SOUND LEVEL ESTIMATION

• US 20170127206A1
• Filed: 10/28/2015
• Published: 05/04/2017
• Est. Priority Date: 10/28/2015
• Status: Active Grant

• Current Assignee: Music Tribe Innovation DK A/S
• Original Assignee: Music Group IP Limited (Music Group Services US Incorporated)
• Inventors: Skovenborg, Esben
• Granted Patent: US 10,708,701 B2
• Time in Patent Office: Days
• CPC Class Codes: G01H 7/00 Measuring reverberation time ; room acoustic measurements
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 29/002 Loudspeaker arrays
• CPC Class Codes: H04R 29/007 for public address systems public address systems per se H04R27/00
• CPC Class Codes: H04S 2420/01 Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]
• CPC Class Codes: H04S 7/305 Electronic adaptation of stereophonic audio signals to reverberation of the listening space H04S7/301 takes precedence

Abstract

Disclosed is a method of determining in real-time an estimate of a Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to the sound system. The method comprises determining in real-time the estimate of the Sound Pressure Level or Sound Exposure on the basis of the input signal. The sound system is a level-calibrated sound system. Also disclosed is a real-time sound level estimator. Also disclosed are a method and a real-time sound level estimator where the estimation is based on an approximation of system properties based on microphone measurements, or established for multiple listening positions, respectively. Also disclosed are methods of calibrating and monitoring a sound system and calibration and monitoring devices therefore.

Claims

1. A method of determining in real-time an estimate of a Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to said sound system, the method comprising

determining in real-time said estimate of the Sound Pressure Level or Sound Exposure on the basis of the input signal;

wherein the sound system is a level-calibrated sound system.

2. The method of claim 1, wherein the method comprises calculating an inter-channel correlation of one or more pairs of channels of said input signal, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said calculated inter-channel correlation in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

3. The method of claim 1, wherein the method comprises providing a pre-determined diffuseness of the acoustic environment, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said calculated inter-channel correlation and said diffuseness of the acoustic environment in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

4. The method of claim 1, wherein the method comprises approximation of a frequency response of one or more of the multiple loudspeakers in the acoustic environment, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said approximation of a frequency response in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

5. The method of claim 1, wherein the method comprises approximation of a reverberation characteristic of the acoustic environment, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said approximation of a reverberation characteristic in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

6. The method of claim 1, wherein the method comprises providing one or more properties of said sound system related to multiple pre-determined different listening-positions, and determining said estimate of a Sound Pressure Level or Sound Exposure for one or more of said multiple pre-determined different listening-positions by using said properties of said sound system.

7. The method of claim 1, wherein the method comprises approximation of a transfer function between each pair of one of the multiple loudspeakers and a pre-determined listening-position in said acoustic environment, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said approximation of a transfer function in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

8. The method of claim 1, wherein the method comprises attenuating said sound produced based on said estimate of Sound Pressure Level or Sound Exposure, in order for the estimated Sound Pressure Level or Sound Exposure to not exceed a pre-determined threshold.

9. A real-time sound level estimator for real-time estimation of Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a level-calibrated sound system in response to an input signal to said sound system, the sound level estimator comprising

an input signal input for receiving the input signal;

a processor;

a memory accessible by the processor, the memory storing instructions for the processor and level-calibration information about the sound system; and

an estimate output for providing the estimate;

wherein the processor is arranged to receive the input signal from the input signal input, simulate a sound level of said sound produced in the acoustic environment and calculate said estimate of Sound Pressure Level or Sound Exposure and provide it at the estimate output;

wherein the simulation of a sound level is based on the input signal and the level-calibration information.

10. A method of determining in real-time an estimate of a Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to said sound system, the method comprising

determining in real-time said estimate of the Sound Pressure Level or Sound Exposure on the basis of the input signal and an approximation of one or more system properties of said sound system with loudspeakers in said acoustic environment;

wherein said approximation is based on microphone measurement.

11. The method of claim 10, wherein said approximation of one or more system properties is pre-determined.

12. The method of claim 10, wherein said approximation of one or more system properties comprises a representation of a relation between an acoustic output level and an electrical or digital input level of said sound system.

13. The method of claim 10, wherein said approximations of one or more system properties comprise approximations of frequency response of one or more of the multiple loudspeakers in the acoustic environment.

14. The method of claim 10, wherein said approximations of one or more system properties comprise approximations of reverberation characteristic of (the sound system in) the acoustic environment.

15. The method of claim 10, wherein said approximations of one or more system properties relate to multiple pre-determined different listening-positions.

16. The method of claim 10, wherein said approximations of one or more system properties comprise a transfer function between each pair of one of the multiple loudspeakers and a pre-determined listening-position in said acoustic environment.

