Although the Tannoy DC4T Revolutions share the same drive units and configurations as their senior Signature cousins, they also incorporate a number of economies, all of which mean the Revolution DC4T costs £300 less than its Revolution Signature DC4T equivalent.

Three basic economies are involved. Although the enclosure is still finished in real wood veneer, with the same choice of 'light oak' or dark 'espresso' options, the curved sides of the Signatures are replaced by flat sides here.

However, the enclosure back is narrower than the front, so parallel sides are avoided, giving a trapezoidal plan section. The alloy trim used on the front port of the Signatures is replaced here by a simple untrimmed rear port.

And the fifth driver-frame earthing terminal has been left out of this less costly model (no great loss, given the rarity of five-conductor speaker cables).

Slim speakers

This is an ultra-compact floorstander, operating in a two-and-a-half-way configuration. The small diameter drivers means the enclosure – about 11 litres in capacity at a rough estimate – is exceptionally slim and quite shallow, which certainly ensures a high WAF rating, but not its physical stability, which is surely marginal if not asking for trouble, especially as fitting the spikes reduces the footprint further still. If ever a speaker was crying out for a separate plinth to prevent it falling over at the merest glancing blow, this is it.

The reason this speaker is so slim is that it uses very small drive units. The little 100mm dual concentric unit, partnered here by a similarly sized bass-only driver, is the smallest DC ever and was originally developed for Tannoy's Arena multichannel audio visual satellites. The fact that this Revolution DC4T has an extra driver to help with the bass could be highly significant.

System components

The actual cones used here are just 80mm in diameter, so the area of each one is only around two-thirds that of the 100mm cones used in the 130mm units that are commonly found in miniature speakers.

Two 80mm cones, however, have a combined area that's not all that far short of those used by the ubiquitous 165mm drivers. Both drivers' coated paper cone diaphragms are driven by 33mm voice coils, while the dual concentric's tweeter uses a 19mm titanium dome, well protected down behind a tulip waveguide horn.

Amongst relatively few luxury touches, the outside edges of both drive units are decorated by shiny alloy trim rings, while the grille is held in place by magnets that are hidden beneath the veneer, avoiding unsightly lugs when it's not used.

Twin terminal pairs provide bi-wire or bi-amp options and are conveniently situated close to the floor. According to Tannoy, the internal wiring and crossover components have been carefully selected on sound quality grounds.

Standard performance

The Revolution DC4T just about achieves its specified 87dB sensitivity. While that below average figure is not particularly generous, especially since there's no bass output worth mentioning below 40Hz, it should also be seen in the context of an unusually easy-to-drive load for the partnering amplifier, which stays above eight ohms across nearly the whole band.

A further bonus here is that an easy load reduces the influence and importance of the speaker cables, though it was disappointing to discover a significant impedance difference between the two samples across most of the midband. Minor resonances were also visible 140-180Hz and 280Hz.

The port here is tuned to a relatively high 58Hz, though this does, at least, provide some compensation for the modest drive unit area. Although far-field in-room measurements show decent port-related output, when the speakers are in free space, clear of walls, output was well down 60-120Hz.

As expected, wall reinforcement boosted that octave significantly, but after considerable experiment best results under our conditions were found with the speakers 33cm out from the wall. It's still not particularly smooth, especially through the bass region, but the overall balance stays within impressively tight limits above 300Hz.

Strong coherence

Although there was no way such a small loudspeaker would deliver serious bass weight or extension, or dramatic dynamic expression for that matter, those are the main down sides and most of the rest is very positive.

Best of all is the overall coherence and openness through the broad midband, which brings considerable expressiveness and believability to human voices, sung or spoken. This is arguably the most important trick that any speaker can pull and the bonus here is that the speaker is free from any heaviness or chestiness and has a fine agility and freedom from boxiness.

Then there's the dual concentric bonus, which brings fine imaging to the table, alongside superior off-axis consistency, so a good stereo image is well maintained across a generous listening zone.

Stunning vocals

One might criticise the Revolution DC4T for some lack of smoothness and sweetness and slightly limited air and transparency, but those are essentially minor criticisms of a speaker that transcends its limitations and is always informative and thoroughly engaging.

Unaccompanied voices are particularly thrilling, as is spoken word and while it doesn't offer the sort of performance that with thrill lovers of Massive Attack or Basement Jaxx, never mind The Prodigy, it does work very well indeed within the inevitable constraints its size imposes, and we daresay it would respond rather well to the addition of Tannoy's Revolution Sub 1001, or similar subwoofer.

Hey there, good looking

On its own, a pair of Tannoy Revolution DC4Ts will give a very good account of themselves provided the scale of the material they're fed isn't too demanding. The fact that they look very nice and take up so little room space will always win friends, though the lack of plinth and consequent poor stability is a handicap.

However, their superior voice-band coherence makes a powerful argument in favour of what is by far the smallest variation on the dual concentric theme that Tannoy has produced to date.

The undoubted quality of this little drive unit through the midrange and treble, makes one wonder how long it will be before Tannoy introduces a speaker that combines it with the serious bass action which was always a hallmark of the original Dual Concentric legacy.