[Comparison Review] AKG K550 & K553
Aug 22, 2015 at 5:17 AM Thread Starter Post #1 of 22


100+ Head-Fier
Feb 4, 2013
Update: Tyll Hertsens at InnerFidelity has expressed interest in doing a review of the K553. I was told to contact him in mid-October. I will be shipping him my K553 for lab measurements; look forward to seeing the results.
The Famed K550 Just Got Better - For Cheaper
I've owned a pair of K550 for over two years now, and while I have grown quite fond of them, I was never fully happy with the way they sound. The treble does sound a bit unnatural - as noted by many professional reviewers - and both the bass and the mid-range could use a bit more body. The K553, it seems to me, is AKG's attempt at directly addressing these issues. I picked up a brand new pair of these for $120 on MassDrop, though many retail outlets are also selling these for $128 shipped.
I honestly cannot imagine a better headphone for these prices. Below are my impressions of the K553.
Craftsmanship & Comfort
The K553 comes in a plain cardboard box that feels rather cheap, but then again, you only pay $120 for them. Some of the details could have been better though - for example the signal cable and stereo plug could have been tied down instead of being allowed to freely bounce around the box during transit. Even the $50 Superlux HD668b was better-packaged, in my opinion.
Packaging issues aside, the K553 is manufactured to the same quality standard as the K550. I read early reports about the earpads feeling "cheap" compared to the K550. That was actually my initial impression as well (the pleather felt harder and more rough, and the foam also feels harder), but after wearing them for a while, they quickly softened and now feel identical to those on the K550. Everything else seemed fine - I spotted no rough seams in the plastic bits, nothing felt loose or badly put together.
Retaining K550's exact designs means those who had comfort or fit issues with the K550 will likewise have them with the K553, so... possibly a problem for some.
Sound Quality
Before I purchased the K553, I had read up on user reviews - some claimed they sounded identical to the K550, while others claimed they sounded very different. I was a bit skeptical about the claimed improvements, since AKG's official specs are identical to the K550, and they certainly look identical in the photos. But, for $120, I figured I could hear them myself.
Listening to the K553 yielded an immediate surprise - there are some very significant and tangible differences. Keep in mind I was skeptical about this to begin with, so I was fully expecting to hear identical, or at least very similar, sounds. I was not looking for differences to spot.
My immediate thought was that perhaps the new earpads were the cause, so I swapped them, and the results remained the same. I then went one step further in my investigation: I suspected the differences were caused by changes made to the driver enclosures, so I took both headphones apart, inspected for physical differences in the enclosures: I spotted absolutely none - no new padding or dampening materials that I can spot. (Also, just for the record, the inside of the K553 enclosures are both stamped with the words K550 Ear Cup Left/Right, indicating they are the exact same parts.)
Then I took yet another step. I de-soldered the drivers of both headphones, and swapped them (so my K550 is now sporting K553 drivers, and vice versa). And get this - the sound signatures got carried over with the drivers. So whatever tuning AKG did to the K553, it's in the drivers themselves. My final theory was that may be AKG used the K545 driver units in the K553 (and forgot to, uh, update the specs on their website... or something), since the K545 is reportedly a much more bassy set. However, the K545 drivers have significantly lower sensitivity rating than those used in the K550, so this can't be the case either (see list below for why).
Before I dig into my analysis, here's how I divide the frequency ranges:
  1. Sub-Bass: 20-40Hz
  2. Mid-Bass: 40-80Hz
  3. Upper-Bass: 80-160Hz
  4. Lower-Midrange: 160-320Hz
  5. Mid-Midrange: 320Hz-1KHz
  6. Upper-Midrange: 1-3KHz
  7. Lower-Treble: 3-6KHz
  8. Mid-Treble: 6-12KHz
  9. Upper-Treble: 12-20KHz
Alright, so here's the list of differences I observed:
