Acoustic Energy Radiance 3 review

The Radiance range is the result of three years of development work at the Acoustic Energy labs. It consists of five models in total, including three stereo pairs. Our review focuses on the largest of these, the three-way Radiance 3; there's also a smaller floorstander and a standmount.

We had a definite feeling of déjà vu when these speakers emerged from their carton. A couple of years ago, and a couple of years before that, we reviewed two subtly different versions of an Acoustic Energy model called the Alite 3, and this new Radiance 3 has much in common with those earlier models, outwardly at least.

Essentially it shares the same basic size and shape of enclosure and the same three-way, four-driver configuration, but all the important details have changed, which is probably just as well, since the price is much higher – £750 for the Alite 3 in 2007; £1,500 for this new Radiance 3 today.

The build

Whether or not the enclosure is similar, this is a handsome floorstander. It has attractive and functional curved sides and front edges, is finished in either pale or dark real-wood veneer (albeit of rather anonymous appearance) and sits on proper cast-alloy outrigger spiked feet that ensure fine mechanical stability.

Proper 8mm spikes with real locknuts provide good floor coupling. The cabinet construction itself is interesting, as the sides are formed by filleting the insides of the 15mm MDF panels with closely spaced, deep grooves, allowing the curved shape to develop.

This increases damping, but reduces the rigidity and structural integrity, so this is restored by using horizontal partitions that also serve to create the separate chambers for each of the cone drive units.

Curved sides are not only fashionable; they're also functional, helping disperse internal reflections and avoid generating focused standing waves. The enclosure is much narrower at the back than at the front, but wide enough to accommodate a terminal panel with two pairs of socket/binders, plus no fewer than three ports – one for each of the cone drivers.

A plug conceals a cavity near the base that can be filled with dry sand, for example, for extra stability, though frankly this is hardly needed. And the optional grille is cleverly held by magnets hidden beneath the veneer, so its removal leaves no visible means of support.

All three metal-cone drivers have AE's pointy dust caps – the two bass units have 160mm cast frames and 120mm cones; the smaller midrange-only driver uses a 130mm frame and a 95mm cone. While based on those used in earlier ranges, these drive units have undergone considerable development.

Finite element analysis (FEA) modelling of cone termination has resulted in break-up points at substantially higher frequencies, while moving mass has been reduced and magnet design optimised to increase sensitivity. Harmonic distortion and thermal compression have both been reduced too.

The tweeter used here has a 38mm 'ring radiator' or annular soft-fabric diaphragm, and is loaded at the front by a DXT waveguide that controls its dispersion (see 'Lens-loading' box over the page). Fed from twin terminal pairs, the crossover network is deliberately kept as simple as possible, reducing the component count, increasing the quality of those components used and eliminating resistors.

Sound quality

It came as no surprise to find that a generously proportioned floorstander with twin port-loaded 160mm bass drivers such as this needs to be kept well clear of the walls. Measured under far-field in-room conditions, the Radiance 3 delivers healthy bass output down to 27Hz, assisted by 40hz port-tuning.

Furthermore, it delivers an overall frequency response that holds within an impressive +/-3dB across nearly the whole audio band, alongside a generous 90dB sensitivity. Although the overall response limits are impressive, the trace isn't without a degree of 'character', showing some lack of output in the midband (250-500hz) as well as some excess in the upper mid (700hz-1.5khz).

Perhaps, complementing the relatively high sensitivity, the impedance is quite demanding in terms of amplifier current, twice dropping to around 4.5 ohms, once at the tuned port resonance 35-43hz, and again a little higher up, 110-130hz, the latter a sector of the audio band where typical program levels are quite high. Above 8kHz the impedance also falls, though there's little program energy at these highest frequencies.

The first thing one notices on plugging in and playing the Radiance 3s is just how 'quiet' the enclosures are. The sort of 'cabinet grunge' that normally serves to restrict and obscure detail resolution at the lower end of the total dynamic range seems largely absent here, or at least exceptionally well controlled. The consequence is a speaker that sounds uncommonly 'clean'.

However, perhaps in part as a result of that very low enclosure signature, the mild imbalance through the broad midrange isn't easy to ignore, leaving the upper frequencies here a trifle too exposed. The result is that voices can sound a little too explicitly projected, with a slightly 'cupped hands' or megaphonic effect.

While this certainly makes it very easy to hear song lyrics and speech when the speaker is playing quietly, it also means that things can get a trifle aggressive and shouty when the volume is wound up high. What is unquestionably nice at low volumes starts to get a bit uncomfortable as levels are increased.

While the dynamic range is unusually wide, the actual dynamic behaviour does fall a little short of that obtainable at higher prices. Although it drives the music along with good purpose and weight, the bass end would benefit from rather more grip and tension, while the midband is slightly softened by a degree of time smear, which again serves to take the edge off the expressiveness inherent in the performance.

Stereo imaging is a major plus, as the soundstage shows no tendency to cluster around the boxes and depth perspectives are well portrayed, especially on recordings with a large and believable acoustic, such as choral material.

The sweet and smooth top end is certainly a major strength, as it supplies plenty of subtle detail without ever seeming to draw attention to itself. The annular tweeter used here has long been regarded as one of the better examples around, even appearing on some very exotically priced models, and its performance here, assisted by the DXT lens, is certainly well up to the expected level.

The only real complaint arose when some friends were visiting and we were rocking out with the sounds of Beefheart, Little Feat, Tom Waits and suchlike at relatively high levels. Under these circumstances the slightly 'shouty' character and lack of tight dynamic grip became mildly irritating, so we changed over to a speaker costing six times the price.

Taking cost into consideration, however, and in regular day-to-day use over a period of at least ten days – using a wide variety of material from diverse sources including vinyl, CD, radio and TV – this Acoustic energy acquitted itself very well indeed, and proved most satisfactory and satisfying.