Control of loudspeaker output

Abstract

A loudspeaker drive circuit uses a dynamic range compressor to implement a non-linear gain function between the input signal to the dynamic range compressor and an output signal from the dynamic range compressor. The output is used to drive a loudspeaker, and the operating parameters of the dynamic range compressor are varied in dependence on a criterion, such as the estimated voice coil temperature, the power consumption or the acoustical distortion.

Description

technical field [0001] The present invention relates to the control of loudspeaker output. Background technique [0002] Loudspeakers are devices used to convert electrical energy into sound energy. [0003] However, most of the electrical energy applied to a loudspeaker will result in heat dissipation, which causes many common loudspeaker deficiencies. In order to prevent thermal damage (permanent or temporary), it is desirable to measure the voice coil temperature of the loudspeaker and adjust the input so that the temperature is not greater than a certain limit. [0004] One method for estimating the voice coil temperature is to use a mathematical model of the loudspeaker that uses a number of estimated parameters, see for example Audio Eng .Soc.52, 3-25, Klippel, W., 2004 "Nonlinear Modeling of the Heat Transfer in Loudspeakers". [0005] A different approach is to use the tone at the evaluation frequency, directly measure the current and voltage in the voice coil, an...

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Problems solved by technology

Furthermore, the complete signal (or, frequency band in the case of the multi-band approach) is affected by the gain control, and even the lower amplitude bands that do not cause heating of the voice coil are also affected by the gain control

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