Expanding 3D Audio Sweet Spot via Virtual Ear HRTF Processing
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Solution Overview
Problem
The existing listening sweet spot in 3D sound systems is highly sensitive to the listener's movement, limiting the area where the maximum 3D sound effect can be experienced due to its fixed position-based binaural synthesis and crosstalk cancellation system.
Innovation Solution
The method involves calculating and applying Head Related Transfer Functions (HRTFs) at various positions of a virtual ear to simulate the listener's movement, allowing for crosstalk cancellation and expansion of the listening sweet spot by processing signals accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed position-based binaural synthesis and crosstalk cancellation system is used, then the 3D sound effect is maximized at a specific listening sweet spot, but the listening area is limited and highly sensitive to listener movement
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed listening sweet spot system to a dynamic system that adapts to listener movement. The system calculates HRTFs at multiple positions along a movement path and combines crosstalk cancellation functions for each position, enabling the 3D sound effect to be maintained across a larger listening area rather than being confined to a single fixed position.
Solution Approach 2:
The patent changes the parameter of HRTF calculation positions from a single fixed position to multiple positions along a movement path. By obtaining HRTFs at different positions (first position, second position, etc.) and combining the corresponding crosstalk cancellation functions, the system expands the effective listening area while maintaining 3D sound quality.
2Adaptability or versatility
If the listening sweet spot is expanded to accommodate listener movement, then the adaptability improves, but the system complexity increases due to multiple HRTF calculations and combinations
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing HRTFs at multiple positions along the expected movement path before the listener actually moves. The crosstalk cancellation functions for each position are prepared in advance, and when the listener moves to a different position, the corresponding pre-calculated functions are selected and combined, reducing real-time processing complexity.
Solution Approach 2:
The patent introduces an intermediary approach by using virtual ear positions as intermediate representations between the fixed speaker system and the moving listener. The HRTFs are calculated at these virtual positions along the movement path, serving as intermediaries that simplify the complex relationship between fixed speakers and moving listeners, making the system more manageable.
Data Source
AI summary
A method and apparatus of expanding a listening sweet spot. A method of expanding a listening sweet spot with respect to signals output from speakers includes: obtaining an HRTF (head related transfer function) at a position of a listener's ear; moving a first virtual ear around the position of the listener's ear; obtaining an HRTF at each position of the first virtual ear; and processing a signal to be input to the speakers using the obtained HRTFs to output to the speakers.