QUAD L Series manual Technology

L Series

The Technology

Underneath the classically British exterior beats an audiophile heart. The long-throw KEVLAR driver is manufactured from a self-damping resin impregnated fibre form of the material. This is then lattice woven to create the appropriate stiffness, strength and weight properties. The material is formed into a cone and mounted on a butyl rubber surround. A high efficiency, double hand-wound voice coil tracks the signal, with the high-gauss magnet assembly providing an impetus for movement. A strong, die-cast aluminium alloy chassis assembly is an essential part of the design, keeping everything taut and under control, even with large transients and extremes of power. A profiled phase plug provides additional cone axial rigidity and also improves off-axis performance.

The dual 25mm voice coil is wound on an aluminium alloy carrier or ‘bobbin’. This ‘wicks’ heat away from the central coil region to maintain peak performance and

the optimum excursion of the long-throw driver. The coils are vented to reduce the effect of any pressure build-up in the central cone region.

Many years of experience have manifested themselves in the high-frequency driver. A compact yet powerful neodymium magnet keeps the tightest control on the diaphragm. Phase coherency is particularly important to ensure the bass integrates perfectly with the treble, and of course, to create a truly holographic stereo image – the hallmark of a classic Quad sound. This tweeter is so controlled; it measures typically less than 1% distortion from 103dB (equivalent to normally loud playback) output at a distance of 1 metre.

The tweeter fascia plate is engineered for a smooth frequency response and excellent dispersion. This is further aided from the flush mountings of this plate and the bass/mid unit into the cabinet front baffle. Both drive units are closely coupled to provide good integration.

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