Array Speaker Sound Localization via Virtual Source Synthesis
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Solution Overview
Problem
Conventional array speaker systems face limitations in installation flexibility, often resulting in suboptimal surround sound generation due to specific room configurations and the requirement for ideal wall reflections, leading to reduced audibility and separation of sound sources.
Innovation Solution
An array speaker apparatus with a sound source localization unit that applies head transfer functions to generate audio signals for virtual sound sources, and a sound emitting direction control unit that adjusts timing and distribution to create sound wavefronts mimicking virtual point sources, allowing for enhanced localization and surround sound experience regardless of room layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sound beams are generated using wall reflections to create virtual sound sources, then surround sound field can be produced, but the system requires ideal room conditions and specific installation positions which limits installation flexibility
Solution Approach 1:
The patent changes the fundamental parameter of sound generation from relying on environmental wall reflections to directly synthesizing virtual sound sources through signal processing. By using head transfer functions and delay processing on the speaker units, the system creates virtual sound sources that are independent of room acoustics, thereby maintaining surround sound reliability while achieving installation flexibility in any location.
2Ease of operation
If a single array speaker body is used to reduce installation complexity, then ease of installation is improved, but sufficient sound separation and localization are difficult to achieve in non-ideal environments
Solution Approach 1:
The patent segments the sound generation function into multiple independent speaker units within the array, each capable of being controlled individually. By assigning different audio signals and delay times to different speaker units, the system can synthesize multiple virtual sound sources with precise spatial localization, achieving high sound separation precision while maintaining the simplicity of a single integrated speaker body for installation.
3Adaptability or versatility
If the listener position is placed close to the speaker units, then installation flexibility is improved, but interference between speaker units becomes remarkable and frequency characteristics vary
Solution Approach 1:
The patent applies preliminary signal processing to compensate for potential interference effects. By pre-calculating and applying appropriate delay times to each speaker unit based on their positions relative to the listener, the system ensures that sound waves arrive at the listener's ears in a controlled sequence that mimics natural sound propagation. This preliminary timing adjustment prevents constructive and destructive interference patterns, maintaining stable frequency characteristics even when the listener is positioned close to the speaker array.
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
This configuration enables listeners to perceive a consistent and immersive surround sound field by simulating ideal virtual sound sources, even in non-ideal installation environments, improving audibility and separation of sound sources.
Implementation Method 1
the same acoustic signal is input, with delays that are a little different from each other, to plural speaker units SPa-SPe that are arranged in line or in a plane so as to produce a sound field as would be produced when speaker units SPa'-SPe' emit sounds simultaneously. Resulting sounds simultaneously reach a single point F (focal point) in the space and the acoustic energy around the focal point F is intensified through in-phase addition.
Implementation Method 2
an array speaker apparatus 1 produces, around a listener H, a surround sound field corresponding to a moving picture being displayed on a monitor 3 by generating virtual sound sources by emitting plural (i.e., multichannel) sound beams simultaneously and causing them to be reflected by walls.
Data Source
AI summary
An array speaker apparatus includes an array speaker in which plural speaker units are arranged in a single body, a sound source localization adding unit which generates left and right audio signals by performing localization processing for adding sound characteristics to audio signals of a front-left channel and a front-right channel on the basis of head transfer functions, and a sound emitting direction control unit which distributes the left and right audio signals to one or plural speaker units of the array speaker, and controls timing with which the speaker units output the audio signals so that a left sound emitted from the array speaker forms the same sound wavefront formed by a sound emitted from one of virtual point sound sources and that a right sound emitted from the array speaker forms the same sound wavefront formed by a sound emitted from the other of the virtual point sound sources.