Nirvana Audio S-X Ltd. loudspeaker cable
By Brian Damkroger   •   October, 2005 Nirvana Audio's cables have long been fixtures in my audio system: first the SL interconnects and speaker cables, and, after their debut in 1998, the S-X Ltd. interconnect. In 2002, after a long development process, designer Stephen Creamer introduced the companion S-X Ltd. speaker cable ($2780/2.5m pair, add $50/pair for biwire configuration). He explored a wide range of options, including dramatically different structures and materials, but always returned to the elements he'd used before—and ended up with a design that combined elements of his two existing speaker cables, the SL and the entry-level Royale. At its core, the S-X Ltd. has the Royale's two conductors, each a symmetrical Litz element consisting of 285 isolated strands of high-purity copper of several different gauges. In the S-X Ltd., the conductors are spaced slightly apart to minimize capacitance, wound into a twisted pair, and wrapped in FEP insulation.

The SL's eight smaller, 95-strand Litz-type conductors—also high-purity copper, in different gauges, and with FEP insulation—are then wrapped around the core in a direction opposite the pair's twist, to promote noise cancellation. A complex array of wire guides locates the conductors and damps vibrations; this assembly is wrapped in an insulating jacket of amorphous PTFE (Teflon) and air, and then an outer sheath of a polyurethane-based composite engineered to reduce static buildup. Each leg of the S-X cable, positive and negative, consists of one inner and four outer bundles.

It all sounds pretty formidable, but the resulting cable is quite manageable, about ¾" in diameter, and reasonably flexible. Like all Nirvana cables, it's beautifully constructed and finished, with solid, high-quality hardware and terminations.

Sound
After a year with the S-X Ltds., I had a pretty good idea of how they performed, but I wanted to specifically address two questions: whether or not the S-X was a big performance jump up from the SL, and how the S-X compared to my reference cables. So, just before deadline, I spent a day listening to some of my favorite albums, revisiting my assessment, making comparisons, and tackling these questions.

The first piece I cued up was a performance of Verdi's La Traviata featuring Beverly Sills, Nicolai Gedda, and the Royal Philharmonic Orchestra conducted by Aldo Ceccato (LP, Angel SCLX-3780). It quickly confirmed what I'd learned over the last year: the S-X Ltd. is a dynamite speaker cable. It was tonally quite neutral but not bleached out—notes had rich, complex harmonic structures. Images were detailed and well defined, but never overetched or disconnected from their surroundings. Transients were big and powerful, but also clean and fast. In short, the Nirvanas delivered just about everything I could hope for from a speaker cable.

The S-X Ltd. did it all, but a few things stood out. I was struck by how powerful and dynamic Beverly Sills's soprano was, and by how definitive seemed the inner details of her vocalizing and her articulation. I also noticed the Nirvanas' incredible transparency, which showed up in instruments' tonal purity and, even more dramatically, in the uncanny reproduction of the hall's ambience between and around the performers. The echoes trailing Sills's notes vividly described the space with a consistency and clarity that made it seem real.

The only nit I found to pick with the S-X Ltd.'s performance was a compression of front-to-back depth. This was pretty minor, and not really obvious on La Traviata, but I did notice it while listening to the Jean-Paul Morel/Paris Conservatoire reading of Albéniz's Iberia (LP, RCA Living Stereo/Classic LSC-6094). The stage wasn't as deep as the ambience cues suggested, and the front-to-back spacing between the rows of players was slightly compressed.

But I love my Nirvana SLs . . .
Was the S-X Ltd. a big jump up from the SL? Yes, absolutely, and in every way, but the biggest differences were the sharper transients, improved detail resolution, and increased transparency. With the S-X, Beverly Sills's notes had crisp, clean leading edges instead of the SL's smooth flow. Her vibratos were sharply defined with the S-X rather than softly rounded, and her timing was sharper and more precise. Finally, with the S-X Ltd. in the system, all traces of the SL's golden warmth and slightly liquid texture were gone.

