Silver-Plated Copper (SPC) — Skin-Effect Optimized

Hybrid conductor: an OFC copper core electroplated with a thin (typically 2–5% by mass) layer of pure silver. The skin-effect concentration of high-frequency current in the outer ~10 μm of any conductor means the silver plating carries the treble component while the copper core carries the bulk audio current.

Sonic result: copper warmth in the lower-mids and bass, silver clarity and treble extension above 8 kHz. The right metallurgical compromise for cables that need treble extension without the cost premium of pure silver.

Used in the SPC IEM cable and the balanced XLR3 interconnect. Cost premium over OFC is approximately 2×.