Bi-wiring Loudspeakers
Many loudspeakers provide for bi-wiring by removing the links that connect the four terminals. The upper two terminals supply the positive and negative feeds to the speaker’s tweeter and the lower two supply the low frequency speaker or woofer.
Atlas Bi-Wire cables employ two conductor types; one pair which is optimised for low frequency signals and another pair designed specifically to carry high frequency information. There are therefore four conductors at the speaker end which are usually joined together into two terminals at the amplifier end. The four conductors at the speaker comprise two that are longer and two shorter. The longer two are designed to supply the tweeter at the upper two terminals while the shorter pair are for the lower two terminals which supply the bass driver(s).
Within a speaker cable, the audio signal moves from the centre of the conductor to the periphery of the conductor according to frequency; the various frequencies occupying differing radial areas within the conductor. The low frequencies occupy the centre and the very high frequencies occupy a few microns at the periphery of the conductor.
It follows that larger diameter conductors employing more metal or copper have the ability to extend the lower frequencies improving bass performance. Until recently the optimum size was between 3.5 and 4.0 sq mm however with the new Atlas Microporous dielectric and it's greatly improved dielectric constant, it's possible to use larger conductors in order to take frequencies even lower. The new Mavros speaker cable uses a total of 4.8sq mm of OCC copper.
The high frequencies at the periphery of the conductor enjoy a greater occupation area and meet less resistance in a solid conductor than would be the case in a stranded conductor. That’s why solid conductors have the ability to extend the bandwidth up into clear, smear free treble. It’s not possible to use a solid conductor that provides both good bass and good treble, because solid conductors become too unwieldy at the cross-sections necessary for good low frequency information and will break when bent, hence the use of two different conductors.
Another factor to be aware of is that of the dielectric or insulation employed. Because the high frequencies occupy the periphery of the conductor, it’s those that are affected by the quality of the dielectric. A poor quality dielectric will reduce the velocity of the high frequency signal, thereby causing a loss in integrity. Dielectrics such as Microporous PTFE, Teflon, Polypropylene or Polyethylene delete less. See Insulation Material Types.
All Atlas Bi-Wire cables employ a stranded conductor for the low frequencies and solid conductors for the high frequencies.
