Sound level estimation

• US 10,708,701 B2
• Filed: 10/28/2015
• Issued: 07/07/2020
• Est. Priority Date: 10/28/2015
• Status: Active Grant

• Current Assignee: Music Tribe Innovation DK A/S
• Original Assignee: Music Tribe Global Brands Limited
• Inventors: Skovenborg, Esben
• Primary Examiner(s): Hamid, Ammar T
• Application Number:
  US14/924,968
• Publication Number:
  US 20170127206A1
• Time in Patent Office: 1,714 Days
• Field of Search: 381 56, 381 58
• 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 providing an estimate of a Sound Pressure Level (SPL) or Sound Exposure (SE) of sound produced in an acoustic environment (AE) by multiple loudspeakers of a sound system in response to an electrical or optical representation of an input audio signal, the acoustic environment having at least one listening position, the method comprising:

an initial step of obtaining an approximation of sound system properties for each of the at least one listening position in the acoustic environment, the approximation of sound system properties being determined using a microphone measurement;

receiving the electrical or optical input audio signal in a sound level detector/integrator (SSLD) in the sound system without using a microphone;

determining in real time with the SSLD, in response to receiving the input audio signal and the approximation of sound system properties, individual estimates of the Sound Pressure Level (SPL-EST) or Sound Exposure (SE-EST) simultaneously at one or more of the at least one listening positions in the acoustic environment; and

providing the determined SPL-EST or SE-EST as an output, wherein;

the determining of SPL EST includes;

(a) frequency weighting;

(b) RMS integration based on;

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

3. The method of claim 2, wherein the method comprises providing a pre-determined diffuseness of the acoustic environment, and further modifying the estimate of Sound Pressure Level or Sound Exposure by using the calculated inter-channel correlation and the diffuseness of the acoustic environment in the determining in real-time estimate of the Sound Pressure Level or Sound Exposure.

4. The method of claim 1, wherein the method comprises attenuating the sound produced by the sound system based on the estimate of Sound Pressure Level or Sound Exposure in order to limit the estimated Sound Pressure Level or Sound Exposure from exceeding a threshold.

5. The method of claim 1, wherein the approximation of sound system properties comprises a representation of a relation between an acoustic output level and an electrical or digital input level of the sound system in the acoustic environment.

6. The method of claim 1, wherein the approximation of sound system properties comprises approximations of frequency response of one or more of the multiple loudspeakers in the acoustic environment.

7. The method of claim 1, wherein the approximation of the sound system properties comprises approximations of reverberation characteristic of the acoustic environment.

8. The method of claim 1, wherein the approximation of sound system properties comprises a transfer function between each pair of one of the multiple loudspeakers and one of the at least one listening positions in the acoustic environment.

9. The method of claim 1, wherein the providing of the determined estimates as an output comprises visually displaying the determined estimates.

10. The method of claim 1, wherein the providing of the determined estimates as an output comprises logging the determined estimates.

11. The method of claim 1, wherein the providing of the determined estimates as an output comprises storing the determined estimates in a memory.

12. The method of claim 1, wherein the providing of the determined estimates as an output comprises transmitting the determined estimates over a network.

13. A method of providing an estimate of a Sound Pressure Level (SPL) or Sound Exposure (SE) of sound produced in an acoustic environment (AE) by multiple loudspeakers of a sound system in response to an electrical or optical representation of an input audio signal, the acoustic environment having at least one listening position, the method comprising:

an initial step of obtaining an approximation of sound system properties for each of the at least one listening position in the acoustic environment, the approximation of sound system properties being determined using a microphone measurement;

receiving the electrical or optical input audio signal in a sound level detector/integrator (SSLD) in the sound system without using a microphone;

determining in real time with the SSLD, in response to receiving the input audio signal and the approximation of sound system properties, individual estimates of the Sound Pressure Level (SPL_EST) or Sound Exposure (SE_EST) simultaneously at one or more of the at least one listening positions in the acoustic environment; and

providing the determined SPL_EST or SE_EST as an output, wherein;

the determining of SE_EST includes;

(a) frequency weighting;

(b) RMS integration based on;

14. The method of claim 13, wherein the method comprises calculating an inter-channel correlation of one or more pairs of channels of the input signal, and further modifying the estimate of a Sound Pressure Level or Sound Exposure by using the calculated inter-channel correlation in the determining in real time the estimate of the Sound Pressure Level or Sound Exposure.

