[Comparison Review] AKG K550 & Audio Technical ATH-A900X

A Review On: Audio Technica ATH-A900X | Art Monitor Headphones (Japan Import)

Audio Technica ATH-A900X | Art Monitor Headphones (Japan Import)

Rated # 139 in Over-Ear
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Pros: Detailed, sparkly treble. Warm, sweet mids. Good soundstage and imaging.

Cons: Mid-bass bloat. Bass isn't particularly tight and extension isn't great (not much sub-bass). Treble is noticeably grainy compared to K550.

Comparison Review: ATH-A900X, AKG K550


Two years ago, when I was looking to upgrade my aging ATH-A9X, I came across the AKG K550 and the ATH-A900X, both then newly-released, with several head-fiers reporting that they are tonally-similar headphones. Unable to decide which one to get, I bought both to do a comparison. I ended up keeping the K550 for myself and giving the A900X to my wife (who still uses it and loves it).


Below are my thoughts regarding how these two cans compare.


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Craftsmanship & Comfort


Audio-Technica ATH-A900X

  • The A900X isn't a bad-looking headphone, but lacks K550's elegance. That said, comfort level is excellent and I in fact prefer it over the K550 in this department. The AT "winged" headband design makes putting them on and taking them off a breeze, and the angled drivers do not press against my ears even after my prolonged use (whereas the K550 causes discomfort).
  • One particular thing another reviewer complained about was the "poor quality" of the wings on the A900X. I looked into this issue, and did not personally find this to be true (relative to previous models). Below are my observations:
    • On the old model A9X/7X/5X, the wings only pivot in one direction (let's call it the Y-axis), which is up and down.
    • On the A900, AT implemented the "3D Wings" which pivot in two directions (X- and Y-). The way they achieved this is by making the wings themselves into a 2-piece design - there's an "outer rim" that pivots around the Y-axis (like the old wings), and an "inner piece" that pivots back and forth (X-axis).  This is actually a fairly intricate design and I imagine, harder to manufacture.
    • On the A900X, AT simplified the "3D Wings" to ease manufacturing process while still retain pivots in both directions. The wings themselves are now back to a 1-piece design and pivots up and down (like the old wings on A9X), but the T-shaped joint where the wings are clipped onto the arms now pivots back and forth (in the older models, this joint is fixed). The joint on the new system makes the wings feel loose, giving the appearance of flimsiness, but having owned this headphone for two years I can attest that the construction quality on the wings are solid.
  • Material quality on the A900X is decent but not great. It's a step up from the A900 (which had the cheapest pleather possible and several plastic bits just look like sub-$100 headphones), but it's not at the same level as its older cousin, the A9X (which had supple protein leather earpads and wings). The earpads on the A900X is a durable-looking pleather that feels a bit on the hard side, and the wings remain fabric-covered like on the A900.
  • One nitpick: The stereo plug on the A900X is the exact same one AT has been using since the mid-90's (starting with the old ATH-AX series). It might have looked ok in the 90's, but looks a bit gaudy by today's more understated aesthetics.



AKG K550

  • The K550 is simply one of the most tastefully-designed headphone I've seen. The construction, materials, and appearance are all superb (my photos don't do them justice).
  • Comfort level is good but there are some nitpicks here... The earpads could be a bit deeper. The top of my ears do press against the drivers because the foam used in the earpads are extremely soft. The earcups are a bit stiff when it comes to pivoting, so they may not conform to the shape of your head without manual adjustment. The clamping force of the headband feels a bit loose, especially if you have small heads (and this is a headphone that already has sealing issues)
  • 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 better. I personally prefer AT's implementation.
  • One material nitpick... The headband padding is pasted onto the headband using basically a double-sided tape. Unfortunately the adhesive becomes a black goop as it ages and, in my case, actually started oozing out from the headband and making a mess on whatever surface I leave the headphone on. I ended up tearing out the padding, cleaned off all the adhesive, then glued it back using a glue gun.


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Sound Quality 


Several Head-Fiers have claimed that the A900X and K550 are tonally similar, which was the reason I was interested in these two cans to begin with. They turned out to be very different-sounding cans, heh.

FR Graph of ATH-A900X (Left) & AKG K550 (Right)


Audio-Technica ATH-A900X

  • Treble: The A900X has a fairly clear and resolving treble. It appears to be tuned to offer sparkle without being offensive or sibilant (there's a dip at 7K which, I suspect, was intentionally introduced to reduce sibilance). Extension is absolutely brilliant, going full up to 20KHz. The only complaint I have is that it's noticeably grainy-sounding compared to the K550, whose treble is simply silky-smooth in texture.
  • Mid-Range: The A900X's mid-range is thicker, fuller, and more engaging than the K550. It is definitely a more engaging presentation (more "musical" if you will), but clarity suffers a bit here. The K550 in comparison is more clean-sounding.
  • Bass: The bass is my biggest gripe with the A900X - there's quite a bit of mid-bass bloat and the control isn't particularly tight. Bass extension isn't very good either - the rolloff starts at 50Hz, which means there's not much sub-bass compared to the excellent extension of the K550. Without any earpad mod, the A900X has a bit of a consumer sound to its lower end (I personally found that swapping the pads for the oval-shaped ones from the A1000X helps dial the bass down a bit)
  • Soundstage: The A900X has a very wide sound stage, likely owing to its excellently-resolving treble. Imaging is likewise excellent - I feel this is one area where it has a definite upper hand against the K550, whose soundstage - while large - feels a bit indistinct.



