Home Headphone Comparisons AKG K550 vs. K551 | ALMOST IDENTICAL


by Stuart Charles Black
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Hi there friend, and Welcome!

My AKG K550 headphone review revealed (sound-wise) an almost perfect closed back reference set of headphones. Closed back vs. Open back headphones. Today in my AKG K550 vs. K551, I will outline some Similarities and Differences between each. Hopefully, by the end of this article, you’ll have a lot more insight.

Before we get started though… grab a snack, sit back and relax because…

You’ve come to the right place!!

What I will bring you in this review

Since these two headphones are so similar, I’m going to review the K550 and then compare it against the 551.

  1. Specifications
  2. Summary
  3. Pros
  4. Cons
  5. Neutral
  6. Video Review
  7. Amp/DAC requirements
  8. Consensus/Conclusion
  9. Similarities/Differences
  10. Final Word

Now without further ado, let’s get rolling!

AKG K550


  • price: Check Amazon! | Check eBay!
  • type: closed back
  • fit: circumaural
  • impedance: 32 Ohm. What is Headphone Impedance?
  • frequency response: 12Hz to 28kHz
  • material: Mostly metal, some plastic
  • headband: Padded
  • color: Matte black with black metal accents


To start off, these are gorgeous. They are actually made mostly of metal, with some plastic. They absolutely exude beauty in my opinion. Everything from the headband, ear-cups, and the overall feel is just solid. They are very comfortable, but the ear-cups could have been wider in diameter. Just be aware that some people do complain of a loose fit, and it entirely depends on the size of your melon. The right amount of snugness really determines whether or not the bass will sound too flat or just right. The earpads are very soft, which can present problems with the fit. You may have to tinker quite a bit with them. Once you do find that perfect fit, they are extremely comfy, and you won’t have to really adjust them at all.

The other big thing of note is isolation. While they do isolate pretty well, they don’t completely block out sound. This makes them pretty exceptional for office situations, but their biggest claim to fame is most definitely a closed-back reference. In terms of that, they allow you to really get a feel for how the music actually sounds. A lot of people may put these on and say that they lack bass. No, that just means that you may have grown a little too accustomed to poor consumer-grade models. And that is understandable. What these give you is a very flat, accurate, and well-extended bass response. There are no glaring speed problems. They are very unforgiving though, so make sure your source is good. Mp3’s probably won’t sound all that stellar. Haha.

One last notable aspect is that there are a couple of different versions of this headphone floating around. I wouldn’t buy a pair on eBay because you may get one that sounds very different from the original 550. Also if you can, demo this before you buy it due to the strange fit.


  • Folds up flat for easy transport.
  • Build quality is fantastic. Mostly metal, with a great headband adjustment.
  • Very comfortable once you get a good fit.
  • Flat and neutral bass that extends quite deep. Very analytical.
  • Best closed-back reference headphones. A great alternative to the open-back HD 600.
  • Relatively fast and detailed.
  • Almost perfect treble range. There is a bit of a boost around 10khz, and some may find this artificially detailed.
  • Nice color matching 1/4″ adapter. Very solid.
  • Great for office. Works for every genre, and isolates sound just enough.


  • No carrying case
  • The cloth that covers the driver may hit your ear(s).


  • Sound-stage is decent. There is some width, but the imaging isn’t particularly great or anything. It is there and that’s about it.

What is Soundstage?

  • Non-removable cable. Depends on your preference really.
  • The cable is very long for portable use. Around 9-10 ft. Could have benefited from a choice of coiled or straight.
  • Strange fit and the ear-cups could have been larger in diameter.
  • It May sound artificial in the mid-range. Very uncolored, but: There is a forwardness at about 1.5khz, a ringing at 4 or 5k, and a spike at 6khz. Metal or electric guitar in that region may become problematic. Some detail is slightly blurred.

Video Review

Credit to my boy @Metal571. Check him out on Twitter!

Amp/DAC Requirements

These don’t need an amp at 32 Ohm. They do just fine with portable devices and come with a 1/4″ adapter for use with interfaces and mixers. However, some say that they truly shine with one.

2 great overall options:

How to choose a headphone amp

Who this headphone benefits?

