Stereophile
May 1998, Vol.21 No.5

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Kimber Kable BiFocal-L(BiFocal-X) & BiFocal-XL loudspeaker cables

There aren't many things you can really count on anymore, other than: James Bond will always save the world and get the girl, the dog will need to go out at 5am on your day off; it may take three hours but the ship will sink, and Kimber Kable will always use their distinctive "open-weave" construction.

Since 1979, the Kimber concept of separating, counter-rotating, and interleaving a cable's positive and negative conductors to prevent the formation of a coherent field has been the basis of their products and a fixture of the High End. Even the for-millionaires-only Black Pearl uses a three-wire braid as its basic conductor unit--they are just encased in an isotropic gel and hidden inside a black braided outer shell.

Well, guess what? Not only do Kimber's new BiFocal speaker cables eschew openweave construction, they're a harbinger of things to come-the first appearance of the designs to be used in Kimber's new Select series. What's next? The Denver Broncos winning the Super Bowl? Kimber's BiFocal-L and XL are biwire configured speaker cables that are supplied factory-terminated with either Kimber's PostMaster spade lugs or VVBT locking banana plugs. Borrowing from the Black Pearl, the BiFocals use a compliant core (rubber-based here, lead-filled in the BP) surrounded by layers of conductors positioned at specific distances from the center. In the full-range XL version, the inner, high-frequency layer consists of 12 Teflon-insulated copper VariStrand' conductors. The conductors are braided tightly around the spongy core, the positive and negative conductors wound in opposite directions.

Next comes a layer of what Kimber calls "electrostatic dissipating yarn," which serves as both an interlayer spacer and a drain for electrostatic energy. The outer layer consists of 24 conductors (also Teflon/copper VariStrand and with counter-rotating plus and minus sets) that carry the low frequencies. Then entire assembly is about 1.25" in diamter and quite flexible, and is finished in an attractive black-fabric mesh.

The smaller 'L version is designed to be a more cost-effective alternative for systems that demand less current transfer in the low frequencies; for example, those built around smaller two-way designs and/or amplifiers of low power or high output impedance. It uses the same conductors as the XL, but half as many in each layer, and with a slightly different radial spacing between the layers.

The BiFocal dropped right in without any dramatic announcement of its presence - always a good sign-and over the course of several weeks I grew more and more impressed with its overall balance. No particular aspect of its performance drew undue attention to itself a few seconds into an album or CD, the system would fade into the background, leaving only the music.

Overall, the BiFocal had a presentation that could be described as slightly light, or perhaps a bit dry. For starters, its tonal balance was close to neutral, but a bit to the lean or cool side of dead center. Violins, particularly near the top of their range, were slightly more prominent, and seemed to have slightly larger dynamic transients-more bloom and swell-than did double bass, lower woodwinds, and cello. With some other cables, the Nirvana S-L being a good example, the opposite is true. Quoting from my notes: with the Nirvanas there "is definitely more weight, a warmer tonal balance, and everything has more body, a rounder sound, more dimensionality."

A second component of the BiFocal's personality was that it placed a greater emphasis on detail and transients than on continuity. On Jaime Laredo's reading of the Mozart Violin Concerto 3 (RCA LSC2957), the solo violin was exquisite. The pure, rich tone and the understatement of Laredo's playing has always given me the feeling of being pulled into and wrapped inside the music, and the BiFocal captured this wonderfully. Low-level details-intricacies of Laredo's fingering, the vibration of the strings, the resonance of the violin's body -- were distinct with the BiFocal, but naturally so, without any sense of artificial emphasis or over-etching. Bow strokes were precise and had a sharp, rosinous bite, but the notes' initial attacks were correctly balanced with their body and decay.

With Classic Records' nifty reissue of Red Rodney's 1957 (Xanadu/Classic S 1206, the trumpet and sax seemed a little light via the Kimber cables, but were alive with inner detail, and with a reproduction of subtle dynamic and pitch shadings that was natural and nothing short of arresting.

Although not treated quite as lavishly as solo instruments were, most orchestral sections were reproduced well, with a good balance of detail, transients, and body within the section. Smaller sections and less complicated passages fared somewhat bet ter in this regard, with the BiFocal's ability to unravel complicated inner details and maintain image dimensionality diminishing slightly as things got more complicated.

A third component of the Kimber's presentation was that it was a little less obvious in its retrieval of ambience cues and produced a less tangible acoustic envelope than did some other cables, or than does a concert hall. There wasn't quite the expansive, seamless soundstage and space that some cables produce, the sense of the entire orchestra sharing a common acoustic space. The Kimbers' soundstage was a bit diminished, both side to side and front to back, yet the sections themselves seemed more widely spaced, as if they were in distinct acoustic spaces that didn't quite overlap. The separation was particularly noticeable between the solo violin and the remainder of the orchestra, as if the violin were highlighted or spotlit -ie, slightly too large. Arguably this is simply a more accurate reproduction of discontinuities resulting from miking patterns, but the overall effect was somewhat disjointed rather than seamless, the way it is in a concert hall.

Switching to another favorite reference disc, a Bellaphon German Pressing of the Ray Brown Trio's Soular Energy (Bellaphon/Concord Jazz LELP 111, the Kimber's subtle flavors remained, but its impact on the music was completely different. Where the BiFocal's discontinuity was a bit distracting with the Mozart, its cooler tonal balance and sharper transients were a perfect match for a jazz trio. Continuity was less of an issue, so the sharper spatial and temporal edges gave everything more of the energy and impact of alive club performance. It was as if everyone woke up and had a second cup of coffee.

