Virtual Surround Filter Selection for Individualized Stereo Sound
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Solution Overview
Problem
Conventional virtual sound generation systems fail to produce optimal stereo sound as they do not account for individual auditory characteristics, relying on standardized head-related transfer functions (HRTFs) that do not reflect personal human spatial perception of sound sources.
Innovation Solution
A method and apparatus that generate and select virtual surround filters based on individual auditory properties, allowing for the reproduction of stereo sound tailored to specific HRTFs, which involves an auditory properties correction unit to classify and select filters, and a virtual surround filter unit to convert multi-channel audio signals into optimized 2-channel stereo sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standardized HRTF is used in virtual sound generation system, then device complexity is reduced and ease of manufacture is improved, but manufacturing precision and reliability of stereo sound reproduction deteriorate due to not reflecting individual auditory characteristics
Solution Approach 1:
The patent segments the standardized HRTF into multiple components (left ear HRTF, right ear HRTF, cross-talk functions) that can be independently processed and adjusted. This allows the system to maintain the simplicity of standardized HRTF while enabling precise individualized adjustments through separate filter banks for different frequency ranges and spatial positions.
Solution Approach 2:
The patent applies local quality by creating position-dependent impulse response functions that are specific to different spatial locations (front, rear, left, right channels). Each position has its own tailored impulse response that reflects individual auditory characteristics, while the overall system structure remains based on the simplified standardized HRTF framework.
2Device complexity
If conventional virtual sound generation system with standardized HRTF is used, then device complexity is reduced, but reliability of stereo sound reproduction deteriorates due to failure to produce optimal stereo sound for individual auditory properties
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing position-dependent impulse response functions for multiple spatial positions before actual sound reproduction. These pre-computed functions are stored in memory and rapidly retrieved during playback, allowing the system to maintain low device complexity while achieving high reliability through individually optimized sound fields.
Solution Approach 2:
The patent changes parameters by adjusting filter coefficients in the impulse response functions to match individual auditory characteristics. The system modifies frequency response parameters, time delay parameters, and spatial positioning parameters within the standardized HRTF framework to reliably reproduce optimal stereo sound for each individual user.
3Productivity
If standardized HRTF is used to down-mix 5.1-channel signals to 2-channel signals, then productivity is improved by simplifying the system, but manufacturing precision deteriorates due to loss of individual auditory property consideration
Solution Approach 1:
The patent achieves universality by designing a down-mixing system that can handle multiple channel configurations (5.1-channel, multi-channel) while maintaining compatibility with standardized HRTF. The same impulse response function generation mechanism serves both standardized and individualized applications, allowing the system to be universally applicable across different scenarios while preserving manufacturing precision through individualized filter selection.
Data Source
AI summary
A method and apparatus to reproduce stereo sound, which generates optimal stereo sound designed for individual auditory properties. The method includes generating a one or more virtual surround filters corresponding to each of a plurality of head-related transfer functions (HRTFs) classified according to one or more individual auditory properties, generating stereo sound for the one or more virtual surround filters, and selecting at least one from the one or more virtual surround filters, and reproducing the stereo sound based on a filter value of the selected at least one virtual surround filter.