AKG K551

  1. GL1TCH3D
    Superb Pair of Headphones
    Written by GL1TCH3D
    Published Jan 28, 2015
    Pros - Great soundstage, good balance, accuracy and sounds natural
    Cons - Sub bass is a bit lacking to my ears. Headband has a bit of discomfort.
    Hello Head-Fi

    It's been a while since I've participated here since I more or less found my end game and now I only have the urge to change my music player.

    Today I'll be writing about the AKG K551 headphones.

    In simple terms, these are superb headphones for all around use.

    To sumarize my points early in case you want to skip the more in depth detail:

    The good is that it's well balanced, it sounds natural, the pads are comfortable and offer good overall isolation. I find the soundstage superb for a closed set of headphones.

    The bad is that for portable headphones, these are huge. The cable is not removable (not a deal breaker for me but with my experience with the Beyerdynamic T5p it's definitely preferred to have a removable cable). The sub-bass is rolled off (but still present). The packaging is lousy and they don't include any accessories, just a cardboard box with the headphones on a platic tray.

    Overall, these are my top pick for headphones under $300 and make a great entry level pair that will last for years (I heard some bad things about the pads getting worn out quickly though).

    So let's start with the aesthetics.

    These are single entry design using a plastic / metal combination for a very sleek set of headphones. The cable feeding into the right side is very discreet.

    I have the white version and find that overall it looks like a very clean design. The only "issue" is that there are markers on the headband to measure the extension which is a bit unnecessary in my opinion. The headband padding is very low profile but sufficient enough for most people to keep a fairly thin headband that will basically just look like a metal band stretching across both ears.

    The rougher plastic with metal accents gives the headphones a good aesthetic contrast.

    Besides the extremely large cups they're aesthetically pleasing. (If I look to the left / right I can see the cups protruding from the sides of my head)


    Moving onto build quality, they feel sturdy for sure. The headband has many notches for more precise control over the sizing and this is extremely appreciated by someone such as myself who has a head that's very sensitive to pressure (if there's too much weight resting on the top of my head it becomes extremely uncomfortable). The headband extension locks well so you won't find it sliding around while wearing it once set properly.

    The cable is very resistant to microphonics which is a nice plus. Unfortunately the jack is really fat and a straight jack. I would prefer having something detachable or something closer to what Sennheiser uses on the momentums where the jack is adjustable. Since this model comes with the inline mic I feel like detachable cables really should have been included since I find the mic just a nuisance given that I use the headphones with my AK120.

    As I mentioned earlier, I've read some complaints about the pads getting worn quickly. Pads getting worn is something that just has to be accepted. It happens even on the HD800 with their super engineered microfiber pads. I haven't owned them long enough to be able to comment on this.

    The headphones seem to be resilient against dirt other things which is nice. Headphones like the Fostex TH900 are magnets for finger prints (though completely different finish and material).

    I used to carry the AKG K551 in a case (I got the Deloop case from kickstarter which is a really nice headphone case but that's a different topic) but decided that I can just fold them up and throw them in my bag. I'm not particularly rough with my stuff (well, I actually am) but I make sure to consider the limits of what I'm using.

    These are sturdy enough that I feel safe putting them in my bag without a case with a bunch of other things but always put them at the top as to not have them crushed.

    Build quality is a solid 8.5/10 with the main points being lost for the cable (well, really all the points lost there are for the cable). Though do consider that the headphones were $150 new and having a removable cable would have likely driven the price up.

    Presentation of the headphones.

    These came in an underwhelming box on a plastic tray. I expected to open these up and find a bunch of goodies hidden underneath the plastic tray such as even a simple soft carrying bag to protect from dust and dirt during transportation or the standard 3.5 to 6.3mm adapter.
    No such thing existed in this box. I can say with certainty that this is not the same box that Schrodinger used in his experiments. There are no accessories and you should not expect any.

    Though at least the box had a plastic window so you can see them before buying them (if you're buying in store).