17. The method of claim 10, wherein the method comprises calculating an inter-channel correlation of one or more pairs of channels of said input signal, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said calculated inter-channel correlation in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

18. The method of claim 10, wherein the method comprises attenuating said sound produced based on said estimate of Sound Pressure Level or Sound Exposure, in order for the estimated Sound Pressure Level or Sound Exposure to not exceed a pre-determined threshold.

19. A real-time sound level estimator for real-time estimation of Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to said sound system, the sound level estimator comprising

an input signal input for receiving the input signal;

a processor;

a memory accessible by the processor, the memory storing instructions for the processor and an approximation of one or more system properties of said sound system with loudspeakers in said acoustic environment; and

an estimate output for providing the estimate;

wherein the processor is arranged to receive the input signal from the input signal input, simulate a sound level of said sound produced in the acoustic environment and calculate said estimate of Sound Pressure Level or Sound Exposure and provide it at the estimate output;

wherein the simulation of a sound level is based on the input signal and the approximation of one or more system properties; and

wherein the approximation of one or more system properties is based on microphone measurement.

20. A method of calibrating and monitoring a sound system comprising multiple loudspeakers for producing sound in an acoustic environment in response to an input signal to said sound system, the method comprising:

approximating one or more system properties of said sound system in the acoustic environment, the approximating being based on measurements in the acoustic environment using a microphone; and

determining in real-time, based on said approximation and said input signal and not on a microphone measurement of said produced sound, an estimate of an acoustic property of said produced sound.

21. The method of claim 20, wherein said estimate of an acoustic property comprises instantaneous or averaged Sound Pressure or Sound Pressure Level.

22. The method of claim 20, wherein said estimate of an acoustic property comprises integrated Sound Pressure, Sound Exposure, or Sound Exposure Level.

23. The method of claim 20, wherein said estimate of an acoustic property comprises speech intelligibility.

24. The method of claim 20, wherein said estimate of an acoustic property comprises Speech Transmission Index, STI.

25. The method of claim 20, wherein said estimate of an acoustic property comprises Common Intelligibility Scale, CIS.

26. The method of claim 20, wherein said estimate of an acoustic property comprises Clarity.

27. The method of claim 20, wherein said approximating one or more system properties comprises determining a representation of a relation between an acoustic output level and an electrical or digital input level of said sound system.

28. The method of claim 20, wherein said determining comprises calculating an inter-channel correlation of one or more pairs of channels of said input signal, and further improving said estimate of the acoustic property by using said calculated inter-channel correlation in said determining in real-time said estimate.

29. The method of claim 20, wherein said one or more system properties being approximated comprise a frequency response of one or more of the multiple loudspeakers in the acoustic environment, a reverberation characteristic of the acoustic environment, and/or a transfer function between each pair of one of the multiple loudspeakers and a pre-determined listening-position in said acoustic environment, and wherein said determining comprises improving said estimate of the acoustic property by using said approximated system properties in said determining in real-time said estimate.

30. The method of claim 20, wherein said approximating comprises approximating said system properties with respect to multiple pre-determined different listening-positions, and wherein said determining comprises determining said acoustic property for one or more of said multiple pre-determined different listening-positions by using said system properties.

31. The method of claim 20, wherein the method comprises attenuating said sound produced based on said estimate of an acoustic property, in order for the acoustic property to not exceed a pre-determined threshold.

32. A calibration and monitoring device for calibrating and monitoring a sound system comprising multiple loudspeakers for producing sound in an acoustic environment in response to an input signal to said sound system;

the calibration and monitoring device comprising;

a calibrator comprising a microphone signal input;

a real-time sound level estimator comprising an input signal input and an estimate output;

a processor arranged to perform processing of the calibrator and the real-time sound level estimator; and

a memory accessible by the processor, the memory storing instructions for the processor and an approximation of one or more system properties of said sound system with loudspeakers in said acoustic environment;

wherein the calibrator is arranged to determine and store in the memory the approximation of one or more system properties on the basis of microphone measurements in the acoustic environment received at the microphone signal input;

wherein the real-time sound sound level estimator is arranged to receive an input signal from the input signal input, simulate a sound level of said sound produced in the acoustic environment and calculate an estimate of an acoustic property of said produced sound and provide the estimate at the estimate output; and

wherein the simulation of a sound level is based on the input signal and the approximation of one or more system properties and not based on a microphone measurement of said produced sound.

