Headset Audio Phase Cancellation Disruption

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Solution Overview

Problem

In acoustical environments where synchronized audio playback occurs, phase cancellation effects between headset devices and external speakers reduce audio volume and distort the intended audio for headset users due to the delayed arrival of audio signals, causing them to be out of phase.

Innovation Solution

A method that preprocesses headset audio by summing random acoustical noise, such as pink noise, with the original audio track to disrupt phase cancellation effects, ensuring the audio remains intact and undistorted by synchronizing the playback and adjusting noise levels accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If audio is played through both headset and external speakers simultaneously, then audio coverage is improved, but phase cancellation occurs causing volume reduction and distortion

Engineering Contradiction:

Improveaudio coverageVSAvoidphase cancellation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary analysis of the audio signal before playback, identifying components that will cause phase cancellation. By pre-processing the audio signal to remove or attenuate frequencies that will cancel out when played through both headset and external speakers, the system eliminates the harmful effect before it occurs, while still allowing simultaneous playback for improved audio coverage.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If acoustic noise is added to disrupt phase cancellation, then audio integrity is preserved, but noise may be perceptible to the user

Engineering Contradiction:

Improveaudio integrityVSAvoidperceptible noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the level of acoustic noise added to the audio signal based on multiple parameters including the detected phase cancellation severity, the type of acoustic environment, and the characteristics of the audio content. By changing the noise parameters adaptively rather than using a fixed level, the system preserves audio integrity while keeping the noise imperceptible to users in most conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system applies different noise levels and characteristics to different frequency bands and time segments of the audio signal. Rather than adding uniform noise across the entire audio, the system targets specific frequency ranges where phase cancellation occurs and applies noise locally, preserving audio integrity in affected areas while maintaining clean audio in unaffected areas, thus keeping noise imperceptible.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10652398B2Systems and methods to disrupt phase cancellation effects when using headset devices

Publication Date: 2020.05.12 THEATER EARS

AI summary

In applications where assisted listening headphones are worn inside of a theater, phase cancellation effects cause the headset wearer to perceive the audio as reduced in volume and distorted. These undesirable phase cancellation effects may be disrupted through preprocessing or real time processing of the headset audio track by summing acoustical noise with the original headset audio track and providing this altered audio track to the headset. The acoustical noise is modulated such that it is imperceptible to the headset wearer while at the same time disrupting undesirable phase cancellation effects, which would otherwise occur if the headset audio track was provided unaltered. Thus, the preprocessing of the headset audio preserves the integrity of the intended headset audio, as perceived by the headset wearer, in headsets worn in a theater environment.