Wireless Earbud Microphone Mixing for Shared Audio Calls

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Solution Overview

Problem

Wireless earbuds typically support only one bud as the active microphone during a phone call, limiting the ability to seamlessly share audio between users, such as in a 3-way call scenario.

Innovation Solution

Implementing a secondary microphone in one earbud that operates in a second mode to capture audio and encode it for transmission to the primary earbud, which mixes and compensates for wireless transmission delay, and uses a sideband channel for data transfer between the earbuds to enhance audio quality and user experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If only one earbud serves as the active microphone during a phone call, then the wireless communication range and simplicity are maintained, but the ability to share audio between users in 3-way call scenarios is limited

Engineering Contradiction:
Improveaudio sharing capabilityVSAvoidmicrophone configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by enabling either earbud to serve as the active microphone depending on the wearing scenario. The system automatically determines which earbud should be active based on detection signals from both earbuds, allowing flexible adaptation to single-user, two-user, or shared scenarios without requiring manual configuration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies dynamics by making the microphone configuration changeable rather than fixed. The system dynamically switches between different earbuds being the active microphone based on real-time detection of wearing scenarios. This dynamic reconfiguration allows the system to adapt to changing usage patterns while maintaining optimal audio performance.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the secondary microphone captures and transmits audio to the primary earbud, then audio quality and echo reduction are improved, but wireless transmission delay occurs

Engineering Contradiction:
Improveaudio qualityVSAvoidwireless transmission delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the secondary earbud pre-encode and buffer its microphone audio stream before transmission to the primary earbud. This preliminary processing allows the audio data to be ready for immediate playback, reducing the perceptible delay while maintaining the quality benefits of the secondary microphone.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the primary earbud receives audio data from the secondary earbud and adjusts timing accordingly. The feedback loop includes the primary earbud compensating for transmission delay by adjusting its playback timing, ensuring synchronized audio reproduction that masks the wireless transmission delay.

Inventive Principle:
Principle #23Feedback

3Reliability

If the first earbud mixes audio from both microphones, then audio quality is improved, but echo may be introduced without proper compensation

Engineering Contradiction:
Improveaudio qualityVSAvoidecho
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback by having the primary earbud continuously monitor the mixed audio output and compare it with the original audio streams. This feedback mechanism allows the system to detect and compensate for echo effects, adjusting the mixing parameters in real-time to maintain audio quality while minimizing harmful echo.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies parameter changes by dynamically adjusting the mixing ratio and timing parameters of the audio streams from both microphones. The primary earbud modifies these parameters based on the detected wearing scenario and audio conditions, optimizing the balance between audio quality improvement and echo reduction.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3895448B1Mixing microphones for wireless headsets
Publication Date: 2025.10.22 GOOGLE LLC
  • EP3895448B1 patent drawingFigure 1
  • EP3895448B1 patent drawingFigure 2
  • EP3895448B1 patent drawingFigure 3

AI summary

An audio playback system may be adaptable to various situations for improved user experience and audio playback quality. For example, earbuds may be both worn by a same user, worn by two different users within audio range of one another, worn by two different users outside of audio range of one another, etc. A second earbud with a secondary microphone operates in a second mode in which it captures audio and encodes it for transmission to the first earbud having a primary microphone. The first earbud with the primary microphone operates in a first mode in which it mixes the audio received from the second earbud with audio received through its own microphone for playback. The first earbud in the first mode may also delay its own microphone stream to compensate for wireless transmission delay and correlate the two audio streams to improve audio quality in case there are sounds that can be picked up by both microphones.