Arc-Configured Speaker Units Suppress Phase Interference

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Solution Overview

Problem

Phase interference among multiple speaker units in line-array speakers causes peak/dip in sound pressure/frequency characteristics, deteriorating sound quality, especially in high frequency ranges, and is difficult to correct due to variations in listening position.

Innovation Solution

Arranging speaker units in an arc configuration with a predetermined interval and using delay means or overlapping adhesion margins to minimize phase interference, ensuring the differential distance between effective vibration regions is less than half the wavelength of the highest frequency, and adjusting the curvature radius and arrangement length to optimize sound pressure/frequency characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If speaker units are arranged in a straight line to form a line source, then the listening area is increased and sound field is uniform in the arrangement direction, but phase interference causes peak/dip in sound pressure characteristics deteriorating sound quality in high frequency range

Engineering Contradiction:
Improvelistening areaVSAvoidsound pressure frequency characteristics
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The speaker units are arranged in an arc shape rather than a straight line, with the curvature radius and arc angle specifically designed to control the differential distance between adjacent speakers. This curved arrangement maintains the line source effect for expanded listening area while reducing phase interference by ensuring the differential distance remains less than half the wavelength of the highest frequency, thus resolving the contradiction between listening area expansion and sound quality maintenance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If speaker units are arranged with larger intervals to reduce device size, then the device complexity is reduced, but phase interference becomes more significant causing sharper peak/dip changes

Engineering Contradiction:
Improvedevice sizeVSAvoidsound pressure frequency characteristics
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent optimizes the interval between speaker units by establishing a specific relationship: the differential distance between adjacent speakers must be less than half the wavelength of the highest frequency. This parameter optimization allows for larger intervals that reduce device size while maintaining sound quality, as the arc-shaped arrangement with controlled differential distance prevents excessive phase interference even with increased spacing.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If speaker units are arranged closely to minimize phase interference, then sound pressure frequency characteristics are improved, but the device size and complexity increase

Engineering Contradiction:
Improvesound pressure frequency characteristicsVSAvoiddevice size
Core Design Contradiction:
Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The arc-shaped arrangement with optimized curvature radius allows speaker units to be positioned at intervals that would cause phase interference in a straight-line configuration. The curvature ensures that the differential distance between adjacent speakers remains less than half the wavelength of the highest frequency, maintaining sound quality while reducing the overall device length compared to a straight-line arrangement with the same number of speakers.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 suppresses sound quality deterioration due to phase interference, maintaining consistent sound pressure across the frequency range and providing a wider sound field range while reducing the size of the speaker device.

Implementation Method 1

a speaker device (5) having a plurality of speaker units (52), arranged in a line when seen from the front side of the speaker device (5)

Methodology Applied
Scientific EffectElectroacoustic transduction:

Implementation Method 2

a phase interference among the plurality of speaker units (92) causes a peak/dip in the sound pressure / frequency characteristics of a reproduced sound

Methodology Applied
Scientific EffectAcoustic wave interference: Interference

Data Source

PatentEP2157814B1Speaker device
Publication Date: 2013.07.31 PANASONIC HOLDINGS CORP
  • EP2157814B1 patent drawingFigure 1(a)~1(b)
  • EP2157814B1 patent drawingFigure 2
  • EP2157814B1 patent drawingFigure 3

AI summary

A speaker device according to the present invention is a speaker device including a plurality of speaker units arranged in a line when seen from the front side of the speaker device. At least one of intervals between effective vibration regions of adjacent speaker units is set to a predetermined length. The predetermined length is a length that is set such that a difference between a distance from an end of one of the effective vibration regions, which form the at least one of intervals therebetween, to a listening position, and a distance from an end of the other of the effective vibration regions to the listening position can be less than half the shortest wavelength of a reproduced sound of each of the speaker units.