Automatic Sound Masking Volume Control for Stable Noise Response
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Solution Overview
Problem
Current sound-masking systems face instability issues in automatically adjusting sound volume based on ambient noise, leading to imprecise control and potential distress for occupants, as they often rely on global energy measurements without distinguishing between background noise and short acoustic events.
Innovation Solution
A system comprising an acquisition unit for collecting sound data, a global level statistics evaluator to compute background and short acoustic event levels, and a controller that adjusts the sound volume by calculating the difference between these levels and a set point, allowing for precise and stable volume adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a retroaction based on global energy is used to adjust masking sound volume, then the system responds to ambient noise increases, but the system becomes unstable due to continuous increase in masking sound level
Solution Approach 1:
The patent segments the sound spectrum into multiple frequency bands and processes each band separately. Instead of using a single global energy measurement, the system divides the audio signal into frequency components and applies independent processing to each band, preventing the feedback instability caused by aggregate energy measurement.
Solution Approach 2:
The patent applies different processing characteristics to different frequency bands. Each frequency band is treated with localized quality adjustments rather than a uniform global adjustment, allowing precise control over specific frequency ranges while maintaining overall system stability.
2Reliability
If the masking sound level is increased to mask distracting noise, then speech privacy is improved, but worker comfort deteriorates due to excessive sound levels
Solution Approach 1:
The system applies different masking levels to different frequency bands based on the characteristics of distracting sounds in each band. This localized approach ensures adequate speech privacy protection while avoiding excessive sound exposure across all frequencies, as only specific frequency bands receiving distracting sounds are intensified.
Solution Approach 2:
The patent dynamically changes the spectral parameters of the masking sound based on real-time analysis of the acoustic environment. By adjusting frequency-specific parameters rather than applying a uniform level change, the system maintains speech privacy where needed while reducing overall sound exposure to comfortable levels.
3Manufacturing precision
If manual equalizer adjustment is performed for each environment, then optimal spectral shape is achieved, but the complexity and time required for setup increases
Solution Approach 1:
The system performs automatic spectral analysis and equalizer adjustment without requiring manual intervention. The algorithm independently analyzes the acoustic environment, identifies distracting sound characteristics, and configures the equalizer parameters automatically, achieving optimal spectral shape while eliminating the complexity of manual adjustment procedures.
Solution Approach 2:
The patent replaces the mechanical/manual equalizer adjustment process with an automated digital signal processing system. The system uses computational algorithms to analyze acoustic characteristics and adjust equalizer parameters, substituting the manual mechanical adjustment process with an automated electronic control system that achieves precise spectral shaping.
Data Source
AI summary
A control method to automatically adjust the volume of a sound transmitter based on the measurement and the computation of the acoustic statistics of the room where the sound is emitted. The system comprises at least one sensor, a calculator determining statistics of the signal collected by the at least one sensor and a controller using these statistics provided by the calculator to adjust the volume of the transmitter in the room.