Tannoy Dimension TD12 loudspeaker

Tannoy Dimension TD12 loudspeaker
Art Dudley, November, 2003
My friend Harvey Rosenberg, who had more clever ideas in a day than most of us have in a lifetime, was a
Tannoy loudspeaker enthusiast. I, on the other hand, had little experience with the brand before 1995, when
Harvey invited me to come over and hear his then-new Tannoy Westminster Royals.
I'm not sure what I expected, although I remember I had to be corrected as to
Tannoy's origins: Something about the sound of the name had always led me to
think, dully, that the brand was Japanese. As it turns out, Tannoy began life in south
London in 1926 when its founder, a man with the improbably colorful name Guy R.
Fountain, started making electrolytic rectifiers by combining tantalum and lead
alloy—and there you go. (In my defense, the mistake might have been fueled by the
fact that Tannoy's biggest and most expensive loudspeakers have always been
popular with the audio cognoscenti of Japan. In fact, Japan imports more Tannoy
speakers than any other brand.)
But getting back to Harvey and his Tannoy Westminster Royals: My first listening
impression may or may not have been conditioned—I mean this seriously—by the
fact that, when I first laid eyes on them, I wasn't entirely sure the speakers I had
traveled to hear were speakers at all. The well-crafted, unabashedly wooden
Westminster Royals looked like very heavy china cabinets. But where one might
otherwise expect to see an entire row of commemorative plates—perhaps featuring
the likenesses of Ron and Nancy Reagan, the crew of the spaceship Challenger,
and Diana, Princess of Wales—each Westminster displayed on its single shelf a
single plate. On closer inspection, the single plates were single drivers, each
marked with insignia in gold leaf.
That first listening impression was extremely positive: For the first and possibly last
time in my life, I heard a stereo sound every bit as dynamic as real music. I wound
up spending the night at Harvey's, sleeping on the couch in the same room as the
speakers, listening until I couldn't hold my eyes open any longer.
That's velvet, isn't it?
The new Tannoys I was sent for review, the Dimension TD12s, don't look like china cabinets or anything else.
They are products of modern thinking. (A bit later, I'll tell you what my wife thought of their impact on our livingroom décor.) The important thing for now is that the TD12 retains a link to Tannoy's past: one of its drive-units is
actually two drivers in one—a Dual Concentric, to use Tannoy's trademarked phrase.
From the earliest days of their involvement with domestic audio, Tannoy believed that one of the great
impediments to making a convincing full-range loudspeaker was the fact that different drivers, covering different
portions of the audible frequency spectrum, create wavefronts that tend not to blend well: Their dispersion
characteristics clash. They aren't properly time-aligned with one another, meaning that various subcomponents of
the resulting complex wave are out of phase with each other as compared with the original. And because these
wavefronts are launched from different physical points, the listener's perception of music playback as a spatial
event is a hit-or-miss affair, depending on where he or she sits in the listening room. Egad.
Tannoy introduced their solution to those problems in 1947, when Sam Tellig was but a wee lad and the end of
World War II made it possible for England to redirect her wartime technologies toward more peaceful things: a
one-piece woofer and tweeter, arranged coaxially. In the interest of physical time alignment, its high-frequency
driver was positioned behind the throat of its low-frequency cone, thus distinguishing the Tannoy from other
coaxial loudspeakers, then and now, where a tweeter is suspended in front of the woofer dustcap. And it differed
from its contemporary, the Voigt driver (footnote 1), in that the Tannoy's two vibrating elements were physically
and electrically separate from one another: The tweeter neither rode piggyback on the woofer nor shared its
voice-coil. Thus: Dual Concentric.
