Hi-Fi Plus: Sennheiser HD 800 Headphones

Loudspeakers for the ears...

[This review originally appeared in issue 65 of Hi-Fi Plus magazine, which is published in the U.K.]

Sennheiser is one of the biggest names in headphones. And yet the company’s last big move into high-grade headphone design was the Orpheus, and that’s at least 10 years old. This has left the top-end of the headphone market open to rivals, at a time when – thanks to the iPod – headphone listening became cool once again.

That’s all set to change with the launch of the HD800, the new top of the Sennheiser line. Unlike the Orpheus of the 1990s, this is no electrostatic design and as such does not require the large valve-based, fan-shaped energiser that the previous top of the tree demanded. That also means that the HD800 can shave something like £9,000 off the price tag of its decade-old predecessor.

The HD800 is a circum-aural design (meaning the headphones sit over your ears instead of gently crushing your pinnae) that look substantial, but extensive use of ABS materials instead of wood and metal mean they aren’t as heavy as you might expect. Some have criticised this, even before the launch of the product; ABS being not as chic as metal – ABS being not as easy to dent or damage and doesn’t vibrate in the audio band, either, of course. The use of ABS extends to the headband, although this is topped off with a metal plate with the serial number etched in and a soft fabric headband. The oversized D-shaped surround for the drive unit and rear-mounted attachment to the headband looks austere on paper but doesn’t look too intrusive on the head. And it’s damn comfortable too; you can sit and listen to these headphones for hours on end with no physical fatigue whatsoever.

Perhaps surprisingly, the ear-cups themselves are uncovered, and the housing that keeps the transducer away from prying fingers is made from stainless steel. Aside from the fact that it keeps your ears less sweaty after long periods listening, this also works for acoustic reasons (less coverings, less things to resonate) and aesthetic ones (sci-fi style). The ear pads that surround these cups are made from a classy microfibre fabric, although not the one originally specified (see below).

The single biggest change that separates the HD800 from all that went before is the unique ring transducer. Most headphones have something not too dissimilar from a tweeter acting as transducer. A single drive unit is problematic though – too small and you get frequency extension problems; too large and the surface of the transducer sets up its own inertial vibration mechanism. At the extremes, this makes the pistonic action of a drive unit turn chaotic. The way to resolve this in loudspeakers is to introduce a second drive unit (or more) to cope with the other frequencies. Unfortunately, that doesn’t work when the drive units are about an inch from your ear, because you hear the two acoustic centres of the drivers as two distinct entities.

Sennheiser spent many years thinking about this, and ended up with a toroidal – or ring – transducer. This manages to deliver the large wavefront sound desired by listeners (bigger, clearer sound that is more extended into treble and bass) but without the aftershocks of transducer chaos. This in itself was only possible thanks to several years of materials science developments, to make a transducer material that was strong and rigid enough to cope with the job, but didn’t sound like a scrunched-up packet of Kettle Chips in the process.

With a wide-bandwidth, high performance driver in tow, the way the headphone interacts with ears suddenly became possible to explore. Smaller transducers effectively point at your ear canals, but the HD800 drivers are angled, to give the appearance of sound hitting the ears as it would when listening to a pair of loudspeakers set in optimal position. This gives you a series of psychoacoustic clues to make it seem like there really are loudspeakers (more realistically, musicians) out in front of you, because sounds arrive at nerve endings in the middle ear slightly earlier than others.

The HD800 comes with three metres of cloth-wrapped, Kevlar-strengthened OFC balanced cable, featuring four individually Teflon-coated insulated wires, for connection to a headphone amplifier. It includes the standard ¼” jack, but no mini-jack – this ain’t no iPod headphone. The cable is supposedly anti-twist, anti-knotty stuff – yeah, right. It twists a bit less than most plastic headphone cables (which seem intent on turning into a Gordian Knot three seconds after you rip open the box) and untangles easier than most, but there is no magic deknotifying technology here.