Acoustic Signal Processing for Virtual Sound Source Directivity
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Solution Overview
Problem
Existing techniques fail to effectively model and implement directional characteristics of sound sources, such as musical instruments, using multipole superposition in acoustic signal processing for virtual sound source creation.
Innovation Solution
An acoustic signal processing device and method that determines focal point coordinates, calculates circular harmonic coefficients, computes weighted driving functions, and convolves these functions into input signals for a speaker array to achieve desired directional characteristics by superimposing multipoles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wave field reconstruction or virtual sound source techniques are used, then acoustic reproduction with live feeling is improved, but directional characteristics of sound sources cannot be accurately modeled
Solution Approach 1:
The patent segments the sound source representation into multiple multipole components (monopole, dipole, quadrupole, etc.) with different directional characteristics. Each multipole is represented by coefficients that can be independently controlled, allowing accurate modeling of complex directional patterns while maintaining virtual sound source capabilities.
Solution Approach 2:
The patent uses composite multipole representations combining multiple primitive directivities (monopole, dipole, quadrupole) with different intensities and orientations. This composite approach enables the system to model any directional characteristics by superimposing multiple multipole components, resolving the contradiction between virtual sound source creation and accurate directivity modeling.
2Measurement precision
If multipole superposition is used to model directional characteristics, then directivity accuracy is improved, but existing techniques cannot effectively implement any directional characteristics
Solution Approach 1:
The patent implements dynamic control of multipole coefficients to adapt the directional characteristics in real-time. The system can adjust the intensity and orientation of each multipole component dynamically, enabling implementation of any directional pattern required by different sound sources or listening scenarios.
Solution Approach 2:
The patent creates a universal multipole superposition framework that can model any directional characteristics by combining primitive directivities with different intensities and orientations. This multi-functional approach allows the same system to accurately represent various sound sources (instruments, voices, etc.) with different directional patterns.
Data Source
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AI summary
An acoustic signal processing device 1 includes: a focal point position determination unit 12 that obtains a plurality of sets of initial focal point coordinates, coordinates of the virtual sound source, and a direction of directivity thereof, and for a pair of sets of initial focal point coordinates with different polarities among the plurality of sets of initial focal point coordinates, multiplies the sets of initial focal point coordinates by a rotation matrix based on the coordinates of the virtual sound source to thereby determine sets of focal point coordinates, the rotation matrix being specified from the direction of the directivity; a circular harmonic coefficient conversion unit 13 that calculates weights to be applied to multipoles including the sets of focal point coordinates from a circular harmonic coefficient; a filter coefficient computation unit 14 that, for each of the speakers in the speaker array, computes a weighted driving function to be applied to the speaker from the sets of focal point coordinates, polarities of the sets of focal point coordinates, and the weights to be applied to the multipoles; and a convolutional operation unit 15 that, for each of the speakers in the speaker array, convolves the weighted driving function for the speaker into the input acoustic signal to output the output acoustic signal for the speaker.