For five decades, QED has been designing and engineering class-leading, award-winning audio cables. From entry-level to super high-end, there's a QED cable for you. A sonic step-up from the Performance series, the Reference premium specialist cable range features enhanced design and components to make your AV set-up sing. A subwoofer's lowest, bass frequencies need to be tight, deep and rhythmically immaculate - which is why QED developed Reference Subwoofer 40. Timing errors are minimised, external noise signals are rejected, and eddy currents are properly controlled. Which makes your bass experience all the more convincing.