The Polk ‘Cobra’ Speaker Cable.
I present (for your enjoyment) the Polk ‘Cobra’ speaker cable.
There were two versions sold of the Polk Cobra cable, a standard round and flat version for under carpet installs. The cable is unique in that each (single) strand of fine pure copper is individually coated then braided in groups with its opposite conductor and jacketed in a clear polyethylene casing. The reason this does not short circuit despite the numerous overlaps, is because each (single) strand is insulation by the clear coating which must be burnt-off in order to make proper termination.
The Polk Cobra cable presents transparent, nature, clean sound with extended highs and deep bass that is accurately controlled by the amp’s damping factor. The aforementioned gives reason for minor caution, while this cable is compatible with solid-state gear it can present reactive loads to the amp and amp’s that don't care for such loads run the risk (typically) of HF-oscillation and/or intermodulation distortion mostly due to poorly implemented amplifier negative feedback designs. I’ve used the Cobra cable exclusively on my Sansui Alpha AU901X in stunning performance with Ohm Walsh speakers for 10-years.
One blogger [High-EndAudio.com] had this to say: “…based on our collective, long-term experiences…this speaker wire (6 or 8 cables in parallel) has proven to be superior to every other cable that I have compared with it, at all prices points, for over 25 years now. It was even far superior to the $15,000, top-of-the-line Kimber at the Las Vegas CES show some years ago. There are no ‘secrets’ or ‘magic’ behind the unprecedented performance of this cable. Polk simply has the lowest inductance of any cable ever made, which means it is the ‘fastest’ cable, and it is also the cable with the most extended high frequencies.” “The actual wire is very fine and pure, and it is very well damped on both its inside and outside by polyethylene. Both the resistance and capacitance are high. The resistance can be easily reduced by both shortening the cable and also running them in parallel (of 6-8 runs). The high capacitance is not a problem for tube amplifiers, but it may be a serious problem for unstable (meaning usually older) transistor models.”