AKG K550

  • Treble: The treble is a bit of a problem area for the K550. Many users have complained about it being "peaky" or "sibilant". I don't find this to be the case, though the lower-treble is definitely too forward, causing the slightly unnatural treble presentation noted by many reviewers (a problem compounded by the thin-sounding mid-range. Both issues were addressed in the K553). I also wish there were less roll-off in the higher octaves, as the K550 could benefit from better extension (it's rolled off from 1.5KHz onward). Complaints aside, clarity is good and treble texture is superb - there is absolutely no grain on the K550.
  • Mid-Range: The mid-range on the K550 has excellent clarity, which I really love. However it is sometimes dominated by the lower-treble, which as I mentioned, is too forward. Additionally it could use some additional body - the overall presentation does sound a bit bright & thin.
  • Bass: The bass on K550 has excellent tightness and extension, however it could likewise benefit from some additional body. I personally do find K550's bass to be thin-sounding due to the lack of mid-bass. There's ample amount of sub-bass and upper-bass, but the mid-bass is intentionally recessed. A 2-3dB boost in the mid-bass would provide a more balanced bass presentation (exactly what the K553 did).
  • Soundstage: The K550 is well-known for its spacious soundstage, and I do agree it feels very wide and airy. However, I feel the imaging is a bit fuzzy and indistinct. Watching movies and playing games, it's much easier to tell where a sound is coming from on the A900X.



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Final Thoughts 

The A900X and K550 are both good headphones with distinct personalities. Neither are perfect, though. I would say the A900X is the more balanced-sounding of the two and more versatile when it comes to musical genres and other usage (games & movies).


The K550 offers better clarity and may be more desirable for analytical listening and editing tasks, but it's not as musical as the A900X and many will find its treble presentation to be problematic.


This review is great and really convinced me that I want a pair of A900x. Unlike you, I'm very much a basshead and am interested in getting used to headphones with a neutral or slightly less than neutral bass response because there's so much more detail to be heard with the bass toned down. Like you, sharp, excess and harsh treble is very fatiguing to my ears and I like it smooth as possible. The ATH-A900x sounds like the ideal closed headphone at it's price. :D
Excellent review. Overall the A900X is a fantastic headphone. Nice detail retrieval across the entire spectrum. Like you I was finding it a bit bassy and also too trebly for my tastes. I tried layering the pads by using foam underneath the pads. Although that took care of the treble, it made it even more bassy. I finally tried your suggestion of making the opening smaller and that seems to have taken care of both issues, the bass and the treble. The change seems a lot to my liking (just hope the liking lasts .. lol .. you know how these things are). Anyway thanks for comparing these two headphones. The AKG 550 was on my radar since I was looking for a good closed session headphone. The AKG 550 sounded awesome when I tried it, but it was only briefly and not with a wide range of music. From what I have read, it seems to stumble when certain songs demand a certain frequency pitch that it can't quite handle. This has been a comment from various sources. So .. given you could only keep one of the headphones, which one would you keep for music listening .. but I guess I already know the answer to that.
Wow glad I found this, I have a K550 on it's way to demo. And I'm hoping AT will let me do a review on the Ath A900x. I got a hold of one of their promotional sponsors. I do like my w1000x but it can move around a little on my head, and the K550 has been reported to sound very much like the dt 880, but this can has ALSO been reported to sound the the dt 880 so... I'm at a loss here >.>
I should how ever have both cans with C5 amp to test them with... I'll be curious honestly to try them both. As the Ath 900x is in the direct price range of the k550... and I wonder how easy this wing system will be to use, as the I struggled with the w1000x for about a week before I got it to fit perfectly everytime, although again using the w1000x daily I should be able to adjust to the Ad a900x rather quickly! Glad I found this review :D
The A900X cable is somewhat messy and too long in my opinion. I'm looking for alternative cable and have the headphones upgraded with detachable cable feature.
Thanks Bagheera
For the awesome and much detailed review I own the A900 closed cans and also the AKG K550s, your review is pretty much spot on. I do at times like the cleaner sounds from the K550 they allow a somewhat more detailed playback my old A900s still had it but not as defined or cleaner sounding however I do agree the A900s are very detailed in the all areas overall and I believe the drivers are angle placed allowing a greater depth and sound stage over the K550s this really allows the A900s to be more fun and bright the K550s sounds flat in comparison. Oddly I preferred male voices on the K550s and female on the A900s during music, overall there is no right or wrong mind you !
One thing though I would say is the K550s support and ear pads are pretty terrible, within a year and half my K550 pads are worn out and AKG are not releasing new pads till late 2015!
I see Audio technica A900x replacement pads already available for $20-30 so far better support then AKG. Am tempted to move onto the A900Xs after your review:)