33. A method of calibrating a sound system comprising multiple loudspeakers for producing sound in an acoustic environment in response to an input signal to said sound system, the method comprising:

providing as the input signal a multi-channel test signal having different spectral content for channels corresponding to different of said multiple loudspeakers;

measuring one or more system properties of said sound system in the acoustic environment; and

calibrating the sound system based on said measured system properties.

34. The method of claim 33, wherein each channel of said multi-channel test signal comprises multiple pure tones distributed across a frequency interval corresponding to an intended frequency interval of the measurement, and where a frequency density of said pure tones corresponds to an intended frequency resolution of the measurement.

35. The method of claim 33, wherein said multi-channel test signal comprises multiple pure tones with frequencies such that no tone is a harmonic of any lower tone.

36. The method of claim 33, wherein said multi-channel test signal comprises noise signals which are band-limited such that the spectral overlap of a noise signal in a first channel, with the noise signal of a second channel, does not contribute significantly to said measured system properties of a second channel.

37. The method of claim 33, wherein said measuring one or more system properties comprises determining a representation of a relation between an acoustic output level and an electrical or digital input level of said sound system.

38. The method of claim 33, wherein said one or more system properties being determined comprise a frequency response of one or more of the multiple loudspeakers in the acoustic environment, a reverberation characteristic of the acoustic environment, and/or a transfer function between each pair of one of the multiple loudspeakers and a pre-determined listening-position in said acoustic environment.

39. The method of claim 33, wherein said measuring one or more system properties comprises measuring said system properties with respect to multiple pre-determined different listening-positions, and wherein said calibrating comprises calibrating the sound system for one or more of said multiple pre-determined different listening-positions based on said measured system properties.

40. A calibration device for calibrating a sound system comprising multiple loudspeakers for producing sound in an acoustic environment in response to a test signal to said sound system;

the calibration device comprising;

a test signal output;

a microphone signal input;

a processor; and

a memory accessible by the processor, the memory storing instructions for the processor, parameters for a multi-channel test signal and system properties and calibration information of the sound system;

wherein the processor is arranged to establish a multi-channel test signal at the test signal output;

to determine and store in the memory the system properties on the basis of microphone measurements in the acoustic environment received at the microphone signal input; and

to determine and store in the memory the calibration information of the sound system on the basis of the system properties.

41. A method of determining in real-time an estimate of a Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to said sound system;

the method comprising

determining in real-time said estimate at multiple pre-determined listening-positions in said acoustic environment, on the basis of the input signal.

42. The method of claim 41, wherein said sound system is a level-calibrated sound system.

43. The method of claim 41, wherein said estimate is determined further on the basis of an approximation of one or more system properties of said sound system with loudspeakers in said acoustic environment.

44. The method of claim 41, wherein said approximation of system properties is based on microphone measurement.

45. The method of claim 41, wherein said approximation of system properties is pre-determined.

46. The method of claim 41, wherein said approximation of system properties relates to said multiple pre-determined listening-positions.

47. The method of claim 41, wherein said system properties comprise a representation of a relation between an acoustic output level and an electrical or digital input level of said sound system.

48. The method of claim 41, wherein said one or more system properties comprise a frequency response of one or more of the multiple loudspeakers in the acoustic environment, a reverberation characteristic of the acoustic environment, and/or a transfer function between each pair of one of the multiple loudspeakers and a pre-determined listening-position in said acoustic environment.

49. The method of claim 41, wherein the method comprises calculating an inter-channel correlation of one or more pairs of channels of said input signal, and further improving said estimate of a Sound Pressure Level or Sound Exposure by using said calculated inter-channel correlation in said determining in real-time said estimate of the Sound Pressure Level or Sound Exposure.

50. The method of claim 41, wherein the method comprises attenuating said sound produced based on said estimate of Sound Pressure Level or Sound Exposure, in order for the estimated Sound Pressure Level or Sound Exposure to not exceed a pre-determined threshold at one or more said multiple pre-determined listening positions.

51. A real-time sound level estimator for real-time estimation of Sound Pressure Level or Sound Exposure corresponding to sound produced in an acoustic environment by multiple loudspeakers of a sound system in response to an input signal to said sound system, the sound level estimator comprising an input signal input for receiving the input signal;

a processor;

a memory accessible by the processor, the memory storing instructions for the processor and listening-positions information comprising information about multiple pre-determined listening-positions in said acoustic environment; and

an estimate output for providing the estimate;

wherein the processor is arranged to receive the input signal from the input signal input, simulate a sound level of said sound produced in the acoustic environment and calculate said estimate of Sound Pressure Level or Sound Exposure and provide it at the estimate output;

wherein the simulation of a sound level is based on the input signal and is performed for the multiple pre-determined listening-positions in said acoustic environment.