Signal Projects Hydra series speaker cables are made from 6N (99.9997%) ultra high purity copper.
Besides the importance of shielding techniques, grounding configurations and insulation materials, a cable manufacturer should equally take into account a number of parameters that will help in controlling the electrical characteristics of conductors in order to achieve optimum performance in any given application.
The proper contaminants of high purity copper, silver and gold, and the efficient combination of both solid-core and multi-core wires, effectively exploit the advantages of these metals and helping our conductors to provide relatively lower resistance a given thickness.
Our hybrid conductors will help audio devices to reveal their sonic characteristics, to deliver signal without adding unwanted colorations and to stimulate the original sound of instruments with impressive accuracy.

https://signalprojects.com/products/hydra-speaker/