Audio Reproduction Apparatus Virtual Speaker Localization
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Solution Overview
Problem
Conventional audio reproduction systems with 5.1-channel speaker configurations struggle to accurately reproduce a seamless sound field across all directions due to speaker placement dependencies and inability to localize sound images at desired virtual positions, limiting the natural surround experience.
Innovation Solution
An audio reproduction apparatus that uses signal processing units with equalizers and level adjusters to simulate virtual speakers between real speakers, allowing sound localization at specific positions, thereby creating a seamless surround experience without being aware of the actual speaker positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If back surround signals are processed using conventional crosstalk cancellation, then sound image localization is achieved, but the viewer must be at the center position surrounded by speakers and the effect is heavily affected by positional relationship
Solution Approach 1:
The patent implements dynamic adjustment of equalizer characteristics based on the actual viewing position. The system detects the viewer's position and dynamically changes the equalizer settings to maintain accurate sound image localization regardless of where the viewer is seated, transforming the static crosstalk cancellation system into an adaptive one.
Solution Approach 2:
The patent changes the equalizer characteristics (frequency response parameters) according to the viewing position. By adjusting these parameters dynamically, the system compensates for positional variations and maintains precise sound image localization across different viewing positions.
2Ease of operation
If surround speakers are placed at 90 degrees immediately left and right, then ease of placement is improved, but accurate sound image localization of back surround signals cannot be implemented
Solution Approach 1:
The patent introduces an equalizer as an intermediary device between the speakers and the viewer's ears. This equalizer processes the audio signals to compensate for the suboptimal speaker placement, enabling accurate sound image localization even when speakers are positioned at convenient 90-degree angles rather than ideal positions.
Solution Approach 2:
The patent modifies the frequency response parameters of the audio signals through equalization to achieve accurate sound image localization. By changing these acoustic parameters, the system compensates for the geometric limitations of simple speaker placement configurations.
3Device complexity
If 5.1-channel speaker configuration is used, then device complexity is reduced, but the sound field reproduction is not seamless across all directions
Solution Approach 1:
The patent creates virtual sound sources by processing signals from the 5.1-channel system. Through equalization and signal processing, it copies or simulates the effect of additional speakers that would be present in a more complex surround system, achieving seamless sound field reproduction across all directions without adding physical speakers.
4Measurement precision
If head-related transfer function is used for crosstalk cancellation, then sound image localization is achieved, but the system is highly dependent on accurate positioning
Solution Approach 1:
The patent incorporates feedback mechanisms that detect the actual viewing position and use this information to adjust the equalizer characteristics. This closed-loop system continuously monitors positioning accuracy and makes real-time adjustments, reducing the impact of positioning errors while maintaining precise sound image localization.
Data Source
AI summary
An audio reproduction apparatus includes: a delay equalizer (301), a delay equalizer (303), a level adjuster (314), and a level adjuster (317). The delay equalizer (301) equalizes an FL signal using an equalizer characteristic EQ9 that converts a characteristic of an audio signal perceived as being reproduced at a position of an FL speaker (104) with respect to a viewing position to be perceived as being reproduced at a position of a virtual speaker (201) with respect to the viewing position. The delay equalizer (303) equalizes the FL signal using an equalizer characteristic (EQ12) that converts a characteristic of an audio signal perceived as being reproduced at a position of an SL speaker (106) with respect to a viewing position to be perceived as being reproduced at a position of the virtual speaker (201) with respect to the viewing position. The level adjuster (314) performs level adjustment, using a first coefficient K9, on an output signal of the delay equalizer (301). The level adjuster (317) performs level adjustment, using a second coefficient K12, on an output signal of the delay equalizer (303).