Multi-listener Stereo Array Asymmetric Positioning

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Solution Overview

Problem

Conventional stereo sound systems fail to provide an ideal stereo image experience for listeners who are not positioned symmetrically relative to the speaker array, leading to uneven sound distribution and interference, which results in a less than ideal audio experience for multiple listeners.

Innovation Solution

A multi-listener stereo image array is configured with adjustable drivers and filter banks that control sound signal output to create separate audio signal patterns for each listener, maximizing sound intensity towards one listener while minimizing it towards others, using techniques like beamforming to restrict signal propagation and optimize directivity indices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If drivers are positioned symmetrically for a single listener, then stereo image quality is optimized for that listener, but multiple listeners positioned asymmetrically experience uneven sound distribution and interference

Engineering Contradiction:

Improvestereo image qualityVSAvoidmulti-listener compatibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent segments the audio signal into multiple independent stereo images, each tailored for a specific listener position. The driver array is divided into multiple groups, with each group responsible for directing audio signals to a particular listener zone, enabling simultaneous optimized stereo experience for multiple asymmetrically positioned listeners

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts driver activation and signal routing based on detected listener positions. The controller continuously monitors listener locations and reconfigures which drivers are active and how signals are distributed, transforming the static speaker array into an adaptive system that optimizes stereo imaging for each listener in real-time

Inventive Principle:

Principle #15Dynamics

2Reliability

If sound signals are directed towards one listener, then that listener receives optimal audio experience, but other listeners experience interference and reduced sound quality

Engineering Contradiction:

Improveaudio experience consistencyVSAvoidsound interference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct audio signal patterns for different spatial zones. Each listener position receives a customized audio signal tailored to their specific location, while other zones receive different or no signals, ensuring that sound optimization for one listener does not create interference for others

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The controller acts as an intermediary that processes audio signals and directs them through specific driver combinations to reach target listeners. It mediates between the audio source and multiple listeners by implementing beamforming algorithms that shape sound propagation paths, preventing direct interference between signals intended for different listeners

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If drivers are configured for symmetrical positioning, then stereo separation is maximized, but asymmetrically positioned listeners experience degraded sound distribution

Engineering Contradiction:

Improvestereo channel separationVSAvoidlistener positioning flexibility

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent embraces asymmetry by configuring driver groups and signal patterns specifically for asymmetric listener positions. Rather than requiring listeners to position themselves symmetrically, the system actively compensates for asymmetric positioning through customized signal routing and driver activation patterns that maintain stereo separation for each listener's unique position

Inventive Principle:

Principle #4Asymmetry

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 solution ensures each listener receives a clear, symmetrical stereo image with minimal interference, maintaining the spatial distribution of sound sources and providing a consistent audio experience even when listeners are positioned asymmetrically relative to the array.

Implementation Method 1

using techniques like beamforming to restrict signal propagation and optimize directivity indices

Methodology Applied

Scientific EffectBeamforming:

Implementation Method 2

a separate audio signal pattern... which is shaped to propagate towards a particular position associated with the respective listener

Methodology Applied

Scientific EffectAcoustic propagation: Sound

Data Source

PatentUS10264383B1Multi-listener stereo image array

Publication Date: 2019.04.16 APPLE INC

AI summary

Some embodiments provide a multi-listener stereo image array which provides multiple separate stereo images of audio content to each of multiple listeners while mitigating interference of audio signals which provide separate stereo images to separate listeners. The array can include sensors which can monitor the environment and can identify relative positions of various listeners and can further control the audio signal patterns generated by the drivers of the array to propagate towards positions associated with particular listeners and be at least partially restricted from propagating towards positions associated with other listeners.