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

• US 9,685,151 B2
• Filed: 10/19/2016
• Issued: 06/20/2017
• Est. Priority Date: 06/25/2015
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Torres, Wade P.
• Primary Examiner(s): Teshale, Akelaw
• Application Number:
  US15/297,229
• Publication Number:
  US 20170040015A1
• Time in Patent Office: 244 Days
• Field of Search: 381 28, 381 92, 381118, 381 714, 381 715, 381 717, 381 82, 381 86, 381 943, 381 947
• CPC Class Codes: G10K 11/17823 Reference signals, e.g. ambient acoustic environment
• CPC Class Codes: G10K 11/1783 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17873 using a reference signal without an error signal, e.g. pure feedforward
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 2210/1282 Automobiles
• CPC Class Codes: G10K 2210/3016 Control strategies, e.g. energy minimization or intensity measurements
• CPC Class Codes: G10K 2210/3026 Feedback
• CPC Class Codes: G10K 2210/3027 Feedforward
• CPC Class Codes: G10K 2210/3215 Arrays, e.g. for beamforming
• CPC Class Codes: G10K 2210/3219 Geometry of the configuration
• CPC Class Codes: G10K 2210/3221 Headrests, seats or the like, for personal ANC systems
• CPC Class Codes: G10K 2210/3229 Transducers

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.

Claims

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 pass an entirety of the command signal to the arrayed speaker controller in response to a first event and pass the entirety of the command signal to the in-phase speaker controller in response to a second event.

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 first event is defined, at least in part, by the magnitude measured by the signal magnitude monitor.

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

4. The noise cancellation system of claim 2, wherein the second event is defined, at least in part, by the magnitude measured by the signal magnitude monitor and wherein the signal director module passes the entirety of the command signal to the arrayed speaker controller, with none of the command signal being passed 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 1, wherein the second event is time-based, and wherein the signal director module passes the entirety of the command signal to the arrayed speaker controller, with none of the command signal being passed to the in-phase speaker controller, in response to a passage of a predetermined period.

6. 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.

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

8. The noise cancellation system of claim 7, wherein the hybrid command signals are derived from the command signal produced by the system controller.

9. 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;

passing an entirety of the command signal to an arrayed speaker controller in response to a first event and passing the entirety of the command signal to an in-phase speaker controller in response to a second event;

producing, by the arrayed speaker controller, when the command signal is passed to the arrayed speaker controller, a respective driver signal for each of a plurality of speakers 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; and

producing, by the in-phase speaker controller, when the command signal is passed to the in-phase speaker controller, a common in-phase driver signal for all of the speakers in response to the command signal.

10. The method of claim 9, further comprising measuring the magnitude of voltage associated with driving the speakers in accordance with the command signal, and wherein the first event is defined, at least in part, by the measured magnitude.

11. The method of claim 10, further comprising passing the entirety of the command signal to the in-phase speaker controller, with none of the command signal being passed to the arrayed speaker controller, in real time response to the measured magnitude exceeding a threshold.

12. The method of claim 10, wherein the second event is defined, at least in part, by the measured magnitude, the method further comprising passing the entirety of the command signal to the arrayed speaker controller, with none of the command signal being passed to the in-phase speaker controller, in real time response to the measured magnitude dropping below a threshold.

13. The method of claim 9, 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.

14. The method of claim 9, further comprising combining each driver signal with the in-phase driver signal to produce a respective hybrid command signal for each speaker.

15. A vehicle comprising:

a passenger compartment;

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 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 pass an entirety of the command signal to the arrayed speaker controller in response to a first event and pass the entirety of the command signal to the in-phase speaker controller in response to a second event.

16. The vehicle of claim 15, 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 first event is defined, at least in part, by the magnitude measured by the signal magnitude monitor.

17. The vehicle of claim 16, wherein the signal director module passes the entirety of the command signal to the in-phase speaker controller, with none of the command signal being passed to the arrayed speaker controller, in real time response to the measured magnitude exceeding a threshold.

18. The vehicle of claim 16, wherein the signal director module passes the entirety of the command signal to the arrayed speaker controller, with none of the command signal being passed to the in-phase speaker controller, in real time response to the measured magnitude dropping below a threshold.

19. The vehicle of claim 18, 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.

20. The vehicle of claim 18, further comprising an adder combining each driver signal with the in-phase driver signal to produce a respective hybrid command signal for each speaker before that hybrid command signal passes to the amplifier.

21. The vehicle of claim 20, wherein the hybrid command signals are derived from the command signal produced by the system controller.