High-end audio cables are cables which are claimed to improve the sound quality of high-fidelity audio systems. Cables between components are called interconnects. Speaker wires carry the signal between the amplifier and speakers.

For analog interconnecting cables, basic system frequency response can be calculated from the electrical properties of the cables, and components on either side of the cables. These electrical properties include resistance, capacitance, and inductance. For small-signal applications the degree of shielding is also important. All of these qualities are taken into account in the design of commercial and broadcast cables. High-end cables for the audiophile market often involve intricate construction geometries and exotic materials such as silver and oxygen-free, long-crystal, high-purity copper.

Cables carrying digital signals, such as S/PDIF and HDMI, are effectively immune to signal degradation for the short lengths used in consumer audio. HDMI uses error correction which makes errors even less likely.

Contents 1 Quality debate 1.1 Analog signal cables 1.2 Digital cables 1.3 Speaker wire 1.4 Mains power cables 2 See also 3 References 4 External links

[edit] Quality debate

There is debate among audiophiles surrounding the impact that high-end cables have on audio systems with audibility of the changes central to the discussion. Bill Whitlock, president of Jensen Transformers, has written that "no other product is as shrouded in hype and mystery as the audio cable!"^[1] Whitlock continues by saying that the high-end segment of the audio industry "abounds with misinformation, myth, and mysticism."^[1] There are claims that, even among audiophiles, in a double-blind test it is impossible to distinguish extremely expensive, exotic speaker cables from ordinary lamp cords or budget 12AWG copper speaker wire.^[2][3]

James Randi, a stage magician and scientific skeptic best known as a challenger of paranormal claims and pseudoscience, offered a prize of one million dollars to anyone who could prove his or her ability to distinguish an expensive high-end audio cable from an ordinary audio cable by means of a controlled listening test. ^[4][5] Michael Fremer of Stereophile magazine took the challenge, but satisfactory testing conditions could not be agreed upon, and the test did not take place.^[6] In rigorous tests performed under controlled circumstances, listeners have not been able to prove there is any audible difference between high end and cheap cables^[7].

[edit] Analog signal cables

Whitlock defines a good analog audio signal cable for unbalanced (consumer) applications as one that has low capacitance and very low shield resistance, such as Belden #8241F.^[1] Signal cables should be kept as short as possible, and longer cables should be ones with heavy gauge-equivalent wiring. "The only property of a cable that has any significant effect on audio noise coupling is shield resistance."^[1]

[edit] Digital cables

One of the more contentious areas is in digital cable design, with high end cables being sold with claims of "distortion-free signal transfer." Some have argued that since the bit rates (approximately 1 Mbit/s) and distance traveled are considerably lower than for other data transfer technologies such as gigabit ethernet, any cable appropriately matched to the correct impedance requirement is sufficient. Others claim that jitter caused by imperfect impedance matching is very detrimental to the audio signal and the most substantial shortcoming of digital audio. This signal deterioration comes about not through corruption of the digital information itself, but instead in the process required to recover the clock signal for the DAC performing the analog conversion^[8]. Mitigation strategies have been proposed^[8], including digital interconnect cables which use dedicated clock lines so as to avoid data-dependent jitter or to obviate clock recovery altogether.

[edit] Speaker wire

Another area of debate is speaker wire "quality". While some speaker wire marketers claim audible improvement with design or exotic materials, skeptics say that a few meters of speaker wire from the power amplifier to the binding posts of the loudspeakers cannot possibly have much influence because of the greater influence from complex crossover circuits found in most speakers and particularly from the the speaker driver voice coils that have several meters of very thin wire. There is however little debate that the overall resistance of the speaker wire cannot be too great.^[2]

An accepted guideline is that the wire impedance should not exceed 5% of the entire circuit. For a given material, resistance is a product of length and thickness. For this reason, lower impedance speakers require lower resistance speaker wire.^[2] Longer cable runs need to be even thicker.^[9] Once the 5% guideline is met, thicker wire will not provide any improvement.^[2]

Roger Russell—a former engineer and speaker designer for McIntosh Labs—details how expensive speaker wire brand marketing misinforms consumers in his online essay called Speaker Wire - A History. He writes, "The industry has now reached the point where [wire] resistance and listening quality are not the issues any more, although listening claims may still be made....The strategy in selling these products is, in part, to appeal to those who are looking to impress others with something unique and expensive."^[2]

[edit] Mains power cables

Another controversial area of audio cabling is that of mains power cables. Products exist that claim to improve the sound or picture with a short length of expensive oxygen-free copper or silver cable connected from the wall socket to the equipment.^[10]. More scientific arguments have been presented, such as building RFI (Radio Frequency Interference) filters into the cables as well as shielding against EMI (Electro-Magnetic Interference) can produce a cleaner noise free supply and hence a better sound or picture quality ^[11]. Although subjective tests have occasionally confirmed this, little objective proof has been given.^[12] One critique of high end power cable questions how a short strand of expensive cable can improve upon electricity delivered by miles of standard electricity transmission equipment outside and inside a home. Given this paradox, he then asks, "how short does the [specialized] wire have to be made before differences can no longer be heard?"^[2]

[edit] See also

• S/PDIF A digital audio interconnect standard
• DAC Digital to analog converters
• Clock recovery on handling of digital data streams
• Speaker wire
• Psychoacoustics on the perception of sound
• Subject-expectancy effect on the possible causes of perceived differences attributable to cables

[edit] References

[edit] External links

• Solving Signal Problems - Belden Corp article for Broadcast Engineering magazine
• Speaker Wire - Roger Russell (former McIntosh Laboratory loudspeaker designer) opinions on loudspeaker wiring