    This was no where near as underwhelming as when I received the Beyerdynamic T5p which I long regard as my worst purchase in this hobby with the only redeeming factor being that I learned not to trust the price when trying to determine quality.

    Presentation for the AKG is 5/10. (This includes the lack of accessories)

    Now onto the main dish, the sound quality.

    My only piece right now for testing is the AK120 (first version) with firmware 1.4 and no EQ.

    The AK120 is noticably unbalanced with emphasis on the midbass.

    My preference is for something balanced and natural. I prefer having headphones that will present everything as naturally as possible so I can sit back and listen to the whole piece or pick out specific parts / areas / instruments.

    I listen to a lot of soundtrack music/ jrock / some classical and pop/rock.

    First I must say the soundstage is superb for a closed back. I saw this as someone who's owned a lot of TOTL headphones in the past. I know that source and amp make a difference and maybe this specific pairing works really well (the AK120 is truly a nice unit) but I must say this is very pleasing as both an audiophile and a gamer. The width is very impressive and has good depth to back it up as well. Imaging is very well done for these headphones. The only thing lacking in this area is the resolution though I find it far superior to the other headphones in the closed back genre of this price point. The resolution isn't the greatest and can sometimes lead to a bit of a thick sound (which in turn makes it sound less delicate) but this is not prominent at all. (I only noticed because I've owned HD800s and Stax 007s). This is speaking from a highly critical stand point and looking at headphones at the $150 price point.

    As for the balance of the headphones, keep in mind that I do have to mentally adjust a bit when rating this because the AK120 has a midbass emphasis, but overall I find the headphones very well balanced with a roll off on the bass. This roll off is very noticeable on the subbass and has caused me confusion on a couple of occassions. Switching from the Nobles to the K551 (or from what I remember of the TH900) I anticipate the bass guitar or something else kicking in at a certain point and feel like I missed something. The subbass is present but rolled off.

    The AK120 does a wonderful job of keeping my headphones sounding smooth. One thing that I heavily disliked about the AKG Q701 is that they sounded very electronic with the O2 (which is a very transparent amp). The K551 has no such issues with the AK120 feeding it. I find the sound very natural and accurate enough for critical listening sessions. It presents a good balance between the two.

    The treble might have a bit of a recess in the higher ranges that was noticeable when listening to my test song, Apparition by Vanilla Mood (in flac CD rip of course). The violin in the climax of the piece was a little recessed compared to what I'm used to but it really could just have been the balance being more natural that it doesn't stand out as much as headphones like the HD800 where the treble is more emphasized than the mids and bass. (or at least has more peaks). I don't feel any sibilance from these headphones.

    The bass is tight but definitely not any kind of bass head level pair of headphones. I hope that my emphasis on these being a balanced pair of headphones has made this clear already. The bass is present with some impact but it's not booming, ear shattering or any of that. I find the bass very appropriate for listening to my music which comprises of cellos, bass guitars, pianos and more. I'll just mention it again that I find the subbass rolled off a bit.

    The mids are full. Not buttery smooth (I don't think anything really ever reached the buttery smooth mids of the SE535 in my mind) but smooth and natural. I used to cringe or feel off when listening to vocals (of which my collection comprises mostly of females) on some of my past headphones because they sounded distant or weak with respect to the rest of the song. I have no complaints about the mids.

    The delicacy of these headphones is one of the two main factors in my mind for what's lacking. While they're amazing headphones for the price they still lack that finesse that I've heard on a lot of the TOTL headphones (this however doesn't include the T1, T5p and roxannes which I feel didn't have any finesse).

    Overall I rate the sound at 9.5/10 for my preferences and this is in respect to a lot of the higher end headphones that I've tried. Keep in mind sound is subjective and it's always recommended to try headphones first.

    Now the dessert / conclusion.