The more distinct image outlines made it easier to follow individual players. For example, it was much easier to track the guitar line under the louder sax solo, and there was a wealth of additional low-level and inner detail. The cymbals' leading edges were particularly crisp with the BiFocal, and seemed to explode with the bite that the instruments have live. There was more air as well, and more shimmer as they decayed. In comparison, a lot of the other cables I tried sounded a little slow and closed-in.

It's not surprising that a description of the BiFocal's strengths sounds a lot like those of Kimber's 4AG: detail, speed, sharp transients, exceptional reproduction of dynamic and pitch subtleties. What was surprising was how different they actually do sound, and how easy it is to view the BiFocal as an evolutionary advance. The BiFocal couldn't quite match the AG's intricate articulation of transients, or its delicacy and air at the very top and razor-sharp control of the lowest lows, but the BiFocal unquestionably had a more natural overall balance. Instead of attention being drawn to the upper midrange and frequency extremes, there was a more even handling of detail across the frequency spectrum that gave the BiFocals a larger, deeper soundstage. Tonally, the BiFocal was much warmer and, in direct comparisons, seemed to more correctly capture an instrument's timbre.

The most noticeable difference, how ever, was how the BiFocal filled things in -a note's body between its leading and trailing edges, an instrument's harmonic structure above the fundamental, even an image's dimensionality and body within its outer edges. On the Ray Brown disc, the 4AG's handling of notes' leading edges positively supercharged the presentation with a live feel but in comparison to the BiFocal it came off sounding like all transients and details. The piano was all struck keys and vibrating strings, but no soundboard or resonating body. Ray Brown's bass was finger snaps and strings slapping the neck, with a sense of the instrument's body resonating only every fifth note or so. With the BiFocal, notes weren't just leading edges, and instruments were far more than just strings or keys.

The effect was spatial as well: the 4AG seemed to highlight image edges or spotlight individual players within an orchestral section, while the BiFocal filled in the bodies and tonal colors, giving images the third dimension. DCC has just released a super 180gm pressing of an old favorite, Joni Mitchell's Court and Spark (DCC LPZ-2044), and "Twisted" was a great example of the differences. With the 4AG, her voice and the bass guitar were pristine, wonderfully detailed, and sharply outlined. Switching to the BiFocal slightly softened the focus on fine details and the temporal and spatial edges, but gave the images body and depth. The bass took on a warm bounce, and Mitchell's vocal felt more like a human voice singing in a real space.

During "Saturn," from the Mehta/ LAPO recording of Holst's Planets (London/Classic CSDC 6734), one section of the orchestra after another enters, builds ominously, and recedes only to be replaced by the next. With the XL, each instrument or section was exquisitely detailed, distinct, and locked in place, but there was absolutely no doubt that all were sharing the same acoustic environment. The space between instruments was actually substantially opened up compared to the 'L version, but was not at all discontinuous. Rather, it was filled with the mix of low-level sounds and the hall's ambience that you hear-or feel -at a live performance.

Another area where the BiFocal-XL excelled was in its ability to sort out complex passages and crescendos. In fact, the more demanding the music, the bigger the differences between the two versions. Toward the end of "Saturn," a veritable cacophony of instruments explodes, with a series of bells laid over the top of everything. The BiFocal-L did a decent job of keeping everything sorted out, but switching to the XL resulted in a significant improvement. The instruments were all more distinct and vibrant, but the difference in the bells was stunning. With the XL they had so much more inner detail, and were so much more dimensional, that I switched back twice to make sure that I was listening to the same passage.

Not surprisingly, there was a substantial difference in the two versions' bass performances, with the XL having far better control, pitch definition, and detail. On "Saturn," for example, it was dead simple to distinguish between bass drum, timpani, and double basses, regardless of how softly they were playing, or even among individual double basses within the section. On one of my favorite bass torture tests "Bali Run" from Fourplay's Fourplay (Warner Bros. 26656-2), the XL was noticeably tighter on the electric bass runs at the piece's opening.

Still, as obvious as the bottom-end improvements were, they weren't as dramatic or as musically significant as the overall improvements in resolution, inner detail, and continuity. I didn't have the opportunity to compare the BiFocals on a single-ended system, or on one based on a set of super twoways, either of which might have made for an interesting comparison. With a big amp and a full-range speaker, however, it was no contest. The BiFocal-L is unquestionably a very good cable and substantially less expensive than the XL, but once you hear the difference in performance, you won't go back. Somehow, some way, that difference in price just isn't going to seem all that big.

Summary

The BiFocal-L and BiFocal-XL are excellent speaker cables and are both highly recommended. The L version offers a wellbalanced mix of characteristics that should mate beautifully with a wide range of systems. In mine its performance fell neatly among those of several different cables that all perform well, if offering slightly different perspectives.

The BiFocal-XL, on the other hand-in the right system-is a big step up in essentially every way, and among the best speaker cables I've heard. At $1500/8' pair it's not cheap, but neither is it particularly expensive in today's cable-pricing sweepstakes-especially given its performance.

Given the transitional nature of the BiFocal, one of the most intriguing findings was that both versions substantially improved on the performance of Kimber's own 4AG, itself a very good cable and noticeably better than its copper-conductor predecessors. Makes me wonder how good the rest of the new Kimber Select wires are going to be.