Wearable Audio Transducer Phase Shift Feedback Cancellation

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Solution Overview

Problem

Existing wearable audio devices face challenges in achieving improved audio output in a compact form factor while minimizing mechanical feedback and optimizing sound transmission.

Innovation Solution

A multi-transducer assembly is arranged on or within wearable audio devices, featuring dipole transducers with enclosures that guide sound pressures out through slits, with one transducer signal phase-shifted 180 degrees relative to the other to maximize audio output and cancel out mechanical feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple transducers are arranged in a compact wearable audio device, then audio output is improved, but mechanical feedback and vibrations increase

Engineering Contradiction:

Improveaudio outputVSAvoidmechanical feedback

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by phase-shifting the signal to one transducer by 180 degrees relative to the other transducer. This creates opposing vibrations that cancel out mechanical feedback and unwanted vibrations before they can propagate, while still allowing the sound pressures to add together constructively for improved audio output.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs asymmetry by creating an asymmetric signal distribution to the two transducers through phase shifting. One transducer receives the original audio signal while the other receives a phase-shifted version, creating asymmetric vibration patterns that cancel harmful mechanical feedback while maintaining symmetric sound pressure output.

Inventive Principle:

Principle #4Asymmetry

2Power

If transducers are arranged to maximize sound pressure output, then audio performance is improved, but mechanical vibrations and feedback increase

Engineering Contradiction:

Improvesound pressure outputVSAvoidmechanical stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The system applies preliminary anti-action by introducing a phase-shifted signal to one transducer that creates vibrations opposing the mechanical instabilities. This canceling effect stabilizes the system by neutralizing harmful vibrations while preserving the constructive addition of sound pressures for improved audio output.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful mechanical vibrations into a beneficial effect by using phase-shifted signals to create counter-vibrations. The same transducer vibrations that could cause mechanical feedback are instead used to cancel unwanted vibrations and stabilize the system, turning a potential harm into a stabilizing force.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If a single transducer is used in a wearable device, then device complexity is reduced, but audio output and sound quality are limited

Engineering Contradiction:

Improvetransducer arrangementVSAvoidaudio output

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The patent merges the output of two transducers to achieve improved audio performance. By combining the sound pressures from both transducers through strategic phase shifting, the system achieves greater audio output and better sound quality than a single transducer could provide, while keeping the overall device structure relatively simple.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system changes the phase parameter of the audio signal delivered to one transducer by 180 degrees relative to the other. This parameter change allows the transducers to work together constructively for sound pressure while canceling mechanical feedback, achieving superior audio output without proportionally increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

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 configuration enhances audio output by ensuring sound pressures add together while minimizing mechanical feedback, effectively eliminating vibrations that could cause noise and improving overall audio performance.

Implementation Method 1

one transducer signal phase-shifted 180 degrees relative to the other to maximize audio output and cancel out mechanical feedback

Methodology Applied

Scientific EffectPhase shifting:

Implementation Method 2

guide a first sound pressure generated by the first side of the first dipole transducer out of the first enclosure via the first slit

Methodology Applied

Scientific EffectSound pressure: Acoustics

Data Source

PatentUS11356757B2Individually assignable transducers to modulate sound output in open ear form factor

Publication Date: 2022.06.07 BOSE CORP

AI summary

A wearable audio device including first and second transducer modules is provided. The first transducer module may include a first transducer. The first transducer module may further include a first enclosure having a top side defining a first slit and a bottom side defining a second slit. The first enclosure may be configured to guide a first sound pressure through the first slit, and a second sound pressure through the second slit. The second transducer module may include a second transducer. The second transducer module may include a second enclosure having a top side defining a third slit and a bottom side defining a fourth slit. The second enclosure may be configured to guide a third sound pressure through the third slit, and a fourth sound pressure through the fourth slit. The third and fourths slit may be arranged diagonally opposite the first and second slits, respectively.