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.