The bouncing oboe lines near the end of Act I of La Traviata were a great example of the comparison and of the S-Xs' strengths. With the S-Xs, there were sharp, tangible images of both the instrument and the column of air rising above it. In contrast, the SLs' oboe was solid and had a rich, woody tonal structure, but wasn't as detailed as with the S-Xs—and the column of air didn't have the physical presence that it did with the S-Xs.

What about my other reference wires?
I've long relied on Nordost's Valhalla and Audience's Au24 speaker cables as references, and of late have begun to include the Silversmith Silvers as well. All three are excellent, but they differ slightly in tonal balance and in how they portray the subtleties of a performance. The Nirvana S-X Ltd. has now firmly established its position in this group, providing another excellent, and again slightly different, set of attributes. Interestingly enough, I found that of the other three cables, the S-X Ltd.'s performance most resembled that of the Valhalla. This was a surprise, given that the two interconnects are polar opposites: the Nirvana interconnect is tonally warm, and relaxed and coherent, whereas the Valhalla is cool, and emphasizes detail and edge definition.

For starters, the S-X Ltd. speaker cable was tonally quite similar to the Valhalla—very neutral, with, if anything, a tinge of coolness on some material. On the other hand, there were other, more subtle differences between the cables that drew attention to different frequency regions. The violins in La Traviata were a good example. With the Nordost, I was more aware of the details and dynamics of the players' fingering and bowing and their initial transients and vibrations. With the S-X Ltd., my attention was instead drawn to the textural differences in the body resonances of the individual violins, and how these resonances defined each instrument and its position.

Expanding the comparison to include the Silver and Au24 spreads things a little further—each has a tonal balance that's slightly but consistently warmer than the Nirvana S-X Ltd.'s. Similarly, whereas neither the S-X Ltd. nor the Valhalla had any trace of background texture, the Silver had a faint, golden sweetness, and the Au24 the tiniest bit of liquid smoothness. Neither was really detectable as an overlay on instruments or voices, but instead as a component of the ambience, a slight thickening and coloring of the air in the spaces between performers.

Nor did the S-X Ltd. concede any ground to the Valhalla in terms of detail resolution or definition. The reproduction of the oboe in La Traviata that I described earlier—the instrument, the column of air—was equally tangible with the Nirvana and Valhalla. This image was a bit less distinct with the Silversmith Silver; with the Audience Au24, the instrument and column of air were there, but not the sharply drawn transition between them.

The Nordost Valhalla did emphasize image edges slightly more than did the Nirvana S-X Ltd. In some cases this resulted in better edge definition, but in others the emphasis overshadowed the initial portions of a note's body—I felt I was hearing more of the note with the Nirvana. On the other hand, the S-X Ltd. painted pitch and volume transients with a bolder, slightly coarser brush than the Valhalla, and occasionally obscured the most delicate associated details. Reproducing a dynamic transient, for example, both would precisely move the level from pp to ff. With the Nirvana, however, I always visualized the transition being drawn with a thick Magic Marker; the Valhalla seemed to draw this boundary with a fine-point Sharpie.

Overall, listening to La Traviata through the Valhalla and Nirvana was like hearing the same performance led by two different conductors, one asking for more body and power, the other using a lighter, more precise and delicate touch. With the Valhalla I had the sense that Sills was projecting a bit more from her throat and mouth; with the Nirvana, it was unquestionably from her diaphragm. There was more inner detail with the Nirvana; Sills's voice sounded richer and more complex. With the Valhalla's more refined, more delicate touch, the tiny details surrounding Nicolai Gedda's voice when he returns at the end of Act I of La Traviata were clear and more precisely located him on the stage. As noted earlier, that stage was a bit deeper with the Valhallas, and more correctly scaled to the other dimensions and the listener's perspective.

Bottom line
Nirvana's S-X Ltd. speaker cable is a big jump in performance from the company's SL. I hate to foster discontent by suggesting that SL owners trade up, but with all due apologies, it's worth it. The S-X isn't just better; it's in an entirely different league. It's one of the very best speaker cables I've heard, and every bit as good as the references I've selected over a decade of careful auditioning. Like the S-X Ltd. interconnects, the S-X Ltd. speaker cables are likely to stay in my regular rotation for a long, long time. Very highly recommended.