Loudspeaker protection against excessive excursion

Patent metadata

Field	Value
Publication number	US-2016192070-A1
Application number	US-201514956492-A
Country	US
Kind code	A1
Filing date	Dec 2, 2015
Priority date	Dec 24, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Systems and methods for loudspeaker protection against excessive excursion are described. In an illustrative, non limiting embodiment, a method may include splitting an input signal into two or more signals, each of the two or more signals within a given frequency band; independently selecting between a power attenuation or an excursion attenuation for each of the two or more signals; independently applying the selected power attenuation or excursion attenuation to each of the two or more signals; combining the attenuated two or more signals into an output signal; and providing the output signal to a loudspeaker.

First claim

1 . A method, comprising:
splitting an input signal into two or more signals, each of the two or more signals within a given frequency band; independently selecting between a power attenuation or an excursion attenuation for each of the two or more signals; independently applying the selected power attenuation or excursion attenuation to each of the two or more signals; combining the attenuated two or more signals into an output signal; and providing the output signal to a loudspeaker.

2 . The method of claim 1 , further comprising converting the two or more signals from a voltage domain to an excursion domain using a transform operation.

3 . The method of claim 2 , wherein independently selecting between the power attenuation or the excursion attenuation for a given one of the two or more signals in a given frequency band further comprises:
calculating an inverse root mean square of the given signal and multiplying it by a target root mean square value; calculating an inverse peak excursion estimate for the given signal and multiplying it by a target excursion for the given frequency band; and selecting the smallest calculated value.

4 . The method of claim 3 , further comprising applying each of the smallest calculated values to its respective one of the two or more signals.

5 . The method of claim 4 , further comprising applying a lossy watermark to each of the two or more signals to reduce an attenuation swing.

6 . The method of claim 5 , further comprising applying a clipper to each of the two or more signals to saturate each of the two or more signals.

7 . The method of claim 6 , further comprising applying a low-pass filter to each of the two or more signals prior to combining them to suppress an intermodulation product falling outside of each signal's frequency band.

8 . The method of claim 1 , further comprising converting the combined signal from the excursion domain to the voltage domain using a transform operation prior to providing the output signal to the loudspeaker.

9 . The method of claim 1 , further comprising:
monitoring each of the two or more signals; and dynamically selecting a power attenuation or excursion attenuation for each of the two or more signals based upon the monitoring.

10 . An electronic circuit, comprising:
a controller; and a memory coupled to the controller, the memory having program instructions stored thereon that, upon execution by the controller, cause the controller to:
independently select between a power attenuation or an excursion attenuation for each of two or more audio signals, wherein the two or more audio signals are split between different frequency bands;
independently apply the selected power attenuation or excursion attenuation to each of the two or more audio signals; and
combine the attenuated two or more audio signals into an output signal.

11 . The electronic circuit of claim 10 , wherein the program instructions further cause the controller to convert the two or more audio signals from a voltage domain to an excursion domain using a transform operation.

12 . The electronic circuit of claim 11 , wherein to independently select between a power attenuation or an excursion attenuation for each of two or more audio signals, the program instructions further cause the controller to:
calculate an inverse root mean square of a given audio signal and multiply it by a target root mean square value; calculate an inverse peak excursion estimate for the given audio signal and multiply it by a target excursion for the given audio signal's frequency band; and select the smallest calculated value.

13 . The electronic circuit of claim 12 , wherein the program instructions further cause the controller to apply each of the smallest calculated values to its respective audio signal.

14 . The electronic circuit of claim 13 , wherein the program instructions further cause the controller to convert the output signal from the excursion domain to the voltage domain using a transform operation.

15 . The electronic circuit of claim 14 , wherein the program instructions further cause the controller to:
monitor each of the audio signals; and dynamically select a power attenuation or excursion attenuation for each of the audio signals based upon the monitoring.

16 . An audio device configured to:
split a received signal into two or more audio signals in different frequency bands; transform the two or more audio signals from a voltage domain to an excursion domain; independently select between a power attenuation or an excursion attenuation for each of two or more audio signals; independently apply the selected power attenuation or excursion attenuation to each of the two or more audio signals; convert the attenuated two or more audio signals from the excursion domain to the voltage domain; and combine the converted more audio signals into an output signal.

17 . The audio device of claim 16 , wherein to independently select between a power attenuation or an excursion attenuation for each of two or more audio signals, the audio device is further configured to:
calculate an inverse root mean square of a given audio signal and multiply it by a target root mean square value; calculate an inverse peak excursion estimate for the given audio signal and multiply it by a target excursion for the given audio signal's frequency band; and select the smallest calculated value.

18 . The audio device of claim 17 , further configured to apply each of the smallest calculated values to its respective audio signal.

19 . The audio device of claim 18 , further configured to convert the output signal from the excursion domain to the voltage domain using a transform operation.

20 . The audio device of claim 19 , further configured to:
monitor each of the audio signals; and dynamically select a power attenuation or excursion attenuation for each of the audio signals based upon the monitoring.

Assignees

• Texas Instruments Inc

Inventors

• Bjoern-Josefsen Anker
• Risbo Lars
• Christiansen Theis

Classifications

• G10L21/034

  Automatic adjustment · CPC title

• H04R3/002

  Damping circuit arrangements for transducers, e.g. motional feedback circuits · CPC title

• H03G7/002

  in untuned or low-frequency amplifiers, e.g. audio amplifiers (H03G7/007, H03G7/001, H03G7/008, H03G7/02, H03G7/06 take precedence) · CPC title

• H03G9/025

  frequency-dependent volume compression or expansion, e.g. multiple-band systems (H03G9/10, H03G9/18 take precedence) · CPC title

• H04R29/001

  for loudspeakers (H04R29/007 takes precedence) · CPC title