A radiating metal dome for use in loudspeakers is made of copper, silver or gold, or of an alloy of one of these metals with additions not sufficient substantially to reduce the thermal conductivity. This ensures good heat dissipation from the coil (14). The dome may comprise a plurality of layers (10, 12), at least one of which is a layer of a metal or a metal alloy, in intimate contact. This sandwich construction enables an improved frequency response characteristic to be achieved. The metal or metal alloy layer or layers may also be provided with one or more layers of a protective material and/or a sound damping material. A non-metallic filler layer (18) may be provided between two layers (10,12) of metal or metal alloy.