What a gap: the Heil Air Motion Transformer first appeared some 30 years ago, pretty much faded from sight, and then - whoosh!!! Up pop a couple of new systems using the legendary tweeter, from two unrelated sources. With the Heil AMT, though, it was only a matter of time: the AMT needed worthy amplifiers and an appreciation of ribbons to succeed - neither of which existed in 1972. After the European offering from the Jecklin crowd, the Heil AMT Aulos reviewed in June by AG, here's one made in the UK...albeit by an American.

And being American, I just had to get my hands on a pair of Orchid LWO Deep Resolution Loudspeakers for a very good reason: I lived with a pair of the original ESS Heil AMT 4s back in my college days - 1973-4 - when my flat-mate and I combined our systems to create a 4-channel set-up. At the time, it was one of the more radical transducers, but then the late 1960s and early 1970s were far more exciting times than the present when it came to choice of speaker technologies: the Ohm Walsh driver, early Magnepans, a slew of electrostatics, plasma drivers, the first stirrings of Bose, and much more. We ended up with Heils because the store I worked in was an ESS agency. (My mother still uses the non-Heil ESS Tempests which I left with her when I emigrated.) While the passage of 27 years means that my memory of the sound is less than dependable, we had no complaints. The system cooked.

As Alvin mentioned, the AMT works by 'squeezing' air; the driver is in effect a long ribbon folded accordion-like into a small frame. And, bugger me if the unit doesn't sound in retrospect like a precursor to the Apogees. Orchid uses the AMT with a Volt 8in woofer and a 5in Beyma driver acting as a phase link, with a bi-wired crossover bearing polycarbonate capacitors and air-core inductors. (See sidebar.) The drivers are fitted to a sloped baffle in a floorstanding enclosure measuring 33x12x14in (HWD), but don't let the compact dimensions fool you: Orchid is firmly of the mass-and-rigidity-are-good school, so each speaker weighs just under 100lb. The cabinet is fashioned from a 1 3/4in-thick bi-layer MDF sandwich, finished in real hardwood veneers. A bass-reflex design, ported at the rear, the LWO enclosure presents each driver with its own acoustically isolated sub-cabinet. Also supplied for the speaker is an integral slate base with four M6 spikes.

Matching the LWO to assorted amplifiers proved simple, provided the amp has a reasonable amount of power on tap, despite the specs. Although the LWO seems conventional, it works best with big powerhouses amps, especially valved. Orchid specifies the speaker as offering 89dB/watt sensitivity, with an 8 ohm nominal impedance and a 4.5 ohm minimum. Thus it is not an amp-breaker, but the least I would recommend to drive it is a 50W/ch-plus tube amp, such as the McIntosh MC275. I also used the Krell FPB300 and the Musical Fidelity Nu-Vista 300, with the Marantz CD12 and SME 10/Series V as sources. Wiring included Kimber Select and Harmonix.

Because of the LWO's compact dimensions, I had no problems in my 12x18ft room. The speakers were positioned by the designer to fire forward; toe-in messed up the sound stage by increasing the front-to-back depth at the cost of much of the stage width. Orchid states that the 10 degree sloping front baffle provides proper time alignment for listening positions from six to twelve feet from the loudspeakers; my hot seat was 8ft from the speaker line and it was hard to better the location.

It's difficult for me to fall back on 'breath of stale air'/blast from the past gags because I simply can't depend on my sonic memory going back as far as the pre-punk/pre-disco days. Moreover, I stayed utterly blitzed on grass throughout my college years - the only way to survive a graveyard like Orono, Maine* - so the sound systems around me served as little more than a backdrop to mind alteration. (I'm amazed my LPs from that era bear no scratches.) Thus, while I do remember being impressed with the first-generation AMT, I can't even begin to suggest what the ESS AMT 4 sounds like by today's standards; I haven't heard a pair since June 1974. What I can tell you about the current Heil AMT, though, is all good. And I suspect that the driver has changed very little in the intervening years.

If I knew then what I know now...the Heil in the LWO has the kind of upper frequency coherence and poise which precious few tweeters can offer. The inverted dome Focal unit beloved of Wilson and others, the Dynaudio ESOTAR - it enjoys their speed but with a dipole-like openness, transparency and freedom from beaming which will immediately find favour with Quad ESL devotees and those who normally loathe boxes. In fact, my overall impression is of a speaker system aimed precisely at the sort of Quad user who craves greater slam but doesn't have the will to turn traitor and embrace Martin-Logan hybrids.

