Out-of-Head Audio Filter Gain Timing for Stable Sound Localization

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Solution Overview

Problem

In out-of-head localization devices, filter processing that emphasizes certain frequencies can degrade sound quality and filter characteristics, leading to a strange feeling for users, and existing sound volume correction methods impose a heavy processing load and do not completely eliminate volume changes during reproduction.

Innovation Solution

A processing device and method that set an appropriate gain value by acquiring frequency and time information from the reproduction signal, using spatial acoustic transfer characteristics and inverse filters to convolve audio signals, allowing for precise sound localization without degrading sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If filter processing that emphasizes certain frequencies is performed in out-of-head localization device, then sound localization accuracy is improved, but sound quality and filter characteristics are degraded

Engineering Contradiction:
Improvesound localization accuracyVSAvoidsound quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameter of gain application timing from continuous monitoring to pre-calculated timing based on frequency and time information. By determining the gain value in advance based on the reproduction signal's characteristics, the system achieves accurate sound localization without degrading sound quality, as the gain is applied only when necessary rather than continuously.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If sound volume correction device monitors signal level at all times, then volume stability is improved, but processing load is increased

Engineering Contradiction:
Improvevolume stabilityVSAvoidprocessing efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent implements periodic action by calculating the gain value in advance based on frequency and time information extracted from the reproduction signal, rather than continuously monitoring the signal level. The gain is applied at specific time points determined by the pre-calculated information, reducing processing load while maintaining volume stability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies preliminary action by determining the gain value before actual sound reproduction based on the frequency and time information of the reproduction signal. This advance calculation eliminates the need for continuous monitoring during reproduction, significantly reducing processing load while ensuring stable volume control.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If gain value is adjusted during reproduction, then volume stability is improved, but feeling of strangeness is not completely eliminated

Engineering Contradiction:
Improvevolume stabilityVSAvoidfeeling of strangeness
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the parameter of gain determination from real-time signal level monitoring to pre-calculated gain based on frequency and time information. By determining the gain value in advance based on the reproduction signal's characteristics, the system achieves volume stability without causing the feeling of strangeness, as the gain adjustments are based on inherent signal properties rather than continuous modifications.

Inventive Principle:
Principle #35Parameter changes

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 approach enables accurate sound localization with improved sound quality by setting an appropriate gain value, reducing the feeling of strangeness during reproduction and eliminating the need for continuous signal monitoring, thus optimizing processing efficiency.

Implementation Method 1

a processing device generates a filter on the basis of a sound pickup signal obtained by collecting measurement signals. The generated filter is convolved to 2-ch audio signals, thereby implementing out-of-head localization reproduction.

Methodology Applied
Scientific EffectConvolution:

Data Source

PatentEP3855765B1Processing device, processing method, reproduction method, and program
Publication Date: 2024.02.28 JVC KENWOOD CORP
  • EP3855765B1 patent drawingFigure 1
  • EP3855765B1 patent drawingFigure 2
  • EP3855765B1 patent drawingFigure 3

AI summary

Provided are an out-of-head localization system, a filter generation device, a method, and a program capable of appropriate processing. A processing device (200) according to an embodiment includes a frequency information acquisition unit (213) that acquires frequency information on the basis of a frequency response of a filter used in filter processing on a reproduction signal, a time information acquisition unit (216) that acquires, on the basis of the frequency information, time information of a reproduction signal, a time signal extraction unit (217) that extracts, on the basis of the time information, a time signal corresponding to at least some time of the reproduction signal, a filter processing unit (218) that performs filter processing on the time signal, and a gain acquisition unit (219) that acquires a gain on the basis of the time signal not having undergone filter processing and a processed time signal having undergone filter processing.