone what "sounds good" when it comes to audio equipment - not only do people's tastes differ, but I suspect people's hearing ability also vary greatly - for example, I sometimes wonder if bassheads have poor bass perception, which is why they need their bass boosted that much... tongue.gif Okay that was a bit rude, for which I apologize.  But in all seriousness, it is very possible that people who listen to bass-heavy music on bass-heavy equipments all the time suffer from hearing degradation, which affects their subjective listening assessments.  This is why when I look at professional reviews, I like ones that are accompanied by graphs of actual measurements.


While I have no measuring equipments on hand, my hearing should be fairly "undamaged" (I don't typically listen to music very loud, and I am very sensitive to both sharp treble and loud bass), so my goal is to (hopefully) provide a neutral, unbiased assessment of the aforementioned headphones - not just by my listening experience alone, but by comparing them against the various reviews of them, both on the forum and on professional sites, and see if there are any consensus (to ensure that it's not "just me" that's arriving at these conclusions).


If you have either the A900X or the K550 on hand, and have a measuring equipment that can confirm my analysis, that would be great!  For now, I will be attaching the frequency response graphs from Golden Ears in my comparison.


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4. Burn-in Status:


Both cans are fully burnt-in for this review (100+ hours); I now own both cans for over a month now.


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5. The Scoring System:


I will be using a scoring scheme to assign points to the "winner" in each category (between the A900X and K550).  The score listed at the end of each category is the number of points assigned for that category only - the total number of points will be tallied at the end of the review. The old ATH-A9X will also be mentioned for comparison, but it will not be participating in the "match" since it's an old model that nobody likely owns in the U.S. and Europe anyway.


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6. The Review:


I. Packaging & Presentation:


Audio-Technica ATH-A900X: The A900X comes in a fairly subtle and classy paper box. The kind of cardboard used on the packaging isn't as thick and sturdy as those used on the AKG packaging, but it doesn't really hurt the presentation. What does hurt the presentation of the A900X a little is the plastic piece that held the headphone in place and kept the cups separated - it's made of thin and cheap plastic and looks a bit tacky in context of the otherwise excellent packaging.

AKG K550: The K550 has a stronger, more aesthetically-pleasing presentation in my opinion. The box is made of very heavy duty, thick cardboard that is surprisingly hefty. The plastic holder is covered by a layer of velvet finish, which lends a strong sense of elegance and class. While the packaging of the A900X is not shabby in any way, it lacks the same kind of presence K550's packaging has. Opening the K550 is akin to unwrapping a piece of expensive jewelry. This round goes to AKG.


Score: A900X - 0, K550 - 1

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II. Design, Aesthetics, Materials, & Craftsmanship:


Audio-Technica ATH-A900X:

  • The A900X is not a pair of bad-looking cans by any means, but it also doesn't look extraordinary. It just doesn't stand out as something classy or luxurious. I don't love it, I don't hate it. It's better-looking than its predecessor, the ATH-A900, at least.
  • I don't have any complaints about the craftsmanship of A900X - it's well-designed and constructed, and though I wished for a bit more metal than plastic on the frames, the plastic doesn't look or feel cheap. These looks like sturdy and durable cans.
  • One particular thing that Katun complained about repeatedly was the "poor quality" of the wings on A900X. I took extra effort to look into this issue, and did not personally find his claims to be true. Below are my observations:
  1. 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.
  2. 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.
  3. 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). This new system is slightly looser, giving the appearance of flimsily-build wings, but I personally don't find the design or construction to be lacking in quality.
  • That said, materials used on the A900X could have been better. I read in a Head-Fi post saying that A900X's stock earpads are the same as the A1000/A900Ti, but that is not true (because I just replaced my A9X pads with the A1000 pads, and I am 100% certain they are better quality than the A900X). The pleather used on the A900X earpads are of a cheaper, stiffer material - similar to the kind used on the Superlux HD668b. The headband's wings still use fabric padding, while my old ATH-A9X has pleather padding (which feels more classy). I feel like in the materials department, the A900X sits squarely between the A900 and the A9X - definitely a step up from A900, but not quite back to the glory days of A9X.
  • One design nitpick - the audio plug used on the A900X is the exact same one used by the A9X; while it isn't bad-looking, it is a bit outdated in style, lacks elegance, and doesn't blend with the design of the A900X. Audio-Technica really needs to update this on their next product cycle for the Art Monitor series.


Audio-Technica ATH-A9X:

  • In comparison to the A900X, the A9X is a lot more eye-catching. It's a bit "out there" in terms of design, but imagine seeing these cans back in the mid-90's - they must have looked sharp.
  • In terms of craftsmanship, the A9X is on the same level as A900X. It's very sturdy, though to be fair, it has less moving parts (the cups don't pivot vertically, and the wings don't tilt in both directions)
  • The materials used on the A9X is superior to the A900X. The stock earpads used the same kind of soft, supple pleather as the A1000/A900Ti pads. The padded wings are enclosed in thick, durable pleather as well (mine hasn't cracked after 10 years), which just looks better and blend in with the earpads when the headphones aren't in use.
  • The fabric used on the audio cable is the same as on the A900X, but it's colored a deep brown to match the color of A9X's frame. It looks gorgeous, and more classy than A900X's black cord (which can easily be mistaken for a typical plastic cable if not examined closely)


AKG K550:

  • Oh my goodness... where to even start. I am sure I am not the only one who was blown away by the design and aesthetic value of these cans. The K550 is hands-down one of the most beautiful set of headphones I've ever laid my eyes on (right up there with my favorite AT woodies).  All the lines just melt into one another... a true work of art. AKG wins out by a huge margin here.
  • Craftsmanship on the K550 is good - that is, as far as I can tell (there are complaints about the swivel mechanism snapping easily because it's simply glued-on, and the headband seems to be very loose in general and lacks clamping force. This I observed as well). One thing I did immediately notice was that the swivel mechanisms are fairly stiff, and therefore the position of the cups tend to "stick", and often don't conform to the contours of the wearer's head automatically when worn. The headband is fairly loose and does not provide a lot of clamping force, which doesn't help the problem.  This, I suspect, is the reason a lot of people have trouble achieving good seal on the K550. What the user needs to do is center the cups before putting them on, or at least adjust them after you put them on so they are flat against the sides of your head. Otherwise, I can find no issues with the craftsmanship here... I'll call this a tie between AKG and Audio-Technica.
  • When it comes to materials, I cannot be happier with the K550. The cups and frames are almost entirely metal, so is the headband. The type of pleather used on the earcups and the headband are top-notch, and the type of padding used for them also feels very good - they feel like high-quality memory foam rather than the regular type of "cheap" foam used by most headphone earpads. Lastly, the audio plugs on the K550 are simply gorgeous - AKG spared no expense at making the K550 look and feel luxurious. AKG easily scores a victory here again.
  • One material nitpick - the plastic used for the signal cord, while fairly high-quality, is still more prone to tangle and deform in comparison to Audio-Technica's fabric-wrapped cords, which retain their shape very well. Not going to discount AKG here though.


Score: A900X - 0, K550 - 2

(Two points awarded to AKG for winning "Aesthetics" and "Materials"; no points awarded to "Craftsmanship" due to a tie)

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III. Comfort & Isolation:


Audio-Technica ATH-A900X:

  • While a lot of people have reported comfort issues concerning the A900X (specifically due to the wings system), I personally found it to be the more comfortable of the two. The wings do not put pressure on the top of my head at all - to the point I often forget that I am wearing anything. The headband also provides a very strong clamping force - these cans do not slide around on my head at all. Audio-Technica scores a win in this one (for me).
  • Isolation is pretty good; these cans seal very easily and very well (thanks to strong clamping force).


Audio-Technica ATH-A9X:

  • The A9X is actually more comfortable than the A900X in my opinion - it has less clamping force than the A900X, and is therefore more comfortable for prolonged use. The downforce provided by the wings are a bit stronger than that of A900X.
  • Isolation is the same as A900X.


AKG K550:

  • The headband on the K550 does not provide much clamping force at all - and that's coming from someone with a big head (the headband settings are at 11 on both sides). While this makes the cups very comfortable around the ears, it also means most of the weight press down on the top of my head.  While the headband is very well-padded on the K550, it does still exert enough pressure for me to constantly realize that I am wearing something on my head. The lack of clamping force actually allows the K550 to slide around slightly when I lower my head. Considering how many complaints regarding this the K550 has received in its own Appreciation Thread, I think it's safe to let Audio-Technica win this one.
  • Due to aforementioned issue with the cup joints being too stiff (as well as lack of clamping force), isolation can be an issue if you don't be careful about achieving proper seal.  Once fully sealed, however, the AKG seems to provide slightly better isolation. The difference isn't big, but I'll let AKG walk away with this one.


Score: A900X - 1, K550 - 1

(AT wins comfort, AKG wins isolation)

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IV. Sound Quality:


While most comparison reviews regard the A900X and K550 as similar-sounding (with K550 being better overall), I have to strongly disagree with these reviews. These two cans, to me, sound significantly different from one another - to the point where it's no longer apple-to-apple. It's most definitely apple-to-orange to my ears. This was actually rather shocking to me, because I expected very similar presentation with minute differences.


