Distributed Speaker Amplifier Layout for Stable Beam Steering

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Solution Overview

Problem

Conventional loudspeaker systems face challenges in achieving accurate sound timbre, stable sound images, and flexible directional control over a wide listening area while minimizing visual impact, due to interactions with the listening environment and limitations in speaker design and placement.

Innovation Solution

A sound reproduction system featuring a column or array of drive units with integrated sound processing, allowing for improved steerability, directional control, and beam overlay, utilizing a configuration of two arrays with a narrow gap and additional high-frequency drivers, and employing signal processing techniques like Legendre shading to simulate curved arrays and adjust beam characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional stereo playback with two speakers is used, then the illusion of continuous sound stage can be created when listener is seated symmetrically, but the phantom image flops to nearest speaker when listener moves away from symmetry position, destroying stereo illusion

Engineering Contradiction:
Improvestereo illusion stabilityVSAvoidlistener position flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system segments the audio signal into multiple independent channels corresponding to each speaker in the array. By controlling each speaker independently with specific delay and level adjustments, the system creates multiple stable phantom images across different positions rather than relying on a single two-speaker stereo pair, thereby maintaining stereo illusion stability while accommodating listener position flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extends the traditional two-dimensional stereo field (left-right) into a three-dimensional speaker array configuration. By adding vertical dimension with multiple speakers at different heights and positions, the system creates a spatial audio field that maintains phantom image stability across multiple listening positions, resolving the contradiction between stereo illusion stability and listener position flexibility.

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

2Ease of operation

If horn-loaded speakers are used, then directional control and efficiency are improved, but distortion increases at high levels due to non-linearity of air at horn mouth

Engineering Contradiction:
Improvedirectional controlVSAvoiddistortion at high levels
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system divides the audio spectrum and directional control tasks across multiple horn-loaded speakers in an array configuration. Each speaker handles specific frequency ranges and directional sectors, allowing the system to maintain controlled directivity while distributing high-level output across multiple units, thereby reducing individual speaker distortion at high levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts operational parameters (delay, level, and assignment) of individual horn speakers based on signal level and frequency content. At high levels, the system redistributes the workload across more speakers in the array, preventing any single horn from operating in its non-linear distortion region while maintaining overall directional control through coordinated operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If low-frequency horn speakers are used, then directional control at low frequencies is achieved, but the horns become extremely large and are rarely used

Engineering Contradiction:
Improvedirectional control at low frequenciesVSAvoidhorn size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The system segments the low-frequency directional control task across multiple smaller horn speakers arranged in an array rather than using a single large horn. By distributing the radiating surface area across multiple compact units, the system achieves the necessary low-frequency directional control while keeping individual horn sizes manageable and suitable for practical applications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines multiple small-to-medium sized horn speakers into a unified array system that functions as a distributed low-frequency directional source. The collective radiating surface of multiple horns provides the necessary low-frequency control equivalent to a single large horn, while avoiding the excessive size and associated problems of individual large horns.

Inventive Principle:
Principle #5Merging (Combining)

4Quantity of substance

If conventional direct radiator speaker systems are used, then low-frequency reproduction is achieved, but directional control is limited

Engineering Contradiction:
Improvelow-frequency outputVSAvoiddirectional control
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The system segments the low-frequency output generation across multiple direct radiator speakers arranged in a controlled array. By coordinating the operation of multiple drivers with specific delay and level adjustments, the system maintains adequate low-frequency output while achieving directional control through the spatial distribution and phase-coordinated operation of the individual radiators.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional single-point or simple stereo low-frequency reproduction to a three-dimensional array of direct radiator speakers. This spatial distribution across multiple dimensions enables the system to maintain adequate low-frequency output while providing directional control through the geometric arrangement and phase-coordinated operation of the distributed radiators.

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

5Manufacturing precision

If speakers are carefully placed to reduce reflection problems, then sound quality is improved within limited area, but the listening area is restricted to a small sweet spot

Engineering Contradiction:
Improvesound qualityVSAvoidlistening area
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The system segments the sound reproduction task across multiple speakers positioned at different locations and heights. This distributed configuration creates multiple overlapping sound fields that maintain consistent phantom image stability and sound quality across a widened listening area, eliminating the restriction to a single narrow sweet spot while preserving acoustic precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extends the traditional two-speaker horizontal arrangement into a three-dimensional speaker array with vertical and depth dimensions. This multi-dimensional spatial distribution creates a volumetric sound field that maintains consistent acoustic characteristics across a much larger listening area, thereby expanding the effective sweet spot while preserving sound quality through coordinated operation of all speakers.

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

Data Source

PatentEP2389011B1Audio and power distribution system
Publication Date: 2017.09.27 THX LTD
  • EP2389011B1 patent drawingFigure 1
  • EP2389011B1 patent drawingFigure 2A~2B
  • EP2389011B1 patent drawingFigure 3A~3B

AI summary

An audio system (1000) comprises an audio control unit (1002) and a speaker unit (1020, 1030, 1040). The audio control unit receives an external power signal (1016) and an audio input signal (1012, 1013, 1014, 1015), and outputs a variable power supply signal (1025, 1035, 1045) and an audio speaker signal (1024, 1034, 1044) to the speaker unit via at least one low power cable. The speaker unit comprises a local output amplifier (1021, 1031, 1041) and at least one drive unit. The local output amplifier is powered by the variable power supply signal and amplifies the audio speaker signal for the drive unit.