|Ever since I first ordered a guest air-mattress through a Frontgate catalogue filched from a SouthWest flight, my mail box has become the relentless target of capitalist terror - unsolicited, expensive, full-color glossy mail-order registers. They hawk everything - from automobile, tool and interior design specialty items to storage, wine, window dressing, writing utensil and other sub-culture icons of equivalent redundancy. The crafty spin jobs of catchy ad copy for presumably vital gizmos -- lunar pens writing upside down and under water; sophisticated military computer watches now available to civilians; industrial-strength paper currency counters -- leave me breathless. The audacious suggestiveness. Overweights coach potatoes turn citadel-storming Delta Force commandoss. Joe Sixpack morphs into Bond - James Bond. The brilliant truth/hype mix whereby The Sharper Image educates us about trademarked aluminum cone driver technology for its clock radios. Help! Where's my credit card limit when I need it?
Did you know that "speakers in small portable stereo systems and radios typically have paper cone diaphragms that dampen frequency response? In contrast, the speakers of ... feature aluminum cone diaphragms with high-compliance suspension rings driven by powerful, oversize neodymium magnets. The resulting state-of-the-art stereo sound has significantly enhanced frequency response [accompanying chart shows 140-20,000Hz] with brilliant clarity, full-range richness and ultra-low distortion..."
Call 1-800-344-4444 to order yours. Or 911 if you feel sick.
Hesitant to whip out your AmEx? Ever since Phil Jones turned the HiFi world on its collective ear with the 1980's release of his original Acoustic Energy AE-1 -- later embellished and modernized in his award-winning 4.5" 2-way Platinum Solo that even caused jaded JA to wonder how this expatriate Brit managed to get 30-something bass from his diminutive woofer -- metal-cone speaker diaphragms have become a mainstay of High-end audio. They've been embraced by stalwarts like Thiel, Revel and many others. Richard Thalheimer's TSI claims really weren't that far off the mark - except for calling 140Hz full-range extension, state-of-the-art and attaching a trademark.
|When talking SOTA metal-cone full-range drivers, one Edward James 'Ted' Jordan is your final bonafide destination, however. As purportedly the oldest independent speaker design and consultation house extant, Jordan has worked with metal-cone drivers 30 years prior to the AE-1; specifically on true full-range devices. EJ Jordan Designs (click logo for site) is his present-day outlet in Great Britain, the JX92s his latest pièce-de-résistence: A 140mm (5.51") chassis diameter, 92 mm (3.62") cone diameter shielded full-range transducer whose usable frequency response spans a staggering just-about nine octaves - or 40-20,000Hz @ -3dB (see published response below, red being 30º off-axis).
|With its aluminum die-cast chassis, "Controflex" metal foil diaphragm and unique spider that attaches to the cone's center via a light metal tube passing axially through the magnet, the JX92s is very special.
Rather than extending HF reach via a Whizzer cone in Lowther-fashion, Jordan uses a dustcap-tweeter dome that's driven not from its own butyl suspension, voice coil or motor but the surrounding cone area of the woofer to which it is affixed - hence the Controflex designation. It points at very sophisticated materials-science flexure patterns that, in a nutshell, allow the driver's center to act in relative independence as a dome tweeter, distinguishing it from the discrete separation of coaxial driver designs.
In Ted Jordan's own words: "Basically, whereas conventional designs endeavour to make the cone as rigid as possible, we accept the fact that it is impossible to maintain this rigidity throughout the audio range. At high frequencies, the cone will flex. We have chosen to work with this deliberately. Our cone profile has been developed to control this flexure such that the effective cone diameter decreases progressively with rising frequency. The ratio between effective diameter and frequency has to be closely defined to match the characteristics of the radiation resistance imposed by the air load. This approach has to be used in conjunction with a specially designed low-mass voice coil but in effect the centre of the cone becomes its own tweeter."
As the published response curve indicates, extending flattened LF reach below 100Hz requires clever cabinet reinforcement. Today's review subject, the Konus Audio Essence loudspeaker, thus uses a quarter-wave triple-folded transmission line. It also incorporates classic instrument-tuning techniques, 3/4-inch resin-impregnated MDF construction, real wood veneers and associated specialty curing with a 6-layer lacquering process. To optimize this driver's response in the absence of the usual electrical network compensation circuits? It cost designer Sead Lejlic endless trial-and-error iterations. Simply, computer modeling can't predict what cabinet shop trickery is required to smoothe and extend frequency response with MDF alone. Understandably hesitant to give away hard-earned secrets, our Bosnian cabinet tuner and European distributor for 47Lab instead smirkingly invokes the 5th. He trusts that our ears will either embrace or reject his solutions. In the latter case, design disclosures won't remedy such reactions. In the former, they'd do little to enhance our enjoyment save for allowing copycats to short-circuit their own learning curve.
At just shy of one foot wide, 4.25 inches deep and 37.5 inches tall when spiked on its integral 1.25" thick, 8-inch deep plinth, the Essence is very compact, counter-intuitively shallow and, in its dramatically grained, two-tone Bosnian pine, dressed for furniture-grade success.
|The clear-acrylic terminal dress plate is more than half-way up the back. It sports small spade-terminated hookup wires fished through sealed holes and captured by copper Philips head screws that unscrew far enough to accommodate even unreasonably chunky spade lugs or bare wire. Banana fiends will slip on their peels however. Grab a spade, clean up your yellow skins and get with the program.
A down-firing transmission-line terminus exits to one side of the plinth stem, three T-nuts on the base's underside receive enclosed spikes for leveling and carpet-piercing.
Anyone contemplating the Essence's solitary driver complement, published raw transducer specs and crossover-less nature will predict a few performance parameters right off the bat: Limited SPLs - a small driver can only move so much air; limited bass extension for the same reason; and the promise of undiluted directness and immediacy inherent in the phase- and time-correct, true point-source single-driver principle. The absence of passive electronic parts implies direct-coupling of amp to driver for the easiest-possible load behavior - no in-line parts to soak up energy, low-power SETs welcome despite 86dB sensitivity. Looking at the published impedance behavior of the raw driver confirms a nominal 5-ohm load admirably free of spikes over most of its range, with a gradual rise to 10 ohms in the treble and a gently contoured peak of 16-ohm at 50Hz.
With the obvious -- and less so -- physical items out of the way, let's enter the mystery of Essence. Let's inspect how predicted frequency extreme compromises will balance against implied advances in tonal coherence, harmonic continuousness and reach-out-and-grab-ya factor in that all-important vocal range. To be honest, Sead's $3,500/pr creation was the first single-driver speaker ever to come through my personal sound system. My CES 2003 report mentions two other such designs that pricked up my ears. Still, listening in a known environment, to one's own music, is always the final equalizer for tradeshow impressions. I was thus as curious and unsure about what, exactly, to expect as I assume you may be. After all, single-driver speakers aren't exactly run-of-the-mill fare in most audiophile circles. Alas, no more conceptual milling about - time for some tunes.