Loudspeaker protection circuitry and methods

This application discloses methods and apparatus for thermal protection of a loudspeaker (102). A controller (106) is configured to generate a control signal (Gmod) for modulating the gain of a signal processing chain (101) that drives the loudspeaker. The controller is configured such that the control signal is generated as a function of each of: an indication of voice coil temperature of the loudspeaker (Tvc); an indication of power dissipation in the voice coil of the loudspeaker (Pvc); and an indication of a reservoir temperature (Tres) of a thermal reservoir for heat flow from the voice coil. The reservoir temperature may be an ambient temperature of the environment or a temperature of a component of the loudspeaker or apparatus that acts as a heat sink. The indications of loudspeaker power and temperature may be calculated from the voltage and current at the loudspeaker (fig.2).