Not the most laid back or easy to listen to with every genre, and don’t expect a boomy bass or anything. As mentioned in the summary, these are highly accurate but don’t have that impact. They are a reference headphone period, and the best closed back one at that. There may be a problem with distinction in instruments however in the mid-range.

If you strictly listen to good sources, these can sound great with a lot of genres. Just know that above all, they benefit producers needing a good mix-down.

I’ve seen it endorsed for:

  • Jazz
  • Classical
  • Pop
  • Opera
  • World
  • Gospel
  • Acoustic
  • Folk

It does well with music that has a lot of different instrumentation going on.

Not good for:

  • Metal
  • Rock
  • Bass-heads

On burn-in time:

Some believe wholeheartedly in it, others don’t. One reviewer mentioned that the K550/551 in particular greatly benefits from about 300 hours.


  1. Put them in a drawer and cover them with a sweater/clothes.
  2. Play bass-heavy Jazz, Classical, or something similar.
  3. Put on repeat at medium to loud volume for a week or 2.
  4. This should really open up the sound, and you may feel as though they are a different set of headphones altogether!


Just about the best closed-back reference can, from a purely analytical standpoint. Be cognizant of the strange fit, and if you can, demo them beforehand. They are supremely built, and the aesthetic is that of pure beauty. Bass is accurate and detailed, with good extension. Mid-range is a bit of a mixed bag, but the treble is almost perfect. Sound isolation is good enough, but the overall sound stage is a bit on the underwhelming side. Still, being a closed-back headphone, you get some characteristics of an open-back design. The best of both worlds perhaps?

Similarities & Differences


  • Both are a bit finicky with regard to clamp pressure and fit. It is widely known that the K550’s need to be tinkered with to get a nice fit, resulting in the best sound possible. The 551’s are very similar in this aspect as well.
  • Neither comes with a carrying case.
  • Neither have a replaceable cable.
  • Both have that same spike at 6khz.


  • Bass. The bass texture is noticeably different in certain genres but very subtle at the same time. Fluid bass tends to sound artificial and exaggerated while solid bass sounds realistic and detailed. You will notice more of a difference in classical music and other similar genres. If you prefer fluid bass, you may like the 550’s more.
  • Shorter cable. The K551’s have a shorter cable than the 550s.
  • Inline mic. The K551’s have an inline mic (volume control), which some say adds a nice touch. It is meant for iOS devices but can be used with your PC/laptop. Some however have complained that it doesn’t work well with Android devices.
  • Choice. The K550’s only come in Black. The 551’s come in Black/Silver or White.

Final Word

If you’re looking for the best closed-back reference can, the AKG K550’s will most certainly do the job. They have a great analytical sound and come across as very flat and neutral. Just don’t expect to be particularly amazed by the low end. They do their job quite wonderfully though. I don’t know if I can recommend the 551’s, as they get bad reviews across the board. It’s strange considering they are almost identical headphones though.


Well that’s about it for today my friend! I hope you came away with some valuable information on the AKG K550 vs. K551 today!

Are you convinced that the K550 is the best closed back reference headphone? Let me know!

If you have any other questions, disagree, or feel I missed something, comment down below or Contact me! I would love to hear from you.

Until next time,

All the best and God bless..





Can’t decide which headphones to purchase? Interested in a complete buyers guide outlining over 40 of the best options on the market? Click on over to the best audiophile headphones to learn more!!

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Willy December 17, 2016 - 7:03 pm

Hello Stu ,
Thanks for the good review on YouTube. It’s very interesting to hear about the problem with the mid-range on some series of this model. Maybe you can tell me more about it. I want to buy a second hand K550 here in the Netherlands or Germany and they are offered by people who want to sell it – not in the shops, but from people at home.

In which years are the “mids” not so good, and from, or in which years are they as good as they should be. Are there serial numbers on them that indicate which country they were made in?

I will be very grateful to hear from you.

With greetings,

Willy Schiil

Stu December 18, 2016 - 11:42 pm

I’m honestly not too sure, but I would buy from a reputable dealer to ensure that you don’t get a counterfeit model. And yeah generally you can send the serial numbers to the company and they will verify if your model is legitimate or not. Hope this helps. If not let me know!