Audio-Technica ATH-A900X:

  • Treble: Personally, I think the A900X easily wins the treble presentation. There are a lot more details in the treble compared to K550 - I think the main reason is because the treble is significantly rolled-off above 15KHz on the K550, while the A900X doesn't roll-off until close to 20KHz. I know human hearing isn't very sensitive above 16KHz or so, but the difference is definitely there. Another reason may be the K550's upper-mids/lower treble is way too bright and energetic, thus burying the details in the upper registers. A lot of subtle instrument textures come out easily on the A900X but are barely audible on the K550. But do not mistake A900X's treble as sharp or sibilant - because it's not. I actually hear a lot more sibilance on the K550 (details discussed under K550's section) - a good test track is Phil Collins' Two Worlds: hardly sibilant on A900X, very sharp and unpleasant on the K550. The overall treble presentation on the A900X is lively, sparkly, without being sharp or sibilant. Just the perfect balance for me - beautiful, beautiful treble.
  • Mid-Range: It was interesting to see how many other comparison reviews claim that K550 has a warmer, more lively presentation, because the moment I tried out both cans I experienced the exact opposite. The mids on A900X are significantly more pronounced and warmer than those of the K550, especially in the lower-mids, where the K550 has a recess. This results in the A900X's sound having a lot more body (the perceived difference for me is bigger than the frequency response graphs may show). According to the frequency response graphs, while A900X's mids response is fairly linear (except for the down slope in the upper-mids), K550 has a dimple around 500Hz, and its overall mid-range response is more jagged / not as linear. The down slope in the upper-mids also helps A900X's lower- and mid-registers sound much more hefty and robust. Vocals sound more intimate, full, rich, and lively on the A900X. Orchestral instruments have both intimacy and presence. Personally, I prefer the mids on A900X; it sounds a lot more natural to me. Another point to Audio-Technica.
  • Bass: The bass is my only issue with A900X's sound presentation. The extension in the sub-bass, while present, isn't pronounced like on the K550 (the one thing about K550 that I really really like). Also, there's a fairly wide peak between 50-250Hz, which makes music drony/boomy to my ears. Instruments that have a lot of both bass as well as lower-mids (such as cello) tends to have their mids drowned out by the bass, which is very unfortunate. I have tried EQing out the peak on the A900X and indeed, all the details in the lower-mids immediately came back. I'll admit that I am a bit of a purist in this regard and would prefer headphones to sound good without EQing or modding. Within the context of a review especially, I don't feel EQing is appropriate; these headphones simply are too bassy for my taste (without EQ), which is a shame because it has an otherwise perfectly balanced presentation in my opinion. It is possible to reduce the bass with different earpads though (see section at end of review).
  • Soundstage: The soundstage on the A900X is very wide - especially for me, coming from the (in)famously narrow A9X. Sound positioning also feels better on the A900X than the K550 - sounds are more "focused" and easier to pinpoint (I had my wife test both cans and she actually pointed this out as one of her first observations, without any prior inputs from me). Additionally, the soundstage on the A900X feels more "layered" / has more depth (more details explained under K550 soundstage section). I think the point goes to Audio-Technica here.
  • Instrument Separation: In my opinion, instrument separation is better on the A900X due to two reasons - more detailed upper-treble, and better sound positioning. Don't get me wrong, the K550 is a very clean-sounding headphone (I would argue quite a bit cleaner than the A900X), but I think its fuzzier sound stage and overly aggressive upper-mids/lower-treble hurt separation in busier tracks.


Frequency Response Graph of Audio-Technica ATH-A900X


Audio-Technica ATH-A9X:

  • Treble: The A9X is actually more similar in this regard to the K550 than the A900X. It is very soft on the treble, especially in the upper region - the details are present, but you have to listen for them. Extension isn't naturally as good as on the K550 - though the A9X's drivers are capable (need EQ boost).
  • Mid-Range: The mids on the A9X are some of the most beautiful I've heard (in my limited experience). It has that very old school Audio-Technica warmth and intimacy. I actually still like the mid-range on the A9X better than the A900X; it is fuller and more engaging, even though it doesn't have quite as much clarity - but nothing's perfect in every way. tongue.gif
  • Bass: The A9X is fairly bass-shy, but that in itself is a pleasant quality for me since I get annoyed with bass-heavy cans very easily.  The amount of bass present is more than sufficient to give orchestral instruments proper presence and impact. The quality of bass is also good - it is fast, tight, and clean. Once again, the drivers are capable - and can be EQ'd to provide appropriate bass for heavier genres like trance or techno.
  • Soundstage: The A9X has one of the narrowest sound stage you'll ever hear, I promise you! I have no idea why it was made this way, but on these cans, vocalists often sound like they are singing right next to your ears; and orchestral pieces usually sound like it was performed in a small room with you standing right in the middle, amongst all the musicians. This makes certain pieces sound very intimate, but it's also a disservice for some music. That aside, sound has good focus and positioning is good.
  • Instrument Separation: The A9X doesn't do particularly well here compared to either of the other two cans; partially due to the rolled-off treble & smooth mids. It's also possible that the older drivers on the A9X just don't offer the same kind of resolution as newer generation stuffs. That said, it doesn't really do all that bad.


AKG K550:

  • Ear Cups Placement: Okay... there's a lot of complaints in K550's appreciation thread regarding the clamping force and achieving proper seal affecting sound quality. While the K550 seals fine on my head without me having to hold the cups to my face, the K550's sound changes VERY drastically with cup positioning (as opposed to the A900X, which sounds pretty much the same regardless of whether you have the cups slightly forward, slightly back, or press them closer to your head).  The K550 sounds very thin and distant if you don't press the cups to your head after you put them on; it becomes much warmer and more full-bodied if you press the cups in.  If you move the cups forward, the mid-range is recessed but the bass comes out. If you wear the cups dead-center over your ears, the mids are more pronounced but the upper-mids get way too bright, and the bass gets buried. If you wear the cups back... well, forget it, you get the idea.  It's very hard to gauge what these headphones are supposed to sound like, as per manufacturer intended - so I am going to go with what I think is the most pleasant-sounding wearing position, which is having the cups slightly forward (the rear of the cups rest gently against the outer edges of my ears).
  • Treble: - Personally, I feel the treble is K550's weakest point. There are three issues with K550's treble presentation - the first of which is the significantly rolled-off upper-treble, which takes away quite a bit of subtle textures from instruments and vocals. The second is the overly bright upper-mids/lower-treble. As you can see in the frequency response graph, the area between 5.5-8KHz are significantly boosted on the K550, while on the A900X this region is deeply recessed. I think this is what's primarily responsible for the slightly unnatural, "plasticky" treble signature of K550 (several Head-Fi'ers attested to the unnatural treble; Tyll on InnerFidelity also mentioned it). While it might not be considered a sharp headphone in the grand scope of things, the K550 is a lot pickier with recordings than the A900X, and the excessive brightness can get fautiguing after a while, depending on what you are listening to (a lot of my J-Pop and trance collections are almost unlistenable on the K550; just way too busy in the upper-mids/lower-treble, but not enough bass and lower-mids to offset it).  The last issue with K550 is that I actually find it fairly sibilance-prone - at least, much more so than on the A900X.  And no, I don't believe the aforementioned peak in the upper-treble/lower-mids is to blame. I suspect the actual culprit for K550's sibilant tendencies lie in the small - but rather pronounced - peak at 12KHz, where the A900X already pushed its treble back down. Overall I find K550's treble a bit disappointing; even though it's not an issue in most music I listen to, when the problems do come out, it isn't very pleasant.
  • Mid-Range: The mids on the K550 is interesting. Let's start by saying the K550 is relatively thin-sounding. Yes, the K550 is a thin-sounding headphone - this opinion has been voiced several times in various Head-Fi threads as well as professional reviews (Headfonia, Sound & Vision, just to name a few). It's not thin to the point of being unenjoyable, but compared to the A900X, the lack of upper-bass/lower-mids body is very apparent.  As you can see in the frequency response graph, there is a dimple around 500Hz. While this is what, I think, lends the K550 its clean, near-black acoustic background, I really do feel it could use a bit more lower-mids presence. Percussive instruments and male vocals often have trouble achieving their full weight on the K550 (female vocals usually sound great, however). The second issue is of course, the aforementioned upper-mids/lower-treble peak, which makes a lot of orchestral instruments sound way too bright (the best example would be trumpets). I seem to remember Tyll on InnerFidelity mentioning that a downward slope between 1-5KHz is desirable - and the K550 indeed showed this downward slope in his measurements. However, the K550 displayed no such slope in Golden Ears' measurements - with the exception of a small dimple at 4KHz, the entire mid-range is fairly flat. The A900X on the other hand displays such a downward slope in the upper-mids. Not sure what's "better" in this case - but personally I find the A900X more natural-sounding and has better timbre.
  • Bass: The bass presentation is definitely in K550's favor. I find K550's bass a lot cleaner-sounding, with much more audible extension. Looking at the frequency response graphs you can easily see why - the sub-bass region is significantly boosted whereas it is rolled off on the A900X. Since human hearing is less sensitive to sub-bass, this was probably a good tuning choice on AKG's part. I was surprised to see that K550 also has a mid-bass bump between 60-200Hz, because these cans sound a LOT less boomy than the A900X - which is a huge plus for me. The aforementioned dimple around 500Hz is probably the reason for the cleaner-sounding bass, though I am not sure.  In any case, I like K550's bass presentation a lot more than that of A900X's.
  • Soundstage: This is where I found things interesting. In terms of sheer sound stage size, I feel the K550 actually isn't quite as wide as the A900X. However, the K550 has a very interesting "spatial" quality to its sound stage. While sounds on the A900X seem to stretch out onto a 2-dimensional plane, the K550's sound stage sounds sort of airy and 3-dimensional. I suspect this has to do with whatever this "Real Image Engineering" AKG used to simulate the soundstage of open-backed headphones on these closed cans.  Personally, I like this effect - however, sounds also feel a less focused compared to A900X, and positioning takes a hit as the result. Furthermore, the K550 seems to push sounds "back" within its soundstage - for example, a vocalist who sounds like she is singing only 1 meter away on the A900X will sound like she's 5 meters away when listened to on the K550. The effect is similar to listening to sounds through speakers (which, to my understanding, is one of the qualities of open-headphones?)  Again, I do like this effect; it makes the presentation less claustrophobic and more relaxing. But it also means the K550 has trouble achieving intimacy or make things sound nearby. This issue is most apparent In movies: when objects fly past the viewer, on the A900X the proximity effect is very convincing, but not so much on the K550. This is what I meant by the A900X sounding more "layered" and has more depth - for example, listening to African vocals on the soundtrack for The Last Lions, both my wife and I can easily tell which vocalist is standing closer, and which is standing farther away. On the K550, this "depth positioning" is more difficult, because everything sounds farther away.
  • Instrument Separation: As I mentioned in the A900X section, I feel the K550 actually doesn't do as good a job at separation, despite it being cleaner-sounding and having a blacker background (paradox!). The missing details in the upper registers and its tendency to get too bright and busy in the upper-mids/lower treble are the primary culprits - and the fuzzier sound stage contributes to it.


