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.
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.