Notwithstanding the refinements afforded by such things as computer-aided design, metal-depositing techniques,
and various new polymers, Tannoy's best speakers of today have the same Dual Concentric technology at their
core. The TD12 is built around a driver that combines a 1.25" aluminum-dome tweeter with a 12" pulp
bass/midrange cone. The dispersion of the former is controlled by a stationary waveguide and by the woofer cone
itself, which acts as a horn, the flare rate of which is best described as "compound." In addition to keeping
electrical sensitivity high, that probably makes for a much smoother resulting impedance curve than would
otherwise be possible. The woofer cone, for its part, has a relatively stiff surround made of impregnated fabric,
and it's reflex-loaded via two ports on the back of the cabinet. As supplied, these are filled with foam to provide
resistive loading.
On paper, the two diaphragms appear to have been engineered as one with the greatest of cunning—yet because
they're electrically and physically separate, some form of crossover is required. Luckily, this has been kept simple:
a combination of a third-order low-pass filter with a first-order high-pass, all hardwired, and with a center
frequency of 1.1kHz. The result is something that sounds impossible: a single-driver loudspeaker that can be
biwired.
But here's another twist: The TD12, like the other models in Tannoy's Dimension series, isn't a single-driver
speaker at all: Tannoy has equipped it with their new SuperTweeter, a 1" titanium dome with a neodymium
magnet. The Dual Concentric driver is allowed to roll off naturally at the top of its range, and the SuperTweeter
blends in with the aid of a third-order high-pass filter. The center frequency of this compound (acoustical plus
electrical) crossover is 12kHz, and the response of the TD12 is claimed to extend way the hell out to 54kHz,
where boy bats whistle at girl bats. The SuperTweeter sits in a chunky ovoid housing machined from aluminum
alloy and mounted on the main cabinet in such a way that its voice-coil is the same distance from the listener as
the other two.
And what a cabinet! Its lines slope and curve, with few parallel surfaces in sight. A cherry veneer that wouldn't
look out of place on an expensive Stickley table shares space with metal trim and a black velvet apron, the latter
ostensibly to absorb and tame unwanted high-frequency reflections. And because it's constructed entirely of Baltic
birch plywood—the baffle is 1½" thick, with 1" wood used for everything else—the TD12 is unusually heavy for its
size: a whopping 108 lbs each. Since I have no friends and most of our floors are hardwood, I wound up moving
the TD12s around by "walking" them onto a little area rug, sans spikes, then pulling them from room to room like a
child pulling a very large toy.
Now I'll tell you why I had to move them at all.
Big speaker, big room
The room in which I do most of my listening—which, in its previous lives, before I bought the house, served first
as a master bedroom, then as a dining room—is 12' wide by 19' long, with an 8' ceiling. I place loudspeakers at
the far end of this room, firing down its length, and when I install a new pair I rely on both my ears and my
AudioControl Industrial SA3050 spectrum analyzer to achieve both the best bass extension and the smoothest
overall response.
I started out using my Naim separates with the Dimension TD12s: Playing a 92dB speaker in a medium-small
room with 35W or so seemed reasonable to me, and there were no technical clashes I could see. The first record
I listened to was the Peter Maag/London Symphony recording of Mendelssohn's A Midsummer Night's Dream
(LP, Decca/Speakers Corner SXL 2060). I was a little disappointed. Even with the Tannoys well into the room and
away from the walls, the sound was more colored than that of the similarly priced Quad ESL-989 speakers,
whose places they'd taken: boomy bass, and odd dips and peaks throughout much of the midrange. Voices and
some instruments sounded dark, and the whole presentation had a slightly hollow quality: obviously, not the
results I or anyone else was striving for.
I tried a more delicate record: Joni Mitchell's Blue (LP, Reprise MS 2038). That one fared better, arguably thanks
to its comparatively limited frequency range. But still, Mitchell sounded darker and thicker than usual, especially
toward the bottom of her singing range, and the piano, which sounds a bit glassy on some of the album even
under the best of circumstances, now sounded glassy and thick. Still, I couldn't help but enjoy the music. Rhythms
and pitches were just fine.