    To summarize, these headphones have amazing value. Packing in a decently portable design, good build quality and aesthetics mixed with the best sound I've had from headphones at this price point, they make for headphones that I will readily recommend to anybody looking to get into hifi at this price point. The sound quality issues I mentioned won't really be that apparent to most people anyway.
    The cons are that there's a distinct lack of accessories with these.

    Overall I give these headphones a 9.5/10 for the price. I would definitely recommend these to others.
      Brooko likes this.
    1. View previous replies...
    2. GL1TCH3D
      The soundstaging extends from the sides to the front which is what I believe you're referring to. Yes, this still occurs.
      GL1TCH3D, Feb 2, 2015
    3. urakur
      I just acquired a pair of these and first off I was a little disappointed with the bass projection, however after listening to an excellent recording of Iron Maidens 'Hallowed be thy Name' my view has changed somewhat with the bass although lacking in a powerful 'punch' BUT hey that is not what these units are about. I still will be seeking out a nice cost effective DAC/Amplifier unit to see what transpires.
      I find the sound stage quite accceptable as I do not listen to any highly arranged music. The only other factor that I became aware of was the ability of these units to show up some of my poor recordings with an annoying level of the all to familiar Hiss present.
      Overall I am happy with the purchase and sure it will suit my broad Apple based needs.
      Bring on the DAC/Amplifier sessions.
      urakur, May 17, 2015
    4. valiant66
      Hmm. Perhaps your model is newer than mine. On mine, the cable feeds into the left side earcup, i.e. the single descending pivot arms point towards the rear of the head when worn. I'm pretty sure I've got it the right way around based on the giant "L" and "R" printed inside the earcups... Is your pair the other way around?
      valiant66, Jan 5, 2016
  2. shepscape
    Great Phones with no major faults
    Written by shepscape
    Published Jun 11, 2014
    Pros - Dynamic range, spacious soundstage, clarity
    Cons - short and flimsy cord, portability
    So, like all of us on this forum, I love music... couldn't live without it. Whilst I own some decent-ish headphones (Bose QC20i, Bose QC15, Sennheiser Momentums) I wanted something with a bit more musicality. The Momentums I never really liked. I also wanted an all round set of phones that I could use in the house or when out and about, which ruled out open back.
    During a single audition session I tried all of the major players in the mid-range closed back field - and I tried them with all sorts of music since, whilst I am no basshead, I do like some depth to my lows. 
    So, imagine my surprise when the K551's emerged as my favourites!
    The soundstage is really fantastic for a closed back set of phones and the clarity is simply awesome for a set of cans in this price range.
    They are reasonably bright in the highs - which to my mind is only as a result of their overall clarity - but they are by no means harsh. In fact, this had been my big fear when trying them out and I went into the listening session fully expecting to prefer their cousin, the K545's, which have a noticeable bass inflection. 
    However, the K551's give lows a real depth when the music calls for them, taut and powerful when need be. However, there is no in-built predisposition for the low end of the spectrum - which might rule them out for some.
    I noticed no difference in the listening experience against the K550's and it was the long cord and the lack of controls which were the deciding factor here.
    The price in the UK is now around the £90 range and yet cost didn't enter into my reckoning. I would have paid much more for the right cans - it was a happy coincidence that the K551's were such a bargain!
    The only niggles I have found in my listening hours since purchase are that a) the cord is far too short and flimsy for a set of headphones that have such illustrious lineage and b) they are not the most portable cans out there, by any means! To those two niggles I'd also add that, whilst these phones aren't difficult to drive overall, if ear-splitting volume is your thing then you might want to consider an amp. I use an FiiO E07K for those times when I want some additional gain - and it also gives me the option of slightly colouring the music without resorting to the equaliser, by tweaking the bass a step.
