Headset Transfer-Function Equalization for Own-Voice Occlusion
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Solution Overview
Problem
Hearing devices with tightly sealing earbuds or earcups cause passive loss of high-frequency sounds and amplification of low-frequency sounds, leading to a muffled and boomy perception of the user's own voice, which existing feedback active noise cancellation methods struggle to fully address.
Innovation Solution
A method and apparatus that utilize signal analysis and processing to determine and equalize audio transfer functions between open- and closed-ear states, using internal and external microphones, and processors to restore natural voice perception by compensating for the occlusion effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tightly sealing earbuds or earcups are used to isolate users from environmental noise, then noise isolation is improved, but passive loss at high frequency occurs making the user's own voice sound muffled
Solution Approach 1:
The patent employs feedback active noise cancellation using an internal microphone near the eardrum and a headset speaker to form a feedback loop that cancels sound near the eardrum, compensating for the occlusion effect and restoring natural voice perception
Solution Approach 2:
The patent introduces an intermediary processing system that measures the user's own voice through the internal microphone, analyzes the occlusion effect, and applies equalization processing to restore the natural frequency balance before outputting the corrected signal
2Object-affected harmful factors
If tightly sealing earbuds or earcups are used to isolate users from environmental noise, then noise isolation is improved, but amplification of low frequency sounds occurs making the user's voice sound boomy
Solution Approach 1:
The feedback loop system continuously monitors the amplified low frequency sounds through the internal microphone and applies real-time cancellation signals to reduce the occlusion effect, maintaining natural voice balance while preserving noise isolation
Solution Approach 2:
The patent dynamically adjusts the equalization parameters based on the user's speech characteristics and environmental conditions, allowing the system to adaptively compensate for the occlusion effect rather than using fixed frequency response correction
3Object-generated harmful factors
If feedback ANC is used to compensate for occlusion effect, then voice naturalness is improved, but all parameters must be preset based on average OE which reduces adaptability
Solution Approach 1:
The patent performs preliminary measurement of the user's specific ear canal characteristics and occlusion effect using the internal microphone before normal operation, storing these personalized parameters for subsequent real-time compensation, thus avoiding the need for preset average values
Solution Approach 2:
The system automatically measures and adapts to each user's unique ear canal structure and speech characteristics through the internal microphone, performing self-calibration without requiring manual presetting or average population-based parameters
Data Source
AI summary
A method of equalising sound in a headset comprising an internal microphone configured to generate a first audio signal, an external microphone configured to generate a second audio signal, a speaker, and one or more processors coupled between the speaker the external microphone, and the internal microphone, the method comprising: while the headset is worn by a user: determining a first audio transfer function between the first audio signal and the second audio signal in the presence of sound at the external microphone; and determining a second audio transfer function between a speaker input signal and the first audio signal with the speaker being driven by the speaker input signal; determining an electrical transfer function of the one or more processors; determining a closed-ear transfer function based on the first audio transfer function, the second audio transfer function and the electrical transfer function; and equalising the first audio signal based on a comparison between the closed-ear transfer function and an open-ear transfer function to generate an equalised first audio signal.