Front Audio System Virtual Surround Sound via Signal Processing

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Solution Overview

Problem

Conventional audio systems that attempt to provide surround sound effects using front-located loudspeakers face challenges in recreating the rear sound channels, often resulting in incomplete surround sound experiences due to the lack of rear acoustic signals and the complexity or cost of using Digital Signal Processors.

Innovation Solution

A method and audio system that process multi-channel audio signals by adjusting phase and amplitude, filtering high-frequency components, and introducing time delays to simulate rear sound channels, allowing for effective surround sound production using front-located loudspeakers without the need for complex Digital Signal Processors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If loudspeakers are positioned at all corners of the listening area to correspond with designated audio channel positions, then surround sound quality is improved, but ease of installation and wiring complexity deteriorate

Engineering Contradiction:
Improvesurround sound qualityVSAvoidease of installation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent merges the functions of multiple loudspeakers (front left, front right, rear left, rear right) into a single front-located unit containing four loudspeakers. This consolidation maintains surround sound quality by providing all necessary audio channels while eliminating the need for complex wiring to multiple locations, thus resolving the contradiction between sound quality and installation ease.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The front-located audio system performs multiple functions: it provides front left, front right, rear left, and rear right audio channels simultaneously. This multi-functionality allows a single device to replace what would traditionally require four separate loudspeakers positioned at different locations, maintaining surround sound quality while simplifying installation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If only front located speakers are used to simplify installation, then ease of installation is improved, but surround sound quality deteriorates due to lack of rear acoustic signals

Engineering Contradiction:
Improveease of installationVSAvoidsurround sound quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses signal processing to create virtual rear sound channels from front-located loudspeakers. By applying time delays, phase shifts, and amplitude adjustments to audio signals, the system creates the perception of sound coming from rear directions even though the physical loudspeakers are located at the front, thus maintaining surround sound quality while preserving installation simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces signal processing circuits as intermediaries between the audio source and the front-located loudspeakers. These circuits process the audio signals to simulate rear sound channels, acting as a mediator that enables surround sound effects without requiring physical rear-located loudspeakers.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If Digital Signal Processors are used to produce virtualised rear surround sound effects, then surround sound quality is improved, but cost and device complexity increase

Engineering Contradiction:
Improvesurround sound qualityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the audio signal processing into distinct functional blocks: time delay circuits for rear left and rear right channels, phase shift circuits, amplitude adjustment circuits, and filtering circuits. This segmentation achieves surround sound quality through virtualization while using simpler, more manageable circuit components rather than a complex Digital Signal Processor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the electronic/Digital Signal Processor system with an analog circuit implementation using operational amplifiers, capacitors, resistors, and other passive components. This substitution achieves the same virtual surround sound effect using analog signal processing, reducing device complexity and potentially cost while maintaining sound quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2497276B1Method and audio system for processing multi-channel audio signals for surround sound production
Publication Date: 2017.11.22 CREATIVE TECHNOLOGY LTD
  • EP2497276B1 patent drawingFigure 1~1B
  • EP2497276B1 patent drawingFigure 2~3
  • EP2497276B1 patent drawingFigure 4~5

AI summary

A method and audio system for processing multi-channel audio signals for surround sound production on a plurality of loudspeakers to a listening area. The plurality of loudspeakers is front located with respect to the listening area. The plurality of loudspeakers comprises an outer left loudspeaker, an inner left loudspeaker, an inner right loudspeaker and an outer right loudspeaker. The multi-channel audio signals comprise one or more low frequency effects audio signals and one or more audio signals categorised as front based left inclined, front based right inclined, rear based left inclined, rear based right inclined, and centre based. The method comprising filtering and adjusting phase and amplitude of one or more audio signals that are front based left inclined, front based right inclined, rear based left inclined and rear based right inclined in a specific manner, and transmitting the one or more processed audio signals in a specific manner to the outer left loudspeaker, the outer right loudspeaker, the inner left loudspeaker and the inner right loudspeaker.