All that technical stuff

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History: The whole truth... Matthew Bond and TARA Labs

From Matthew Bond: I have been working with wires and creating audio cables since I was 17. I delivered milk in the evenings and bread in the mornings to make money to pay for my expensive hobby. I had a Linn LP12 and Quad electronics, and Infinity loudspeakers. The electronics changed later, (I needed more power) but I rewired the loudspeakers and the Quad electronics. How did I get into the wire hobby and business? One of the Infinity tweeters went dead, and so I removed it... and I saw the cheap wire and automotive type clips that went to the metal connecting tabs on the tweeter. I felt that this was a compromise, so I rewired the Infinity loudspeakers and soldered the wire to the terminals at the crossover and the drivers. The difference was absolutely stunning. After that, I made speaker cables and compared different wire gauges/sizes. I had experimented with solid core conductors of different diameters. I came to the conclusion that an 'optimum diameter' of 18 AWG (American Wire Gage)]] or 1 millimeter was ideal for audio frequencies because there was minimal high-frequency attenuation caused by the principles known as the Skin Effect. A few years later, in my twenties, I researched and studied what was known about wire and cables at audio frequencies. There was very little information available. In the early 1980’s I found the most important information from the National Bureau of Standards, in a table presented as the DC to AC resistance ratio versus frequency in wires of different diameters. This confirmed the results of my listening tests. Soon after I created the Phase 2 speaker cable, 2 phase coherent solid-core conductors.

In 1984, I founded the Absolute Reference Audio Labs, (ARAL) in Australia. Shortly after, ARAL became TARA Labs, The Absolute Reference Audio Labs. I was and am the sole founder of TARA Labs. In late 1986, I went to the USA to sell my cable products. I had an office in the RCA Building, 6363 Sunset Blvd, Los Angeles. Just over a year later in January 1988, I exhibited my cable products in a room at the CES Show in Las Vegas. In 1988 I met Merrill Bergs who would later become my business partner. I also met Dick Olsher who wanted my Phase 2 speaker cables for a review in Stereophile magazine. In July of 1988 Dick Olsher’s review called Cable Bound revealed the Phase 2 speaker cable to be a Class A product beating out all of the known brands at the time. With the incredible demand in the USA for my cables, I moved permanently to the USA.

I am credited with the invention of solid-core wires for audio use because my work from 1978 predates Dennis Morecroft (1984) and any of the early solid-core wires developed for use in audio in England in the 1980’s.[4] Later, in 1990, I introduced the world’s first cable to have a floating conductor unterminated at one end that would allow for an increased high-frequency bandwidth to be coupled to the signal-carrying conductors (US patent No. 5033091). Later, a control device inside a box fitted to the cable (The Temporal Continuum) allowed the user to adjust the amount of high-frequency bandwidth to be heard. I introduced Rectangular Solid Core cables in 1992.[5] These cables employed solid core conductors with a rectangular cross-section and can be made in specific proportions (width and height). This affects the tuning of the frequency response of a conductor as compared to around a conductor of the same size or DC resistance.[6] In 1999 I created the "Zero" interconnect with a Vacuum dielectric system.[9][10] In 2014, I created a new line of high-end cables for TARA Labs called The Evolution Series.[11

Inductance and the speaker cable… 

The symbol for inductance is L. 

The electrical current or signal flowing in the conductor from the amplifier is an electromagnetic wave that travels through and around the conductor. This electromagnetic wave induces a current that flows in the opposite direction in the conductor. So, when a signal current is causes more high frequency roll off. A doubling in C causes the HF bandwidth to be reduced by a full octave. When the capacitance is increased, it will reduce the bandwidth and reduce high frequency extension. Capacitance is commonly measured in pico-Farads. 

Resistance is caused in a conductor by free electrons. These free 

electrons collide with each other and with the ions and atoms that 

oppose their free movement. This obstruction is known as resistance. Resistance is commonly measured in Ohms and is not a determining 

factor in speaker cables equal to or larger than 14 AWG flowing in a wire, a force is created that opposes that signal. The opposing current impedes the flow of the wanted signal current. The force is known as ‘back emf’. In a speaker cable, it is important to make the inductance as low as possible to reduce the back emf. 

Inductance is commonly measured in micro-Henries. 

Capacitance and the interconnect cable… The symbol for capacitance is C. Capacitance in an interconnect cable is an electrostatic charge between the positive and negative conductors. The space between the conductors is called the electrostatic field. The closer the conductors, the higher the capacitance which 

It seems to me that audiophiles, reviewers and cable manufacturers lack a basic understanding of how cables work and behave in the audio system. For 45 years I have listened to different conductors, different wire gauges, different conductor materials and the same conductors with different insulation or dielectric materials. In many cases, I have been able to use electrical measurements and testing systems to correlate with the listening experience.

