Beamforming Loudspeaker Array Spatial Audio Rendering

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Solution Overview

Problem

Current audio systems fail to effectively reproduce stereophonic recordings with both clarity and immersion in confined spaces, as they struggle to accurately recreate the spatial distribution of sound sources and adapt to varying room acoustics and listener positions.

Innovation Solution

A loudspeaker array system with integrated drivers and amplifiers, a rendering processor, and decision logic that selects sound rendering modes based on room features and listener location, using beamforming techniques to produce omnidirectional and directional sound beams, allowing for dynamic switching between mid-side and ambient-direct modes to enhance spatial audio reproduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional loudspeaker systems are used to reproduce stereophonic recordings, then the system structure is simple, but the spatial distribution of sound sources cannot be accurately recreated and immersion is lost

Engineering Contradiction:
Improvespatial distribution accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The loudspeaker system is segmented into multiple independent drivers arranged in a specific geometric configuration, with each driver capable of independent signal processing. This segmentation enables precise control over sound radiation patterns and spatial distribution, allowing accurate recreation of sound source positions while maintaining manageable system complexity through modular driver units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs dynamic signal processing where the rendering processor continuously adjusts the audio signals sent to each driver based on real-time parameters such as listener position, room acoustics, and desired sound field characteristics. This dynamic adaptation enables the system to maintain accurate spatial distribution across varying listening conditions without requiring a completely complex reconfiguration of the hardware.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If fixed rendering modes are used in loudspeaker systems, then the system is easy to operate, but adaptability to varying room acoustics and listener positions is poor

Engineering Contradiction:
Improveadaptability to room acousticsVSAvoidoperation complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The rendering processor automatically analyzes room acoustics characteristics and listener position information, then independently selects and adjusts the appropriate sound rendering mode without requiring manual user intervention. The system self-adjusts parameters such as beamforming patterns, delay times, and signal levels to optimize performance for the current acoustic environment, maintaining ease of operation while achieving high adaptability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements multiple sound rendering modes that can be dynamically selected based on changing parameters such as room size, acoustic properties, and listener position. By pre-configuring different rendering modes with optimized parameter sets and allowing automatic switching between them, the system achieves versatile adaptability to various acoustic conditions while keeping the user interface simple and intuitive.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If beamforming techniques are used to produce directional sound beams, then spatial selectivity is improved, but the system complexity increases due to multiple drivers and signal processing

Engineering Contradiction:
Improvespatial selectivityVSAvoidsignal processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges the functions of multiple drivers into a unified beamforming array that operates as a single coherent sound source. By combining the output of multiple drivers with precisely controlled phase and amplitude relationships, the system achieves high spatial selectivity and directional control. The signal processing complexity is managed by integrating the beamforming algorithms into the rendering processor, which coordinates all drivers simultaneously to produce the desired spatial patterns.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If multiple loudspeakers are used to create spatial sound fields, then immersion is improved, but the system becomes less adaptable to confined spaces

Engineering Contradiction:
Improveadaptability to confined spacesVSAvoidsystem size
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The system transitions from traditional horizontal speaker arrangements to a three-dimensional configuration with drivers positioned in multiple spatial dimensions. This vertical and spatial dimensionality allows the system to create immersive sound fields that effectively utilize the available space in confined environments. By radiating sound in multiple directions simultaneously through vertically arranged drivers, the system achieves immersion without requiring large horizontal distances between speakers.

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

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 achieves clear and immersive audio reproduction by dynamically adjusting sound beams to match the acoustic environment and content characteristics, providing improved spatial awareness and adaptability with a single loudspeaker cabinet, even in small rooms.

Implementation Method 1

the loudspeaker drivers (collectively being operated as a beamforming array) produce sound beams having a principally omnidirectional beam (or beam pattern) superimposed with a directional beam (or beam pattern)

Methodology Applied
Scientific EffectBeamforming:

Implementation Method 2

A loudspeaker array system with integrated drivers and amplifiers... using beamforming techniques to produce omnidirectional and directional sound beams

Methodology Applied
Scientific EffectSound wave propagation: Sound

Data Source

PatentEP3301947B1Spatial audio rendering for beamforming loudspeaker array
Publication Date: 2020.05.13 APPLE INC
  • EP3301947B1 patent drawingFigure 1~2B
  • EP3301947B1 patent drawingFigure 3A~3C
  • EP3301947B1 patent drawingFigure 4~5

AI summary

A process for reproducing sound using a loudspeaker array that is housed in a loudspeaker cabinet includes the selection of a number of sound rendering modes and changing the selected sound rendering mode based on changes in one or both of sensor data and a user interface selection. The sound rendering modes include a number of mid-side modes and at least one direct-ambient mode. Other embodiments are also described and claimed.