QED XT40i Speaker Cable

The "i" in XT40i indicates evolution. The original XT40 was already one of the most respected speaker cables at its price point. QED took it as a starting point and added Air Gap dielectric technology, which cuts signal losses roughly in half and produces a cable that is genuinely hard to improve on without spending significantly more money.

Air Gap works by physically separating the conductors from the jacket using a structured air gap. Air has a dielectric constant of 1.0, the theoretical minimum, so replacing solid insulation with an air-dominant structure dramatically reduces the energy stored and wasted in the insulation on every audio cycle. The 4mm cross-sectional area oxygen-free copper conductors keep DC resistance extremely low, and the low self-inductance figure means the cable does not restrict current delivery to the speaker on dynamic peaks.