Triple C is a different and an advanced forging process and stands for "Continuous Crystal Construction"
Copper is compressed to 70% by forging tens of thousands of times by gradual application of pressure with a fixed angle and direction. (The constant angle continuation transfer forging method). By using this forging process, the transverse crystal grain boundary changes and becomes more longitudinal, crystals now have consecutive connections which makes current flow extremely smooth.
In addition, by forging, the conductor density is dramatically improved by destroying the internal air grains. This, in turn, improves the conductivity and the acoustic signature of the copper.
Now sonicaly with CCC you get a smoother, cleaner and more refined sound, better extension at extremes, tighter bass, but sacrifice a tiny little of mid sweetness and weight compared to PCOCC.
This is my sounding understanding and experience of both technologies.
OCC-DUCC = Dia Ultra Crystallized Copper, is coming from Mitsubishi industries, is a different forging method to OCC but still an optimal aligned long-grain molecular stracture is created.
I have no sounding experience of OCC-DUCC, but may do for in my plans is a new speaker cable and that would be either Furutech DSS-4.1 (OCC-DUCC) or Acoustic Revive SPC Reference (Triple C).