Frequency Response Graph of AKG K550


Score: A900X - 4, K550 - 1

(AT wins treble, mids, sound stage, separation. AKG wins bass)

~ ~ ~ ~ ~


V. Total Scores & Final Verdict:


The Audio-Technica ATH-A900X and K550 both finished with 5 points - and believe me when I say this was not the intended result. I went into this review expecting two very similar-sounding pairs of cans, with K550 consistently out-classing the A900X in every way - and this was not the case at all. As you can see, the K550 won most of its points in aesthetics and materials, while A900X won most of its points in sound quality. This would indicate that A900X has superior sound quality overall.


However, this is not necessarily the case - because this is where the listener's subjectivity as well as needs come into play. Do I prefer listening to music on the A900X over the K550? Absolutely.  But would I entrust the A900X with video-editing or audio-mixing work? Probably less so. The A900X does beautify the recording a bit more, in my opinion - and the K550's cleaner sound/black background are good qualities for sound mixing.  One also needs to take overall sound balance into account - the A900X's heavy bass gives me a headache after a while; the K550, while being overly bright on occassions, doesn't have this issue. If I keep the volume down, the K550 is the less fautiguing of the two for long-term sessions.


In summary: If you like a rich, lively musical presentation that isn't overly exaggerated and sounds natural, the Audio-Technica ATH-A900X is the choice to go with. If you want a clean-sounding headphone with a fairly black background and fairly relaxed presentation (either for sound mixing or listening to slow music), then the K550 is for you. Personally I can't really recommend the K550 for general music/multimedia usage, especially not for the average user. It is simply too picky with recordings and genre.


Like I said before, apples and oranges. rolleyes.gif

~ ~ ~ ~ ~


Usage in Video Games & Movie-Watching:


Since a lot of people were wondering how these two cans compare for usages outside of music, I did some testing with both cans. And to put it simply: The A900X is much, much better for entertainment usage.


ATH-A900X: My observations in music listening tests are confirmed once more - the A900X has much better sound focus, and therefore much better sound positioning in games & movies. The perceived difference is not small, either - one particular film I love to use for testing surround effects is the anime Sky Crawlers; it has one of the best surround sound mix I've heard in any film. The aerial battle sequences sound nothing short of spectacular, and listening to it on the A900X is like having an eargasm.  The sound stage is very wide, and like I said the sound positioning is superb; you can hear all the planes circling around you and accurately pinpoint each of their individual location within the soundscape. Another movie that had very audible difference in sound positioning for me is Summer Wars, in a scene when a bunch of books were falling down from the shelves - you can hear the books land all around you on the A900X, but on the K550 the positioning just sound kind of fuzzy and indistinct  Lastly, the boosted bass on the A900X, while an annoyance in some music, serves movies & games very well here. Car engines and airplanes have that proper weight and roar; gunshots and explosions have tremendous impact.


K550: The K550 is simply not that ideal for movies and video game usage. I am not saying they are bad for such purposes - I just watched Jurassic Park on them and they sounded fabulous. But the aforementioned "airy" and "3-dimensional' soundstage creates some issues with sound positioning/focus, and the "thin" mids on the K550 make things like car engines and machine gun fire sound overly bright and "hollow" (since there's no meaty bass or lower-mids to give these sound effects weight and presence, and the aggressive upper-mids/lower-treble contributes to this issue). To help you understand what a big difference this makes: A machine gun that goes "tuk-tuk-tuk-tuk-tuk" on the A900X sounds like "tak-tak-tak-tak-tak" on the K550.


So if you are looking for closed-back headphones for games & movies, the A900X is simply the far more ideal choice.

~ ~ ~ ~ ~


ATH-A900X Earpads Replacement


I ended up doing a little tweak to the ATH-A900X since I wanted them to be less bassy, and it turned out the solution was staring me in the face. :)


I was looking at my ATH-A9X and the ATH-A900X side-by-side.  My A9X has the A1000 pads installed (which is similar in shape and material to its stock pads; it has better pleather than the A900X pads). The A1000 pads has oval opening, while the A900X pads have round opening (which makes the holes a lot bigger).


Bigger holes = more trapped air = more bass.


Since the A9X is bass-shy, and the A900X is too bassy, I came to the sudden realization: Why didn't I think of swapping their pads???


The ATH-A9X with ATH-A900X earpads installed.




The ATH-A900X with ATH-A1000 earpads installed.


The result? Fantastic! :)  The A900X is no longer droning whenever there's even the slightest bass present; the bass no longer bleeds into the mids and I can actually hear the sub-bass extension now. xD The A9X on the other hand received a bass boost - still far from as bassy as the A900X, but since the A9X doesn't even have D.A.D.S., to expect otherwise would be silly.


The A900X is very clearly superior in every way to the A9X - much better treble, much better bass, and much much better sound stage and positioning.  Aside from the subpar stock earpads, I really can't complain.


So, A1000 pads on A900X - simple and highly recommended mod!  Not only does it clean up the bass, but the pleather is a lot softer, more supple, and hugs the face better (which helps reduce sliding - especially if you have issues with the wings). So it's both a comfort & sound quality mod. :)


Pros: Sound, Overall quality, Comfort, Closed-back but they don't sound like it, Bang for the buck

Cons: Non-removable cable, Cable is very long (3m), Can be hard to drive from small devices, not recommended for small heads because of sealing issues

This a review, as well as bit of a comparison to the Focal Spirit One, as those are the last headphones I owned and I absolutely loved them. 

Man, where to start with these; right off the bat let me tell you that I absolutely love them. They are totally different from the Spirit One, and in a very positive way. When I first got the 550's, I was surprised at how heavy the box is. Now to anyone who thinks you get a lot of accessories with the K550's, I have to disappoint you. All you get are the headphones and a quarter inch adapter, the latter of which is gold plated and screws on top of your cable. Everything about the headphones exudes quality, which couldn't be said about my Spirit Ones, as their headband and joints are made only of plastic, and thus cracked under my big head. The 550's cable is not removable and it is 3 meters long. That's definetly something to keep in mind. Alternatively, you could go with K551, which have a detachable cable. Me, I just couldn't justify the hefty price difference between the two.


When you put the K550's on your head, there are two things you immediately notice (coming from Spirit Ones): Man, there things are huge! And; Man these things are comfortable! Seriously, comfort is insanely good, which once again can't be said for the S1.
I don't know if I would take these out in the public though, as they are quite big and the cable is looooooong for mobile use. 


Enough of the chatter now, and let's get to the sound :)

I listen to music through the following setup: 
-HP Envy 17 Laptop with FLAC's or Spotify- FiiO E07-K Andes USB DAC/amp (To bypass the HORRID beats audio on the laptop, that RUINS anything connected to it)- AKG K550

When I first started listening, I noticed that you absolutely need a good seal with these headphones, in order to enjoy them. For me, that's easy. But for anyone with small heads, and/or women, this might be a real issue. Try not to buy them blind like I did, and try them in a store to see if they fit. Once I found the perfect seal, I was amazed at how much bass there was. Compared to the Focal, which are said to have a lot of bass, I was really surprised because the AKG have more of it. The bass is deep and very well extended into the sub-bass range. It also never sounds boomy or muffled, nor is there too much of it. 
Next, I wanna mention the soundstage: WOW, do they sound different than anything I've owned before, even though they are closed as well. They sound very similar to the K701, which I had the pleasure of testing. Instrument separation is excellent, and there is no "overlapping" of treble sounds, like I've noticed in the Focal. Mids are not as warm as the Focals' and overall, the K550 sound more detailed and technical, while the Spirit One are very warm and love vocals. Not to say that the AKG's don't, it's just a different kind of love :) . (The upper mids can sound a little (too) prominent at times)
Now for the highs, as they were the most notable change for me in comparison to the Focal; they are a lot more prominent and not rolled off, especially in the lower to mid-highs. They provide a nice amount of sparkle and excitement in my opinion, but sometimes at a cost: The 550's are kind of "unforgiving" when it comes to older recordings and lower bitrates. They will bring out every imperfection in the sound and can thus produce hissing and siblances. This was notable on older rock/metal recordings or such that weren't perfectly mastered, which is most of them. (Dream Theaters older albums are an example here).

