| Ply Loudspeaker Cables |
| SUPRA Ply - A Logical and
Progressive Design Ply 2x2.0 & Ply 2x3.4 Audio cables performance is initially determined by their loop resistance (R) & inductance (L) & shunt capacitance (C). For most speakers R & L must be low, but capacitance value, C doesnt matter [1,2] as speakers already act as large cap loads. But simply using larger wire makes R low, at the expense of an increasing ratio to L with musically unacceptable effects. Ways to make inductance L low also with low resistance, include tapes, either stacked or arranged in ribbons. But these types are impractical to fit to nearly every speaker connector without discontinuities, & are stressed & often unsightly when bends are required in real installs & also arent suited to mobile uses. Litzing with multiple, insulated conductors is more practical, but quality Litzes are expensive and termination not easy. Other types are gross, like industrial pipes, unsuited to many domestic spaces. |
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| Simplistic fat conductors rising
impedance (due to L) of +6dB/octave is further raised by internal eddy currents
causing Skin effect, like the square root of
inductance, adding. +3dB/oct, to the L-reactance slope. For typical cable
runs, nett inductivity is such that performance in heavy plain conductors is
measurably affected with steady signals just above 1kHz. Cables with copper or silver stranded conductors suffer from complex oxidation. The semiconductive diodes between the strands arent seen by steady tests, but look like a high capacitance to music signals. This causes energy storage/release cycles, that regular tests miss, yet which is audible with music. This problem is also describable as the electron flow being trapped inside strands & twisting away from the direct route. Supra Ply is a largesection, low resistance cable, overcoming skin effect & transient distortion, using pure tin plating. Tin melds to copper with-out any diodic barrier, & also protects the copper from common corrosions - ideal for outdoors & 12 volt. Most audiograde cables conductors are damaged by contamination, by plastic out-gassing, from the impure atmosphere, & liquid spills. Some are protected but only by a thin coating thatll one day crack with use and age. Neatly, oxidation forming on Ply is sonically benign. |
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Ply with Combicon Banana |
Ply with Combicon Spade |
| Other Advantages When installing, Plys rectangular conductor is readily circularised for insertion into receptacles of most regular connectors. Square outer profiling suits most housings too - unlike ribbons, tapes & litzes. Ply is readily coiled, more like thinner, basic cables - making it friendly in temporary setups. Demostrating the Difference Unlike some audio products, benefits of Supra Ply are readily shown by repeatable measurements. Plys low-loss behaviour for hf audio (incl. bass transients), is evident. Figs. 1, 2 are time domain scope pics, showing typical dynamic/damping differences with a square wave. After transients, Supras Ply restrains the peaking & accelerates the signals return to 0 volts at the speaker end. Peaking in wide spaced cable shows limp damping & hf loss, because it has high L & low C, the opposite of whats required to drive most speakers. Research References Ben Duncan, Loudspeaker Cables, Case Proven, Proc. The Institute of Acoustics, UK, Nov 95. Also published in Studio Sound & Broadcast Engineering (UK); and Stereophile (USA) - both Dec 95. Ben Duncan, Modelling Cable, Electronics World (UK), Feb 96. Ben Duncan, Measuring Speaker Cable Differences, Electronics World (UK), June/July 96. Ben Duncan, Black Box (column), Hi-Fi News & Record Review (UK), June & July 96. Other References [1] Malcolm Omar, Mawksford, The Essex Echo, Hi-Fi News, Aug 85; Aug & Oct 86 & Feb 87. [2] Fred E. Davis, Effects of Cable, Loudspeakers & Amplifier Interactions, J. AES, June, 91. [3] T. Ohasi, E. Nishina, N. Kawai, Y. Fuwamoto & H. Imai, High Frequency Sound Above the Audio Range Affects Brain Electric Activity & Sound Perception, 91. |
![]() Fig.1 Oscilloscope graph of losses for Ply 2.0 ![]() Fig.2 Typical wide-spaced type of cable |
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