The diaphragm, the central element of a loudspeaker, is at the heart of our engineers' research. For loudspeakers designed for outdoor use, we had to design a membrane that would deliver both sound performance and environmental resistance. The result is the Fiber IP membrane, a sandwich cone made of non-woven glass fibre. The sandwich layers increase damping and offer greater versatility. For even greater durability, this membrane is certified IP65, an international standard attesting to its soundproofing and resistance to dust intrusion.