Overall, I'd call the sound open, pleasent and enjoyable. 


Should you buy these headphones? -Absolutely. That is, if you can find a good seal, and you don't plan taking these on your commute every morning. The great sound, quality and comfort, as well as the the awesome bang-for-buck ratio are reason enough to buy them. But for small heads, and a closed portable, I'd still favor the Spirit One.


Pros: imaging, clean sound

Cons: no carrying case included

I have been using AKG K550 for past few weeks and enjoying them pretty well. This is my first foray into mid fi and I think its a solid contender for getting into mid fi sound especially as it has very low barrier for entry (whole setup). I am driving it with Audinst hud mini, entry level dac/amp and it drives it with authority and good clarity.


I have been using Sennheiser HD518 extensively, and have auditioned HD595 as well as HD650 before this. So thats my reference point here as HD5XX series is rather popular and what you can expect to get if you go for K550.


First some sound signature differences between sennheiser and akg. k550 requires you to be engaged to music instead of being half asleep to enjoy. k550 has this comparatively thin sound that changes very fast according to notes being played, thus conveys note level information with much more clarity. this clarity improves dramatically in hd650 but still k550 is clearer. For me, I need to actively listen to music and be engaged to enjoy k550.


So is one inherently better than other? I don't think so. both sounds are usable according to mood. (its not that I am feeling sleepy all the time, so why Sennheiser only collection?)


So now about K550. First some observations about K550 that are striking:


Great isolation without any clamping pressure whatsoever. No seal issue for me. I would attribute this to ear pad material. Its most certainly is something special that blocks sound very well. It must be in contact with your skin to achieve seal.


Very forgiving for low bit rate material. my much lower hd518 is almost un listenable out of phone with lower bit rate tracks as I could see some holes in music. k550 polishes it and makes it listenable, I think. It might have something to do k550 being easy to drive, not sure why it does that.


Very clean sound. no grain whatsoever. hud mini is inherently grainy and with grainy old recordings of the old like led zeppelin, it was almost un listenable on hd518. (all three recording, dac/amp, headphone are grainy making too much of it). on k550 its pristine.


Now I would describe frequency response a bit:


Bass: awesome. Goes very deep, is tight and reasonably textured. Exactly what I wanted.


Mids: Rich, detailed, not upfront. very enjoyable.


Treble: Now I am terrified of sibilance or bright sound. But k550 sounds exactly like I wanted it to. I don't think its dark sounding, but its got this peculiar way of doing treble. Treble extension is good but detail is very less thus to my ears sounds perfect. (better safe than sorry. won't cut any points here cause of my preference. I am looking for enjoyable headphones than perfect ones).


A word on soundstage:


Good sized. Its a closed headphone and has good width and depth with that limitation. Most impressive part has to be imaging. Pin point imaging if its present in recording, even if two same instruments are playing, it places them very well in sound stage.


Comfort is very good as it exerts very little pressure on head, but as its a sealed design, it gets sweaty. Ear pads don't allow a lot of breathing.


Build quality is good mixture of metal and plastic. not built like tanks and I intend to take good care of them. especially i don't want to change alignment of cups and thus affecting seal.


All these things make them a worth can but what makes them 5/5 special is, well they are very enjoyable. Even with their relatively thin sound, they have this deep and satisfying bass thus make for a very convincing presentation. Their sound stage is wide but they don't have diffused presentation like my HD518 that renders each component of music completely separate. Instead it presents a good mix of music, instruments often inter lapping but still sounding separate with note level detail, harmonious with each other. If you think about it, that is how you hear music when in a hall with musicians. Not completely separate from each other.


Pros: Great detail especially in the treble, Well defined bass, Outstanding soundstage, Extremely comfortable, Built like a tank

Cons: Treble can be harsh at louder listening, Not enough bass for bassheads (Not a con for many)


I got these headphones around Christmas time in 2012. I loved the design at first sight, I find it understated and classy where others find it hulking and ugly, it's all a matter of opinion. After the excitement of unboxing them and plugging them straight into my phone I was horrified by how quiet, lifeless and lacking of detail they were. But rest assured this first impression didn't last long.


Design & Build Quality

As you can probably tell from the introduction, I'm a fan of these headphones looks. For me they fit my head perfectly but for others the size of this headphone is just too big to get a good seal, so it may be wise to try them out to see where you stand in this regard. Build quality is excellent, the headphones are largely made from metal which feels very solid and has some sort of powder coating which feels very nice to the touch. The plastic on these headphones is similar to the soft touch you find on many phones these days, it's certainly not as solid feeling as the metal but it is seemingly high quality plastic. I have had these headphones well over a year now and I am glad to say that the build quality hasn't degraded and they feel as solid as the day I bought them.


The earcups can be rotated 90 degrees which is useful if you're taking them travelling to save space, but the absence of an included carry case makes this a useless feature for me.


The inclusion of a removable cable would've been a welcome one but it's certainly not a deal breaker for me. Another note about the cable is that it is very long, so I have resorted to tying part of my cable up to shorten it. Obviously this is a pro for some people but it definitely makes the headphones cumbersome for portable use. The cable itself is very high quality though and the jack feels solid with plenty of stress relief on both ends.



If you're used to a plethora of accessories coming with your headphones prepare to be disappointed. The AKG K550 box comes with the headphones themselves, a 1/4" to 1/8" screw on adapter, some paperwork and that's pretty much it. Not a whole lot. However for me the only disappointment was that AKG didn't include a carry case, even if it was soft case it'd be better than nothing.



These headphones have a generous amount of cushioning on the earcups making for a extremely comfortable fit around the ears themselves. However I would have opted for adding more padding on the headband as after a few hours or more there is a certain point on the headband that gives me a slight ache, nothing too uncomfortable but something could have so easily been fixed by adding more padding. Overall, the headphones feel light on the head, soft around the ears and I can wear for a few hours at a time with no discomfort. 



First off, I love the sound of these cans. They are relatively neutral, while still sounding a little exciting and not too analytical. They have a flair for the high end, producing magnificently detailed trebles which I find brilliant at this price point. Bass, although possibly lacking the presence of other headphones around this price I find the bass to be extremely well defined, this is accentuated in songs where you have short, punchy stabs of bass more so than when you are listening to a thicker, more full-on bass centric track. The mids aren't as well defined as the rest of the spectrum with some warmer sounding guitar tracks not providing quite as much presence in the mids as the bass and treble. With that said I still think the over signature of these headphones is very good. 


I have been using these headphones with my PC, using an Asus DGX sound card. Quite basic as sound cards go but I think they provide just the right amount of amplification to get the most out of these headphones. I use the 32Ohm amplification setting in the Asus control panel. When using the headphones with either a mobile phone or my PCs integrated sound card I found volume to be lacking which in turn affected how well define the headphones were but by using the equipment and settings stated above the sound is extremely well defined and the volume of the headphones is boosted a lot with no distortion. The soundstage also opens up a lot with amplification. For a pair of closed back headphones I find this pair extremely open sounding and seperation between instruments and the width of the soundstage is all very good.



Overall I am even more impressed with these headphones now than when I first bought them. A recent price drop to £109 in the UK means that these headphones represent amazing value. I don't feel like they can be beaten as far as sound quality and build quality goes, as long as you like the fairly neutral sound signature.



Pros: Balanced response, Versatile, Closed-back with an open sound, Build quality

Cons: Lack-luster with classical, ears touch drivers, take a while to break in, lose some personality with time

            When I purchased my AKG K550, I was in the market for a closed-back headphone that gave me the best open-back sound while containing the noise so I could use them in a dorm room. The AKG K550 does that and much more.


            After a few days of pink noise break in and heavy music listening, they really showed their true high-performance colors. The highs were balanced and resolving, the mids forward as in any AKG headphone, and the lows are rich and placed perfectly within the frequency spectrum. I was initially blown away by the response of these headphones for being closed back, as they offered a very distinct open-back like sound, while being a convenient closed back headphone. The isolation on these headphones is beyond excellent if you can find the right seal and headband adjustment. Many people have had issues with fit, but with a little tweaking they are easy to seal and will accommodate any head size.  I’ve had these headphones for a few months now, and sadly they have become a bit more dull and less dynamic with time, but not to the point where they aren’t fun to listen to anymore.


