Planar Loudspeaker Array Control for Localized Sound Fields
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Solution Overview
Problem
Polyhedral loudspeaker arrays are not suitable for realizing personal acoustic spaces due to their large size, which hinders effective sound field localization.
Innovation Solution
A compact acoustic output device featuring a two-dimensional loudspeaker array with an amplifier array that controls the amplitude and phase of drive signals based on eigenvectors of predetermined radiation modes, allowing for reduced size and enhanced sound field localization capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyhedral loudspeaker array is used to achieve sufficient distance attenuation for sound field localization, then the distance attenuation performance is improved, but the size of the loudspeaker array becomes large and unsuitable for personal acoustic spaces
Solution Approach 1:
The patent transitions from a polyhedral (three-dimensional volumetric) loudspeaker array configuration to a two-dimensional planar array configuration. This dimensional change allows the system to achieve the required distance attenuation and sound field localization performance while significantly reducing the overall volume and physical footprint of the loudspeaker array, making it suitable for personal acoustic space applications
2Device complexity
If eigenvectors at a certain frequency are used to control amplitude and phase of loudspeakers, then the control complexity is reduced, but the frequency range coverage must be maintained
Solution Approach 1:
The patent utilizes the observation that eigenvectors exhibit low frequency dependence within the same radiation mode. By selecting eigenvectors at a representative frequency and applying them across a broader frequency range, the system reduces computational complexity and control difficulty while maintaining adequate sound field localization performance across the required frequency spectrum
Data Source
AI summary
Proposed is an acoustic output device that obtains enough distance attenuation to achieve localization of a sound field by controlling the driving of a loudspeaker array by use of a more compact shape. The acoustic output device 10 comprises: a loudspeaker array 20 that includes a plurality of loudspeakers 20-1, 20-2, . . . , 20-N arranged in a two-dimensional plane; and an amplifier array 40 that includes a plurality of amplifiers 40-1, 40-2, . . . , 40-N that control the amplitude and phase of the drive signals for each loudspeaker according to the eigenvectors of the predetermined radiation mode of the loudspeaker array 20.