Many years ago, Hitachi released a white paper about their development of 6 Nines pure copper(99.9999%). They claimed that they had compared it to a conductor made from mercury held inside a polymer tube and that the sound quality of the 6N copper had the same ease of signal transfer as the Mercury conductor(I’m paraphrasing). You might ask, didn’t the conductors sound different? And one critical point, what was the wire gauge of the conductors? They claimed that the sound quality of the new 6N copper had no harshness like copper of lesser purity. After many years of A/B testing and listening to conductors I have found that conductor purity is not an important factor. It makes a small difference, but one that is easily swamped by conductor size and conductor spacing. Quite simply, a 17 AWG copper conductor of Six Nines 6N 99.9999% purity has high frequency roll off when compared to an 18 AWG 4 Nines 99.99% pure copper conductor. So, conductor purity along with conductor technologies are something that should be regarded with skepticism. The most exotic and peer reviewed copper conductor technologies are 6 Nines and OCC copper. Anything else is marketing hype. And much of this doesn’t make any difference. I have been told that one new cable manufacturer uses antique copper and they have a block of it to draw from. Wow, antique copper… it must have a beautiful mid-range, right? In any case, for what qualities should we be listening? What descriptive words are needed to enjoy the music? Read on…

I am still using 1mm or smaller diameter pure copper conductors. In 1988 my simple solid core 99.99% pure Phase 2 speaker cable was Class A in Stereophile beating out Monster, Audioquest, MIT and every other(10 or so in total) speaker cable. In an industry with so much hyperbole I have remained silent, but as I get older I am tired of the hype, and the miraculous and fictional technologies. Cables make sonic differences to be sure, but the differences must in my opinion, render the sound more like live music. Clarity, transparency, detail etc. may be important. But, palpable images and instrumental outlines and a sound that replicates real voices and musical

instruments must be the goal. Instead we have a whole lexicon devoted to the sound of cables and no clearly articulated description of what is perfect.

In the following I will use the interconnect cable as my example. The most important element in cable design is the size of the conductor(s). If the conductor is larger than 18 gauge, then the high frequencies will be rolled off, so we must choose a conductor that has frequency linearity; no more than 1mm or 18 gauge. After that, the geometry and spacing become important. If the conductors are too close, the Capacitance or electrostatic charge between the conductors will cause high frequency roll off. With the conductors spaced properly, the insulation materials and the dielectric between the conductors now become audible. The audio signal does not travel through the dielectric as easily as through the conductor. The conductor and its insulation likely act similarly to a capacitor, absorbing and releasing an electrical charge, distorting the audio signal. The worst polymer material for insulation/dielectric materials is PVC and the best is PTFE (Teflon).

And finally we have metallurgical treatments, with this I mean conductor purity, cryogenics, metal alloys and grouping of conductors made from different conductor materials. Too many cable companies are making nothing more than what I call cocktail cables... a mix of this and that, and the cables simply sound different as if that were the goal of cable design.

I could nominate many audio cable companies for the Uri Geller cable technology award, but I’ll just name a few. First from the envelope, is Purist Audio Design with a plastic tube filled with water. Insulated copper conductors are loosely held inside the water dielectric. If you hold the tube just right the air bubble reveals the AWM conductor marking on the PVC insulation. A Home Depot and faucet miracle.

The second nominee van den Hul, using carbon conductors so resistive that they often didn’t pass a signal and needed a conductive wire in parallel to make the cable work. Since the current flow will choose the least path of resistance, the addition of the new conductor becomes the sonic characteristic to be heard. And further, we have cables with devices like the Synergistic Research SRX of which Ted Denney writes are not in the signal path. If the devices on a cable are not in the signal path then how do the devices make a sonic difference? The signal path Ted, is within and around the conductors and cables. That’s why the devices work. That’s why cable lifters work. My personal

favorite is van den Hul who showed of his Liquid Nitrogen cooled speaker cables, claiming that the resistance in the cable was zero. I’ve left the best for last… he also claimed that the inductance was zero. I tried to clear up his assertion and educate him but he wouldn’t listen to me. I will leave this for some of you, the readers, to figure out. Don’t worry, if you can’t figure it out I will enlighten you in a follow up article.

Inductance… I’ll start with an example, an inductor first, which is a simple coil of wire found in the crossover of a loudspeaker. The inductor is used to roll off high frequencies and as the coil gets bigger and longer the inductance of the coil rolls off more and more high frequencies along with mid-range frequencies. The inductance of the coil does not change with temperature. When I tried to explain this, vdH told me that there were no inductors in his invention which he proposed to sell for $250,000. I didn’t have my checkbook with me at the time.

Inductance and the speaker cable… The electrical current or signal flowing in the conductor from the amplifier creates an electromagnetic wave that travels through and around the conductor. This electromagnetic wave induces a current that flows in the opposite direction in the signal conductor. So, when a signal current is flowing in a wire, a force is created that opposes the signal from the amplifier. The opposing current impedes the flow of the wanted signal current. The force is known as ‘back emf’. In a speaker cable, it is important to make the inductance as low as possible to reduce the back emf. Inductance is commonly measured in micro-Henries. Finally, the Inductance in a speaker cable is not affected or reduced by temperature.