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
Read more about the Orchid Two Deep Resolution loudspeakers on Page 2.
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
*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
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
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.'