            The build quality of the K550s is fantastic. The top headband is made of brushed aluminum with the AKG logo laser-etched into the top. You can bend and shape the headband in anyway if you do it sensibly (don’t fold it or snap it…). The hinge where the band is connected to the ear-cups is a high-quality soft-touch plastic. I sometimes find it difficult to gauge what some people mean by high-quality plastic, so for comparison purposes, the plastic used is like what you would come across in the interior of a car’s dashboard; solid and sturdy, but lightweight and soft to the touch (if that helps at all). The lower part of the hinge is a textured aluminum that is also soft to the touch and feels like it will last for ages. The hinge and ear-cups are held on by a solid aluminum bolt, which looks mighty-fancy, and screams quality and durability. The back of the driver encasings are aluminum with the AKG logo again laser-etched into the metal, and the outer ear-cups are the same soft touch plastic used for the hinges. The leather for the ear-cups is very-high quality, although I think it is a pleather material as opposed to a genuine leather material. I like to compare it to that of the Bowers&Wilkins P7. The cable could be considered a bit long for portable use. I’m not sure why they made it so lengthy as these were marketed as a portable headphone. There are easy remedies for this though, I used a suggestion from the K550 appreciation thread and tied a Chain Sinnet (monkey braid) knot with the cable (I’ll post the link to how to tie this at the end of the review). Although these headphones are designed in Austria and made in China, AKG did not skimp out on anything on the quality side of things. I can tell they will be in good condition for a good amount of time. Also, I’m not really sure what brands are trying to go for when they state, “Designed in ________.” It doesn’t mean anything different to me. It seems to me as if they are trying to say something designed in Austria is better than something designed in China, and without stating this, a consumer would be turned away by the “Made in China” decal. Don’t let this influence your purchase when dealing with any headphone.


            I’ve seen some occasions where people have had issues with the comfort of these headphones, but for me that was not the case. Once you break the leather in, it becomes soft and cool. At first, the ear cups made my ears a bit sweaty after a few hours of listening, but with time, the leather has worn in and become a bit cooler for long listening sessions. My one complaint would be that my ears do touch the drivers and become a bit sore after a while. If I shuffle them around on my head a bit it takes care of the problem and I can go on until I need to repeat the readjustment. If that’s something that bothers you, these may not be for you, although there are some mods that can take care of the issue. Many people also complain about the lack of padding on the headband, but I find it to be adequate and haven’t noticed any issues with comfort on the top of my head. If you find the right fit and seal, these headphones are very comfortable, just note that the drivers aren’t to deep inside the ear-pads, which is not ideal for most people.


            I listen to a wide variety of music, and I believe that it is important to include a descriptive listening evaluation in these reviews so I can convey to you how they sound throughout the spectrum of music because everyone has a different taste and wants something different when they are trying to decide which headphones to purchase (the broader the review, the better). Before I go into a listening analysis, as stated, I’ll just again say that these headphones are my favorite closed back cans that have the capability to be portable, are extremely durable, and still sound incredible. Remember that they wont be as detailed and honest as an open backed counterpart, but they’ll come close to performing as an open backed headphone with the benefit of not having sound leakage and having good isolation. As compared to many of the closed-back headphones around this price range, they are some of the best, and I HIGHLY recommend giving them a listen and if you’re in the market, considering to purchasing this product. You will not be disappointed.


Test Songs (all FLAC files)


1. Pop (female vocal): ZZ Ward – Put the Gun Down


            ZZ’s vocals sound a bit recessed but resolving. A bit of distortion when the snare is on top of her voice. The drums sound harsh, a bit trebly, but nothing unbearable. The kick drum is supposed to be “decayish” on this song, so I’m disregarding the thickness of the low end drum response. Guitars sound detailed but a bit laid back. Bass is full and round, not too forward, there’s enough there to be honest to the mix. Overall a great sounding track on the K550s. There just seems like there’s something missing dynamically.


2. Pop (male vocal): John Mayer – Paper Doll


            John’s vocals sound exquisite. When the harmonies come in they sound separated and lush. The guitar is panned but doesn’t lose ANY tone. It’s a full and dynamic guitar sound. This is my favorite part of listening to this song on the K550s. The bass is full, maybe a little light. Sean Hurley, John Mayer’s bassist uses a fender jazz bass on this recording though, so it is very true to the sound of his instrument. The synth effect at the end has a “middy” push. It is very clear and harmonic. The K550 handles male vocals exquisitely. This is a great example of what this headphone can pull off.


3. R&B (female vocal): Beyonce – Listen


            Again I find that Beyonce’s voice is a bit recessed, but resolving. This seems to be how the K550 handles female vocals. Nothing too noticeable, but if you are listening for it, you will definitely notice. The strings sound fantastic. The balance between the instruments is breathtaking. The background vocals are very deep and full, maybe a bit back in the mix. The peak of the song sounds great. Everything is separated. It sounds very theatrical (this was in the musical and movie Dreamgirls, so that might be where the theatrics come from). Bass sounds a little light for my taste; it sits right in the frequency range where this headphone has a bit of a struggle. The piano is very clean and precise, this headphone loves acoustic instruments.


4. R&B (male vocal): Luther Vandross – Never Too Much


            This song sounds spectacular. The bass is so detailed and fun to listen to. The midi instruments sound so true and artificial, but that’s what the track is going for here. The strings again sound fantastic. I cant get over the sound of the strings, it’s bright and lush, but so easy and pleasing to listen to. Guitar sounds a little treble heavy, but that could be what they were going for in the production. Luther’s vocals are simply incredible. I feel like he is singing to me. They are so dynamic and intimate. These headphones pair so very well with his vocal timbre, it impresses me every time I listen to this song. The whole harmonic range is so smooth and it feels as if the K550 just dances around the frequency spectrum with ease.


5. Jazz (instrumental): Bob Acri – I Remember Clifford


            Wow. That trumpet. The warmth and resonance is so defined and resolving. The bass is deep and detailed; I love how the producer placed it in the mix and how this headphone responds to it. The drums sound so full. This song paired with the K550s is just right. It sounds most like a home theater in the sense that everything sounds so open and responsive.


6. Jazz (instrumental… again): John Coltrane – Giant Steps


            I chose to do another instrumental jazz tune because the previous one is slower. This contrasts that with a fast saxophone melody and an analog recording style as opposed to the newer Bob Acri recording. Everything just sounds so easy. The saxophone is all in the left channel, which is where its supposed to be because of the old stereo recording style. You can really hear John Coltrane’s real sound on this track. These headphones respond so well to instrumental jazz. It’s a joy to listen to. The piano, bass, drums, and saxophone sound perfectly separated. The honesty of the sound is remarkable for these open-backed headphones. All of John’s notes come out sounding full and dynamic. A lot of other headphones struggle with doing that on this song.


7. Jazz (female vocal): Dinah Shore – Then I’ll Be Tired of You


            As opposed to the pop and R&B female vocals, female jazz vocals sound very forward and proper in the K550. I was going to listen to a Norah Jones tune, but that is more of a pop production style, older female jazz vocal production is different. This is a true jazz performance and standard. This headphone also loves Dinah Shore’s voice. It’s rich and detailed. Close your eyes and you will feel as if you are there sitting next to her. The band sounds very mid-heavy, which I like, but the bass is thin while the vocals are present. The drums sound great out to me, which is odd because drum production back then wasn’t spectacular by any means. This headphone isn’t at it’s best for female jazz vocals, but it can still handle it remarkably well.


8. Jazz (male vocal): Frank Sinatra – Theme from: New York, New York


            The horn intro sounds fantastic. Frank’s voice is full and intimate. The horns are spectacular, lush and vivid. There is little distortion and listening on the K550 makes you feel as if you are there in the concert hall this was recorded in. The realism of this track is fantastic. Everything sound “right.”


9. Ambient: Grouper – Vital


            The accuracy in this song is great, although it sounds a little thin overall. Open-backed headphones do this song justice. This song just sounds normal on the K550s. Ambient music can be very dull if it is not in full detail, and unfortunately that is the case here. The only thing that sounds up-to-par is the acoustic guitar, but with the thinness of the vocals, there is really nothing special here.


10. Hip-Hop: Blu – SLNGBNGrs


            If you mainly listen to hip-hop and aren’t a bass head (uncommon), these are the headphones for you. This is just magical. The bass and vocals are perfectly mixed in with the synth and the beat. Everything is so rich. When the instruments hit the lower frequencies, it is so rich and punchy as it’s supposed to be with this style of music. I could listen to hip-hop all day with these because its so fun and pleasing.


11. Electronic: Squarepusher – The Exploding Psychology


            Boy, if you want an accurate headphone for electronic instruments, you can’t go wrong with the K550, simply incredible. Everything is so dynamic and rich; it’s presented in a way in which every nuance can be picked out. The bass is thick and I find these better for listening to electronic than an open backed pair because of the accurate and punchy bass response electronic artists go for. The sound field is fantastic and all the different textures sound perfectly separated. If you purchase these, you will automatically appreciate dynamic electronic music.


12. Classical (orchestral): Bela Bartok – Musik fur Saiteninstrumente und Celeste


            Hm. Not much here. The soft strings are very unrefined. The louder part of the piece is thicker, but the strings nonetheless sound thin and undetailed. The cello and bass sound ok, there is not to much to say about the lower strings. Although smooth, this is where the K550 struggles a bit. The dynamics sound brittle, maybe a bit loose. It struggles to handle the whole orchestra without distortion. The bass is nice at the louder sections, but the highs are just so bland and relaxed.


