March 2004

Acoustic Energy AE1 Mk III Loudspeaker
The Legend Continues...
Review By Alvin Gold
Click here to e-mail reviewer

  In each product generation a handful of loudspeakers defines the state of the art. In ultra compact loudspeakers the most famous example is the LS3/5a, the BBC inspired compact which was often specified for outside broadcasts in small control rooms back in the 1980s, but it had some peculiarities, not least a deliberately bloated upper bass/lower midband which helped ensure that the sound of air conditioning systems could be clearly identified. Seductive, but flawed about sums it up, but the design enjoyed a long spell of popularity as a high class home speaker, its reputation enhanced by association with the BBC, which in those days was the byword for technical legitimacy. No more unfortunately....

But the eponymous LS3/5A wasn't the only speaker in its category that could be described as seminal. Another was the AE1, the first loudspeaker from Acoustic Energy, then an independent British loudspeaker specialist and now Malaysian owned, though its technical direction and engineering are still set here at their UK base. Phil Jones designed the AE1 originally for a studio audience, but to an even greater extent than the LS3/5a, it's reputation and subsequent success was achieved in the domestic audio arena. It certainly sealed Acoustic Energy's reputation as a manufacturer of exotic and exacting compact loudspeakers, and it is fair to say that none of the larger variants on the theme ever achieved anything like the same level of success.

The AE1 was somewhat larger than the LS3/5a thanks mainly to a deeper enclosure, but it too was designed as a nearfield monitor. It was a two way front-vented design, with a 120mm bass/mid unit and a 25mm dome tweeter, but in every other respect the AE1 could not have been more different to the BBC inspired model. The AE1's enclosure was based on a wooden carcass with a utilitarian textured finish designed not to show scuff marks in a busy studio environment, and the inside was asymmetrically filled with a Plaster of Paris like compound which eliminated parallel internal walls, as well as damping and stiffening the structure. The AEI used an anodized spun alloy cone bass unit, and an alloy dome tweeter, and it was designed for hard driving, with an almost unstoppable ability to handle power, and a much higher maximum volume capability than the severely limited LS3/5a before obvious compression set in. The high power handling capacity however was achieved at the cost of low sensitivity and a limited low frequency bandwidth, but the midband was exquisitely articulate, the treble was proportioned exactly right, and imagery was practically holographic.

The design was progressively developed over the years until it was eventually displaced by the AE1 Mk II in 1996, at which point its star faded somewhat, partly thanks in part to greater competition. The model ran to near the back end of 2003, when the AE1 Mk III finally replaced it.

Although intended as the true successor to the original AE1, the Mk III is different in almost every respect. Although it remains a compact, it is slightly larger, and the proportions a marginally different to the original, and although it is a bass reflex design, the twin front vents have been replaced by a single vent on the back panel, probably to reduce the audibility of wind noise through the port, but also reinforcing the need to place the speaker some distance from the rear wall. Cabinet integrity has also been addressed in typically uncompromising fashion, but not in the same way. The old asymmetric internal lining is gone, replaced by a steel cladding on the internals walls, with steel cross bracing, and an aluminum billet covering the baffle. The result has an almost brick like solidity, and a virtually completely absence of response to the knuckle rap test.

But this is only the beginning. The whole focus of the AE1 has now shifted for the Mk III. Aesthetically for example it has left its utilitarian predecessor far behind, with a range of high class wood veneers, and as well as the superb black piano gloss finish of the test pair, which is said to be the most popular option despite the extra cost. I can only report that the latter, which uses seven coats of lacquer, each meticulously hand rubbed down before the next is applied, looks nothing less than magnificent, especially when set against the 10mm thick aluminum front billet that reinforces the baffle. The speaker weighs in at over 24 lbs., which is about what you'd expect of a compact floor stander, but is quite out of the ordinary for a loudspeaker that measures just 185 x 310 x 250 (HxWxD in mm), which is on the cusp between shelf and stand mount in size. But don't even think about using the AE1 on shelves.

The drive units and crossover have changed too, though not the use of a metal cone bass/mid unit, which was more than novel when the AE1 was first released. The unit used here is a brand new 120mm unit with a 'curvilinear' anodized variable thickness cone, an open diecast chassis and a glass fibre voice coil former with a shielded neodymium magnet assembly, where the old one used an anodized spun alloy cone bass driver from a different source. The tweeter is all new, a fabric ring unit from DST, which is also the source for the bass/mid driver, again with a neodymium magnet, replacing an alloy dome unit. Naturally, the crossover has had to be modified to fit its new circumstances, but it remains a relatively complex 3^rd order 14-element design, the input provided by a single pair of WBT terminals.

Illustrious Sound
There has been a subtle but significant reordering of design priorities. The original AE1 was strong on dynamics, low on sensitivity and bass extension. The new model has been designed for a more extended bass at the cost of reduced (but still prodigious) power handling. Although the maker claims higher sensitivity (87dB/W/m), this does not appear to be the case in practice. Although the impedance characteristic is said to be reasonably benign, the AE1 Mk IIIs appetite for volts remains undimmed, and you'll need a powerful amplifier, or better still, an even more powerful one. Think in terms of 100 Watts or more, even in medium size rooms, but I had no problems partnering it with a mega powerful Boulder 1060 power amplifier -- don't ask.