This is not to imply that we should join and stay loyal to near-religious factions, or that straying from a perceived path of true righteousness is the way to perdition. I live quite happily with original Quads, ESL 63s AND a full five channels' worth of Martin-Logan hybrids, along with LS3/5As and WATT Puppies. Why limit one's options because of some absurd, quasi-political, monomaniacal bias? (Horn guys: take note.) And if ever I've heard a speaker attempting to provide the best of both worlds, the LWO is right up there with the Martin-Logans.

Y'see, its designer has his background in the studio world, where no mercy is shown for wimpish speakers with truncated bass and an inability to go loud for protracted periods of time. Moreover, all studio monitors are notorious for their naked, warts'n'all playback, as that is part of their raison d'etre: to allow the listener to hear every tiny detail. As such, the LWO skates close to a monitor's ideal of accurate portrayal; conversely, the sound is non-fatiguing and musical, as well as huge and wide-open. It doesn't take long to appreciate that Orchid has engineered this for pleasure rather than professional purposes, for the very first impression to hit the listener is one of huge scale and sweeping vistas. The LWOs disappear, and the soundstage is filled to the brim.

What pleased the LS3/5a fanatic in me was the system's way with vocals - both spoken and sung, male or female. The box is so solid and dead that there are no unwanted, wooden colorations. Fed the supersweet Judds' interpretation of 'Don't Be Cruel', most of Mel C's stunning solo debut CD, a bushel of Alison Krauss and the recent Eva Cassidy collection, the LWOs kept all of them free of harshness or edge, and sibilance just didn't intrude at all. With textured voices, including Louis Armstrong's (with Ella), the system conveyed the throatiness and the rasp in realistic quantities, with no exaggeration nor added phlegm.

But voices don't challenge the bass extension, the speed, nor the capacity for slam, whereas Castle's new Black Sabbath hits collection does. Thrash fans and those who worship at the altar of speed guitarists will find much in the LWOs to covet, especially as they go loud without showing any strain and their attack is rapid yet controlled. On the other hand, what I consider loud would hardly impress Beavis or Butthead, so maybe I'm just imagining the Orchids' appetite for destruction.

Aside from looking like something out of the 1976 - apt in light of the tweeter's age - the LWO is a serious contender in the current middle-to-high-end sector. A tag of £3995 places it among some serious competition, including the Quad 989 at the exact same price, but it is not extortionate by today's standards. Moreover, the robust build quality and sheer mass are convincing displays of perceived value. What will please the house proud, given the prosaic styling, are the compact dimensions: here is a system which behaves like a big Yank monolith while occupying the space of a room-friendly two-way Britbox on a stand. And, to please the iconoclastic audiophile who hates to follow the crowd, the tweeter is one hell of a conversation piece. Leaving aside my predisposition toward this speaker because of personal nostalgia, as well as its appeal because it's an oddball, I've just gotta brand it a hit.

Orchid Precision Audio
Compton Court, Long Compton
Warwickshire CV36 5JW England
Telephone/Fax: 01608 684 694
www.orchid-precision-audio.co.uk

*Stephen King was a student at the University of Maine, which explains his preferred subject matter of death, decay, rural horror, low foreheads, dragging knuckles and general weirdness. Upstate Maine that scary.

SIDEBAR: THREE-WAY VERSUS TWO
Despite the truism that a single, full-range driver should in theory be the ultimate solution as it precludes the need for crossovers, Orchid makes much of its use of three drivers and its 'trinary crossovers'; its literature even includes a separate sheet on the crossover technology alone. To split the frequency spectrum into two halves, for the typical woofer- and tweeter-based two-way loudspeaker, a normal crossover employs a low-pass and a high-pass filter to feed bass frequencies to the woofer while filtering the higher frequencies, while the high pass filter does the reverse for the tweeter. Alas, in the middle both filters allow some overlap and, 'It is in this region that things go wrong. For the simple system described above there is mathematically a third set of frequencies that are centred in the overlap region and if this third term is not given expression, then the crossover produces errors. These errors could be errors in amplitude or in timing or both.'

If, on the other hand, a third driver covers this set of frequencies, which Orchid calls a 'phase linking driver', then 'the filter mathematics are fully satisfied and a much more naturally full audio output is delivered.' Orchid names this 'alignment' a 'trinary crossover' because 'for every time we try to split the musical frequency spectrum we use three loudspeakers instead of the ordinary two.'

Orchid further explains that the LWO is a actually two-way system that uses three drivers. (A conventional three-way system using a woofer, a midrange, and a tweeter, would need five drivers acting as 'phase links' to meet the Orchid criteria.) LWO uses the Volt woofer crossing over to the Heil Air Motion Transformer at around 1.8kHz. The driver between the woofer and the Heil, then, is not a midrange but a phase link driver and it 'expresses the frequency and phase information that more conventional crossover networks would lose.'