Sonus Faber Guarneri Homage loudspeaker Page 2

However, Serblin's putting the music first, coupled with the novel and acoustically optimal cabinetry, has resulted in a speaker that's not only superbly musical, but also Sonus Faber's most accurate to date. As an acoustic engineer, I find that particularly rewarding (footnote 3).

Whether just sitting there or playing music, the Guarneri is never boring—it's fundamentally true to the spirit of the music it plays.

Musical instruments
The Guarneri is loosely based on the "larger-than-life" Sonus Faber Minima Amator (reviewed in December 1993, Vol.16 No.12, p.174), which costs a fraction of the Guarneri's price. As the Guarneri's every detail has been fine-tuned, it's worth exploring in greater depth how the speaker is built. Again, quoting Sonus Faber:

"The [cabinet] comprises 42 separate elements hand-sawn from solid wood. Each element is bonded to its neighbor using organic glue and heat pressing techniques identical to those used centuries ago in the manufacture of violins.

"The walnut, maple, and limewood used for the various parts is dried naturally for two years and then stabilized in kilns. The rear of the enclosure is shaped from a single block of limewood. The interior walls of the enclosure are selectively damped using proprietary sheet copper and lead tuning elements."

To which I would add that the 1"-thick driver baffle, covered in grained black leather, consists of 15 layers of birch multi-ply. An aluminium-alloy extrusion forms the inner section of the sculpted rear deck and carries the bass-reflex loading duct and the terminal array.

The main curved body of the enclosure is said to be partly voiced by the specific technique of layered finishing, in the manner of a violin body: "The surface of the wood is prepared for finish by first sealing it with albumin to prevent penetration of the multilayered varnish. The application of many coats of varnish is the time-honored tradition in violin-making that has a profound effect on the final sound. We assure you that the sound of 'Guarneri Homage' benefits from the special finish produced by blending natural organic substances, including Venetian larch turpentine, linseed oil, propolis, wine alcohol, gamboge, copal gum, and oliban. No fewer than ten coats of varnish are applied to each cabinet, hand-sanding then accompanying each finishing coat."

After the final polishing, which is done by hand, each Guarneri cabinet is buffed to a mirror-like finish. The finish is certainly deeper and clearer than speakers that have polyurethane or cellulose-based piano-gloss finishes.

With few exceptions, cabinet resonances are major influences on the a speaker's sound quality; it's well-known that even a speaker's finish affects its sound. "Special Edition" loudspeakers can thus prove surprising: Even a multi-coat, synthetic-lacquer finish can improve the sound, as in the case of the Monitor Audio Studio series. The original Wilson Puppy woofer enclosure had a very tough plastic-laminate finish that appreciably reinforces the cabinet. Even with inexpensive speakers, the use of real-wood veneers can result in sound different from that with wood-print, vinyl-film finishes.

The Guarneri's side enclosures are between ?" and 1" thick, and the internal mass loading comprises nine lead-weighted copper strips of different lengths, disposed in a staggered formation to fine-tune and distribute the resonances. This technique is also applied to the top panel. Both top and bottom are made from solid, 1"-thick walnut. Internal damping is confined to one piece of acoustic foam in the lower rear section. The idea is that the speaker's irregular shape helps dissipate standing-wave energy, while the minimizing of acoustic damping helps retain a "free" sound.

The knuckle-rap test invoked an interesting result: The 10-liter (internal volume) enclosure is certainly solid, but the panels lacked the familiar knock-on-woodblock sound. The decay signature was more subtle and harmonious, reflecting the enclosure's complex structure and form.

As befits a musical instrument, no specifications are provided for this loudspeaker—fascinating, if a tad frustrating for the reviewer. Sonus Faber intends that their dealers be accorded total responsibility for designing a complementary audio system that will bring out the Guarneri's promised performance in the owner's home. How this is achieved is not necessarily the purchaser's concern.

Footnote 3: While there is much the design community doesn't yet understand about loudspeaker engineering, acoustic performance, and the subjectively optimal blend of all design parameters, it's certain that, if all other aspects are held constant, an acoustically even, flat response directed at the area occupied by the listener is a positive factor. (In this context, "flat" means a uniform perceived amplitude frequency characteristic for the predominantly direct soundfield.) Accurate tonal balance with low coloration are primary criteria, though they by no means guarantee that a speaker will be musically involving, or capable of re-creating a sense of event or performance.—Martin Colloms
Sonus Faber
Distributor: Sumiko
3101 Telegraph Avenue
Berkeley, CA 94705
(510) 843-4500