ANC Audio Playback Using Low-Frequency Noise Canceling Signals

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Solution Overview

Problem

Conventional active noise cancellation (ANC) earphones experience an increased noise floor when the ANC function is turned on and no audio is played, due to the replay of high-frequency noise signals.

Innovation Solution

An audio playback method that involves obtaining a noise signal, performing a noise reduction process to generate a noise canceling signal, and playing a low-frequency portion of this signal through a first speaker, specifically a bass speaker, to avoid replaying high-frequency noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the full noise canceling signal is played through the speaker, then the noise cancellation effect is improved, but the noise floor increases and sound quality deteriorates

Engineering Contradiction:

Improvenoise cancellation effectVSAvoidnoise floor

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The noise canceling signal is segmented into low-frequency and high-frequency portions. Only the low-frequency portion is played through the speaker, while the high-frequency portion is filtered out. This segmentation resolves the contradiction by maintaining the essential noise cancellation function (low-frequency) while eliminating the harmful high-frequency noise that increases the noise floor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful high-frequency portion is extracted and removed from the noise canceling signal before playback. By taking out only the necessary low-frequency components and discarding the high-frequency components, the system maintains noise cancellation effectiveness while reducing the noise floor and improving sound quality.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the ANC function is turned on, then the noise cancellation capability is improved, but the noise floor becomes more obvious

Engineering Contradiction:

Improvenoise cancellation capabilityVSAvoidnoise floor

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The noise canceling signal is segmented by frequency, playing only low-frequency portions through the speaker while filtering out high-frequency portions. This resolves the contradiction by maintaining noise cancellation capability through low-frequency playback while eliminating the high-frequency noise that makes the noise floor more obvious.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different frequency portions of the noise canceling signal are treated differently: low-frequency portions are preserved and played back for noise cancellation, while high-frequency portions are filtered out to reduce noise floor. This local quality differentiation resolves the contradiction between noise cancellation capability and noise floor visibility.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12614538B2Audio playback method, audio playback device, and storage medium

Publication Date: 2026.04.28 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

The present disclosure discloses an audio playback method, an audio playback device, a computer-readable storage medium. The audio playback method includes: obtaining a noise signal; obtaining a noise canceling signal by performing a noise reduction process on the noise signal; and playing a low-frequency portion of the noise canceling signal through a first speaker.