Abstract: A loudspeaker system has a diaphragm for producing sound, a loudspeaker driver mechanism operable for moving the diaphragm in response to an applied electrical signal from an audio signal source, a blower positioned for directing air under pressure over the loudspeaker driver mechanism so that heat generated by the loudspeaker driver mechanism can be convectively removed, and a control circuit electrically connected to the blower and adapted for connection to the audio signal source such that an increase in the applied electrical signal causes a corresponding increase in speed of the blower. The control circuit includes a power limiting device and a switching device that is connected in parallel with the power limiting device. The switching device is actuable from a normally closed state to an open state when the applied electrical signal is above a predetermined level to regulate the speed of the blower.

Abstract: A thermal protection circuit for a loudspeaker system includes a load device that is connected in series with a loudspeaker driver mechanism, and a thermally sensitive resettable switch that is connected in parallel with the load device and thermally connected to the loudspeaker driver mechanism, such that heat generated by the loudspeaker driver mechanism is at least conductively transferable to the switch. The switch is changeable between a closed state wherein the load device is at least substantially bypassed, and an open state wherein the electrical signal from an amplifier or crossover circuit is at least substantially directed through the load device when a temperature of the switch is above a predetermined temperature and the electrical signal is above a predetermined signal level. As the temperature of the loudspeaker driver mechanism increases, the temperature of the switch also increases, which in turn decreases the signal level required to trip the switch.

Abstract: A thermal protection circuit for a loudspeaker system includes a load device that is connected in series with a loudspeaker driver mechanism, and a thermally sensitive resettable switch that is connected in parallel with the load device and thermally connected to the loudspeaker driver mechanism, such that heat generated by the loudspeaker driver mechanism is at least conductively transferable to the switch. The switch is changeable between a closed state wherein the load device is at least substantially bypassed, and an open state wherein the electrical signal from an amplifier or crossover circuit is at least substantially directed through the load device when a temperature of the switch is above a predetermined temperature and the electrical signal is above a predetermined signal level. As the temperature of the loudspeaker driver mechanism increases, the temperature of the switch also increases, which in turn decreases the signal level required to trip the switch.

Abstract: A loudspeaker system has a diaphragm for producing sound, a loudspeaker driver mechanism operable for moving the diaphragm in response to an applied electrical signal from an audio signal source, a blower positioned for directing air under pressure over the loudspeaker driver mechanism so that heat generated by the loudspeaker driver mechanism can be convectively removed, and a control circuit electrically connected to the blower and adapted for connection to the audio signal source such that an increase in the applied electrical signal causes a corresponding increase in speed of the blower. The control circuit includes a power limiting device and a switching device that is connected in parallel with the power limiting device. The switching device is actuable from a normally closed state to an open state when the applied electrical signal is above a predetermined level to regulate the speed of the blower.