13. Classical (film score): Hans Zimmer – Time (Incetpion OST)


            A bit better than the Bartok symphony, but there is still something missing. The better production quality makes up for the K550’s lack of harmonic response in the strings. Not much distortion as opposed to the previous piece. The electronic instruments in this song sound accurate, and have a nice dynamic effect when paired with the K550s sound stage. Again, the strings sound like they’re just… there.


14: Classical (solo piano): Yundi Li – Chopin: Scherzo no. 2 in B Flat minor op. 31


            The piano sounds a bit thin. When Yundi hits the lower range of the piano it fills up a bit, nothing to write home about though. The reverb is nice, maybe a bit thin as well. The K550s do not do the piano justice here.


15. Folk: Wesley Jensen – Of Life of Love of Tears


            This song sounds great. The reverb and accuracy of the instruments is well presented. The acoustic guitar sounds full, rich, and balanced. Vocals sound nice and detailed. You can hear all of the tones coming from the guitar and by this I mean fingers sliding across strings, fret buzz, etc. The main focus of this tune is the vocals, and boy do they sound great.


16. Rock: Tom Petty: You Don’t Know How it Feels


            Sounds very familiar to the folk example. The vocals are well presented, the drums sound great, acoustic guitar shines as it’s supposed to. Maybe a bit too laid back though, everything could be a bit more forward although just boosting the master makes up for that but can make the K550s get a little messy distortion wise.


17. Hard Rock: Iron Maiden – The Number of The Beast


            The intro to this song sounds great. The guitars are well presented with good detail. The bass is accurate, maybe a little light when in unison with the guitar. The only complaint here is that it sounds a little treble heavy, a little more low end would do this genre good.


18. Metal: Meshuggah – Lethargica


            The distortion on the guitars sounds great. The bass and kick drum don’t interfere with the other instruments. Vocals are very detailed; the mids are very apparent and blend well with the rest of the songs dynamic level. The lower register of the eight-string guitar really stands out to me here, great tone, not too “floppy” as lots of other headphones make this song sound.


After listening to these pieces and evaluating how they sound with the K550, I’ve come to appreciate this headphone even more than I had before. It’s got such a great sound that is so unique to its closed-back design. Although it does lack a bit of precision and detail for classical music, it is well rounded for the other genres, which have a more forward-sophisticated production style. The bass is deep and refined, the mids forward, and the highs sparkly and detailed. The build quality is phenomenal, the sound is unique and balanced, and if you find the right fit, these headphones will keep you well isolated from outside noise. They used just the right amount of tuning in these cans and it really shows how great the engineers at AKG are. What they’ve created here is a masterpiece. If you get the chance, give them a listen; you will be glad that you tried them out.


If you are considering buying these and would like me to listen to anything to tell you how its sounds, I would be more than happy to do so, just message me and I’ll respond shortly after.


Here’s the link to the Chain Sinnet (monkey braid) knot for cable management: http://www.animatedknots.com/chainsinnet/index.php?Categ=decorative&LogoImage=LogoGrog.jpg&Website=www.animatedknots.com


Pros: Looks sturdy, bass is tight and midrange is lovely

Cons: Hard to get a good seal. A bit-lean sounding. Treble is a bit odd but still good

This headphone has a great neutral sound but I can see many people finding the bass a bit too lean yet not light. This can be due to poor seal which as mentioned earlier is a bit tough to get for some. I personally did find the bass very good however there are times where I feel it’s a bit lacking. But even with the perfect seal, people who are used to big bass and stuff may find this headphone a bit light in the bass.


With a good seal, I think the bass is very good. It’s flat, impactful but not overbearing at all. There’s not much emphasis on the upper bass and lower mids area so it’s not as warm as what I would call as a warm-sounding headphone. Overall midrange sounds natural


The treble part is a bit raised but I didn’t find it bright at all as some would call it. It can be somewhat grainy depending on the audio track that you’re listening to but the mid to upper treble region has good clarity for this type of headphone. Some people also find the treble a bit artificial or indistinct and while I did find it to be true, it isn’t really that much. I think some of the AKG's cans have this same treble signature.


Soundstage is pretty good for a closed back headphone but perhaps this might simply be due to the cups being too big that it creates that perception. Imaging is average and it gets confusing when I listened to some treble-heavy Dream Theater tracks. But the overall dynamics is good.


I only tried Fiio e11 and it did make the bass a tiny bit more prominent but other than there's really not much change.


For full review and some pictures, feel free to read the original review post here: http://www.headphone.ph/akg-k550-review/


Pros: Good mids, and decent treble

Cons: Subpar build quality for a 300$ pair of headphones

Well, the K550s don't sound bad by any means, however, the sound signature isn't really for me. I like a little less mid focus and a bit more bass. Less neutral and more fun, really. 

Now the build quality of the K550s are not superb by any means. Firstly, the headband cushion was peeling off in the corner right out of the box. Which was really disappointing. The construction of these headphones felt flimsy, even though it is built of aluminum. The M50s have much better build quality than the K550s. 

It's really love or hate for me. The comfort isn't great either. My ears touch the drivers which causes them to hurt my ears after only an hour of use. 


Pros: Neutral Sound, Tight Bass, Full Bodied Mids, Isolation, Comfort

Cons: Lacking Mid Weight, Poor Treble Attack, Too Little Bass for Some



AKG K550 [Price $160 Used]


Test Process


Source Win 7[Foobar2000 WASAPI] -> oDac -> MonoPrice Premium Coaxial Cables -> Matrix M Stage [0  [w1000x Akg K550/+18 db Gain Lme 49990 OpAmp]


Will be compared again'st my w1000x and my Beyer Dt 990, since I intend to use this headphone as a portable, with all genres. I want to see how it does against my two "specialists" Specifically, the Dt 990 will be compared only with Classical and EDM [I got lazy and only did classical and Dub Step] genres. Songs 2 and 7.


As always gain and volume are adjusted for each headphone. [To ensure each has equal volume levels, despite gain.]


7/9 Songs are without EQ, Benga-Invasion and Kidnap Kid-Animaux  do feature an EQ added by me. This should demonstrate the ability of a headphone to handle EQ.


          In addition, from this review and out, italic text will contain comparisons against my reference headphones. In addition, comparative points of interest will be included in Head Fi review posts, with all Blog Posts reaming more simple and to the point!


Personal Back-story  


I recently sold my old Beyerdynamic Dt 880 Pro 250 ohms, and since then I've been in search of something that captured it's sound! I think I may have found just such a can.



Build [5/5]


I am impressed, the headband is metal with a nice extension feature. Nice physical feel in the hands, not as tough as the Dt 990, but not nearly as fragile as the w1000x. A solid build! Still these are composed of more plastic than metal. Yet the plastic has a nice look and finish to it!


Very Sturdy



Closed Back Dynamic Operating Principle

32 Ohm Impedance

114 db Sensitivity

32 Ohms

12-28.000k response


Ease of Use [Comfort/Fit/Isolation] [4/5]

People complain about the fit, and the lack of clamp force and sadly I did not experience any of this, I put them to 4 on each side slapped em on, pressed them in ever so slightly and enjoyed. I will mention that they sound DRASTICALLY changes depending on how far from the front of the pads the front of your ears are. Essentially for me, the closer the back of my ears are to the back of the pad the Thicker the lower mids are, the closer the front of my ears are to the front of the pads, the thinner the entire can sounds!


In addition, these cans actually isolate very well! Much more so than the w1000.


But still these are STILL easier to put on my head and adjust than the w1000x, yet a little more fickle than the Beyer Dt 990!


Sound Signature and Character


          Sound Stage:  A very wide sound stage, good instrument seperation.


The Akg K550 is fickle with it's sound stage, with vocals it really shines and widens. Not as initimate with vocals as the w1000x, yet with pianos and wood instruments it's not quiet as wide as the w1000x or the Beyer Dt 990, how ever my w1000x is Modded so it's... well much tighter than stock.


          Sound         Signature-  Easily the most neutral balanced headphone I have heard to date. The bass is tastefully tight and deep, the mids are warm and delicate, with good punch. The treble as well is smooth and very refined! Although it still retains some of the Closed Back sound.



Song by Song Breakdown with Comparisons to w1000x & Beyer Dt 990 Pro (Click to show)




1 - Lisa Ekdahl _ Of My Conceit


A vocal jazz piece, Lisa's voice is the main focus. Yet behind her is a lovely piano and a delicate guitar strumming! The piano provides a nice upper Mid and Treble balance, while the guitar provides lower mids and some bass. Both of these elements compliment Lisa's voice. A song best on a warm neutral can, a larger sound stage is excellent with this song as well!


          Treble- It's nice. Great detail, yet lacking sparkle and quick decay. Air and extension are nice. Again very neutral, as I know that I honestly prefer bright cans.


The w1000x, is brighter, faster and has better decay in the treble. Treble on the w1000x is not quiet as smooth, but again I'm not a huge fan of overly smooth treble. I enjoy the extra dynamics of a slightly  sharper treble.


          Mids- The details in the vocals is excellent! There is a good balance of smooth lush sound and detailed quality!


Actually, the k550 have more details than the w1000x, which is slightly smoother and more enjoyable. While the w1000x retains and projects just as much detail, it's not as tight with vocals as the k550 is. Still the w1000x's more smoother intimate vocals are just as punchy and more enjoyable imo, although ever so slightly less detailed. In addition, the K550 places Lisa's voice a little farther away from me. Showing it's transparency and neutrality! Still I'm a sucker for the more intimate vocals of the w1000x. It's also important to note the Angled drivers of the w1000x really give it a slight edge.


