Center-Height Loudspeaker Null Forming for Virtual Overhead Audio
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Solution Overview
Problem
Existing multichannel audio systems lack the ability to efficiently reproduce height channel sound without the need for dedicated elevation speakers, leading to setup complexities and audio flaws due to direct sound radiation.
Innovation Solution
A single enclosure loudspeaker system with a center/height speaker and signal processing that forms a null at the listener's position, allowing height channel signals to be played back through a three-speaker array, enhancing sound perception from above without additional elevation speakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated elevation speakers are used to reproduce height channel sound, then height channel reproduction quality is improved, but device complexity and setup complexity increase
Solution Approach 1:
The patent combines the center channel speaker and height channel speaker into a single integrated speaker unit. The center channel speaker and upward-firing height channel speaker are merged into one physical device, eliminating the need for separate dedicated elevation speakers while maintaining both center channel and height channel reproduction capabilities. This reduces setup complexity and the number of required components.
Solution Approach 2:
The integrated speaker unit serves multiple functions: it reproduces both center channel audio and height channel audio through different radiation patterns. The single speaker unit can direct sound forward for center channel content and upward for height channel content, making it a multi-functional device that replaces what would traditionally require separate specialized speakers.
2Reliability
If upward-firing speakers are used to create height channel sound, then height perception is improved, but direct sound radiation causes audio flaws
Solution Approach 1:
The patent employs active noise cancellation using anti-phase signals to counteract the direct sound radiation from the upward-firing speaker. A signal processor generates an inverted version of the height channel audio signal and plays it through the center channel speaker, creating destructive interference that cancels out the unwanted direct sound from the upward-firing speaker, thereby eliminating the audio flaws while preserving the height perception effect.
3Device complexity
If a three-speaker array is used to reproduce height channel signals, then height channel reproduction is achieved without dedicated elevation speakers, but setup complexity is reduced
Solution Approach 1:
The patent merges the center channel speaker and upward-firing height channel speaker into a single integrated unit, creating a three-speaker array system (left, right, and integrated center/height) that achieves height channel reproduction without requiring multiple separate dedicated elevation speakers. This simplification reduces setup complexity while maintaining the capability for immersive audio reproduction.
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 system provides enhanced height channel reproduction by canceling direct sound at the listener's position, creating a convincing apparent sound image from the ceiling while reducing setup complexity and cost.
Implementation Method 1
forms a null at the listener's position... canceling direct sound at the listener's position
Data Source
AI summary
A loudspeaker system includes a three-loudspeaker array and signal processing method for rendering and playing audio content in a listening environment. The three-loudspeaker array includes a left loudspeaker element, a center/height loudspeaker element, and a right loudspeaker element. A signal processor/renderer can be programmed or configured to process input audio content with a plurality of (e.g., at least five) playback channels (e.g., left, center, right, left elevation, and right elevation channels). The right loudspeaker can be driven by a right main signal and a right elevation-cancellation signal, and/or a combined signal thereof. The left loudspeaker can be driven by a left main signal and a left elevation-cancellation signal, and/or a combined signal thereof. The center/height loudspeaker can be driven by a combination of a center main signal and an elevation/height signal derived or rendered from the input audio signal.