ISU 690

The diaphragm, the key component of a loudspeaker, is at the heart of our acoustic engineers' research. Polyglass technology, exclusive to Focal, consists of applying fine glass microbeads to a cellulose pulp cone. This process reconciles the excellent damping of paper with the rigidity of glass. The stiffness index is almost 10 times that of polypropylene. Adjusting the mass-rigidity-damping ratio results in a remarkably linear frequency response curve, right from the membrane design stage. This innovation also significantly increases definition in the midrange register.

Membrane shape and materials are essential. For the finest treble, our engineers have patented the inverted dome tweeter, a Focal signature. The inverted dome shape offers the advantage of low directionality and a small-diameter, lightweight coil for better acceleration. As for the materials used, they combine the key points of a good loudspeaker: aluminum increases dome rigidity and reduces distortion, while the addition of magnesium provides excellent damping. The surround that connects the dome to its support uses Poron, a shape-memory material. This surround is derived from the famous Utopia Beryllium tweeter, and reduces distortion by a factor of three between 2000 Hz and 3000 Hz, where the ear is most sensitive.