Speaker Array Grid for Wave Field Synthesis Scale Reduction

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Solution Overview

Problem

Existing sound field reproduction techniques require a large number of speaker arrays, increasing the apparatus' scale and complexity.

Innovation Solution

A speaker array is arranged in a grid pattern with virtual lines, using multipoles of a given order to achieve wave field synthesis, with a signal processing apparatus calculating weighting coefficients and convolution calculations to optimize speaker output signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wave field synthesis or multipole sound source techniques are used to reproduce sound fields, then sound field reproduction accuracy is improved, but the number of speakers required increases, leading to larger apparatus scale

Engineering Contradiction:

Improvesound field reproduction accuracyVSAvoidnumber of speakers

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the sound field reproduction task into multiple frequency bands using filter banks. Each band is processed independently with optimized speaker configurations, allowing accurate sound field reproduction across the full frequency range while reducing the total number of speakers needed compared to treating all frequencies uniformly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to different frequency bands. Low-frequency components use different speaker configurations and weighting coefficients compared to high-frequency components. This local optimization allows accurate reproduction of each frequency range's characteristics while minimizing the overall speaker count.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If traditional wave field synthesis is used to cover the entire screening venue, then sound field coverage is improved, but the apparatus scale and complexity increase

Engineering Contradiction:

Improvesound field coverage areaVSAvoidapparatus scale

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent transforms the sound field reproduction problem from spatial domain to frequency domain by applying filter banks. This dimensional transformation allows the system to achieve broad spatial coverage through frequency-selective processing rather than requiring dense spatial speaker distribution, thereby reducing apparatus scale while maintaining coverage area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the processing parameters (weighting coefficients, filter characteristics) based on frequency bands and speaker positions. This parameter optimization enables efficient use of each speaker's contribution across different frequency ranges, achieving comprehensive venue coverage with fewer speakers and reduced system complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11871181B2Speaker array, signal processing device, signal processing method, and signal processing program

Publication Date: 2024.01.09 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

The scale of an apparatus that reproduces a sound field is reduced. A speaker array 1 includes a plurality of speakers arranged at intersections of a first plurality of virtual lines arranged parallel to each other at equal intervals and a second plurality of virtual lines that are perpendicular to the first plurality of virtual lines and are arranged parallel to each other at equal intervals, wherein multipoles of a given order are superimposed using the plurality of speakers to realize wave field synthesis.