This invention provides a method of manufacturing speaker diaphragm for a loudspeaker that has a composite material formed of two layers of ceramic material separated by a light metal substrate and where the core is formed by stamping a sheet of standard gauge aluminum to form a speaker core and then deep anodizing the core to obtain a ceramic layer of alumina on each surface (Al.sub.2O.sub.3) that is at least about 1 mil. thick. The invention further provides for a loudspeaker diaphragm, where the diaphragm is a composite material formed of at least two layers of ceramic material having a metal substrate therebetween and where the thickness of the metal substrate is no more than 86% of the thickness of the composite material.