Willy December 17, 2016 - 10:25 pm

Hello Stu ,
This is a very interesting review. I am interested in buying a second K550 and the remarks of problems with sound at 6 kHz prompted me to ask a question. How can you know that a second hand 550 has this problem or not? Is it not so with the 550 MK 2 ?
I hope you shed some light on this.

Thank you in advance.


Stu December 18, 2016 - 11:49 pm

Hey Willy,

You can’t really know without a shadow of a doubt, as people are shady and will sell you counterfeit gear from time to time. It’s always wise to purchase from reputable dealers to ensure that the product you get is real. I’ve read so many reviews over the last 2 years and I’ve seen good products get punished score-wise because of bad apples floating around, aka dishonest people selling fake models and passing them off as the real thing. This hurts the overall score.
Hope that helps. If not let me know. The K550 is an extremely solid model that is at its best in a studio setting. Perfect for mixdowns, mastering, etc. The fit is a bit awkward and takes a good seal to get the best sound.
Talk soon,

Willy Schuil December 21, 2016 - 3:59 pm

Hello Stu ,
Thanks for your reply! If I’m looking for better sound, should I go with a K551 MKII or the K553 (only in USA available until now). That is how I understood your message. Is that right? And with a K550 it just depends?

Thanks already for you reply and I wish you a very nice Christmas time!


Stu December 23, 2016 - 3:16 am

Hey man I would go with the K550 over the others to be honest. It’s the best out of those. Hope you have a blessed holiday as well! Anything else just let me know.

Willy Schuil December 23, 2016 - 8:33 am

Hello Stu,

Thanks for your reply. I see that I made a mistake in my question. I did not mean that I should get a K551 MKII but of course a K550 MKII or a K553. And with the K550 MKI it depends?

Stu December 23, 2016 - 9:06 pm

Hey man no problem!

So I would just bypass the MKII altogether; it’s not really a worthy upgrade from the MKI.

Between the K553 and K550 MKI, the similarities and differences are as follows:


1. All three look pretty much identical.


1. K553 has a clearer bass response, with more body. The mid-bass is a lot different, contributing to a sound with more thump.
2. K553 has a more controlled treble range. It’s less congested with less roll off.
3. The upper mid-range on the K553 is more recessed. Some people claim this makes the 553 sound more natural by comparison. Whereas with the K550 the mid-range is more forward and apparent.
4. The K553 has better imaging. You get a better sense of instrument placement.
5. K553 has slightly less padding on the underside of the headband. Some people find this difference to be irritating, others say the comfort is about the same.
6. Overall the K553’s sound much better. More balanced, more pleasant, more musical.

So basically:

K553 > K550 MKI > K550 MKII.

My recommendation? The K553. I know I said K550 MKI in my last comment but I goofed.


Willy January 6, 2017 - 10:29 am

Hi Stu,

Thanks for your reply two weeks ago. I understand but I do not know the word “goofed”, does it mean “I made a mistake”?

On head-fi.org I also read two interesting reviews: A comparison review AKG K 550 & K 553 from Bagheera, who agrees more or less with you.
Also on the same site there is a review from Rockstar 2005 under “AKG K 553 Pro vs. AKG K 550 MK II (and thoughts on the AKG K550 “MK I” and his conclusion is that all three sound exactly the same.

So, I think that everyone has different ears and also hears different, but the overall conclusion is that the 550 MKI, MKII and 553 are very good headphones, with perhaps very little differences.

I wish I could compare them in Holland, but they are very difficult to get and the 553 is only sold in the USA.

Instead of one of these AKG’s I bought a second-hand PSB M4U from a person on German ebay (two months old, he bought the same with noise cancelling for he travels in plains and trains) and this one pleases me very much.

Maybe you can review this model in the (near) future; I think many people can enjoy the quality of this headphone and enjoy your review.

A very good and healthy 2017 from Holland,


Stu January 7, 2017 - 10:11 pm

Hey man!

Yeah goofed is just a nice way of saying I messed up, lol. Anywho, I’m sorry to hear that they are so hard to get a hold of. A review of the PSB M4U is a definite possibility. Keep in touch or Contact me because I may forget with everything going on.


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