  1. Based on my subjective listening, I estimate the K553 to be 2-3 dB louder than the K550 (despite the drivers having the same sensitivity rating on paper). This is interesting, especially considering that the new ear pads, being firmer, should have placed the drivers further away from my ears (I also tried pressing both pairs of headphones closer to my ears to eliminate the difference; the K553 remained louder).
  2. The K553 is significantly more bassy, particularly in the mid-bass region (I tested this with EQ). The two headphones seem to be comparable in the sub-bass region (20-40Hz), meaning the K553 retains the excellent bass extension of the K550. The mid-bass region (40-80Hz) is what makes a headphone "thumpy", and this is where the K553 really deviates away from the K550: Based on my EQ tests (centered around 60Hz), the mid-bass is about 4dB louder on the K553. If you liked the way bass was handled on the K550, you may not like the changes to K553 - but in my opinion this was an improvement as I felt the K550's bass did lack body (in spite of the excellent sub-bass). The upper bass (80-160Hz) remains clean and appears comparable on both headphones.
  3. The midrange on the K553 bears one distinction from the K550: The upper-midrange (around 1KHz) is more recessed. The effect is very noticeable in female vocals, which sounds much more forward on the K550. Based on my EQ tests, the difference is about 3dB (meaning if I lowered the 1KHz slider by 3dB while listening to the K550, the vocals would sound comparable to the K553 - not counting the differences in the treble, more on that later). The FR graph for the K550 from Innerfidelity does show a small peak in the 1KHz region; I suspect the curve for K553 may be more linear here. Whether or not this is a welcome change will depend on the listener - I personally think the K553 sounds more natural.
  4. The treble is another area where the K553 really deviates away from the K550. My first impression of the K553 (aside from the significant bass boost) is that it sounds less "congested" in the lower-treble region (3-6KHz), and looking at the FR graph for K550, there is a peak at 6KHz. Lowering this region in the EQ by about 3dB on the K550 (in conjunction with the adjustment in the upper-midrange) produced a sound signature that, I feel, is similar to the K553. Additionally, I feel the K553 have less of a roll off in the upper treble (centered around 16KHz), and some textures that sound a bit indistinct on the K550 are more clearly heard on the K553. The mid-treble (centered around 8KHz), which affects metallic instruments, sounds comparable.
  5. Lastly, sound imaging has been improved over the K550. The K553 does sound less "airy", but I feel whatever allowed the K550 to sound that way also hurt the accuracy of its imaging. The K553 addressed this and I can much better pinpoint the location of sound sources on the K553.
The overall sound of the K553 is just that much more pleasant and balanced to my ears. They are much more musical due to the improved treble presentation and added bass body, but still tonally neutral enough for analytical listening and sound editing work. Aside from the minor issue of the bass sounding a tad loose at times, IMO the K553 successfully addressed all the shortcomings of the K550 while retaining all of its merits.
Seriously, at $120, the K553 is an absolute steal. In this price range the only competitor I can think of would be the ATH-M50 (you can't even buy the M50x for this price), and the K553 easily outperforms the M50/M50x in every category, and has better material & construction to boot. I cannot imagine another closed headphone for under $200 that sounds this good.
Aug 22, 2015 at 5:44 AM Post #2 of 22
Thanks very much for this very thorough review!
I am a K550 lover, with two pairs of them plus a K551.  I also have a K845BT, which so far as I can tell is precisely a K545 plus Bluetooth (and accepts a cable so you can run it as a normal headphone).  The K845BT's sound has a very strong family resemblance to the K550, but is clearly tuned toward a little more bass and midrange presence, a little less treble presence and airiness.  When I read the original K553 announcement, it did sound as though the K553 was going to be a K550 retuned in that same general direction (making it more appealing to most people, but less appealing to me).  But that was just a guess, and I wasn't entirely sure until your review.  So thanks again.
Aug 22, 2015 at 7:06 AM Post #3 of 22
Very helpful! Had the same concerns about the 553s. Would like to get a set of 'neutral-ish' over-ear, closed cans for a good price. May have to pick a set up when Massdrop does their next run.