15. The method of claim 14, wherein the method comprises providing a pre-determined diffuseness of the acoustic environment, and further modifying the estimate of Sound Pressure Level or Sound Exposure by using the calculated inter-channel correlation and the diffuseness of the acoustic environment in the determining in real-time estimate of the Sound Pressure Level or Sound Exposure.

16. The method of claim 13, wherein the method comprises attenuating the sound produced by the sound system based on the estimate of Sound Pressure Level or Sound Exposure in order to limit the estimated Sound Pressure Level or Sound Exposure from exceeding a threshold.

17. The method of claim 13, wherein the approximation of sound system properties comprises a representation of a relation between an acoustic output level and an electrical or digital input level of the sound system in the acoustic environment.

18. The method of claim 13, wherein the approximation of sound system properties comprises approximations of frequency response of one or more of the multiple loudspeakers in the acoustic environment.

19. The method of claim 13, wherein the approximation of the sound system properties comprises approximations of reverberation characteristic of the acoustic environment.

20. The method of claim 13, wherein the approximation of sound system properties comprises a transfer function between each pair of one of the multiple loudspeakers and one of the at least one listening positions in the acoustic environment.

21. The method of claim 13, wherein the providing of the determined estimates as an output comprises visually displaying the determined estimates.

22. The method of claim 13, wherein the providing of the determined estimates as an output comprises logging the determined estimates.

23. The method of claim 13, wherein the providing of the determined estimates as an output comprises storing the determined estimates in a memory.

24. The method of claim 13, wherein the providing of the determined estimates as an output comprises transmitting the determined estimates over a network.

25. A real-time sound level estimator for real-time estimation of Sound Pressure Level (SPL) or Sound Exposure (SE) of sound produced in an acoustic environment (AE) by multiple loudspeakers of a sound system in response to an electrical or optical representation of an input audio signal, the acoustic environment having at least one listening position, the sound level estimator comprising:

an input;

a processor coupled to the input;

a memory accessible by the processor, the memory structured to store instructions for the processor; and

an output coupled to the processor;

wherein the processor is arranged to perform the following steps;

an initial step of obtaining an approximation of sound system properties for each of the at least one listening position in the acoustic environment, the approximation of sound system properties being determined using a microphone measurement;

receiving the electrical or optical input audio signal in a sound level detector/integrator (SSLD) in the sound system without using a microphone;

determining in real time with the SSLD, in response to receiving the input audio signal and the approximation of sound system properties, individual estimates of the Sound Pressure Level (SPL_EST) or Sound Exposure (SE_EST) simultaneously at one or more of the at least one listening positions in the acoustic environment; and

providing the determined SPL_EST or SE_EST as an output, wherein;

the determining of SPL_EST includes;

(a) frequency weighting;

(b) RMS integration based on;

26. A real-time sound level estimator for real-time estimation of Sound Pressure Level (SPL) or Sound Exposure (SE) of sound produced in an acoustic environment (AE) by multiple loudspeakers of a sound system in response to an electrical or optical representation of an input audio signal, the acoustic environment having at least one listening position, the sound level estimator comprising:

an input;

a processor coupled to the input;

a memory accessible by the processor, the memory structured to store instructions for the processor; and

an output coupled to the processor;

wherein the processor is arranged to perform the following steps;

an initial step of obtaining an approximation of sound system properties for each of the at least one listening position in the acoustic environment, the approximation of sound system properties being determined using a microphone measurement;

receiving the electrical or optical input audio signal in a sound level detector/integrator (SSLD) in the sound system without using a microphone;

determining in real time with the SSLD, in response to receiving the input audio signal and the approximation of sound system properties, individual estimates of the Sound Pressure Level (SPL_EST) or Sound Exposure (SE_EST) simultaneously at one or more of the at least one listening positions in the acoustic environment; and

providing the determined SPL_EST or SE_EST as an output, wherein;

the determining of SE_EST includes;

(a) frequency weighting;

(b) RMS integration based on;