Harmonic Technology Pro9+, uses solid core OCC Cu. These sound great but were too short when I renovated our living room, so I temporarily replaced them with some cheapo junk cables. They were so bad I bought some Duelund 12AWG in cotton the right length to neatly fit the newly completed layout and they were a huge improvement on the cheapos.
After about a year of listening to the Duelunds I reinstated the HT Pro9's for a sanity check and they are still there making beautiful sounds having destroyed the musical but slightly coloured Duelunds, driving 96dB sensitive speakers. The HT cables IMO are outstanding and bettered many very expensive cables when compared at friends places and at home. They can be found used at about $400
@bolong, the Duelund cable I mention is based on the original Western Electric and has a similar signature. As an experiment, try making up jumper cables from bass to tweeter terminals with WE wire but no terminals, just bare wire. Money saved and better sound.