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.
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 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 ear pads 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 mostly definitely 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 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 headphone. 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
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.
Non-removable cable. Depends on your preference really.
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.
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 spike at 6khz. Metal or electric guitar in that region may become problematic. Some detail is slightly blurred.
Credit to my boy @Metal571. Check him out on Twitter!
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.
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:
It does well with music that has a lot of different instrumentation going on.
Not good for:
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.
Put them in a drawer and cover with a sweater/clothes.
Play bass heavy Jazz, Classical, or something similar.
Put on repeat at medium to loud volume for a week or 2.
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 come with a carrying case.
Neither have a replaceable cable.
Both have that same spike at 6khz.
Bass. The bass texture is noticeably different on 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 550’s.
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.
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 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.
Stu is determined to provide the truth about all things audio, and strives to deliver excellent content to you the reader! In his spare time, he likes to fish, paint, play guitar, attend church, take photos, record videos, graphic design, and more. His attention to detail and perfectionist attitude are what allow him to excel, but it can be both a blessing and a hindrance at times.