Audio Signal Processing Stabilizing Virtual Surround Localization
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Solution Overview
Problem
In virtual surround systems, the localization of sounds from virtual speakers is unstable due to the influence of subwoofers, which emit low-frequency bands that can pull the perceived sound localization towards their position, especially when main speakers are miniaturized, leading to inconveniences in space usage and aesthetics.
Innovation Solution
An audio signal processing device that generates virtual process audio signals with opposite phases for main speakers and subwoofers, using phase inversion or delay techniques to ensure that the localization of virtual sounds is not affected by the subwoofer's emission, thereby stabilizing the perceived sound localization at the intended virtual speaker positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If main speakers are miniaturized to reduce space usage and improve aesthetics, then space efficiency and appearance are improved, but the ability to emit low-frequency bands is degraded
Solution Approach 1:
The audio signal is divided into high-frequency components (for main speakers) and low-frequency components (for subwoofer), allowing each component to be handled by appropriately sized speakers. This segmentation enables miniaturization of main speakers while maintaining low-frequency emission capability through a separate subwoofer.
Solution Approach 2:
A subwoofer is introduced as an intermediary device to handle the low-frequency band that miniaturized main speakers cannot emit. The subwoofer receives low-frequency audio signals and emits them independently, compensating for the limitation of small main speakers.
2Power
If subwoofer is added to emit low-frequency bands, then low-frequency emission capability is improved, but device complexity and space requirements increase
Solution Approach 1:
The subwoofer is designed to handle only the low-frequency band (100 Hz to 500 Hz) that main speakers cannot emit, while main speakers handle high-frequency bands. This division of labor allows each component to be optimized for its specific function, reducing overall system complexity despite adding a subwoofer.
3Quantity of substance
If subwoofer emits low-frequency bands in virtual surround system, then sound completeness is improved, but localization stability of virtual speakers is degraded
Solution Approach 1:
Different frequency bands are assigned to different speakers based on their capabilities and the virtual surround system requirements. Main speakers emit high-frequency bands for virtual surround localization, while subwoofer emits low-frequency bands. This local quality assignment ensures that localization stability is maintained for high frequencies while low frequencies provide completeness without interfering with virtual speaker positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the influence of subwoofer emissions on virtual sound localization, improving the stability and accuracy of sound perception, allowing for more flexible subwoofer placement without affecting the perceived sound field.
Implementation Method 1
generates virtual process audio signals with opposite phases for main speakers and subwoofers, using phase inversion or delay techniques
Implementation Method 2
using phase inversion or delay techniques to ensure that the localization of virtual sounds is not affected by the subwoofer's emission
Data Source
AI summary
A postprocessor mixes audio signals for an LSch and an RSch indicating virtual surround sounds generated by a virtual surround processing unit with audio signals of an Rch, an Lch, and a Cch, performs a high-pass filter process, and then outputs the processed audio signals as audio signals for an Rsp and an Lsp which are main speakers. Further, the postprocessor performs phase inversion on the audio signals for the LSch and the RSch indicating the virtual surround sounds generated by the virtual surround processing unit, mixes the processed audio signals with audio signals of the Rch, the Lch, the Cch, and an LFEch, performs a low-pass filter process on the mixed signals, and then outputs the processed audio signals as audio signals for an SW which is a subwoofer. Thus, in a sound field realized by a virtual surround system, an influence of the sounds emitted from the subwoofer on localization of sounds of channels of virtual speakers is reduced.