          Bass- Very tight, good warmth in the bass with a nice little bit of impact.


Both cans handle this bass well! The Akg K550 however does it a little nicer.


                   Dynamics- Very nice, the left and right channels feature different instruments, and they flawlessly shift from louder to softer notes.


These two cans handle dynamics very similarly! Both do a great job!


2-  Anne Gastinel & Francois-Frederic Guy Sonata for Cello & Piano No. 2 in G minor, Op. 5


Classical track features heavy focus on mids with sparkles of lower treble and the balance between the Cello and Piano!. Another song benefitting from a larger sound stage and a well balanced head phone. The bass of the cello accentuates nicely against the Piano.  Both having deep beautifully lush tones. Air and extension make this piece come alive and lack of it, can kill the mood entirely! Then entire audible spectrum is equally beautiful through the entire song!


          T- The treble is very smooth, well defined and good clarity and details Truly the treble is very neutral! Yet it's still retains beauty and flawless detail.   


Not as smooth airy and well extended as the Dt 990,  in addition the is not as airy  and bright as the w1000x

          M- Nice tone, this is an extremely mid heavy piece... the piano and upper mids are flawless. Decay is good, yet could be a little quicker.


Again, the w1000x... has the better mids... a little more lush  yet also punchier than the K550. Slightly, more sound stage and clarity on the w1000x as well..  Still the Dt 990, remains the Classical King, with more delicate, detailed and well extended mids. Not to mention more sound stage! Non the less, honestly even with the slight, lack of refinement. The k550 does a wonderful job with classical!


          B- Very tight and well placed, the bass never impedes on the delicate mids!


All three do the bass equally well, each with a delicate touch of the cellos bass every time it's needed, stll the w1000x and Dt 990 are just ever so slightly tighter, with that lower mids bass combo punch!


Dyna-Really wonderful. Very quick, no sluggish change in dynamics at all.  


3. Yoshida Brothers -Love


The two brothers are performers of the traditional Japanese music style of Tsugaru-jamisen which originated in northern Japan. They debuted in 1999 in Japan as a duo playing the shamisen, and it remains a main instrument. In addition to traditional Japanese percussion, this track features a very gusto male shout. What sounds like a verbal battle cry, is over top the delicate shamisen. The punchy yet warm mids of the male vocals pair well with the light upper mids and treble of the Shamisen.


          T- Shamisen has a great tight snap to it, good smooth extension to those higher notes!  

          M- The mids of the Shamisens are, just as lovely and gentle as they should be. Quick on their feet, and with a deadly accurate attack. The mood of the song is capture nicely in the mids. The male vocals are actually wonderful! Not too deep, but warm enough with power. A good balance of warmth and power.


The w1000x has more Gusto, more body in the mae vocals, making them a little less punchy but more powerful,  Honestly, both do These male vocals really well, both have a good balance of power, punch and warmth. With a little more warmth and power on the w1000x, with the K550 maintaining  the same power and a little more punch over warmth. Also the Shamisen, has a better attack on the w1000x. Due to a little more weight in the mids, where as the K550 has a nice snap to it, a little lighter but just as quick as the w1000x. Still the K550, lacks that... mystic woody tone in the Shamisen.


          B- The bass is very... super tight. More percussion than an actual bass line, non the less what's there is well represented by the K550.


w1000x, does equally as well considering how little bass there is in the track.


                   Dyna- Amazing as always. This can is proving just as light on it's feet as my others!


4 Kidnap Kid- Animaux


A nice Vocal DnB Tune. A really demanding tune, as the mids and bass over overly overtop another. The sound is very... wonderful! The beauty of the mids right atop deep tight bass, followed by drops of nice punchy vocals. Best of all, the pesky 150hrz makes a return in this tune for a lovely meaty support for those mids. The layering and texture of the bass is, something I'm still not used to! I feel a little spoiled each time I hear it!


          T- Good energy and balance on the mids. Smooth and pleasant, in no way drowned out or invasive of the rest of the frequency.


The highs are equally enjoyable on both cans. Not much to say about them really. Both maintain good energy and relative placement of the highs.


          M- The mids have nice body, but still lack a little in weight. Yet they remain playful and smooth. Over top the bass line, the warm mids work well with the deeper more impactful tight bass.


Again the w1000x maintains more mid warmth body and weight, the track as a whole is more intimate, yet the increased sound stage of the w1000x [again mine is modded] keeps the separation of mids and bass clean. It should be noted though, that with EQ the w1000x get's a little smudged in it's mids,. where as the K550 does not. The K550 also lacks some of the imaging of the w1000x. The sound is a touch more forward, yet not as intimate. .


          B- Bass is wonderful, this being a more laid back tune the bass line stays nice and tight, while still having impeccable weight and body.


Being that this is a DnB song, I do prefer to eq my DnB. Using FooBar a +4 @110hrz and -4 @156hrz gives the bass a little more body while not removing any weight and still remaining tight!


Immediately the w1000x displays a bass with slightly less control and more body. Using the same Eq setting drowns  up the mids ever so slightly on the w1000x.  The k550 displays a little more clarity when eq'd over the w1000x, yet the w1000x has full bodied weighty mids along with a punchy yet laid back bass [it matches the mood of the song very well]. Ultimately, it seems the K550 needs to be eq'd to have the more laid back and intimate sound that pairs so well with this Drum n Bass tune!  Yet Some may prefer the Tighter less intimate presentation of the K550 over the equally clear but more intimate presentation of the w1000x in this DnB tune.


                   Dyna- Dynamics are smooth, the neutral sound aids in a clean shift in the dynamics of the tune!


The w1000x is has a touch faster dynamics, or rather the increased attack in the mids leads to a better dynamic shift, as both cans have equal mid decay. Both cans handle the bass and highs exceptional well!


5- Dai Qing Tana & HAYA Band- Missing You


Beautiful Mongolian vocals, and a world music sound that breaches more than just Asian styles. This track features a lovely guitar to your left, a cello to your right with Dai Qings delicate yet warm deep lyrics right in the middle. A perfect tonal balance is ideal for this track, as it's simplicity does not allow for any distraction from the overall mood of the song as a whole!


          T- This song has a VERY thick and warm bottom end sound, that being said the bright energy of the guitar is never lost in the mid warmth. The highs prove to be well defined without being bright! 


Actually, the highs in this song some times get a little lost in the upper mids, seeing as the guitar is only peaking at about 2.3 2.4k hrz these are the lower most highs, and for these lower treble, the K550 keep a slightly better serration between them and the upper mids. Yet the w1000x is brighter by a touch though. Both are very pleasant with these low treble notes, in addition the w1000x has a little more attack on the notes as well.


          M- The powerful lower mids from the guitar have nice body to them, and sufficient weight,  a real master of balance, the Akg K550 clearly defines it's upper and lower mids. Each having nice body and a little bit of weight.  The upper most mids [also lower treble] maintain good presence despite the powerful lower mids and beautiful airy weight and body of Dai Quing Tana's voice. The deatils in the vocals are wonderful  Her voice remains the focal point, with a lush body and just a touch of weight. Which suits her airy voice very well! The Cello in the right channel as well has a lovely tone to it, good body but it could use a little more weight.


The w1000x also adds an intimacy to the vocals that the K550 does not, yet both do a good job with this mid heavy track. Still the w1000x has a little more sound stage, thus the weighty sounds remain intimate and yet well spaced. Not to mention there is the beautiful tone of the woody mids on the w1000x. Where in which the Cello really shines.



          B- The bass is as always, well controlled on the K550, yet the more controlled less full bodied bass does take away from the Cello's beautiful weight. Non the less the Cellos retains it's lovely body on the tighter bass notes!


It should be noted these Bass Notes, are in conjunction with the lower mids very much in this track. As the Guitar and cello each have a sense of Mid and Bass in their lower notes due to nature of the instrument.


Here both cans do really well, where the K550 lacks weight it does a little better job of retaining a clear sense of body. Where the w1000x adds weight, the body get's a little too much decay. Again these are for the very lowest notes on the bass and cello respectively. The we1000x still has a touch to much bass decay, especially when compared to the more neutral K550.


                   Dyna- The K550 as always does a great job with it's dynamic shifts, the Cello especially fades in and out of the track often!   Always coming into focus nicely, and exiting cleanly.


 Still though, the extra decay in the bass of this track especially take away slightly from the dynamic quickness of the w1000x. So for a track like this, with multiple heavy mid presence, the K550 remains a little more dynamic than the slightly mid focused w1000x.


6- 3nd_ Algorythm       


Great tune from a Japanese Rock band, wonderful energy and great layering. A nice high energy rock tune. The kick of the drums and the clash of the cymbals, combined with sweet guitar mids and a mellow bass line. The bass in particular shifts a lot, the skilled bassists really shows off from time to time, combined with dual guitar tracks. Balance is a great benefit, as is a good sound stage to this song.


          T- The symbols and upper range of the guitar are nicely presented by the k550.  The drums especially have great energy on them!  


