Sonus Faber Guarneri Homage loudspeaker Page 3
It's fairly easy to estimate some of the Guarneri's basic parameters: Its bass response will extend to a modest 45Hz or so, along with a probable power handling of 100W peak program, a nominal 6 ohm impedance, an average sensitivity of 87dB/W (rather higher than an LS3/5a or a Celestion SL700, for example), and a maximum in-room sound level of perhaps 102dBA. This is a good level for the peaks on classical music, but not really sufficient for disco or rock. Deep bass will be absent, but, as the Minima Amator demonstrated, this doesn't mean the speaker will be incapable of producing a well-balanced, convincing sound.
The Guarneri's bass driver, custom-made for Sonus Faber by Scan-Tech, employs a larger-than-usual voice-coil 54mm (2") in diameter. This is energized by a huge magnet with a deep, 14mm top plate. The light, polypropylene diaphragm has a decorative milled surface, and is suspended on a half-roll surround of natural rubber, with minimal loss at low frequencies. The diecast woofer frame is nominally 165mm (6.5") in diameter, and the rear port, ca 1.6" in diameter by 4" long, tunes the system to 52Hz.
The tweeter, also custom-built, is a version of Dynaudio's Esotar unit and features a 28mm surface-damped soft dome made of silk. The unit is fitted with a special, large, rear chamber carved from solid walnut. The two drive-units are vertically aligned on the contoured, low-diffraction front baffle, the tweeter on the top.
The hard-wired crossover networks are mounted on a solid MDF tray. All the components are dipped in resin for mechanical stabilization. Selected multistrand OFC wire is used. The filters are nominally 6dB/octave over the crossover range, augmented by additional components to shape the acoustic output. The treble high-pass section thus has three elements: two film capacitors and an air-core shunt inductor. For the woofer's low-pass section, the primary element is a large series air-core inductor with an RC Zobel network and an additional film capacitor. The multi-way binding posts allow for normal and bi-wiring, or even bi-amping.
The grille is based on two enameled castings that push-fit on stainless-steel bars mated with the enclosure. Strung like the strings of a guitar between the grille sections is a vertical array of closely spaced, woven black threads.
The Guarneris are supplied with a pair of very tall, well-proportioned pillars (see below). These stands are no less than 39" high, placing the intended listening axis a little below the bass/mid unit. The main column of each pedestal is disguised by a full-height array of threads similar to those in the grille, again strung between precision castings. With the speakers sitting on the stands, the system is heavy but stable; spikes are unnecessary, though the enthusiast might try shallow cones under the massive travertine base. These speakers thrive on free space, and don't need a nearby wall to achieve their optimum bass performance—finicky setup is not required.
The Guarneris sounded pretty good straight out of the box (footnote 4), but it was obvious from the first audition that they would continue to reveal additional layers of performance subtlety, mandating lengthy experimentation. Power amplifiers used included Meridian 605 monoblocks and the Naim NAP 250, augmented by the new Krell KSA-100S and KSA-200S. The Musical Fidelity A-1000 class-A amplifier, although out of the Guarneri's price class, showed that these speakers need an amp that is sweet and harmonically balanced.
Because the Guarneri has good bass (within its natural limits) and rhythm, the power amplifier must be competent in these areas. My less-than-comprehensive list includes the Jadis Defy-7, the Acoustic Research VT130 (with BL-1 unbalanced-to-balanced converter, as required), and the Conrad-Johnson Premier series. From my electronics I expect an easy, subjective transparency; a good sense of air and delicacy; natural stereo perspectives; and, above all, harmonic neutrality. Conrad-Johnson Premier Twelve monoblocks offer all these things. The Premier Eleven can also produce civilized results, provided you don't require flat-out maximum loudness.
On the front end, I found a passive line-level controller (Audio Synthesis Passion Vishay) to have the least editorial effect on the system (my cable runs were suited to passive drive). On the preamp side, the zero-feedback Conrad-Johnson PF-2 (review forthcoming), with its MC stage, was a fine starting point. I also still favor the base-line Audio Research LS3 for its uncomplicated vitality. Toward the end of the evaluation period, I borrowed a Conrad-Johnson PV10 and found it to be a very good match—particularly with the Premier Eleven.
I used the Lingo'd Linn LP12 with the Koetsu Rosewood 2 phono cartridge mounted in a Naim ARO unipivot tonearm. The Guarneri featured classic audiophile sound on black discs, yet also conveyed the good rhythm and timing of which the Linn combo is capable—most entertaining. Digital sources included the PS Audio Reference Link/Lambda combination connected directly to the Audio Research VT 130 in balanced mode, and in unbalanced mode to the other amplifiers listed earlier. The Audio Synthesis DAX decoder also sounded very good in this system.
Cables mattered. I found that van den Hul The First and Second carbon-fiber cables worked best. Bi-wiring the speakers maximized clarity and transparency. Heavy-duty speaker cables were unnecessary; I tried van den Hul Revelation with very good results, but they fit awkwardly to the terminals. Lighter-grade silver cables, such as Siltech and Kimber, were effective.
Footnote 4: They came wrapped in red silk, cocooned in foam hollows carved into a wooden packing case with a screwed-down lid.—Martin Colloms