Transitioning between arrayed and in-phase speaker configurations for active noise reduction

Patent metadata

Field	Value
Publication number	US-9508336-B1
Application number	US-201514749823-A
Country	US
Kind code	B1
Filing date	Jun 25, 2015
Priority date	Jun 25, 2015
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A noise cancellation method and system comprises a system controller that produces a command signal in response to a signal from at least one microphone detecting sound in an area. The system controller includes an arrayed speaker controller for producing a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone. The system controller includes an in-phase speaker controller for producing a common in-phase driver signal for all speakers in response to the command signal and a signal director module for proportioning the command signal between the arrayed and in-phase speaker controllers in response to a magnitude of voltage associated with driving the speakers in accordance with the command signal.

First claim

What is claimed is:

1. A noise cancellation system comprising:
a plurality of speakers disposed within an area;
an amplifier in communication with the speakers; and
a system controller, in communication with the amplifier, producing a command signal in response to a signal from at least one microphone detecting sound in the area, the system controller including:
an arrayed speaker controller configured to produce a driver signal for each speaker in response to the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field having a magnitude and phase adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone,
an in-phase speaker controller configured to produce a common in-phase driver signal for all of the speakers in response to the command signal; and
a signal director module configured to proportion the command signal between the arrayed speaker controller and the in-phase speaker controller in response to a magnitude of voltage associated with driving, by the amplifier, the speakers in accordance with the command signal.

2. The noise cancellation system of claim 1 , further comprising a signal magnitude monitor measuring magnitude of voltage associated with the amplifier driving the speakers in accordance with the command signal, and wherein the signal director module changes the proportioning of the command signal between the arrayed speaker controller and the in-phase speaker controller in real time response to the magnitude measured by the signal magnitude monitor.

3. The noise cancellation system of claim 2 , wherein the signal director module transitions to proportioning all of the command signal to the in-phase speaker controller, with none of the command signal being proportioned to the arrayed speaker controller, in real time response to the measured magnitude exceeding a threshold.

4. The noise cancellation system of claim 3 , wherein the signal director module transitions to proportioning all of the command signal to the arrayed speaker controller, with none of the command signal being proportioned to the in-phase speaker controller, in real time response to the measured magnitude dropping below a threshold.

5. The noise cancellation system of claim 2 , further comprising a signal divider for dividing the command signal in accordance with the proportioning determined by the signal director module, and wherein the signal director module directs the signal divider to increase a proportion of the command signal passing to the in-phase speaker controller, while decreasing a proportion of the command signal passing to the arrayed speaker controller, in real time response to an increase in the magnitude measured by the signal magnitude monitor.

6. The noise cancellation system of claim 2 , further comprising a signal divider for dividing the command signal in accordance with the proportioning determined by the signal director module, and wherein the signal director module directs the signal divider to decrease a proportion of the command signal passing to the in-phase speaker controller, while increasing a proportion of the command signal passing to the arrayed speaker controller, in real time response to an decrease in the magnitude measured by the signal magnitude monitor.

7. The noise cancellation system of claim 1 , wherein a gain applied by the amplifier to the in-phase driver signal for all of the speakers is inversely proportional to a number of the speakers.

8. The noise cancellation system of claim 1 , further comprising an adder combining each driver signal with the in-phase driver signal to produce a hybrid command signal for each speaker before that hybrid command signal passes to the amplifier.

9. The noise cancellation system of claim 8 , wherein the hybrid command signals are derived from the command signal produced by the system controller.

10. A method of attenuating noise comprising:
producing a command signal in response to a signal from at least one microphone detecting sound in an area;
proportioning the command signal between an arrayed speaker controller and an in-phase speaker controller in response to a magnitude of voltage associated with driving a plurality of speakers in accordance with the command signal;
producing, by the arrayed speaker controller, when a first portion of the command signal is proportioned to the arrayed speaker controller, a driver signal for each of the speakers in response to the first portion of the command signal such that combined sound emitted by the speakers in response to the driver signals produces a substantially uniform sound pressure field having a magnitude and phase adapted to attenuate a noise field corresponding to the sound detected by the at least one microphone; and
producing, by the in-phase speaker controller, when a second portion of the command signal is proportioned to the in-phase speaker controller, a common in-phase driver signal for all of the speakers in response to second portion of the command signal.

11. The method of claim 10 , further comprising measuring the magnitude of voltage associated with driving the speakers in accordance with the command signal, and changing the proportioning of the command signal between the arrayed speaker controller and the in-phase speaker controller in real time response to the magnitude measured.

12. The method of claim 11 , further comprising transitioning to proportioning all of the command signal to the in-phase speaker controller, with none of the command signal being proportioned to the arrayed speaker controller, in real time response to the measured magnitude exceeding a threshold.

13. The method of claim 12 , further comprising transitioning to proportioning all of the command signal to the arrayed speaker controller, with none of the command signal being proportioned to the in-phase speaker controller, in real time response to the measured magnitude dropping below a threshold.

14. The method of claim 11 , further comprising increasing a proportion of the command signal passing to the in-phase speaker controller, while decreasing a proportion of the command signal passing to the arrayed speaker controller, in real time response to an increase in the magnitude measured.

15. The method of claim 11 , further comprising decreasing a proportion of the command signal passing to the in-phase speaker controller, while increasing a proportion of the command signal passing to the arrayed speaker controller, in real time response to an decrease in the magnitude measured.

16. The method of claim 11 , further comprising applying a gain to the in-phase driver signal for all of the speakers that is inversely proportional to a number of the speakers.

17. The method of claim 11 , further comprising combining each driver signal with the in-phase driver signal to produce a hybrid command signal for each speaker.

18. A vehicle comprising:
a passenger compartment; and
a noise cancellation system comprising:
a plurality of speakers disposed within an area in the passenger compartment;
an amplifier in communication with the speakers; and
a system controller, in communication with the amplifier, producing a command signal in response to a signal from at least one microphone detecting sound in the area, the system controller including:
an arrayed speaker controller configured to produce a driver signal for each of the speakers in response to the command signal such that combined sound emitted by the speakers in respo

Assignees

• Bose Corp

Inventors

• Torres Wade

Classifications

• G10K2210/1282

  Automobiles · CPC title

• G10K2210/3219

  Geometry of the configuration · CPC title

• G10K2210/3016

  Control strategies, e.g. energy minimization or intensity measurements · CPC title

• G10K2210/3221

  Headrests, seats or the like, for personal ANC systems · CPC title

• G10K2210/3027

  Feedforward · CPC title