Setting aside for a moment the matter of tone, I thought the sound of Levon Helm's snare drum on The Band's
Music from Big Pink was better than I'd ever heard: The Tannoys did an amazing job of getting across the idea
that I was hearing a real human being whap a wooden stick against a drumhead with considerable force.
I returned my attention to speaker placement, paying careful attention to the changes, both measured and heard,
as I went along. More than anything else, I noticed that small shifts in loudspeaker and microphone position
yielded greater measured differences than I'd expected—although the octave between 125Hz and 250Hz was
consistently elevated by at least 3dB relative to the rest of the midband, which may have accounted for the dark
quality. It was easy to get flat bass response all the way down to 25Hz, although not so easy to do it without
bringing a 6dB peak at 31.5Hz along for the ride. I dealt with a slight (3dB) peak at 4kHz by aiming the speakers
more or less straight ahead, rather than toeing them in drastically toward the listening seat.
Thinking such finicky behavior might be mitigated in a larger room, I brought the TD12s—as well as the sources
and electronics I'd been feeding them—into our living room, which measures a comfortable 28' by 21', again with
an 8' ceiling. Décor, or what passes for it, required me to arrange the speakers along the long wall, spaced a
healthy +14' apart and firing across the room's short dimension.
Bingo.
I don't feel constricted in a room of less than 230 square feet, but the Tannoys apparently did. Giving them more
breathing space made a significant difference in the TD12s' overall tonal performance and the cleanness of their
bass response—although I found it interesting that the spectrum analyzer still found small peaks at 31.5Hz, 4kHz,
and 160-200Hz, again varying somewhat with microphone placement. Of those artifacts, the only one that proved
persistently audible in the larger room was that lower-midrange hump—and then only slightly. Given enough
room, the Tannoys distinguished themselves as great speakers with a darkish midrange, not as loudspeakers
with an objectionable coloration.
Whatever dark quality remained was most audible on voices, male artists taking on more thickness than I'm used
to—as I heard from Frank Sinatra on Moonlight Sinatra, my favorite of his Reprise-era records. And alto Kerstin
Meyer, doing the honors on Barbirolli's recording of Mahler's Symphony 3 (BBC Legends BBCL 4004-7), sounded
slightly chesty. But the sheer presence of well-recorded voices wasn't dimmed in the least; in fact, I enjoyed vocal
music of all sorts at least as much as usual through the Tannoys: This was just how they sounded.
It was clear sailing from there. Spatial performance was superb, with surprisingly good depth from far left to far
right, even when I had the TD12s fairly close to the wall behind them. Perhaps most significant of all, the Tannoys
had a tremendous sense of scale, as good as any horn I've tried at home. Whereas my Quad ESL-989s are large
speakers that behave like small speakers when it comes to the spatial aspects of stereo reproduction, the
Tannoys are large speakers that behaved like large speakers. Imaging precision, and even the ability to sound
tidy when called for, were not beyond them—the Joni Mitchell disc and others like it never sounded freakishly
big—but the TD12s fairly lived to play orchestral music. They helped bring my enjoyment of Ein Heldenleben and
other Strauss tone poems to a new level, letting me appreciate the physical aspects of the big, often gaudy
arrangements in a way I hadn't before.
Yet the TD12s did something else I've come to associate with efficient speakers: They played music convincingly
at low levels. Sometimes I want to hear orchestra music at less than orchestral volumes—but I still want color and
presence and scale. The Tannoys did all of that with apparent ease. At volumes where conventional loudspeakers
can't manage a convincing center image, the TD12s filled the imaginary stage with real, involving music that just
happened to be quieter than real. I remember listening one afternoon to Curzon and Knappertsbusch play the
Adagio un poco moto from Beethoven's Piano Concerto 5, the "Emperor" (LP, Decca/Speakers Corner SXL 2002,
one of the loveliest records ever made), at a very low volume, just because that's the way I wanted it. The
Tannoys sounded wonderful. As I've said before, hi-fi is good only when it does what we want. This was very
good.
