Pros: Comfort, style, and sound are 2nd to none in its price range.
Cons: 3.5mm connector too large to fit some portables. Cable replacement is hard to find. Price continues to go up with demand, specially outside the US.
I have only owned this for a couple months, but it did not take long to see why these are highly regarded. They quickly became my favorite all-rounder headphone for home use. I also own the Sennheiser HD 25-1 II, and Grado SR60i, I will make some comparisons to these also. Although sound quality is important, I will take a more balanced look at how practical these are to use on a daily basis.
I consider the comfort and design of a headphone to be just as important as sound quality, because this is what will ultimately determine whether I will find it practical to use on a daily basis, and whether it will last for many years to come.
The HD 558 is hands down the most comfortable headphone I have ever worn. The open design, the Velour headband and ear pads, the light weight construction, the perfect clasping force, and the roomy size inside for the ears all work in harmony to create what many consider to be one of the worlds most comfortable headphones, in any price range. I can wear them all day long (even with my glasses on), with no hint of discomfort, no heat or sweat issues. Grado SR60i's being on ear style do get slightly uncomfortable with glasses on over extended periods. This is a non issue with the HD 558. In terms of style, these look fantastic on your desk, or on your head. The fusion of comfort and style is truly a feat of engineering on Sennheisers part.
Some have concerns about the plastic construction, and what affect it will have on durability. Although I have only owned them for a couple months, I have no doubt they will last many years. The Sennheiser HD 25-1 II has legendary durability, and is completely plastic also. The look and feel of the plastic is top notch. There were reports of cracking on earlier models, but this has been addressed with newer models. Sennheiser has been great in honoring their 2 year warranty from what I have read of those affected. Heck, you have 2 years to “break” them in ;).
The only real conn in terms of design for me is the cable. The 3.5mm connector is huge, and wont fit many portables, specially ones with protective cases. And even if your lucky to have it fit, it will stick out by nearly 4inches, more than doubling the size of most portables, making them not so portable anymore. On my desktop, I use Logitech Z-2300 2.1 speakers, which have a 3.5mm input on the remote control that I used to use for my other headphones, but this connector is too big to fit, really annoying.
The length of the cable at 3m is over double what most people need. The fact it's replaceable is nice, however, I can't seem to find any of these cables to buy. The headphone connector is 2.5mm, but its a really narrow shaft, and most 2.5mm cables I found are too fat to fit. Plus, theres that nifty locking mechanism that only the official Sennheiser cables have. My only option seems to be to cut this one down and re-terminate it myself, or find a pro to do it for me.
The sound stage on these is similar to the Grado SR60i, that is to say, its fantastic. Yes, it will occasionally have your head turning to locate that “noise” behind you, on tracks you heard hundreds of times already. The HD 558 does this all with slightly better separation on more complicated compositions, especially in the mid range. In comparison to the SR60i, the highs are more subdued, which I consider an improvement. SR60i's are great, but the highs are a little overdone in my opinion.
The area where the HD 558 really takes the cake is the mids. The mids are in your face, right where you want them. They are far superior to any headphone I have in this regard. The only real conn in terms of sound, for some, will be the bass response. It is a noticeable step up from the SR60i. It keeps up well, you hear it all, but not with that satisfying punch or rumble that you would get with a closed or more expensive ($400+) open headphone.
The nice thing about these is your average source or portable will be able to to run them with no problem. It seems when you break the $250 price range your going to need to double your budget to get a decent source to enjoy their full potential. Not the case with the HD 558. As with most higher end headphones, these can shine even more when connected to high end amplification, but it is by no means required.
If your looking for a great all-rounder for the home under $200, these are hard to beat. At home people tend to leave headphones on for extended periods, and you will have a hard time finding something more comfortable or better sounding in this price range. The only way I can't recommend these, is if your a complete bass head, in which case, your alternatives in this price range will be destroyed in every other area besides bass, and will leave you in a puddle of sweat within the hour. And if your looking for something portable, you should not be looking for an open headphone, specially a full size one. My HD 25-1 II is my portable headphone of choice, and the HD 558 has become my home all-rounder of choice. Between these two, I have a quality headphone for any application, at home, or on the go. Viva la Sennheiser!