Loudspeaker driver

The driver has an electro-mechanical transducer 205 for converting at least part of an electrical input signal into an output comprising mechanical oscillations. Coupling means 206 couple these oscillations to a displacement member, such as a rigid diaphragm, for converting the oscillations into sound waves. The coupling means 106, 206 acts as a mechanical low-pass filter to absorb energy from frequency components of oscillations of the transducer above a normal operating band for the displacement member so as to prevent said energy from being transmitted to the displacement member. The mechanical filter may replace or augment an electrical crossover for the loudspeaker, and may be incorporated into a build ring which also acts as the coupling means.