Spatial Sound Generation via Boundary Surface Control
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Solution Overview
Problem
Conventional sound reproduction systems fail to generate a realistic three-dimensional acoustic wave front in virtual spaces where contents can be freely moved, lacking the necessary sound image localization accuracy for immersive experiences.
Innovation Solution
A spatial sound generation device and system that includes a controller connected to multiple speakers, which varies transfer characteristics based on the movement of a sounding body and applies inverse filtering to calculate input signals for each speaker, forming a three-dimensional acoustic wave front under boundary surface control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional surround reproduction system is used, then more channels than stereo sound are provided, but sound image localization accuracy remains low
Solution Approach 1:
The patent changes the fundamental parameters of sound field reproduction by implementing boundary surface control that directly manages sound pressure and sound pressure gradient on the boundary surface. This transforms the reproduction approach from channel-based signal mixing to physical field control, enabling accurate sound image localization with the available speaker channels
Solution Approach 2:
The patent replaces the conventional mechanical/electrical signal routing approach with a physics-based acoustic field control system. By using boundary surface control equations that relate speaker outputs to actual acoustic pressure distributions, the system achieves precise sound image localization without relying on complex multi-channel signal processing
2Reliability
If BoSC sound system is used, then sound pressure and sound pressure gradient on boundary are controlled for immersive feeling, but the system is not interactive with user's body motion
Solution Approach 1:
The patent implements dynamic adaptability by continuously updating the transfer function based on detected user body motion. The system transitions from a static boundary surface control to a dynamic system that adjusts acoustic parameters in real-time according to user movement, maintaining immersive feeling while adding interactivity
Solution Approach 2:
The patent introduces feedback mechanisms where user body motion is detected and used to adjust the sound field reproduction parameters. The detected motion information feeds back into the transfer function calculation, creating a closed-loop system that adapts the acoustic environment to user actions while preserving the immersive BoSC effect
3Measurement precision
If acoustic wave front is recorded by microphone array, then three-dimensional sound field can be reproduced, but it is impossible to generate realistic acoustic wave front in virtual space where contents move freely
Solution Approach 1:
The patent performs preliminary calculation of the transfer function between speakers and boundary surface points before actual sound reproduction. By pre-computing the acoustic transfer characteristics for the specific speaker arrangement and room geometry, the system enables accurate generation of three-dimensional acoustic wave fronts for moving virtual sound sources without requiring physical microphone arrays
Solution Approach 2:
The patent creates a virtual model (copy) of the acoustic environment including speaker positions and boundary surface geometry. This computational model allows the system to generate realistic acoustic wave fronts for moving sound sources in virtual space by simulating acoustic propagation rather than recording physical sound fields
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
Enables the creation of a sound field with a realistic three-dimensional acoustic wave front, enhancing sound image localization accuracy and immersion in virtual environments.
Implementation Method 1
The inverse filtering outputs the input signals into the speakers to form a three-dimensional acoustic wave front under boundary surface control
Implementation Method 2
applies an inverse filtering to calculate a plurality of input signals for the respective speakers from a sound source signal
Data Source
AI summary
A spatial sound generation device including a storage (106) and a controller (102) and connected to a plurality of speakers (116) is provided. In the spatial sound generation device, referring to information indicating a movable sounding body, the controller varies a transfer characteristic for each time in accordance with movement of the sounding body and applies an inverse filtering to calculate a plurality of input signals for the respective speakers from a sound source signal indicating a sound emitted by the sounding body. The inverse filtering outputs the input signals into the speakers to form a three-dimensional acoustic wave front under boundary surface control in accordance with a transfer characteristic for a space in which the plurality of speakers are arranged.