Sennheiser HD800 S
Excepting only the HE 1 Orpheus successor, the HD 800 is Sennheiser’s top-of-the-line headphone: “reference class” they call them, “crafted for perfection”. Earlier this year a new version arrived, the HD 800 S, the main external differentiator being a change from grey to black for the skeletal shell of aviation-grade plastic that surrounds the gleaming silver inner cover. This gives a new sense of purpose to a glamour which is almost entirely engineering-based — their form follows function so much that the aesthetic design team didn’t even get to veto the bold 30pt ‘L’ and ‘R’ indicators painted large at the rear. The open headshells are shaped not in a circle, nor an oval, nor an ear-mimicking sculpture, but as two curves of differing radii slammed together to form a bulging letter D, within which the circular acoustic port sits surrounded by its skeleton of supports, through which you can see (worryingly touch as well) the shiny silver cone around the source transducer, which is embedded at its end in a specially manufactured stainless-steel gauze.
Sennheiser HD 800 S The diaphragm inside is legendarily large at 56mm, and is a ring design rather than a complete circle. This has various potential benefits — instead of sound emerging as from a point source, the ring radiator delivers a more planar wave (see image right), which may allow the ear and brain to better localise different details, while in distortion terms a ring dramatically reduces cone break-up.
This second effect has been further assisted in the new HD 800 S by the inclusion of “absorber technology” that was pioneered in Sennheiser’s IE 800 in-ear phones, designed to reduce masking effects where low and medium frequency resonances can prevent or obscure the reproduction of higher frequencies. Absorber chambers are included to absorb any such resonances, which should further allow detail to shine. Sennheiser doesn’t specify where the resonances might occur, but the HD 800 S frequency response has reduced peaks over the non-S version at 6kHz and down around 100Hz. In a nice touch, you get the individual response of your headphones provided as a digital certificate supplied on a USB stick.
HDVD 800
Another change in the new model is the support of balanced symmetrical cables, as suited to the lovely driver unit we were supplied for the HD 800 S. The is a magnificent piece of electronics (pictured overleaf), looking more high-end Japanese than German, the internals showing proudly through a transparent taop plate lit by blue LEDs, as is the main power ring and the bright light of the input selector light which blazes over the too-small-to-read input labels next to the lovely volume knob. The HDVD 800 is a DAC as well as headphone amp, good to 24-bit/192kHz from four digital inputs — optical, coaxial, AES/EBU and USB-B for computer connection — and with two analogue inputs (balanced and unbalanced). Four headphone outputs are provided (two for balanced, two for unbalanced jack headphones), and useful balanced outputs to the rear can also carry connected sources through to a full hi-fi system. We used the HDVD 800 with various headphones (and as a USB DAC into our main system) and it proved flawless throughout in its speed and presentation from both digital and analogue sources, as well as being a simply gorgeous thing to have glowing on your rack.
HD800 S
The headphones themselves we were surprised to find less completely enchanting. Their greatest character is the absolute openness given to recordings — we were thrilled, for example, by their presentation of the opening sweep from horn to strings and flute on Nat King Cole’s ‘Nature Boy’, here given a cinematic spread across the soundstage and a riveting rasp to the Cole vocal as he takes up the strain.  
Placement of the soundstage is solid, with central elements held firmly front of head. But panned elements, natural or artificial, could end up wide indeed, and on a number of occasions the sensation was that elements were pushed distinctly behind us — the whole band in the case of Sinatra and Basie’s ‘Hello Dolly’, leaving just Frank isolated and lonely on the stage in front. 
HD800 SThis image of over-wide sides with a gap to the front was evident through much of our listening. Sennheiser makes a point of noting that “sound waves are directed to the ear at a slight angle. This ensures a particularly natural and spatial sound perception.”  But should headphones exaggerate width? They inevitably spread beyond the normal direct-plus-first-reflection presentation of stereo loudspeakers, but if a mix is designed to sit within that loudspeaker soundstage, then widening like this must either stretch elements apart or portray them as wider than real-life. Banging out some von Karajan-conducted Wagner, it sounded like the first violins were playing from the Grand Circle boxes left of stage.
It was this stretching of the soundstage that made another visiting headphone, HiFiMan’s Edition X, so notably superior in delivering images of a singer or instrumentalist more believably than did the HD 800 S. The other difference between them was the brightness of presence on the HD 800 S compared with the milder reality of the Edition X. We found ourselves reaching out to turn down the Sennheisers, particularly when casually listening and doing other things — and we just don’t do that with our favourite headphones. The edge they give to vocals and upper midrange elements was just sharp enough to add artifice, and occasionally such that we just wished they’d calm the hell down. 
The quid pro quo for that is that clarity of detail is beyond reproach — we found them excellent with Beatles stereo remasters not only for enjoyment but for close analysis, hearing how a song like ‘I Want To Tell You’ is built from a single-channel combo track of piano, snare and percussion to the clarity of the whole. We also found their bass delivery wonderful — full and fast; we didn’t need the time to adjust to this as we did when we reviewed the original non-S version.
HD800 SNothing gets to hide in this transparent delivery; the recently remastered ENZSO version of ‘Message to My Girl’ has wide sweeping strings with great depth, but the Sennheisers also revealed a level of hiss, and over the space behind the first verse something almost like turntable rumble, masked as soon as the orchestration built. 
One other niggle — even though we could be only a cable’s distance away from that lovely knob on the HDVD 800, we badly missed the convenience of remote control.
So we had fine moments with the HD 800 S, but they didn’t call us back for endless long sessions, as have other designs at this level. In years gone by, of course, there has been almost nothing against which to benchmark Sennheiser’s premium design. Now there is far more competition at this level, it’s easier to hear what the Sennheisers do differently, and thus establish a preference. Anyone auditioning this system is bound to love what they hear. But compare it with others at the price level, and you might just find something you love even more.