One of the reasons why you might want so much power is a little more subtle than simply its voltage sensitivity. It has something to do with the way the speaker is voiced, which encourages, even rewards higher replay volume levels. Probably the distortion levels are produced by this design are very low, as the volume can be turned up and up, while the sound retains its clarity and composure. It is very difficult to put it under audible stress. Of course like all loudspeakers, the AE1 Mk III is subject to the rules of physics, and it does eventually run out of headroom, but it is in its nature that it very gently compresses the dynamic range even at fairly low volume levels, but that the compression remains at what appears to be a fairly constant level as the volume is turned up, retaining consistency in the way that dynamics are handled over a wide volume range. The treble response appears to dip perceptibly in (say) the final half octave before 20kHz, and this may be one reason behind this observation.

The point about dynamics should not be misunderstood. This is by any ordinary standards a very dynamic loudspeaker, but compact loudspeakers by nature tend to under-respond to dynamic peaks, and the reality is that this one does so less than most. But it has a reassuring way of behaving, especially with what are often called microdynamics, the subtle shading that separates one note from the next, or one instrument from its neighbor. The music emerges from an inky black background, with the output of the two speakers in the pair meshing in an unusually coherent way whether heard head on for from well off axis. There is virtually no sense that the sound is being produced from a pair of boxes, and the virtual center image and those associated with positions between the center and full left and full right sound no less physically real, which is surely a tribute to the lack of box signature.

Of course the bass is objectively lacking, but here there has been considerable progress from the original AE1. In practice, although the low frequency fundamentals sound thinned out compared to wider bandwidth loudspeakers, the AE1 Mk III has enough bass to cope on a day to day basis with almost any material you may care to name. Full orchestral music for example is reproduced with impressive scale and architecture, with the bass and cello lines sounding reasonably fully developed. Full on organ recordings, and bass guitar lines can sound undernourished, but still very acceptable, as bass quality is firmly integrated into the rest of the speaker output. Piano recordings were very impressively reproduced, again with a sense of physical force that is more than slightly surprising from a loudspeaker so compact.

It is possible to add some weight to the sound by using boundary reinforcement if the speakers are positioned close to the rear or side walls, but I would caution against doing so. Although the mid bass is boosted this way, there is little effect on the very lowest frequencies, and imagery and coloration levels definitely suffer. Similarly, the speaker stands you use will have a very real impact on the way the AE1 Mk III performs. I used old style tall Acoustic Energy AE1 pedestal stands which work very well, and the new version, introduced concurrently with the Mk III, is said to perform even better. Low mass stands do detract from bass weight, however, and shorter stands also tend to weaken the impact of the sound.

Conclusion
Tonally, this is a cool and rather dry loudspeaker, but it produces a solid and well-anchored sound, and an extremely uncolored sound of real sophistication. Orchestral strings reproduce in a manner that is smooth, yet has bite and astringency when necessary. Human voice is open, pure and lacking in chestiness, and instruments with a rich complex harmonic structure -- clarinet for example -- come across with real bite and character, and the necessary sense of solidity that brings music to life. This is a design that helps defines what can be achieved from such compact dimensions just as its predecessor did almost 16 years ago. There is an obvious objection that will be raised here, which is that it is very expensive -- almost UK £2,000 in the case of the model with the piano gloss finish - and of course it is true that there are plenty of much wider bandwidth loudspeakers of real class that can be bought for less. But the AE1 Mk III has an openness and easy clarity that is not readily matched at any price. In its way, it is worth every cent.

Specifications
Type: Two-way /moving coil rear vented stand mount loudspeaker

Frequency Response: 55Hz to 20kHz (± 2.5dB), 38Hz to 30kHz (-6dB)

Sensitivity: 87dB/W/m Impedance: 8 Ohms nominal (mean value 10 Ohms, minimum 5.8 Ohms)

Crossover Frequency: 3kHz

Bass/mid unit: 120mm unit with 105mm hyperbolic aluminum alloy cone, anodized with glass fibre coil former, 32mm voice coil, closed field neodymium magnet system with vented rear suspension.

Tweeter: 32mm Ring Dome radiator with doped fabric diaphragm, central clamp and phase corrector. Shielded neodymium magnet.

Power handling: for use with amplifiers up to 200 Watts

Weight: 24.2 lbs. / 11kg. each

Dimensions: 185 x 310 x 250 (WxHxD in mm)

Recommended positioning: Free space, typically 1.4 meters from side wall, 0.8 meters from rear wall

UK Price: £1,690 to £1,990 pair depending on finish

Company Information
Acoustic Energy Ltd
16 Bridge Road, Cirencester
Gloucestershire
England GL7 1NJ

Voice: +44 (0)1285 654432
Fax: +44 (0)1285 654430
E-mail: info@acoustic-energy.co.uk
Website: www.acoustic-energy.co.uk