The TD12s were supremely dynamic, playing all sorts of music with realistic amplitude contrasts and,
consequently, a fine sense of drama. Were they as capable of startling a listener as Harvey's Westminster
Royals—or other fine horns, for that matter? Probably not. But they were more satisfying than most, and for sheer
physical impact of drum sounds on well-recorded rock, they had few peers. When the kick drum and electric bass
came in near the beginning of Procol Harum's "Shadow Boxed" (The Well's On Fire, Eagle ER 20006-2), I could
feel it in my sternum—yet pacing wasn't the least bit slow. Utterly, utterly cool.
Drawbacks? For one, I wound up thinking the Tannoys sounded better—more open, even more neutral—with
their grilles removed. It had nothing to do with the blocking of this or that frequency range; the structure that
covers the main driver itself is a row of regularly spaced strands or strings. (Think whale's mouth and must strain
plankton.) The very heavy grille panels—11 lbs each, which is more than some speakers weigh—might be storing
resonant energy. Just a guess.
Neither my wife nor I cared much for the styling. All that black velvet picks up dirt too easily. The chrome-like trim
and the eye-like tweeters are jarring, especially next to the nice cherry veneer. Putting the bad grilles in place
adds a chrome porthole to the mix, making it look like the sort of thing that has Ted Williams' head in it. You may
respond differently; in any event, the Tannoy's very high build quality is indisputable.
Little amp, little room
Harvey Rosenberg, who passed away shortly before the destruction of the World Trade Center, was led to
Tannoy by his nascent interest in low-power amplifiers: His horn-loaded Westminster Royals had a sensitivity
rating of 100dB. Still, it's fair to say that all the company's Dual Concentric speakers are more efficient than
average.
Before sending the Dimension TD12s back, and acknowledging my own fondness for the breed, it made sense to
try them with a couple of single-ended triode (SET) amplifiers.
Dragged back to the smaller room, powered now by my 300B-tubed Audio Note Kit One (about 7Wpc on a good
day), the Tannoys did all right, but just. Heldentenors and loud pianos pushed the envelope, taking on that
distinctive, clipped-tube mushiness. My Fi 2A3 amp sounded beautiful through the Tannoys, but only at
consistently low volumes. I didn't even try driving the Tannoys with SETs back in the big room, where the 35W
Naim was itself getting into a peck of trouble here and there. While the TD12 is undeniably efficient, then, I
wouldn't buy a pair for only that reason.
But if my musical diet leaned heavily toward large-scale orchestral music, and I wanted to build a dramatic,
dynamic, and altogether engaging music system into a large living space, the TD12 would be at the top of my
list—exceeded only by my abiding interest in building my own ridiculously large horns some day, and knowing in
the back of my mind that my wife would never let me spend $23,000 on Westminster Royals. Money I don't have
anyway, and probably never will.
Most readers look at review conclusions the wrong way, if you don't mind my saying so: Either the reviewer
wishes he or she owned the thing under review, or they don't—the latter constituting various and imagined
different shades of black. That's silly, of course, and in spite of how we might want the hi-fi marketplace to work,
nothing's that simple. So the truth will just have to do, and the truth is this: The Dimension TD12s may be a little
too colored for a reviewer to use, but they're also a little too entertaining, exciting, and involving for a reviewer to
use: He'd never want to put anything else in their place. Strongly recommended for music-lovers who know what
they like—and are comfortable with it.
Description: Three-way, reflex-loaded, floorstanding loudspeaker. Drive-units: 1" titanium-dome SuperTweeter,
1.25" aluminum-dome tweeter, 12" pulp-cone woofer (latter two drivers in coaxial configuration). Crossover
frequencies: 1.1kHz, 12kHz. Frequency range: 30Hz-54kHz. Impedance: 6 ohms nominal. Sensitivity: 92dB/W/m.
Dimensions: 47.6" H by 17.3" W by 17.3" D. Weight: 108 lbs each.