Bone Conduction Speaker Amplitude Control for Audio Leakage
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Solution Overview
Problem
Wearable devices with bone conduction speakers face challenges in controlling sound leakage, which can compromise user privacy and cause disturbance to others, especially in varying noise environments, as the amplitude of audio output needs to balance between intelligibility and minimizing leakage.
Innovation Solution
A head-mounted wearable device dynamically adjusts the amplitude of the bone conduction speaker based on noise level data, using an air conduction microphone to determine constraint parameters that ensure minimum intelligible audio output for the user while minimizing sound leakage to bystanders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplitude of bone conduction speaker output is increased to improve audio intelligibility in noisy environments, then sound leakage to bystanders increases causing privacy compromise and disturbance
Solution Approach 1:
The patent implements dynamic amplitude adjustment of the bone conduction speaker based on real-time noise level detection. The system continuously monitors environmental noise and adjusts the audio output amplitude dynamically, allowing high amplitude in noisy environments for intelligibility while maintaining low amplitude in quiet environments to minimize sound leakage and protect privacy.
Solution Approach 2:
The system uses air conduction microphones to detect environmental noise levels and provides feedback to the control circuitry. This feedback loop enables the system to automatically adjust the bone conduction speaker amplitude based on the detected noise level, resolving the contradiction between maintaining intelligibility and minimizing leakage through continuous monitoring and adaptation.
2Object-generated harmful factors
If the amplitude of bone conduction speaker output is decreased to minimize sound leakage, then audio intelligibility for the user deteriorates in noisy environments
Solution Approach 1:
The system dynamically adjusts amplitude based on environmental conditions rather than using a fixed low amplitude setting. In noisy environments, the system automatically increases amplitude to maintain intelligibility, while in quiet environments it decreases amplitude to minimize leakage, thus resolving the contradiction through context-dependent adjustment.
Solution Approach 2:
The patent changes the amplitude parameter of the bone conduction speaker based on noise level measurements. By adjusting this critical parameter dynamically according to environmental conditions, the system maintains audio intelligibility when needed while minimizing sound leakage when possible, resolving the contradiction through parameter adaptation.
3Measurement precision
If fixed high amplitude is used for bone conduction speaker output, then audio intelligibility is maintained but sound leakage causes disturbance to others in quiet environments
Solution Approach 1:
The system transitions from fixed amplitude to dynamic amplitude adjustment based on environmental noise levels. In quiet environments, the system automatically reduces amplitude to minimize disturbance to others, while maintaining intelligibility for the user. This dynamic adaptation resolves the contradiction between maintaining user experience and preventing disturbance to bystanders.
Solution Approach 2:
The air conduction microphones provide feedback about environmental noise levels to the control system. This feedback enables automatic amplitude reduction in quiet environments, preventing noise disturbance to others while maintaining audio intelligibility for the user through context-aware adjustment.
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
The solution effectively mitigates sound leakage and maintains user experience by dynamically adjusting the audio output amplitude in response to changing noise levels, ensuring privacy and reducing unwanted noise exposure to others.
Implementation Method 1
an air conduction microphone (AC mic) may be used to obtain samples of sounds
Implementation Method 2
a bone conduction (BC) speaker (BCS). The BCS comprises an actuator that provides a physical displacement responsive to a drive signal
Data Source
AI summary
A head-mounted wearable device (HMWD) may incorporate bone conduction speakers (BCS) to generate audio output that is perceptible to a wearer. Due to the mechanical connection between the BCS and the rest of the device, when the output amplitude of the BCSs is too great, the air-conducted audio “leaks” and may be heard by other people. This leakage may result in eavesdropping by, or generate a nuisance to, those other people. The noise level in the environment around the HMWD is determined and used to dynamically adjust the amplitude of the audio output generated by the BCS. This adjustment improves the comfort and intelligibility of the audio output to the wearer while minimizing audio leakage to the surrounding environment.