In the spirit of Gilbert Briggs, who was well known for experimenting with new driver materials, Wharfedale investigated a range of options to match the sensitivity and accuracy of the AMT treble unit.
The designers settled on a proprietary woven glass fibre matrix, formed into a 150mm cone. This provides a superb combination of low mass and high strength, with the addition of a high-plasticity coating to control its acoustic behaviour. With such a low-mass cone, only a low-damping, foamed, rubber-like material would match the surround – again, coated for durability.
Drive energy for the cone comes from a 25mm, 2-layer voice coil centred in a magnetic gap fitted with an aluminium ring to control eddy currents, linearise inductance and so increase bandwidth and reduce distortion. The whole assembly is fitted to a die-cast aluminium basket with large ventilation windows below the spider to improve transient response.