    All in all, these are an awesome set of headphones - especially when considering the bargain price. The clarity is a cut above the rest - easily, in my view, worth a lack of in-built disposition for the low end of the spectrum, which might prevent some from making the purchase. This would be a shame - those individuals would definitely be missing out.
    I've rated them 5-stars, despite the one or two niggles, because at this price there is simply nothing better out there.
      nephilim32 likes this.
    1. Bytor123
      Just got these for £49.99; very impressed (through FiiO E09K/E07K and 320's). 
      Bytor123, Dec 17, 2014
  3. SonyMDRer
    A class of it's own.
    Written by SonyMDRer
    Published Jan 14, 2014
    Pros - Very spacious, tight bass with punch, sparkle treble region, easy to drive
    Cons - Some people might not like the treble region, the cable seems flimsy
    Personally, this is my favorite headphone.
    I gave this headphone a conservative 4/5 because I simply have not had the chance to try all the headphones in the world, so I'm sure there are some headphones that can hit 5/5.
    First of all, these are closed back headphones with a good amount of isolation. With that said, it is amazing how 'airy' these headphones feel. They offer tight bass with punch which is quite unique to its class. Furthermore, this headphone has a beautiful treble region which gives tons of sparkle giving you the feeling that this headphone reveals a lot of detail.
    The only negative thing I can say about these headphones, it is that some people have complained that the spike in the treble region becomes bothersome. With that said, I personally love the treble spike so it does not bother me at all!
    For a more detailed review, please see my video review located here:
    1. WhiskeyJacks
      I really liked your review, I am not currently looking for a pair these I was just browsing around but it is always nice to see some one with a headphone they are really happy with. 
      WhiskeyJacks, May 8, 2014
    2. SonyMDRer
      Thank you so much for the kind words! I'm glad I made an impression on you :)
      SonyMDRer, May 8, 2014
  4. partyHat24
    Really Good (newbie)
    Written by partyHat24
    Published Nov 6, 2013
    Pros - Extremely clear, amazing bass, dynamic range, nice earmuffs, seems easy to drive
    Cons - Non-detachable cable, huge, cable could use an extra 6"-12"
    I'm a newbie to hi-fi headphones, but I'll do what I can.
    The bass is fantastic, and I point this out because so many people complain about the lack of bass. It isn't this thumping and muddy sound, but very clear with an entire range to it. For bass-heads this might not be what you want. Although, when I sampled dub step on them (not really a fan of the genre) I could get the bass poppin' by changing the EQ.
    The sound is very clear and even, however I would call the high's a little bit harsh (but not unbearable).
    The range is amazing. They're very warm in the winter.
    The cable should be detachable for this much money and could be a little bit longer. The K550's is far too long, though.
  5. Chiek
    Favourite headphones for outdoor use , great ear muffs for the cold winters of Norway
    Written by Chiek
    Published Sep 3, 2013
    Pros - Audio quality, comfort, short cable for outdoors, sound control on cable, powerful enough for iphone and ipods, no excessive bass
    Cons - If you don't like the Princess Leia look also not suitable for cycling because of safety helmets issue
    Built for outdoor use like jogging and walking because of the shortness of the cable and the remote volume control. I enjoyed listening to classical music, folk, rock music with it. Sounds were rich and well balanced, highly differentiated but with  no overpowering bass.
    The head phones do justice to Noah and the Whale's music for their complex string orchestra and rock music mix.
    Great jogging companion. Some dispute that the grip is too loose and falls off from jogging movements. Mine stayed well on my head and were extremely comfortable. I guess we all have different head sizes and shapes. To see if these headphones fit your jogging lifestyle, the only way to find out is try them on for size and go jogging.
    If you like the  Princess Leia look, then it is a bonus for you to put on one of these pairs of sweet babies.
    They are excellent ear muffs for the cold winters of Norway.
    I prefer it to Senheisser's momentum because of a better sound.
    Unfortunately, one cannot cycle with it because of helmet issues
    1. JoeDoe
      JoeDoe, Sep 3, 2013
    2. thatBeatsguy
       It ain't good for jogging at all. It has a really weak clamping force that makes it fall off of your head really easily. I wouldn't even think about it if it were for mere walking.
      thatBeatsguy, Sep 4, 2013