Once you are at 5-9's any claimed additional purity will have an vanishingly
Minute audible affect on signal integrity.
Crystal structure and boundary will impart a much greater affect on signal integrity http://www.neotechcable.com/technology.php
NEOTECH seem capable of marketing a high purity, rectangular , long crystal structure copper wire at less than $15 a meter .
"The unidirectional UP-OCC has no electric resistance and practically no crystal boundaries. Accordingly, it is able to transmit electrical signals faster, and with less distortion than ordinary OFC and silver wires. All of these features make the pure OCC copper and silver the state-of-the art conductor materials for the audiophile cable industry"