Fwiw...just checked Amazon. The 550s are now $139. :)
Aug 22, 2015 at 7:31 AM Post #4 of 22
Very helpful! Had the same concerns about the 553s. Would like to get a set of 'neutral-ish' over-ear, closed cans for a good price. May have to pick a set up when Massdrop does their next run.

Fwiw...just checked Amazon. The 550s are now $139. :)

Actually I saw a few online retailers selling K553 for close to the Mass Drop price (around $130, shipping included), not sure if those deals are still up (since they might have been competing with the Mass Drop deal)
Aug 22, 2015 at 1:09 PM Post #5 of 22
Nice review! I don't have a 550 to compare to...but within the first day of listening to these and I have shelved my faithful D2k's again. My HE-400s were the only other headphone to do that prior.

These 553s aren't as comfy, but are my no means uncomfortable.
Aug 22, 2015 at 4:02 PM Post #6 of 22
Hmmm...just made me recollect the fit on the 550s was a tad loose. Is that true for the 553s?
Aug 22, 2015 at 6:23 PM Post #7 of 22
Very nice to know that it's not just a pad/slight aesthetic change, but the drivers are re-tuned after all.
Aug 22, 2015 at 8:42 PM Post #8 of 22
Hmmm...just made me recollect the fit on the 550s was a tad loose. Is that true for the 553s?

Depends on your head size - clamping force feels comparable between the K550 and K553, to me. I have a larger head though, so both set provided sufficient seal for me. If the K550 was too loose for you then... you will probably be spending a few hours bending the headband on the K553. xD
Aug 22, 2015 at 8:54 PM Post #9 of 22
Just did some quick comparisons with the ATH-A900X (which I also really enjoy). Here are my impressions:
  1. The A900X remains a more "fun" listen, with more pronounced upper-mid bass and upper treble. Gunshots and explosions in movies as well as percussive instruments in music still have more heft on the A900X (the "punch" provided by the upper-mid bass). K553 remains the more analytical-sounding of the two; in spite of the bass increase from the K550, the upper-mid bass on the K553 remains (relatively clean) and doesn't bleed into the mid-range the same way it does on more "fun" headphones. A good test scene was the motorcycle chase in Mad Max: Fury Road, the background music is more clearly audible over the sound effects on the K553 than the A900X. I would say the bass emphasis on the K553 remains in the sub-bass region, a trait carried over from the K550; the extension remains excellent.
  2. The K553's soundstage remains more "open" (I wouldn't say wider... A900X actually has a pretty wide soundstage, but the orientation is different) than the A900X. This may be due to the fact that A900X is meant to sound like closed cans, while K553 continues to try and emulate the sound of open cans. Not as open as the K550, though.
  3. K553 reveals more details in instruments - particularly in the upper-midrange/lower-treble region, an area where the A900X feels a bit recessed (even though A900X is sparklier at the top). I personally find the timbre of instruments to be more natural on the K553.
May 11, 2016 at 1:40 PM Post #11 of 22
That photo of the box just about confirms my theory that my model was tampered with. Mine came with no wrapping and sounded muddy and V-shaped. Someone at either MassDrop or AKG ****ed with my order.
Jul 25, 2016 at 7:57 PM Post #12 of 22
My buddy that's looking for drivers for a DIY project was informed by AKG over email that 550, 551, and 553 all share the same drivers.  So what Bagheera heard between his 550 and 553 drivers was probably manufacturing variation.
Aug 24, 2016 at 2:25 PM Post #14 of 22
Same size, yes.
Dec 14, 2016 at 5:07 PM Post #15 of 22
My buddy that's looking for drivers for a DIY project was informed by AKG over email that 550, 551, and 553 all share the same drivers.  So what Bagheera heard between his 550 and 553 drivers was probably manufacturing variation.

This would mean the K550 and K553 are identical since the cups were inspected. I question whether sales really knows the answer. It might be better to speak with engineering. It wouldn't be the first time a headphone changed some design feature and the sales person was uninformed. The 400i backplate removal as investigated by @fjrabon and @DavidA when they "only" changed (as initially acknowledged by sales) the design from SMC to 2.5 mm connectors is at least one beaming example. Did anyone ever follow up on this?

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