System and method for loudspeaker protection
View Patent ↗Systems, devices, and methods are described for providing loudspeaker protection. An upstream loudspeaker model estimation component receives sensed electrical characteristics of a loudspeaker and generates an impedance model from which an excursion model, and associated parameters, of the loudspeaker as well as a gain change parameter may be generated. The impedance components are fitted to features of an estimated impedance, based on the voltage and current sense data, to generate the estimated impedance model that is converted to an excursion model of the loudspeaker. A downstream audio signal processing component, based on the excursion model, or parameters thereof, limits a predicted excursion of the loudspeaker utilizing excursion-constraining processing circuitry that includes a non-linear constraint filter. Processed audio signals associated with the limited excursion are subject to distortion suppression prior to releasing the output audio signals for playback on the loudspeaker.
1. A loudspeaker protection system comprising an audio signal processing component that includes:
first audio signal processing circuitry comprising a non-linear constraint filter that is configured to:
receive an audio signal;
receive one or more parameters of an excursion model of a loudspeaker from a model estimation component; and
generate a processed version of the audio signal corresponding to a constrained predicted excursion based on the one or more parameters of the excursion model; and
second audio signal processing circuitry configured to apply a gain change parameter to the audio signal prior the audio signal being received by the first audio signal processing circuitry, the gain change parameter being based on a temperature of a component of the loudspeaker.
2. The loudspeaker protection system of claim 1 , wherein the first audio signal processing circuitry includes first excursion model circuitry and second excursion model circuitry;
the first excursion model circuitry configured to:
receive the audio signal and at least one of the one or more parameters of the excursion model,
process the audio signal according to the excursion model to generate a predicted excursion signal, and
provide the predicted excursion signal for further processing by the audio signal processing component;
the second excursion model circuitry configured to:
receive a limited predicted excursion signal from a limiter of the audio signal processing component and the at least one of the one or more parameters for an inverse representation of the excursion model,
process the limited predicted excursion signal according to the inverse representation of the excursion model to generate an excursion-constrained audio signal, and
provide the excursion-constrained audio signal for further processing by the first excursion model circuitry and as an output audio signal of the first audio signal processing circuitry.
3. The loudspeaker protection system of claim 2 , wherein the first audio signal processing circuitry further includes the limiter, the limiter configured to:
limit the predicted excursion signal from the first excursion model circuitry prior to the processing of the limited predicted excursion signal by the second excursion model circuitry; and
provide the limited predicted excursion signal to the first excursion model circuitry and to the second excursion model circuitry for processing.
4. The loudspeaker protection system of claim 3 , wherein the first excursion model circuitry is further configured to:
use each of the at least one of the one or more parameters of the excursion model to generate a predicted excursion; and
provide the predicted excursion signal to the limiter for processing.
5. The loudspeaker protection system of claim 4 , wherein the second excursion model circuitry is further configured to:
use each of the at least one of the one or more parameters for the inverse representation of the excursion model to generate the processed version of the audio signal corresponding to the constrained predicted excursion; and
provide the processed version of the audio signal to the first excursion model circuitry for processing, and as an output of the audio signal processing component.
6. The loudspeaker protection system of claim 1 , wherein less than all of the one or more parameters of the excursion model are used to generate the processed version of the audio signal.
7. The loudspeaker protection system of claim 1 , wherein the component of the loudspeaker is a voice coil of the loudspeaker.
8. The loudspeaker protection system of claim 1 , wherein the loudspeaker is a microspeaker.
9. A method in a loudspeaker protection system comprising:
receiving an audio signal by first audio signal processing circuitry comprising a non-linear constraint filter;
receiving one or more parameters of an excursion model of a loudspeaker by the first audio signal processing circuitry from a model estimation component;
generating a processed version of the audio signal corresponding to a constrained predicted excursion based on the one or more parameters of the excursion model by the first audio signal processing circuitry; and
applying a gain change parameter to the audio signal by second audio signal processing circuitry prior to receiving the audio signal by the first audio signal processing circuitry, the gain change parameter being based on a temperature of a component of the loudspeaker.
10. The method of claim 9 , further comprising:
performing by first excursion model circuitry of the first audio signal processing circuitry:
receiving the audio signal and at least one of the one or more parameters of the excursion model,
processing the audio signal according to the excursion model to generate a predicted excursion audio signal, and
providing the predicted excursion signal for further processing by the first audio signal processing circuitry; and
performing by second excursion model circuitry of the first audio signal processing circuitry:
receiving a limited predicted excursion signal from a limiter of the first audio signal processing circuitry and the at least one of the one or more parameters for an inverse representation of the excursion model,
processing the limited predicted excursion signal according to an inverse representation of the excursion model to generate an excursion-constrained audio signal, and
providing the excursion-constrained audio signal for further processing by the first excursion model circuitry and as an output audio signal of the first audio signal processing circuitry.
11. The method of claim 10 , further comprising:
performing by the limiter of the first audio signal processing circuitry:
limiting the predicted excursion signal from the first excursion model circuitry prior to the processing of the limited predicted excursion signal by the second excursion model circuitry; and
providing the limited predicted excursion signal to the first excursion model circuitry and to the second excursion model circuitry for processing.
12. The method of claim 11 , further comprising performing by the first excursion model circuitry:
use each of the at least one of the one or more parameters of the excursion model to generate a predicted excursion; and
provide the predicted excursion signal to the limiter for processing.
13. The method of claim 12 , further comprising performing by the second excursion model circuitry:
using each of the at least one of the one or more parameters for the inverse representation of the excursion model to generate the processed version of the audio signal corresponding to the constrained predicted excursion; and
providing the processed version of the audio signal to the first excursion model circuitry for processing, and as an output of the first audio signal processing circuitry.
14. The method of claim 10 , further comprising processing the audio signal according to the excursion model at a frame-rate; and
wherein receiving the one or more parameters of the excursion model comprises receiving the one or more parameters asynchronously at a rate that is less than the frame-rate.
15. The method of claim 9 , wherein less than all of the one or more parameters of the excursion model are used to generate the processed version of the audio signal.
16. The method of claim 9 , wherein the loudspeaker is a microspeaker.
17. The method of claim 16 , wherein the loudspeaker protection system is included in a mobile device.
18. The method of claim 9 ,
wherein the component of the loudspeaker is a voice coil of the loudspeaker.
19. A computer readable storage device comprising a storage medium encoded with program instructions that, when executed by a computing device, cause the computing device to perform a method for loudspeaker protection based on processing of an audio signal, the program instructions comprising:
first instructions for receiving an audio signal;
second instructions for receiving one or more parameters of an excursion model of a loudspeaker from a model estimation component;
third instructions for generating a processed version of the audio signal corresponding to a constrained predicted excursion based on the excursion model using a non-linear constraint filter; and
fourth instructions for:
processing the audio signal according to the excursion model to generate a predicted excursion audio signal,
limiting the predicted excursion audio signal,
processing the limited predicted excursion audio signal according to an inverse representation of the excursion model to generate an excursion-constrained audio signal, and
providing the excursion-constrained audio signal for further processing according to the excursion model and as the processed version of the audio signal for playback by the loudspeaker.
20. The computer readable storage device of claim 19 , wherein the loudspeaker is a microspeaker of a mobile device.