QED Reference Subwoofer 40 Cable (3m Single)

The QED Reference Subwoofer 40 sits within QED's Reference range — the company's highest tier of interconnect cables, positioned above the Performance series. It shares its core engineering with the Reference Audio 40 stereo interconnect but is optimised specifically for single-channel subwoofer duty, with a 25% smaller conductor diameter tailored to the demands of low-frequency signal transfer.

Complementary Conductor Technology

At the heart of the Reference Subwoofer 40 is QED's Complementary Conductor Technology, which uses two silver-plated 99.999% oxygen-free copper conductors of different diameters. The principle is that the differently sized conductors provide an alternative signal path for more subtle audio components, improving timing accuracy and rhythmic coherence in the bass signal reaching the subwoofer.

Ferrite Noise Shielding

A floating internal Zn/Mn ferrite jacket surrounds the conductors, absorbing high-frequency noise signal components outside the audio band. This is supplemented by a 99.999% OFC braid screen providing 100% electromagnetic screening coverage, and an aluminium wrap layer beneath, creating a comprehensive multi-layer shielding arrangement that protects the low-level subwoofer signal from interference.

Analoc2 RCA Connectors

The cable is terminated with QED's twin-leaf 24-carat gold-plated Analoc2 RCA plugs. These feature a hollow central pin designed to reduce eddy currents and combat skin effect at the connector interface — a common source of signal degradation in conventional solid-pin designs. The gold plating ensures long-term corrosion resistance and consistent contact quality.

Construction

The cable uses a foamed low-density polyethylene (LDPE) dielectric, chosen for its low dissipation factor and reduced capacitance compared to solid insulation materials. The coaxial geometry, combined with the OFC braid screening, provides effective rejection of electromagnetic interference. The outer diameter is 6mm, making the cable flexible enough to route behind equipment whilst maintaining its shielding integrity.