Dynamic Sound Field Direction via Phase Adjustment

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Solution Overview

Problem

Conventional mobile devices with two loudspeakers are unable to dynamically control the direction of the sound field, limiting the auditory experience by maintaining a fixed sound field orientation, which is not adaptable to specific application scenarios such as directing sound towards a person.

Innovation Solution

A method and device that utilize at least two loudspeakers in a mobile terminal, where direction information is set and filtering parameters are determined to adjust the phases of audio signals, allowing the superimposed sound to be consistent with a specific direction, achieved through image processing to detect the facial direction of a target object and using filters to regulate frequencies, amplitudes, and phases of the audio signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional mobile devices use two loudspeakers with fixed sound field orientation, then the device structure remains simple, but the adaptability to different application scenarios is limited

Engineering Contradiction:

Improveadaptability to application scenariosVSAvoidsound field control complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic sound field control by adjusting the phase of audio signals output by different loudspeakers based on detected facial direction. The filtering parameters are dynamically modified to change the phase characteristics, enabling the sound field direction to adapt to different application scenarios while maintaining a manageable device structure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the phase parameter of audio signals by applying filtering operations with dynamically determined filtering parameters. By modifying the phase parameter according to facial direction detection results, the system achieves adaptable sound field orientation without significantly increasing device complexity

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If audio signals are filtered to adjust phases for directional sound field control, then the sound field direction accuracy is improved, but the processing complexity increases

Engineering Contradiction:

Improvesound field direction accuracyVSAvoidsignal processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or hardware-based directional control systems with signal processing operations. By using digital filtering to adjust phase characteristics of audio signals, the system achieves accurate sound field direction control through software-based phase manipulation rather than complex physical mechanisms

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple loudspeakers are used to create directional sound fields, then the auditory experience is enhanced, but the device structure becomes more complex

Engineering Contradiction:

Improveauditory experience qualityVSAvoidloudspeaker system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the existing two-loudspeaker system multi-functional by enabling it to produce directional sound fields through phase adjustment. The same loudspeakers that provide basic audio output are also used to create directional sound fields by modifying the phase of signals sent to each loudspeaker, eliminating the need for additional specialized components

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 the sound field to be accurately directed towards a specific target, enhancing the auditory experience by ensuring sound propagation in the intended direction while minimizing sound in other directions, thereby improving user interaction with mobile devices.

Implementation Method 1

Through an electromagnetic effect, a piezoelectric effect or an electrostatic effect, audio electric energy can cause the paper cone or a diaphragm to vibrate and resonate with surrounding air to produce a sound.

Methodology Applied

Scientific EffectElectromagnetic effect: Electromagnetic Induction

Implementation Method 2

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

Methodology Applied

Scientific EffectElectrostatic effect: Electrostatics

Implementation Method 4

The audio signals are output by the at least two loudspeakers. After the audio signals output by the different loudspeakers are superimposed, the superimposed signal is consistent with a direction indicated by the direction information.

Methodology Applied

Scientific EffectSound wave superposition: Interference

Data Source

PatentUS11172321B2Method and device for controlling sound field, and storage medium

Publication Date: 2021.11.09 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

AI summary

A method, applied to a mobile terminal having at least two loudspeakers, includes: setting direction information of a target sound field; and determining filtering parameters of at least two filters according to the direction information. The filters have a one-to-one correspondence with the loudspeakers, and are configured to filter audio signals to be output. The audio signals are filtered using the filtering parameters, to at least adjust phases of the audio signals. The adjusted audio signals are output by the loudspeakers. After the audio signals output by the different loudspeakers are superimposed, the superimposed signal is consistent with a direction indicated by the direction information.