Shunyata Research Sigma Signal Cables


Equipment report
Loudspeaker cables,
Shunyata Research Sigma Signal Cables

How has Shunyata significantly mitigated some of the apparent fundamental problems with signal transfer through cables—at least at their respective price levels? I would say it starts with Shunyata’s principal and founder Caelin Gabriel. Gabriel is a scientist by education and worked for a military wing of the NSA in digital signal acquisition and encoding in the early part of his career. He cut his teeth by working on equipment that could detect weak and previously unintelligible transmission signals and then resolve them to usable levels. Much of this approach from his earlier work has carried over to his career at Shunyata. Gabriel uses methodical research results to develop effective combinations of materials, construction, and technologies to reduce noise, reflections, and interference that adulterate signal integrity.

 Shunyata uses Ohno Continuous Cast (OCC) OFE101-grade copper—the purest form of certified copper available—in both its conductors and connectors. (OCC, invented by Atsumi Ohno in Japan, is a process of casting copper wire in molds. As the wire cools, a single crystalline structure is formed throughout the length of the wire as opposed to the standard wire-drawing method, which leaves multiple internal crystalline structures in place.) The sonic benefits of OCC are widely known in the specialty audio cable industry—generally, a smoother, purer sound. What is apparently exclusive to Shunyata’s conductors is their formation to function as a virtual hollow tube. Shunyata says this hollow structure (called VTX) greatly reduces eddy currents—and their associated distortions—randomly generated within a typical conductor’s interior as the signal travels down its exterior.

Shunyata treats all Sigma conductors and connectors with something called the Kinetic Phase Inversion Process (KPIP), which essentially does away with the need to determine a cable’s correct signal direction and to undergo sufficient burn-in before its function is optimized and remains stable. After three years of research to identify the key issues associated with directionality and burn-in, Gabriel developed KPIP to address both. Shunyata actually reveals precious little about what KPIP is and how it works, other than to say it does away with the need for cryogenic treatment. I can tell you, though, the KPIP-treated Sigmas stabilized within the first two or three days of use as opposed to the minimum three weeks I am used to with other audio products. KPIP actually does more than address burn-in and directionality issues. I had some treated and some untreated, completely broken-in—but otherwise identical—Shunyata power cords for a while about a year ago. The treated ones helped my system sound more relaxed and free-flowing with no diminution of any other positive quality. KPIP works and is worthwhile.

Sigma carries over Shunyata’s patented ZiTron technology from the Anaconda model. ZiTron addresses what Shunyata characterizes as “dielectric absorption and re-radiation in signal transmission.” A small, passive electric-field circuit cancels out the electromagnetic field that builds up in the dielectric, and it does so—essentially in real time—as the charge difference between the dielectric and the conductor fluctuate with the flowing signal. With less electromagnetic field absorption in the dielectric and release back into the conductors, the resulting signal is less distorted and transient response is reportedly closer to that of the source itself. Shunyata also uses high-energy sonic welding to join the speaker cables’ conductors to its connectors instead of traditional soldering, brazing, or crimping. Sonic welding apparently joins the wire and connector together at the molecular level and is said to be superior to soldering or brazing. Solder introduces yet another metal, usually with a high tin content, and additional surfaces into the mix and causes signal degradation. Crimped junctions are susceptible to mechanical failure when cables have excessive flexing or twisting forces exerted upon them. Sonic welding reportedly enhances transient response in signal transmission and in its equivalent in power applications—Dynamic Transient Current Delivery (DTCD), as Shunyata calls it.

Exclusive to Sigma are two new technologies—TAP (Transverse Axial Polarizer) in the interconnect and HARP (not initials) in the speaker cable. The TAP device, contained in a small cylindrical-looking structure, is not a “cable network” like those found in Transparent and MIT cables. Rather, some of the TAP parts simply have a larger diameter than the interconnect itself and need to be housed in a larger solid structure. TAP reportedly blocks much of the collateral longitudinally oriented electromagnetic waves that surround the cable while allowing the transverse-oriented waves to pass through. The net result is said to amount to the aural equivalent of the effect one has while looking through polarized sunglasses. TAP reduces sonic glare caused by parallel electromagnetic waves interfering with the signal. I did not have a pair of the same cables without TAP to make a side-by-side comparison, but I will say that I found the Sigma ICs seemed to allow the attached system to have a less “splashy” quality on transients and more coherent sonic characteristics—along with the previously noted positive attributes—than with any other IC that I auditioned during the review period.

HARP is also contained in a small, network-like box, but it too is not a network. In fact, HARP does not alter the frequency response or transfer function of the cable in any way. It does not change measurable capacitance, inductance, or resistance. So how does it work? As with KPIP, Shunyata shares very little about the workings of HARP. I can tell you, with great certainty, though, that HARP is highly effective in improving the overall performance of the system. I heard A/B/A demos of a HARP prototype in systems at the Shunyata facility in Poulsbo, Washington, a while back, and was astonished by how much across-the-board improvement HARP made to even a modest system used in one of the demos. It was as if the entire system’s performance were enhanced in every regard—tonal purity, image focus, dynamic precision, soundstage, and resolution of detail and timbre. It is best applied as close to the speaker as possible; thus, the HARP unit is positioned near the speaker terminal end of the speaker cable.