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Speaker Cables

Music Club Presentation

January 2005

About this presentation:

We will be exploring various philosofy or concepts about what makes good speaker cable, according to a few popular speaker cable makers, each with their own belief. Then, there's Jon Risch's design, which is like opensource audio cable and DIY, allowing you to make a cable performing as well or better than name brand cables costing 10 times, so they claim.

Due to time constrain and the extensiveness of interconnect cables (Today, there are 2 main streams, the traditional analog, and newer digital cables used extensively in today's home theater systems. ), we will only be briefly discuss about their basic pros and cons.

Before going into theories, I'd like to add a few words from experience. image of cable construction
Every component matters!
Every component, be it an interconnect connector, soldering, cable, pre-amp, amp, source, speaker cable, speakers, listeninig area, and even the power and power cord that drives these equipment makes differences.
Also, speaker cable differes from interconnects is that they not only need to carry the wide frequency of signals, they also need to carry the current and power to drive the speakers.

Electric Cables in general

Skin Effects :

"There is a textbook equation which describes the reduction in current and power density at any depth from the surface of an electrical conductor. For copper the equation is: 6.61 divided by the square root of the frequency (Hz) equals the depth in mm at which the current density will be 1/e. Since 1/e is 37%, this equation tells us the depth at which the current density has been reduced by 63%. For 20,000Hz, current density is only 37% at a depth of 0.0467 mm, which is the center of a 0.934 mm (18 awg) conductor. Conventional use of the above formula falsely assumes that it is acceptable to have a 63% reduction in current flow and an 86% reduction in power density at the center of a conductor. However, this formula does not by itself describe at what depth audible distortion begins. Listening (empirical evidence) shows that audible distortion begins at somewhat lesser depths.
There is a solution to skin-effect-using a single strand of metal which is just small enough to push skin-effect induced audible distortion out of the audio range. Simple evaluation of multiple sizes reveals that audible skin-effect induced anomalies begin with a strand (or conductor) larger than 0.8 mm. " Quoted from AudioQuest

Risistance:

Causes power loss, and reduced dynamic contrast, harmonic and subtlety.

Inductance:

The property of an electric circuit that causes it to store energy in the form of a magnetic field and because of which a varying current in a circuit induces an electromotive force (voltage) in that circuit or a neighboring circuit. Measured in henrys.

Capacitance:

capacitance is like a buffer that softens and smoother the signal. (draw a sine wave, and sine wave with capacitor, ask audience) it also introduce time shift between various frequencies. Also, different capacitances work mostly in a particular range of frequency, the audio of that particular frequency is therefore "influenced".


Magnetic interaction:

Magnetic property exist when the freqnecy and current moving thru tthe cable. Magnetic field is stronger with low freq high current of bass while weaker with high frequency signals. As it is known that magnetic field intefere with signals in a cable (ie generator, traffic light sensor loop under the ground. etc) Because of this, bi-wiring can be beneficial.

Strand shift location in the bundle:

considering skin effect and strainds in a cable shift positions, the electron needs to travel between strainds that's near surface. Each strainds when making connection to another straind is same as connecting 2 connectors, where capacitance, inductance, resistance, and all the arrays of electrical properties are observed and hens can change characteristics of the signal when arriving at the other end of the cable.

Material quality:

Cables are often made of these ingridents: gold, nickel, brass, aluminum, copper, silver.

Impedance

Measured in ohms (EE guys please explain what's difference between impedance and resistance?) The impedance must be matched, esp between speakers and cable, and amplifier.

Insulation Material:

When they exist between 2 conductors, they act like capacitors which stores and releases energy. Most generic cables use some kind of PVC which causes some capacitance. Air is the best insulators between connectors but it's not likely in a cable. Today, most low capacitance cables uses foamed teflon.

Connection:

Mechanical compression using proper crimp is best connection one can get. Next comes soldering. Again, quality soldering material makes difference too.

What Audio Cable Companies Say About There Cables

Theories from some of the most popular speaker cable makers

AudioQuest:

HyperLitz(R) construction. Conventional litz construction uses multiple individually insulated strands arranged so that no matter how big the cable, skin-effect is only that effect which would be associated with a single strand. But does not address magnetic effects. AudioQuest is on their 3rd generation HyperLitz construction, it supposed to adress magnetic field effect and other elctrical properties that "modifies" signal.

