Audio Phase Rotation for Howling Suppression

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Solution Overview

Problem

Existing audio systems struggle to effectively suppress howling without identifying the howling frequency, which requires complex configurations and processing, and often cause variations in audibly perceptible characteristics like pitch.

Innovation Solution

A computer-implemented sound processing method that generates a second audio signal by rotating the phase of the first audio signal in one direction over time, using a sound processing system with a processor and memory to acquire and process audio signals, effectively suppressing howling without frequency identification and maintaining sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If audio signal analysis is performed to identify howling frequency, then howling suppression is achieved, but device complexity and processing complexity increase

Engineering Contradiction:

Improvehowling suppression effectivenessVSAvoidconfiguration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts only the necessary phase information from the audio signal and processes only this extracted component to suppress howling, rather than analyzing the entire audio signal spectrum. This allows howling suppression without full frequency identification, reducing system complexity while maintaining effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of identifying howling frequency through complex spectral analysis and then suppressing it, the invention inverts the approach by directly manipulating phase relationships in the time domain to prevent howling feedback, eliminating the need for frequency identification while achieving suppression

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If audio signal analysis is performed to identify howling frequency, then howling suppression is achieved, but processing complexity increases

Engineering Contradiction:

Improvehowling suppression effectivenessVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical/spectral analysis processing with simpler phase rotation operations in the time domain. By substituting frequency-domain analysis with time-domain phase manipulation, processing complexity is reduced while maintaining howling suppression capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the processing parameter from frequency spectrum analysis to phase angle rotation. By operating on phase parameters directly in the time domain rather than analyzing frequency components, the processing becomes simpler while achieving the same howling suppression goal

Inventive Principle:

Principle #35Parameter changes

3Reliability

If phase rotation is applied to suppress howling, then howling is suppressed without frequency identification, but audibly perceptible characteristics may vary

Engineering Contradiction:

Improvehowling suppression effectivenessVSAvoidaudible characteristic variation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention applies partial phase rotation only to the extent necessary to break the howling feedback loop, rather than rotating phase excessively. By using minimal effective phase rotation, howling is suppressed while preserving the original audio characteristics and minimizing audible variations

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The invention uses periodic phase rotation that varies over time in a controlled manner. This periodic action allows the system to maintain audio fidelity while periodically disrupting the howling feedback path, achieving suppression without permanent distortion of audible characteristics

Inventive Principle:

Principle #19Periodic action

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 method suppresses howling without altering the frequency of the audio signal, thereby maintaining the audibly perceptible characteristics of the playback sound, and can be implemented with a simple configuration and uncomplicated processing.

Implementation Method 1

generating a second audio signal by rotating a phase of the first audio signal in one direction over time in conjunction with receipt of the sound

Methodology Applied

Scientific EffectPhase rotation: Phase Modulation

Data Source

PatentUS20240147152A1Sound Processing Method, Sound Processing System, and Recording Medium

Publication Date: 2024.05.02 YAMAHA CORP

AI summary

A computer-implemented sound processing method includes: acquiring a first audio signal representative of sound received by a sound receiving device; and generating a second audio signal by rotating a phase of the first audio signal in one direction over time in conjunction with receipt of the sound.