technical glossary on audio cables

For a better understanding of

physical phenomena and more...

The capacitance of a cable is a measure of its ability to store an electrical charge. This property is fundamental in electronics and electrical engineering as it affects how electrical signals propagate through the cable. Capacitance is typically measured in farads (F). However, in the context of cables, sub-units like microfarads (μF), nanofarads (nF), or picofarads (pF) are often used due to the low capacitance values involved.

The capacitance of a cable is primarily generated by two factors: the proximity of the conductors (the wires inside the cable) and the dielectric material (insulator) that separates them. When two conductors are close to each other, separated by an insulator, they form a capacitor. The capacitance of this capacitor (or the cable’s capacitance) depends on the conductors’ surface area, the distance between them, and the type of dielectric material used.

The question of capacitance being “positive or negative” in cable specifications might be misleading. In physics, capacitance is always a positive quantity because it represents a capacity to store energy. However, in the context of cable specifications, discussing capacitance as “positive” or “negative” is not usual. What can vary is the effect that capacitance has on the performance of the cable in certain applications:

Positive Effects: In some cases, a certain amount of capacitance is desirable. For example, in filtering circuits or in applications where the cable acts as an integrated capacitor.

Negative Effects: In other cases, high capacitance can be detrimental. For example, in high-speed data transmission cables, too much capacitance can cause signal distortion or attenuation, thus reducing the quality of the transmission.

In summary, the capacitance of a cable is an intrinsic characteristic that describes its ability to store an electrical charge. Although the value of capacitance is always positive, its effect on a cable’s performance can be considered “positive” or “negative” depending on the application. Cable specifications often include capacitance to help engineers and technicians select the right cable for a given application, based on how capacitance will affect the system’s performance.

The triboelectric effect occurs when cable insulation materials rub against each other or other objects, generating an electrical charge due to electron transfer. This effect can induce noise or interference in audio signals, particularly in environments where cables are subjected to frequent movement.

To reduce the effects of triboelectricity, we recommend using cables with high-quality dielectric insulation. Cables designed with anti-static materials or friction-minimizing properties can also help. Additionally, avoiding over-handling or moving cables in dry environments can reduce the generation of electrostatic charges.

Quartz sand and shungite offer superior protection against electromagnetic interference (EMI), ensuring the purest signal transmission for audio. Quartz sand, with its exceptional insulating properties, reduces signal loss and enhances sound clarity. Shungite is renowned for its ability to absorb and neutralize EMI, thus protecting audio signals from external disturbances. Together, these minerals contribute to sound fidelity by preserving the integrity of the audio signal for an unparalleled listening experience.

Literary references:

(1) “Electromagnetic Shielding” by Salvatore Celozzi, Rodolfo Araneo, et Giampiero Lovat

(2) “Materials for Electromagnetic Interference Shielding” – diary of Materials Chemistry.

(3) Advanced Materials for Electromagnetic Shielding: Fundamentals, Properties, and Applications” by Xingcui Guo, Xingyi Huang, & Yuvaraj Haldorai.

(4) Shungite Waste – An Effective Mineral Additive for Concrete Modification

(5) Nanomaterials for Electromagnetic Shielding” – the magazine ACS Applied Nano Materials.

(6) The Role of Carbon Materials in Enhancing Electromagnetic Interference Shielding Effectiveness

Quartz sand and shungite play a crucial role in protecting against EMI through their unique properties. Quartz sand acts as a natural insulator, preventing electromagnetic interference from penetrating and affecting the audio signal. On the other hand, shungite has a special molecular structure that enables it to absorb harmful electromagnetic waves, significantly reducing interference. The combination of these minerals in cable shielding ensures effective protection against EMI, allowing for a purer signal transmission.
While both minerals offer EMI protection, they do so in slightly different ways. Cables shielded with quartz sand focus more on physical isolation of the signal, offering a barrier against external disturbances. Conversely, cables shielded with shungite utilize the unique ability of this mineral to actively absorb and neutralize EMI. Depending on the specific environment and the level of electromagnetic interference, one may be preferred over the other. However, for optimal protection, the combined use of both minerals in audio cable shielding can offer the best results.
The use of minerals in cable shielding dates back several decades, when various materials were explored for their protective properties against interference. Initially, metals were the most commonly used for shielding; however, the discovery of the unique properties of certain minerals expanded the available options. Quartz sand and shungite, in particular, have gained popularity due to their effectiveness in neutralizing EMI and preserving signal quality. This evolution reflects the industry’s ongoing commitment to finding innovative solutions for improving signal transmission in an increasingly interference-filled world.

Quartz sand and shungite find shielding applications far beyond audio cables, in various fields where protection against electromagnetic interference is crucial. For example, they are used for shielding communication cables, precision electronic equipment and even critical infrastructures such as medical facilities and data centers, or highly complex installations such as particle colliders*. What’s more, their ability to shield against electromagnetic interference makes them invaluable in the development of materials and technologies for environmental protection and advanced manufacturing, demonstrating the versatility of these minerals when it comes to shielding against electromagnetic interference.


(1) CERN 82-05 Super Proton Synchrotron Division June 4th, 1982 “Radiation-Resistant Magnets” CERN European Organization for Nuclear Research – RL. Keizer and M. Mottier -1982

(2) NUREG/CR-6384_BNL-NUREG-52480 “Literature Review of Environmental Qualifications of Safety Related Electrical Cables” Brookhaven National Laboratory – M. Subudhi -1996

(3) “Mineral Insulated Conductors for Magnetic Coils” Los Alamos National Laboratory – A. Harvey – 1970

(4) SLAC-PUB-4910 Stanford University “Radiation Hardening of Magnet Coils” Stanford Linear Accelerator Center – A. Harvey – 1989

(5) CERN Geneva, Switzerland ”Dielectric Insulation and High Voltage Issues” – D. Tommasini

Basalt sheaths, made from volcanic rock fibers, offer excellent thermal and electrical insulation properties. They are particularly effective in reducing triboelectric effects, thanks to their ability to absorb and dissipate electrostatic charges. What’s more, as basalt is a naturally high-temperature resistant and non-conductive material, it improves cable durability while minimizing the risk of electrical interference due to friction. These characteristics make basalt sheaths a preferred choice for high-end audio applications where signal purity is crucial.

In the realm of high-fidelity audio, the quest for perfect sound often focuses on the apparent components like amplifiers, speakers, and audio sources. However, a crucial and often underappreciated component plays a fundamental role in the audio chain: the cables.

Pierre Johannet, a researcher at EDF, conducted in-depth research that highlighted the significant impact of Interface Microdischarges (MDI) on audio cables, which are not directly measurable by the cables’ standard technical specifications.

Microscopic differences in the manufacturing or material of cables can influence the frequency and intensity of MDIs, leading to subtle but perceptible variations in sound quality. This underscores the importance of considering factors beyond traditional technical specifications when evaluating the performance of audio cables.

Interface Microdischarges (MDI) are distinctive because they originate from microscopic irregularities at the interface between the conductor and its insulator, generating high frequencies that directly disrupt the audio signal through modulation of the background noise. Unlike electromagnetic interference (EMI) or usual background noise, MDIs are challenging to detect and analyze with conventional measurements due to their transient nature and high frequency.
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