TANNOY DEFINITION DC8 T

 From Hi-Fi World - March 2012 issue

Dual opinion

The Tannoy Definition DC8T 'Dual Concentric' loudspeaker split opinion in World Towers. Noel Keywood loved it; Rafael Todes wasn't so sure.

Tannoy loudspeakers are great fun and impressively accurate, by design – and I like this. All the same, I had some reservations about the upmarket £4000 DC8T I reviewed in our July 2009 issue, ones that weren’t apparent in the larger but otherwise similar DC10T reviewed later in our November 2010 issue. Following my comments and those of their Japanese distributor, Tannoy decided to tweak the DC8T late 2011 to rid it of an obvious deficiency, a small midrange suck-out identified in our measurements that made it sound soft; it was too laid back even for my tastes. This review is an update on the DC8T that, I feel, is one of the market’s more interesting loudspeakers.

I thought reviewer and classical violinist Rafael Todes might like its qualities too – but he had reservations. You can read what he thought of them in our March 2012 issue magazine.

Here’s a quick resume of the Definition DC8T. It is a one metre tall floorstander that incorporates the best Tannoy technology in a beautifully made and finished domestically acceptable loudspeaker. By this I mean it uses their Dual-Concentric drive unit, but it isn’t part of their Prestige range, where size plays second fiddle to performance and Pickfords deliver. The DC8T is man handle-able and you could substitute ‘woman’ for ‘man’ since it is no macho lift, weighing 21kgs (76lbs). Tall and slim, the original wasn’t so stable, so Tannoy have now fitted a plinth to widen its footprint. The lacquered wood veneer used is lovely to look at and touch and helps make this Definition look classy. Tannoy’s trims are tasteful too and at the rear sits a bi-wire connecting panel with green earth terminal that earths all internal metalwork, something that technically makes sense as there are a lot of coils of wire inside, able to pick up Radio Frequency (RF) signals and earthing chassis work should help prevent this.

The entire frequency range is handled by a modern Dual Concentric drive unit incorporating a horn loaded 25mm titanium dome tweeter firing out through the centre of the 8in bass/midrange cone. This cone uses a treated paper pulp cone with rubber edge surround and it has the damped, dull ‘thwack’, when struck with the finger, of a well damped polymer cone; there’s none of the ‘ring’ of a metal cone. I make this point deliberately – more later!

Bass from the Dual Concentric drive unit is augmented by an 8in bass unit sitting below it, both units being reflex loaded by a rear port. Tannoy don’t make loudspeakers lacking bass and the DC8T is no exception. Aware that it may over-excite some rooms they provide foam bungs that, we found from measurement and listening, audibly reduce subsonic output below 40Hz. Tannoy’s foam bungs were more needed than those of most loudspeakers,

because this loudspeaker is capable of very heavy subsonics; it runs almost flat down to 20Hz. Sounds good if you are a bass freak – and I like to feel the room move! – but it can really set some rooms off badly, according to their dimensions, so the bungs are quite important. Because our listening room has a main mode at 24Hz, below the lower limit of most loudspeakers but not the DC8Ts, the bungs were pushed in and out quite a lot in our attempts to maintain a sense of balance. It provoked our room strongly at a very low 24Hz and this did at times border on excessive.

There are a few interesting technical features of this loudspeaker. The tweeter reaches an octave lower than most, doubling wavelength at crossover. This improves phase matching and off-axis dispersion and is, I found when dealing with this whilst designing World Audio Design loudspeakers, an important point. At 3kHz a half-wavelength is just 55mm, making random mechanical phase error due to drive unit spacing of a distant tweeter significant. With the Dual Concentric this extends to an easier to cope with 110mm.

Also, the tweeter is brought closer to the bass/midrange cone apex that radiates at high frequencies, than is possible in loudspeakers with separate tweeters, again improving phase matching. These twin benefits together result in a more solid sound to instruments like violin in particular, an instrument that suffers both from amplitude and phase variation of other loudspeakers, making it sound vague and hazy in embodiment and uneven in power.

Capitalising on this Tannoy have steadily flattened and smoothed the amplitude response of their pressure loaded tweeter, by use of a Tulip waveguide. By any standards the DC8T measures very flat to 20kHz as modern loudspeakers go. But as most loudspeakers these days have raised midband and treble output, the Tannoy sounds – shall we say – less bright. Add in the fact that it throws less treble energy at walls and ceiling, and overall it comes across as warm or, as Rafael says, “chocolatey”.

Fair enough, but to me, as an engineer and long term listener, I prefer this form of accuracy than the shriek (as I hear it) of most loudspeakers that have been made quite deliberately bright by their designers (or sales team) to compete in a showroom, where they will appear detailed and insightful. This isn’t a good loudspeaker, it is a contrived loudspeaker.

A truly good loudspeaker will sound fabulously detailed whilst also tonally balanced and here we turn to Quad electrostatics, notably the One Thing Audio ESL-57 revamp, a Martin Logan X-Stat panel or an Eminent Technology magnetic planar drive unit. All these reproduce real detail whilst retaining tonal accuracy and demonstrate what is possible. All put more treble energy into a room than a Tannoy Dual Concentric so all have a brighter demeanour. So whilst the DC8Ts measure flat to 20kHz and are accurate, they seem very mild, even warm and rich, or ‘chocolatey’. It is the nature of a horn: they throw acoustic energy in one direction, in this case at the listener, but not at walls and ceiling. I can live with this; I find it mild and relaxing. But there is much more to a Tannoy’s sound than this.