[caption id="" align="alignright" width="198" caption="The HD 800 is as stunning sounding as it is striking to look at."][/caption]Simply put, the Sennheiser HD 800 is the best full-sized headphone I've ever heard. But that's not a very interesting review, is it? We should get into this a little deeper. The HD 800 was introduced to the world at the 2009 Consumer Electronics Show, and began shipping in June. By then the world's headphone enthusiasts had been frothing at the mouth for six months. Just for fun, if you'd like to read all about it, here's 380 pages of raging frenzy and speculation that started after Head-Fi owner Jude Mansilla posted his first impressions of the HD 800 he heard at CES. It may be more informing to look at the official "HD 800 Appreciation Thread" as it contains the initial listening experiences and then further listening by the Head-Fi members. Let's get through some of the details of what all the excitement is about. My first exposure to the HD 800 was quite some time ago while I was on a factory visit maybe five years ago now. The engineers were very excited about the opportunity to have a "clean slate" developing the world's best dynamic headphone. At the time the dialog mostly centered on developing large diaphragm drivers for dynamic headphones that would deliver a flatter wave-front as it approached the ear and that wouldn't suffer "cone break-up." It was obvious to me they were also having the time of their lives with the whole variety of issues surrounding headphone design and were up to their necks in all manner of design ideas and visions. Interestingly, the final product was very unlike what I saw on computer screens that day years ago --- the sound however is not unlike what I had imagined: spectacular. [caption id="" align="alignright" width="198" caption="The HD 800 is rather large but quite comfortable."][/caption] The Sennheiser HD 800 is a full-size, open headphone design. Its earpieces are rather larger than most, fully and easily encompassing the ears. Ear cushions are a micro-fiber, velour-like material that are quite comfortable and don't inspire perspiration. There is a small cloth protector over the driver which is easily removable and washable; and there is a further permanently installed synthetic mesh material covering the driver to protect it from dirt and hair. The driver and ear pad are mounted in the outer earpiece, which is a framework cast of Leona plastic --- a 60% glass fiber filled, high stiffness specialized plastic used in the automotive industry. A very fine stainless steel mesh is also supported in the frame which separates the “inside” from the “outside” of the earcup. A one-sided bail piece attaches the earpiece to the headband and has two pivot points which allow adequate freedom for the earpiece to tilt and swivel to conform with the side of the head for a proper fit. The headband has a middle section which includes a comfortable pad made from the same material as the earpads. The sliding adjustment side pieces of the headband are plastic and run on a metal piece in the main headband part; Sennheiser claims that significant mechanical damping is provided by the construction and materials of the headband assembly. [caption id="" align="alignleft" width="198" caption="The balanced to unbalanced adaptor made from the end of an HD 800 cable after modification for balanced mode."][/caption] The OFC (oxygen free copper) cable is a "Y" cord attached to each earpiece with some very nice connectors; a large and very nice custom 1/4" stereo headphone plug is at the other end of the cable. There is no 1/4" to 1/8" adapter for use with portable players and the like. (You can use one of these.) These headphones are clearly worth the trouble to run in a balanced configuration, and HeadRoom offers a couple of options. The first is to modify the cable that comes with your headphone when purchased; we snip of a foot of cable at the 1/4" plug end and add the two XLR connectors needed to connect to our balanced amplifiers, and then we also add two female XLRs to the snipped end so that you have an adaptor to restore it to normal unbalanced mode for normal headphone jacks. Recently Cardas has begun to make after market upgrade cables for the HD 800, which are available in both normal unbalanced and balanced configurations, and in a number of different lengths. The major technological advance in the Sennheiser HD 800 is their "ring radiator" driver. This driver delivers a couple of advantages: it reduces "cone breakup," which distorts high frequencies; and it provides better imaging by being angled back towards the ears from a slightly forward position and emmitting a rather more planar wave front than a normal headphones driver. I’ll stop here as I've written an in-depth post about these drivers previously which can be found here. Now, to the good stuff: How does it sound? [caption id="" align="alignleft" width="298" caption="Notice how the HD 800 does not have wildly fluctuating and/or falling response above 7kHz. Possibly due to large planar wavefront at ear. "][/caption]The Sennheiser HD 800 is simply the best full-size dynamic headphone I've ever heard. (I narrow it to full-size because I think the JH13 custom in-ear headphones are even more transparent; and dynamic because I've had some brief experience with a few tweaky high-end electrostatic systems that may be better.) The "sound" of the HD 800 is essentially non-existent being as nearly a perfect audio straight pipe as I have heard. I have a habit of including pink noise listening in my evaluation process and --- other than a slight emphasis at around 5kHz to 8kHz, which can be seen in the frequency response data --- I would say they are very near perfect in terms of their technical performance. Though pure neutrality can sound slightly boring, the HD800 have one stand-out area of performance that is astonishingly pleasant and almost unique in headphonedom: great imaging. The sense of sound source position in space and depth with these cans is something I've only similarly experienced with the now discontinued AKG K1000 ear speaker, and possibly The Stax Lambda or Sigma Pro headphones. Nothing else comes close in my experience, and I suspect that the slight emphasis of the highs is somewhat related. Now the bad: these are not "fun" headphones. I would suggest it is logical to consider these headphones more akin to the scientific research instrumentation used so heavily in their design rather than considering them as an entertainment device. As long as an open headphone is appropriate, I would say that these cans are one of the finest tools a professional audio engineer or very serious audio enthusiast could have to hear exactly what's on the track. To the extent that a serious listener wants to have an absolute reference for evaluating the quality of a recordings or front-end audio gear, the Sennheiser HD 800 is currently the best tool for the job. But … I guaranty they are not going to make your old Django Reinhardt sound anything but like the scratchy old transfers that they are. Expect brutal honesty---not analytical or detailed (though all the information is there with which to accurately analyze the details) or anything that suggests that they are anything but completely transparent sounding. Just straight ahead honesty. There are a lot of great sounding high-end headphones out there that beautifully editorialize in one way or another: the luscious warmth of the Denon D7000; the punchy smoothness of the Ultrasone Edition 8; the on-the-stage immediacy of Grado cans; or the airy speed of the Sony SA5000 all legitimately attempt to deliver a signature sound pleasing to listeners of particular aural taste-buds. Finding headphones the tickle your fancy is part of the fun and I certainly admit to reaching for some of the above headphones to lush up my old Eddie Lang records, but … they’re not accurate, and the Sennheiser HD 800 is. [caption id="" align="alignright" width="298" caption="The HD 800 and HD 650 have similar damping time, but the HD 800 is a bit "dirtier" than the smoother --- some would say overly-smooth --- sounding HD 650."][/caption]I do have one gripe with the sound; as I mentioned above there is a slight glare … that may be a bit too strong a word, maybe it’s better to call them a bit dry sounding. I’ve found the cable changes make a substantial difference in this characteristic. Re-terminating the stock cable and running the HD 800 in balanced mode seems to help, but what really does the trick is a new cable. HeadRoom sells Cardas Headphone Cables in both a single-ended HD 800 Cable and a Balanced HD 800 Cable. Cardas is known for being a smooth sounding cable and they do seem to tame the slight edge I hear with the stock cables. Summarizing, I think owning a pair of HD 800s is a worthy first goal for every serious headphone listener. If you want a sweeter or punchier or bassier or whatever headphone that you’ll find beautiful and pleasing go for it … after you get simply the best full-size headphone reference available today: the Sennheiser HD 800. Please visit HeadRoom’s website to purchase your Sennheiser HD 800 with our Best Price Guarantee.