AudioQuest Type 9 Speaker Cable (Pair) A 15-gauge PSC+ full-range speaker cable When Type 4 was introduced about 1983, it wasn’t the prettiest cable, but the performance advantage of its polypropylene insulation was dramatic and much appreciated. Several evolutionary steps later, the current version of Type 4 was introduced in 1995—a design whose foundation is so well balanced that it hasn’t changed since then—and still isn’t changing.Types 9 is essentially Type 4 with better metal (and better again than a Type 5), and with added layers and techniques of noise dissipation for more effective noise control than any previous Type X iteration. Features Solid perfect-surface copper (PSC+) conductors Noise dissipation using multi-layer carbon loading, and direction-controlled conductors Balanced star-quad geometry reduces time-smearing while preserving dynamics and clarity Specifications Metal: Perfect-surface copper plus (PSC+) Gauge: 15 AWG Geometry: Star-quad Noise dissipation: Multi-layer carbon based