The slightly brighter w1000x however is a little more pleasant. The additional sound stage really brings adds  enjoyment to the brighter and airier treble.  In addition to an slightly bigger sound stage and a little better 3D imaging. [But again my w1000x is modded]


          M- The K550 does rock very well, everything is well placed and the decay is excellent throughout. The mids retain great body.


Tough battle here, the w1000x is magic for rock. The big sound stage and excellent separation pair excellently with the forward mids. There is an warm high energy to the w1000x in rock that the k550 doesn't quiet have  Yet the K550 has a touch more detail due to it's less forward mids! There are in fact 3 guitars in this track, one to your left right and center! The K550 and w1000x both do a great job to balance these out! Still in the end, the combinations of forward punchy mids and bigger sound stage leave the w1000x more engaging! Still both are equal in clarity and detail, with the k550 being not quite as fun  seeing as it lacks some of the aggressive attack [and sound stage] of the w1000x.


          B- Bass, the k550s best feature. The bass line in this rock track has such great texture placement!


Ahh bass, the w1000x one shortcoming, this is not an aggressive bass line. It's very clean and punchy but still a strong bass line. The w1000x adds a little to much attack and decay to the bass. which is nice yet it losses a little bit of the texture because of this. Granted I've modded A LOT of the decay out of the w1000x bass, but it's still no match for the k550 very neutral bass!    


                   Dyna- The k550 does a great job as always, it's slightly less aggressive attack and always quick decay make it nice with the rock dynamics.


Again both do a good job, but I give dynamics to the K550 for it's tighter bass line. The bass on the w1000x still has a touch to much decay to be as quick with dynamics in rock as the k550. Yet where the w1000x lacks in it's bass decay, it makes up for with quick dynamics in it's punchy forward mids. [Having both excellent attack and decay on those mids] Where as the k550 does not have the attack of the w1000x, which for rock is a little missed.


7-  Benga- Evolution  


A lovely mid intro, builds to a very aggressive and tight drop. While the mids are an excellent addition to this song, the cymbals and bass are the focus here! Aggression is key in this track, the tighter and deeper the better. The faster and punchier the more enjoyable!


I will admit, I do enjoy my Dub Step eq'd ever so slightly. That being said, I do use the same modest eq for both cans. A +1 boost at 55hrz leading to a +4 boost to 110hz, followed by a -6 decrease at 156hz following a slight incline to +2 at 1.2k hz then back to +_0 I prefer the mids boosted a pinch, and that pesky 156hrz when removed or eq'd out bring a VERY tight bass line to any track, As this frequency is a VERY meaty upper Bass... that said I remove it as it lacks deep impact or TIGHT punch imo.


          T- Treble is accurate and neutral with the K550, although the often lush mids of this tune drown out the treble a touch. Some brightness is nice for DubStep.


About the same, both have great treble detail, the Dt 990 has a little more air and extends nicer. Quicker on the decay as well. With EdM the brigher treble of the W1000x and Dt 990 are preferred.


          M- Mids are a strong point in this Dub Step tube for the K550. The slight touch of weight and nice full body are great again'st that DEEP bass line!

Mids are lusher on the w1000x, but a little too weighty and lush. On the Dt 990 the punchier nature of the mids cut's against that deep bass a little more pleasantly! Like the Dt 990, the K550's nicely bodied [but neutral] mids are a better contrast to the bass!


          B- Great tight bass. A perfect balance of attack and decay.


The Dt 990 and k550 both have a nice tight bass. Although the Dt 990 just has more bass to it! The open back design allows all of that BASS to stay nice tight and super aggressive. Where as the k550 while equally as tight, lacks sheer bass quantity when compared to the Dt 990. The w1000x doesn't even need to be mentioned,  as this track is best with a TIGHT bass line. While having more bass than the k550 it's not tight enough and has to much decay. Still enjoyable though.


                   Dyna-  Excellent, good fast shifts!


What... Dub Step song with Dynamics... you mean other than... BASS no BASS... just kidding. Seriously though, the song has nice dynamic shifts, and the massive bass stays tight and decays faster through these shifts on the DT 990. An as always the w1000x is a little slower with it's bass decay. K550 is as always nice and quick with it's bass.


Should be noted, the Dt 990 and K550 struggles a little bit with deeper acoustic bass notes. The w1000x is a little more natural with wooden instrument bass, than is the Dt 990 or k550. The extra decay of the w1000x bass is a big part in that, as woody bass has more decay than does synthetic or metallic bass.



8- Lenny White, Jamey Haddad, Mark Sherman -Seven [Binarual Recording] From _ (Explorations In Space and Time)


A percussion trio, this binarual recording has only one thing that makes it wonderful... imaging. The Width and depth of the recording is really wonderful, not to mention the dynamics of the track as a whole. A headphones Sound Stage, width and height are very important. However too wide a sound stage and the 3D imaging can get a little veiled.


          T-  Good energy in the drums and cymbals, but the lack of brightness and attack is a little missed.


Cymbal are wonderfully airy, great energy and the linear space is good, the 3D position, imaging how ever is not as nice as the w1000x.


          M- Good body on the drums, yet they lack a weighty tightness. Still very solid and enjoyable. Not to mention the placement in this track is not as 3D as one would like with the k550


w1000x added sound stage and over all forward and punchy mids are nice with this percusion tune. The 3D imaging is better as well, yet the K550 is still very enjoyable!

          B- Nice and tight, very pleasant!


Can't complain much here, both do a nice job with the drums bass


                   Dynamics- once again, pleasantly tight and quick.

Both cans do a nice job with dynamics


9 The Modern Jazz Quartet- Reunion Blues


A lovely classic jazz piece, what makes this such a great tune is the  balance of each instrument, as well as the placement of each in the sound stage. This song... is spilt literally into left and right. A soft Piano and Percy Heath's Double Bass to your right, with the drums and cymbals to your left, Also in the left channel is a magically warm and lush Xylophone! Best of all despite extreme stereophonic sound, the track as a whole is very balanced and incredibly enjoyable! Here a wider sound stage takes heed over a tall one.


          T- Lovely, cymbals have good extension and fabulous air.


But not as airy as the w1000x.

          M- the upper mids are excellent, as are the lower mids! The piano and Xylophone work together for a wonderful mid core!


Proving jack of all and master of none, the K550 is nice with jazz. Great balance but it again lacks the energy and airy brightness of the w1000x

          B- Excellent, tight,


Yet again the 3D imaging shows to be a little weaker than the w1000x, and the bass is a little too fast for the Double Bass, the lack of attack and extra decay do take away from the joy of the double bass in this jazz number!



                   Dynamics- As always, fast and accurate. Great for this classical Jazz piece!





Sound [4/5]


Treble [3.8/5]- Very neutral, which isn't always my cup of tea. I miss the energy of slightly brighter cans. Not to mention the lack of air.


Mids [4.2/5]- A beautiful tone to mids, with the right mix of body and a touch of weight to be enjoyed with all kinds of music.


Bass [5/5] - Excellent bass all the time.               


Conclusion- For $220 and around $170 used, it's one of my favorite all time closed cans! Great sound for almost all kinds of music and the bass lovers will enjoy it with everything! Good dynamics and fantastic build quality. A must have for any one getting into Audio Phila!


Pros: Comfortable, spacious open sound, great build quality

Cons: Very sensitive to seal, overall lean sound, somewhat raw treble, slightly heavy

Along with the summary below, I have posted a Youtube video review of the K550. If you like the video, check out my channel for more reviews :)







The AKG K550 has excellent build quality, with a great fit and finish and a solid, durable feel to the materials. The earpads are very large and may not fit everybody's head; despite being very comfortable and supple the earpads are sensitive to seal and small changes to positioning will affect the already quite lean bass. The headband padding is quite sparse and because they are quite heavy, after a few hours they may make the top of your head a little sore.




The AKG K550 has a very lean, dry sound. What is most noticeable is the spacious soundstaging and clean sound despite the closed design. The K550 has no real sense of congestion or anything characteristic of closed headphones. However the sound is very lean; bass extends very deep but there isn't much slam or warmth. The treble can be slightly raw on occasion. Overall they are balanced headphones good for a variety of music but on the leaner side of neutral and not to my personal preference. Fans of more analytical signatures may enjoy these.




These are well made headphones with a good sound, but the fit issues mean that you may need to trial these before buying them. The lean sound may also not please everyone, though I commend AKG for designing a closed headphone that sounds very much like an open one.

AKG K 550

With the K 550s, AKG engineers have struck a masterful balance between the noise-isolating qualities of closed-back headphones and the spacious, dimensional sound of an open-back design – creating reference-class headphones ideal for private listening both at home and on the go. 50mm drivers, the largest in our product line, deliver great AKG sound from your hi-fi system or virtually any portable device. The large ear cups and new headband design ensure an amazingly comfortable fit, and the 2D-axis mechanism folds flat to stow or go. Acoustic Seal: Closed Driver Type: Dynamic Ear Coupler Type: Full-Size Coupler Size: Large Cord Type: Straight Left-Side Cord Length: 9.5ft Detachable Cable: No Impedance @ 1kHz: 32 Ohms Isolation: -12dB ~ -18dB Weight: 305 grams w/o cord Connector Type: 1/8 Headphone Type: Full Size Manufacturer Warranty: 2 years Sensitivity: 114 dB

Model Name/TypeMPNEAN/UPC
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