Monster Cable:

Time Correct Technology: Basically, Monster Cable's way to compensate the magnetic field, skin effect, by using multiple guage windings to help various frequencies of signals to arrive to end point at same time, in their theory that low frequency signal travels closer to center of straind at slower speed than higher frequency closer to skin of a straind.

Transparent Cable:

Uses a network and shielding techniques to filter out noise and correct balance. "Cables are important because they are the longest parts of a system and therefore act as efficient antennas that pick up and/or radiate noise."
"... One simple, but often overlooked, method of minimizing noise in a system is to limit the system bandwidth to that required by the signal. Use of a circuit bandwidth greater than that required by the signal allows additional noise frequencies to enter the circuit." HENRY W. OTT, Distinguished Member of Technical Staff, AT&T Bell Laboratories
Transparent's networks are designed to help the cable transfer lower audio frequencies more accurately and efficiently and reject noise. They are also designed to compensate for the length of the cable so that all cables in a system regardless of their lengths deliver a predictable level of performance. Transparent Network Technology insures that your components will be able to provide the rich, smooth, and musical sound that they were designed to deliver.

More complete technical details can be found on their website at http://www.transparentcable.com/design/destech_techtalk.html

Transparent Cable's Opus MM Cable

Transparent Cable do not believe flat or coax cables are answers because they have too much bandwidth for noise and likely to contain electrical resonance in essential frequency range needed.

JPS Labs:

Alumiloy(R) wires.
"The wire used in our designs is a proprietary, non-ferromagnetic, solid core blended alloy wire, Alumiloy. Alumiloy cleanly transfers audio frequencies and up better than any other conductor available. Extensive measurements and testing have proven that this proprietary alloy material has superior qualities to copper, silver, gold, or any combination of these materials, in terms of bandwidth, dynamic range, and neutrality. JPS rewrote the book and created a unique conductor to allow for maximum clarity without the veiling even the purest silver and copper conductors have in the mids and highs, and a faster bass region with greater impact than anything you have ever heard. We are the only cable manufacturer in the world who works with their own patent-pending conductor materials" Quoted from jps labs website

Nordost

Flat cables

Nordost cables are really very "flat", the original Flatline cable is still just 5mm of thickness, and is usually easily identified visually.

Nordost cables are still being manufactured using their proprietary FEP extrusion process. A tough extruded FEP jacket makes the cable highly durable allowing it to withstand huge extremes of temperature, but it also makes the cable impervious to water and chemicals and it will not split apart or de-laminate.

The first Nordost cables incorporated solid conductors, flat ribbon solid oxygen free copper conductors, or fine and micro litz round conductors. This eliminated strand interaction thereby significantly reducing the well documented audible distortions caused by skin effect and magnetic fields interactions

This high end speaker cable shown to the right has:

Kimber Cable

VariStraind(TM) conductor geometry

OSCaR Objective Subjective Correlation and Results engineering process.

Analysis Plus

Hollow Oval cable


Figure 2a (top) shows uniform current
distribution at DC.
Figure 2b (bottom) shows the effect of
current bunching and skin effects at 20kHz.
The primary advantage of an oval conductor design rather than cylindrical conductor geometry is that the oval shape allows more of the return current to be closer to the outgoing current, thus reducing the negative effects associated with excessive current bunching.

Current bunching (also called proximity effect) occurs in the majority of cables on the market that follow the conventional cylindrical two-conductor design (i.e., two cylindrical conductors placed side-by-side and separated by a dielectric).

Since the center part of the conductor is not used at high frequencies, we can simply eliminate it. By using a hollow conductor, it minimizes the change in resistance with frequency and the cable becomes more efficient. The mpedance is maintained near constant thruout freqnecy range, and it is virtually EMI immune.


APL cable vs a regular cable w/ emi noise injection.

For full theory, please go to http://www.analysis-plus.com/Pages/thedesign.htm

Cardas

Constant Q strainding (Golden Section)

Advantages:

Disadvantages:

This construction is patented by Cardas Audio, and is their belief.




MIT Music Interface Technologies

MIT believes in removing the noise from both externally induced as well as the signal inside of cable bouncing back and forth. Since energy does not dissapear, it has to turn into something, and that interfere with deliverying clean music signal. For more details of the theory, see their white paper.


DIY High-End Speaker Cables