Speaker Array Directivity Control for Sound Leakage Masking
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Solution Overview
Problem
Conventional area reproduction systems face challenges in preventing masking sounds from leaking to non-reproduction areas, where the masking sound intended to mask the reproduced sound is heard by the listener, and the increased volume of the reproduced sound to counter noise results in unwanted leakage to other areas.
Innovation Solution
An area reproduction system with a speaker array, audio input, sound collection, noise and leakage sound acquisition, and a directivity control unit that generates a masking sound with higher sound pressure than the leakage sound and adjusts its directivity to avoid the listener, ensuring the masking sound is emitted only to the non-reproduction area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a masking sound is synthesized to mask the reproduced sound reaching the non-reproduction line, then the reproduced sound leakage is masked, but the masking sound is heard by the listener of the reproduced sound
Solution Approach 1:
The patent applies local quality by creating spatially differentiated sound characteristics. The masking sound is generated with specific directivity patterns that concentrate its energy in the non-reproduction area while minimizing presence in the reproduction area. This is achieved through directional control mechanisms that assign different spatial properties to different regions, allowing the masking sound to be localized where it is needed without affecting the listener's experience
Solution Approach 2:
The patent utilizes the spatial dimension to resolve the contradiction. By controlling the directional characteristics of the masking sound across multiple speakers arranged in space, the system creates a three-dimensional sound field where the masking sound occupies specific spatial zones. This dimensional approach allows simultaneous presence of masking sound in the non-reproduction area and absence from the reproduction area where the listener is positioned
2Reliability
If the sound pressure of the reproduced sound is increased to exceed the noise level, then the reproduced sound is audible over noise, but the reproduced sound leaks more to the non-reproduction area
Solution Approach 1:
The patent segments the sound field into distinct reproduction and non-reproduction areas using directional control. By dividing the spatial domain and assigning different sound characteristics to each segment, the system can increase overall sound pressure for audibility while confining the reproduced sound to specific directional segments, thereby reducing leakage to other areas through spatial separation
Solution Approach 2:
The patent enhances local quality by creating directionally selective sound distribution. The reproduced sound is given specific directional properties that concentrate it in the reproduction area while suppressing it in the non-reproduction area. This localized sound distribution allows high sound pressure where needed without proportionally increasing leakage, as the sound energy is spatially optimized
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively masks the reproduced sound leakage in non-reproduction areas without being heard by the listener, while minimizing discomfort from noise or sudden sounds, and reduces processing load by generating masking sounds in advance for recorded sounds.
Implementation Method 1
a sound beam of the reproduced sound is emitted
Implementation Method 2
a masking sound is synthesized with the reproduced sound so that the masking sound reaching the non-reproduction line exceeds the sound pressure of the reproduced sound reaching the non-reproduction line
Data Source
AI summary
An area reproduction system includes a speaker array with a plurality of speakers arranged side by side, receives an input of a reproduced sound, collects an environmental sound in a non-reproduction area different from a reproduction area in which a sound beam of the reproduced sound is emitted, acquires noise included in the environmental sound and a leakage sound leaking to the non-reproduction area, generates a masking sound having a sound pressure higher than that of the leakage sound based on the frequency characteristics of the sound pressures of the noise and the leakage sound, adjusts the directivity of the masking sound to be output from each of the plurality of speakers in such a manner that the sound beam of the masking sound is emitted to the non-reproduction area while avoiding a listener, and causes each of the plurality of speakers to output the adjusted masking sound.