Real-Time Sound Pressure Level Estimation Without Microphones
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Solution Overview
Problem
Existing methods for estimating sound pressure level (SPL) and sound exposure in acoustic environments with multiple loudspeakers are impractical due to the need for multiple microphones, high maintenance costs, and inability to account for varying sound levels across different positions, especially in complex acoustic spaces.
Innovation Solution
A method that estimates SPL and sound exposure in real-time using the input signal to the sound system, eliminating the need for microphones by calculating inter-channel correlation, approximating frequency response, and considering reverberation characteristics, allowing for accurate estimation at multiple positions without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sound level meters are deployed to measure SPL at different positions, then measurement accuracy is improved, but device complexity and maintenance costs increase
Solution Approach 1:
The patent uses digital copies of the input signal to estimate SPL at multiple positions simultaneously. Instead of deploying multiple physical sound level meters, the system creates virtual measurements by processing the single input signal through digital signal processing techniques that simulate the acoustic response at different listener positions.
Solution Approach 2:
The patent replaces the mechanical/physical measurement system (multiple sound level meters with microphones) with a digital signal processing system. By using inter-channel correlation and frequency response approximation, the system substitutes physical measurement devices with computational methods that estimate SPL without requiring additional hardware.
2Reliability
If sound level meters are permanently installed, then continuous monitoring is improved, but maintenance requirements and costs increase
Solution Approach 1:
The system uses the existing sound system's input signal as its measurement source, eliminating the need for separate measurement devices that require maintenance. The sound system itself provides the data needed for SPL estimation, making the monitoring system self-sufficient and free from the maintenance requirements of traditional sound level meters.
Solution Approach 2:
The patent extracts SPL estimation capability from the physical measurement device and embeds it within the sound system's existing signal processing chain. By taking out the measurement function from separate hardware and integrating it into the digital signal processing of the sound system, continuous monitoring is achieved without the maintenance burden of additional measurement equipment.
3Measurement precision
If traditional measurement methods are used, then SPL at single position can be measured, but inability to account for varying sound levels across different positions occurs
Solution Approach 1:
The patent segments the acoustic space into multiple listener positions and estimates SPL for each position separately by processing the input signal through position-specific transfer functions. This segmentation allows the system to provide tailored SPL estimates for different locations in the acoustic environment rather than a single averaged measurement.
Solution Approach 2:
The patent creates a universal SPL estimation system that can simultaneously estimate sound pressure levels at multiple different positions using a single input signal. The system processes the same input signal through multiple transfer functions to generate position-specific estimates, making the measurement system multi-functional and adaptable to various listener locations.
Data Source
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AI summary
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.