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So what's all the fuss about?
First and foremost it's the new
driver included in the headphone. A headphone drive
unit is typically like a loudspeaker driver in that
a flat or slightly conical diaphragm is propelled by
a few turns of wire in a magnetic field.
In this case, however, the driver
diaphragm is actually an annulus, or flat doughnut
shape. Sennheiser calls it a 'Ring Driver' and
explains that it has a significant advantage over a
circular diaphragm, in that it doesn't resonate in
the same way at high frequencies.
Headphone drivers suffer from the
same compromise as loudspeaker ones regarding size.
Bigger is better for bass but leads to resonance
problems in the treble. The Ring Driver is 56mm in
diameter, larger (by a couple of mm) than any other
headphone driver in current production, but is
claimed to have a much greater resistance to
resonance.
Sennheiser doesn't go into detail on
this, but speaker designers have long understood
that the centre of a circular driver is a problem
point as energy arrives there from all directions
and has nowhere to go: the result is not only
resonance but uncontrolled, chaotic behaviour that
can have nasty effects on audio. Dealing with this
is a black art in both headphone and speaker
(especially dome tweeter) design.
Having neatly sidestepped that
issue, Sennheiser has employed various measures to
ensure that nothing else in the HD800's design lets
the performance down. Construction is based on
high-performance plastics which we would have sworn
were metal, but no – metals would have been too
inclined to resonate and colour the sound, so
ultra-hard polymers were used instead.
Cabling uses four cores of
high-purity copper with Teflon insulation, and the
outer insulation and braiding of the cable have been
carefully chosen to minimise mechanical
noise-coupling up the wire.
Even the headband has been designed
against resonance, using both metal and plastics,
well-padded, of course, for comfort. The ear cups
are also luxuriously padded and every part of the
HD800 is designed to resist resonance and rattling.
There's one more feature that
deserves mention. The Ring Driver, with its large
size, produces a good approach to a planar wavefront
which seems to the ear to have travelled from afar,
aiding sound naturalness.
Sennheiser has angled the driver so
that the sound appears to come from slightly in
front of the head. The precise acoustics of
headphone coupling is a tricky subject, but this is
an ingenious approach to ensuring a flat and
realistic frequency balance.
Sound
quality
We've had plenty of exposure to
high-grade headphones over the last couple of years,
so expectations were high for this newcomer. We were
not in any sense disappointed, for this is certainly
one of the most revealing bits of audio kit it has
been our pleasure to encounter.
Like a lot of really fine gear, it's
not 'impressive' on first listen, but it doesn't
take long to realise that something rather special
is going on in the neighbourhood of one's ears.
If you're not a regular headphone
user, you may not be familiar with the advantages of
good 'cans'. Viewing them as second-best to
loudspeakers has some justification – no headphone
will ever whack your whole body like good speakers
can, imaging takes a little getting used to and it's
a rather solitary experience. But very few
loudspeaker designs on the planet can come even
close to the level of detail resolution that
headphones like these can provide.
The first impression of this model
is likely to be of a very slightly 'soft' sound –
not in the sense of 'not loud' but soft in
presentation. To put it rather coarsely, the sound
does not stab you in the ear the way some cheap
headphones can seem to do.
Any idea that the balance is
treble-shy, however, will very quickly be corrected.
In fact the treble is both lively and rich, but it
is so clean that its sheer quality needs a little
adjustment time.
This quality is at its most apparent
when textures are thick but include lots of treble
detail, or conversely when subtle high-frequency
instruments are playing, such as those various
little dangly bits of metal whose names only
professional percussionists know. Listen to sounds
like that and the chances are you will suddenly
think, as we did, 'Damn, regular hi-fi is just so
coloured'.
It's not just the treble. Midrange
is amazingly detailed. Voices and instruments all
have exactly the timbre that they do in real life
and they don't interfere with each other the way
they can when played via less exalted reproduction
equipment. A single flute at the back of an
orchestra is just as clear as two dozen violins at
the front, just like real life.
Of course if the recordings you
listen to are below par you'll get the proverbial
warts and all, but even that's not so bad: the HD800
is ruthlessly revealing, but somehow still seems to
make the best of whatever redeeming features a
recording possesses. |
