Virtual Loudspeaker Sound Field Stabilization
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Solution Overview
Problem
Existing methods for maintaining a stable sound field in audio systems, especially in applications like computer games, are computationally expensive and result in impaired distance cues and directional localization accuracy due to neglecting signal characteristics and sub-optimal speaker placements, leading to issues like virtual sound sources appearing inside the listener's head.
Innovation Solution
The method involves generating virtual loudspeakers by determining Head Related Impulse Responses (HRIRs) and using direct gain optimization based on energy and velocity vectors to stabilize the sound field, applying panning functions to each virtual loudspeaker signal feed, and filtering with HRIRs corresponding to physical loudspeaker locations, which reduces computational costs and maintains accurate sound source localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If existing methods for maintaining stable sound field are used, then sound field stability is improved, but computational cost increases and localization accuracy deteriorates
Solution Approach 1:
The patent segments the sound field into multiple virtual loudspeakers, each processed independently with specific panning functions. This allows stable sound field maintenance through structured processing while improving localization accuracy by treating each virtual source separately with optimized gain coefficients.
Solution Approach 2:
The patent changes parameters by applying direct gain optimization based on energy and velocity vectors, and by using psychoacoustically optimized gain coefficients stored in lookup tables. This maintains sound field stability while improving localization accuracy through parameter optimization rather than computationally expensive processing.
2Stability of the object's composition
If existing methods for maintaining stable sound field are used, then sound field stability is improved, but computational expense increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing psychoacoustically optimized gain coefficients in lookup tables. This allows real-time sound field stabilization without expensive computational processing during actual operation, as the optimization work is done in advance.
Solution Approach 2:
The patent uses lookup tables that store pre-computed gain coefficients as copies of optimized values. Instead of recalculating complex transformations in real-time, the system copies and applies pre-determined gain values, dramatically reducing computational expense while maintaining sound field stability.
3Device complexity
If virtual sound sources are generated without proper processing, then device complexity is reduced, but sound sources appear inside listener's head
Solution Approach 1:
The patent introduces virtual loudspeakers as intermediaries between the audio signal and the listener. These virtual loudspeakers, processed with specific panning functions and gain coefficients, act as mediators that externalize sound sources in the acoustic scene without requiring complex physical speaker configurations.
Solution Approach 2:
The patent applies parameter changes through direct gain optimization and psychoacoustic optimization to virtual loudspeaker signals. This externalizes sound sources by modifying signal parameters (gain coefficients) rather than requiring complex spatial processing, maintaining simplicity while improving localization accuracy.
Data Source
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AI summary
Provided are methods and systems for updating a sound field in response to user movement. The methods and systems are less computationally expensive than existing approaches for updating a sound field, and are also suitable for use with arbitrary loudspeaker configurations. The methods and systems provide a dynamic binaural sound field rendering realized with the use of "virtual loudspeakers." Rather than loudspeaker signals being fed into the physical loudspeakers, the signals are instead filtered with left and right HRIRs (Head Related Input Response) corresponding to the spatial locations of these loudspeakers. The sums of the left and right ear signals are then fed into the audio output device of the user.