Today, based on two decades of research and comparative listening, audio engineers agree that the most natural sound is achieved by a combination of low series inductance L and a low loop resistance R. A low L is instrumental in minimizing high end roll off and frequency dependent phase shift, and a low R is important for a true and powerful bass and low mid-range.

A low series inductance L is achieved by placing the two conductors in the cable as close together as physically possible, and in the patented GOERTZ design they are wide bands of solid copper or silver which are sandwiched together, only separated by a micro thin film of a high grade dielectric. This geometry will result in a an extremely low L, and a capacitance C much higher than that of conventional cables. The combined effect is to reduce the characteristic impedance of the cables all the way down into the single digits to almost match the nominal impedance of a typical speaker load. The impedance match minimizes distortion caused by ringing and signal reflections and would not be possible without the high relative capacitance. This combination of a low L and R, and a high C value is the secret behind the exceptional performance of GOERTZ loudspeaker cables.

For purpose of comparison R must be measured as loop resistance or the sum of the resistance in both conductors. Some manufacturers incorrectly state the resistance in just one conductor, thus arriving at a figure which is only 50% of the true R.

SPEAKER CABLES IN THE ORDER OF DESCENDING L

The main parameter setting the SERPENTS/GOERTZ series apart is their DC resistance, also expressed as equivalent AWG or gauge. The gauge you should select is a function of the output power of your system and the length of the run. A wider and heavier cable with a low AWG will serve a more powerful system and longer runs than a lighter cable.

Goertz MI 1 cable equals 13 AWG, Goertz MI 2 10 AWG and MI3  7AWG. The difference of 3 between the gauges indicates that the DC resistance of MI 2 is only half that of MI 1 and that the DC resistance of MI3 is half again of that of MI2. Each step thus means cutting the loss of signal strength in half, but another more important effect is the improved speaker diaphragm damping which translates into a largely undistorted, truly powerful mid-range and bass, even at high power levels and over long runs.

 The following table may provide a rough basis for selection in single wire configuration:

Most other speaker cables, even sophisticated high-end cables, have a characteristic impedance between 50 and 200 ohms and a correspondingly high inductance resulting in a loss of fidelity due to high frequency roll-off. Besides, the impedance of most speakers is not a fixed parameter but varies according to the signal frequency. A loudspeaker rated at 4 ohms may well have a considerably lower impedances at low frequencies and maybe an impedances of 8 ohms or higher at the high end of the audible range. Experience indicates that a perfect match is neither feasible nor required, and all Goertz MI cables will work well with speakers rated at 2 ohms up through 8 ohms.

Even more than with speaker cables this is a question of taste. In general the heavier Sapphire or Tourmaline are often selected over TQ2 for the sometimes longer runs between a pre-amp and power amps placed near the speakers. We have seen many cases, however, when TQ2 has served very well in this type application. TQ1 (the earlier version of TQ2) was developed, initially, for tube lovers but has become immensely popular also for solid state gear. When asked we usually start by recommending TQ2 over the heavier Tourmaline or more expensive Sapphire for the short runs between source components and pre-amp. We recently introduced the even lighter gauge "Micro Purl" which seems to have an even greater potential as an all round interconnect cable, analog and digital.  In addition the Micro Purl seems to be carving its own niche as a microphone cable in professional recording studios, greatly outperforming traditional, even much higher priced coax designs.

Are GOERTZ cables EMI/RF shielded ?

No, they do not incorporate a shield like e.g. the braided wire hose which is often seen surrounding conventionally designed interconnect cables. In general, due to the much stronger signals involved, shielding is not required in speaker cables, but rejection of cross talk and RF interference is a must in an interconnect cable. An open geometry ribbon cable used as an interconnect will function as a loop antenna literally inviting RF interference, whereas the closed GOERTZ geometry exhibits excellent noise rejection in itself. The insensitivity to noise is even further enhanced in the Micro Purl series, where the close sandwich of extremely thin, relatively wide conductors is twisted or "purled" in the manner of twisted pairs used so widely in telecommunication.

