Control of a loudspeaker output

A loudspeaker and processor technology, applied in the direction of sensors, transducer circuits, sensor components, etc., can solve the problems that the diaphragm displacement prediction is impossible to be accurate, and the closed box model is no longer valid.

Active Publication Date: 2012-10-17
GOODIX TECH HK CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, if a closed box model is used, but due to a mechanical defect, the loudspeaker becomes a box with an opening, the closed box model is no longer valid
[0007] When the model fails, and thus the loudspeaker transfer function obtained from the model and its parameters fails, the prediction of the diaphragm displacement cannot be accurate

Method used

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  • Control of a loudspeaker output
  • Control of a loudspeaker output
  • Control of a loudspeaker output

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Embodiment Construction

[0027] The present invention proposes a modeling method based on measurements of the electrical impedance of the loudspeaker rather than complex parameter-based models. Apart from the measured impedance values, the only parameters used to derive the model are the hindered electrical impedance and the coupling coefficient of the loudspeaker. These parameters can be assumed to be constant and can also be assumed to be independent of the nature of the loudspeaker enclosure. Thus, it turns out that changes in speaker characteristics or enclosure characteristics are primarily measured impedance changes rather than changes to values ​​assumed to be constant. Thus, the model remains valid and can be updated with new impedance measurements.

[0028] Impedance measurements may be performed at system startup, after fixed time intervals, or on demand or continuously. Therefore, the choice of how to schedule impedance measurements will depend on the application.

[0029] The impedance ...

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Abstract

A method of modelling the frequency-dependent input-voltage-to-excursion transfer function of a loudspeaker, comprises, for a plurality of measurement frequencies, measuring a voltage and current and deriving an impedance at the measurement frequency. A frequency-dependent impedance function is derived. By additionally using the blocked electrical impedance and a force factor for the loudspeaker, a frequency-dependent input-voltage-to-excursion transfer function can be calculated. The invention provides a modelling approach which is not based on a parametric model, but computes the transfer functions for a set of frequencies separately. As a consequence, it does not require prior knowledge regarding the enclosure (e.g. closed or vented box) and can cope with complex designs of the enclosure.

Description

technical field [0001] The present invention relates to the control of loudspeaker output. Background technique [0002] It is well known that the output of a loudspeaker should be controlled in such a way that the loudspeaker is not simply driven by an arbitrary input signal. For example, a significant cause of loudspeaker failure is mechanical defects, which occur when the displacement of the loudspeaker diaphragm exceeds certain limits, usually provided by the manufacturer. Exceeding this displacement limit can either damage the speaker immediately, or can significantly reduce the life expectancy of the speaker. [0003] There are several ways to limit the displacement of the loudspeaker diaphragm, for example by processing the input signal with a variable cut-off filter (high pass or otherwise), the characteristics of which can be controlled via a feedforward or feedback control loop. The measured control signal is called a displacement predictor, and this requires mod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04R3/00H04R3/08H04R29/00
CPCH04R3/08H04R29/003H04R3/007
Inventor 泰穆金·高塔马
Owner GOODIX TECH HK CO LTD
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