Audio Playback Device Using HRTF Beam Forming for 3D Sound Localization

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Solution Overview

Problem

Conventional methods struggle to recreate highly realistic three-dimensional audio experiences in home or personal settings where speakers cannot be freely arranged, as they fail to accurately simulate distance and positioning of sound sources, especially behind the listener.

Innovation Solution

An audio playback device that converts three-dimensional playback position information into corrected two-dimensional coordinates, using signal processing units like beam forming and HRTF to localize sound images on a two-dimensional plane, allowing for realistic sound reproduction even with restricted speaker arrangements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If speakers are arranged three-dimensionally to achieve realistic audio playback, then sound image localization accuracy is improved, but device complexity and installation difficulty increase

Engineering Contradiction:

Improvesound image localization accuracyVSAvoidspeaker arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses virtual surround technology to create a copied acoustic environment through signal processing. Instead of physically arranging speakers in three-dimensional space, the system processes audio signals to simulate the effect of three-dimensional speaker arrangements, creating virtual sound images that appear to come from various directions including behind the listener.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical system of physical three-dimensional speaker arrangements with signal processing methods. By using beam forming and HRTF-based processing, the system achieves sound image localization without requiring complex physical speaker configurations, substituting acoustic field manipulation through electronic processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If conventional signal processing methods are used with limited speaker arrangements, then device complexity is reduced, but sound image localization accuracy deteriorates

Engineering Contradiction:

Improvespeaker arrangement simplicityVSAvoidsound image localization accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the parameters of audio signal processing by introducing HRTF (Head-Related Transfer Function) based beam forming. This involves modifying how audio signals are processed across different frequency ranges and time delays, using multiple speaker arrays with different orientations to achieve accurate sound image localization even with limited physical speaker arrangements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent divides the audio processing into multiple segments handled by different speaker arrays. The system separates audio signals into different spatial components and processes them through multiple speaker arrays with different orientations (horizontal, vertical, angled), then combines the outputs to achieve comprehensive three-dimensional sound image localization.

Inventive Principle:

Principle #1Segmentation

3Reliability

If three-dimensional speaker arrangements are implemented, then audio realism is improved, but ease of operation and installation worsen

Engineering Contradiction:

Improveaudio realismVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent creates a virtual copy of three-dimensional acoustic space through signal processing rather than physical speaker arrangement. The system processes audio signals to simulate how sound would propagate in a three-dimensional speaker configuration, allowing users to achieve realistic audio playback without the complexity of installing speakers on ceilings or in three-dimensional patterns.

Inventive Principle:

Principle #26Copying

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

Enables highly realistic audio playback with accurate sound source positioning and distance simulation, including behind the listener, using beam forming and HRTF, within limited speaker configurations.

Implementation Method 1

at least one speaker array which converts an acoustic signal to acoustic vibration

Methodology Applied

Scientific EffectAcoustic signal conversion: Sound

Implementation Method 2

using signal processing units like beam forming and HRTF to localize sound images on a two-dimensional plane

Methodology Applied

Scientific EffectBeam forming:

Implementation Method 3

using signal processing units like beam forming and HRTF to localize sound images on a two-dimensional plane

Methodology Applied

Scientific EffectHRTF (Head-Related Transfer Function):

Data Source

PatentUS9788120B2Audio playback device and audio playback method

Publication Date: 2017.10.10 SOCIONEXT INC

AI summary

An audio playback device which plays back an audio object including an audio signal and playback position information indicating a position in a three-dimensional space at which a sound image of the audio signal is localized, includes: at least one speaker array; a converting unit which converts playback position information to corrected playback position information which is information indicating a position of the sound image on a two-dimensional coordinate system based on a position of the at least one speaker array; and a signal processing unit which localizes the sound image of the audio signal included in the audio object according to the corrected playback position information.