Virtual Surround Sound Circuit for Flat Panel Displays
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Solution Overview
Problem
Existing surround sound technologies, such as multi-channel surround sound, are complex and occupy space, making it difficult to achieve immersive sound experiences in flat panel display devices like TVs and large screens, as sound waves are not directed towards the viewer due to rear or lower sound wave emission, reducing sound quality and viewer immersion.
Innovation Solution
A virtual surround sound production circuit using a two-channel system with a subtraction unit, addition units, phase inverter, and frequency compensation, based on head-related transfer function (HRTF) and interaural time difference (ITD) principles, to create a virtual surround sound effect using two speakers, simplifying spatial arrangement and enhancing sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-channel surround sound technology is used, then surround sound effect is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent uses signal processing to create virtual copies of surround sound channels from a two-channel input. By applying HRTF filtering and signal manipulation, the system generates virtual rear and side sound channels that mimic the effect of physical speakers positioned around the listener, eliminating the need for multiple physical speakers while maintaining surround sound experience
Solution Approach 2:
The patent replaces the mechanical system of multiple physical speakers with an electronic signal processing system. Instead of using multiple speakers distributed in space, the invention uses digital signal processing techniques including subtraction units, addition units, phase inverters, and HRTF filters to synthesize virtual surround sound from a two-channel stereo input
2Area of stationary object
If speakers are arranged in flat panel display, then compact design is achieved, but sound wave direction towards viewer is reduced
Solution Approach 1:
The patent introduces signal processing as an intermediary between the audio source and the speakers. By processing the audio signals through subtraction units, addition units, phase inverters, and HRTF filters before output to the speakers, the system creates virtual sound images that appear to come from directions other than the physical speaker locations, effectively directing sound waves towards the viewer even with front-mounted speakers
Data Source
AI summary
A virtual surround sound production circuit includes: a subtraction unit configured to perform subtraction operation on first and second signals to output a third signal; a first addition unit configured to perform addition operation on the first and second signals to output a center channel signal; a surround sound adjustment unit configured to adjust the third signal or another third signal that has undergone frequency compensation to output a fourth signal; a center compensation unit configured to adjust the center channel signal to output a fifth signal; a second addition unit configured to perform addition operation on the first, fourth and fifth signals to output a first output signal; a phase inverter unit configured to perform phase inversion on the fourth signal to generate a phase-inverted signal; and a third addition unit configured to perform addition operation on the second, fifth and phase-inverted signals to output a second output signal.