The slotted, Rhodium plated GOERTZ terminals are available in three styles: Spade lugs, Banana Plugs and Pin connectors. They come in boxes of four. Two boxes are required for a pair of speaker cables.

Before termination cables are cut to length, the outer polymer jacket is removed, and the conductors stripped of their insulation by sanding or a sharp instrument. This task is not difficult but can be avoided entirely if cables are ordered already cut-to-length, stripped and termination ready.

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The Audio Glossary

Low impedance, matched speaker cables represent the ideal path from the amplifier to a loudspeaker but in rare cases may cause  small percentage of solid state amplifiers to become unstable when combined with certain speakers. The symptom is audible oscillation or overload shutdown. Fortunately the problem is easily solved, by installing an Alpha-Core RC link across the terminals of each speaker. A pair of RC links is provided free of charge with our ultra low impedance GOERTZ and Serpent series cables.

  The advantage of the low impedance, matched path is that the amplifier is rendered able to exert control and damping of voice coil resonance, and all frequency bands are transferred with the same interrelated magnitude irrespective of cable length. This also means that the cables to the left and right channels of a stereo system can be of unequal length if desired, largely without ill effects.  

Read on for full technical explanation:

  The impedance of voice coils in dynamic loudspeakers and their crossover networks rises with frequency, causing a corresponding decrease in audio output at high frequencies.

  At low audio frequencies a voice coil behaves almost like a purely resistive load but at for example 20 kHz its impedance may rise to more than 10 times the DC resistance. This is mainly due to self-inductance, which causes the almost purely inductive impedance to rise even further above 20 kHz.

  Unfortunately the feedback loop in certain solid state amplifiers does not satisfy the Nyquist or Bode criterion for stability. The amplifier may at times exhibit gain band widths in the internal feedback loop in the megaHertz order, meaning that things may start happening above the audible range. The problem arises when this type of amplifier is connected with loudspeakers that exhibit high impedance at high frequencies, via an otherwise ideal low impedance matched cable. Under certain circumstances, instead of stabilizing the gain via the internal feedback loop as intended for a low impedance output, the amplifier is turned into a HF power oscillator operating at a frequency well above the audible range. This may load the amplifier excessively, resulting in higher than normal operating temperature or overload shutdown.

  Our remedy is to place a resistive load across the speaker terminals, which becomes effective at frequencies well above the audible range. Tests have shown that a 0.1 microfarad capacitor in series with a 10 ohm resistor will do the trick if applied across the speaker terminals. The combination “RC Link” also called a Zobel network, is supplied free of charge by Alpha-Core to be applied when needed.

  A simple calculation shows the impedance of the RC link to be 14 ohms at 159kHz, amply illustrating that they in no way affect performance at audio frequencies.

  Incidentally, the situation described in the above does not occur with electrostatic speakers or with tube amplifiers containing output transformers.

R/C match links are available through Alpha-Core.

What is the difference between Nordost Flatline and GOERTZ ?

They are both flat cables, but the resemblance really stops there. The Nordost geometry with its two groups of conductors arranged side by side in an open pattern will exhibit a medium to high series inductance, and due to the skinnier conductors, also the loop resistance is much higher than that of equally priced GOERTZ cables. It is worth noting that the premium series of Nordost cables utilize silver plated copper conductors whereas GOERTZ's AG series all have solid, high purity silver conductors.

The Alpha-Core web site was originally designed and built by Triad Communications in Connecticut and launched in 1996. It was redesigned in Fall 1997 by pRCarter in exchange for Goertz cables for his home theater system. The goals for the upgrade were to dramatically improve the quantity and flow of information and to make the site design distinctive without resorting to klunky browser tricks or huge graphics (not that there's anything wrong with that!). Updated information (including new retail price lists, dealer lists, and this new FAQ) was organized into a few medium-sized pages with nested tables and minimal graphics. New hyperlinks between pages were carefully added to couple useful references. HTML was extensively upgraded to make the site as widely browser-compatible as possible, and a variety of Metatags were added to aid web crawlers categorizing Alpha-Core for searches. Existing page names were retained to service old user's bookmarks.