Normally screened cables suffer from screen distortion when they are prepared for production. (If you've ever wired a plug or connector which uses a screened cable, you've done this yourself, cutting back and probably twisting the screening braid for termination). This distortion of the screen has a measurable impact, effectively changing the impedance and therefore the performance of the cable.
Our ‘dd’ configuration is based on a simplified version of the techniques we developed for our top-of-the-range Mavros and Asimi interconnects. Twin symmetrical drain wires (each attached to 180° segments of the plug) are inserted between a 100% copper/Mylar™ foil and screen. The unique dd system connects the screen effectively to the cable return/plug interface, meaning the cable can be terminated without distorting, twisting or mechanically stressing the precision-laid screen. The benefits are in maintaining a consistent low impedance load to the plug, and a total 360° screening against noise and signal loss caused by RFI (Radio Frequency Interference).
Using Your Atlas Product
The concept of ‘burning-in’ cables in may sound strange, since the terms ‘burning-in’ or ‘running-in’ are more usually usually used to explain the improvements experienced with mechanical devices after a period of use. However, cables also change with use. We recommend a minimum of 72 hours of sustained ‘burn-in,’ to attain maximum performance from new, during which time the cable’s dielectric (the material insulating the actual signal conductor) becomes ‘charged.’
To help shorten this process, a collection of test signals are available from us on completion of your product registration. Digital as well as analogue cables benefit from this process.
After a cable has been burned in, we recommend that you do not change the direction by reversing the cable, because the quality will revert to that of the cable in its original state before burn-in.
Using Your Atlas Product
Many loudspeakers provide for ‘bi-wiring’ as an option to standard 2–2 connection, generally indentifiable by having four connection terminals on the speaker (or in some cases on an external crossover). Typically these are factory-supplied with low grade connector bars bridging the terminals. Even if you don’t wish to bi-wire your system, we strongly recommend replacing these with good quality ‘jumper links,’ ideally of the same type of cable as your main speaker leads.
These terminals should clearly indicate which is which; two terminals supply the positive and negative feed for high frequencies and two supply the low frequency driver.
Atlas bi-wire cables employ two conductor types; one pair optimised for low frequency signals and a second 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 copper (or silver) have the ability to extend the lower frequencies improving bass performance. Until recently the optimum size was between 3.5 & 4.0 mm.² However with the latest microporous dielectric which has a greatly improved dielectric constant, it’s possible to use larger conductors in order to extend the lowfrequency range. The Mavros speaker cable for instance uses a total of 4.8mm² of OCC (Ohno Continous Casting) 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, conferring the ability to extend the treble bandwidth. It’s not possible to use a solid conductor that provides both good bass and 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 considered is that of the dielectric (insulation) employed. Because high frequencies occupy the periphery of the conductor, it’s primarily those which 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 signal integrity. Dielectrics such as PTFE (Teflon™), Polypropylene or Polyethylene offer best performance in this area (see Dielectrics for more information).
All Atlas biwiire cables employ a stranded conductor for the low frequencies and solid conductors for the high frequencies.