Earpiece Occlusion Effect Cancellation via Bone Conduction
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Solution Overview
Problem
The occlusion effect, which occurs when the ear canal is blocked, leads to an undesirable distortion of sound perception, particularly in devices like earpieces and hearing aids, as it enhances low-frequency sound pressure, causing an unpleasant experience for users who need to speak while wearing these devices.
Innovation Solution
A system comprising an earpiece with a speaker element, a vibration sensor, and a signal generator that operates to generate sound waves to counteract the occlusion effect by canceling bone-conducted vibrations, using a signal modifier to set phase and amplitude based on the vibration sensor's output, and optionally incorporating a microphone for adaptive modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ear canal is blocked by an earpiece to provide noise isolation and audio playback, then external noise is reduced and audio quality is improved, but the occlusion effect causes distortion of own-voice perception and low-frequency sound pressure increases
Solution Approach 1:
The patent uses the vibration sensor to detect bone-conducted vibrations and the speaker element to generate anti-phase sound waves that cancel the occlusion effect. The harmful bone-conducted vibrations are converted into a useful cancellation signal, transforming the occlusion effect from a harmful phenomenon into a beneficial noise cancellation application.
Solution Approach 2:
The patent introduces a vibration sensor as an intermediary element that detects bone-conducted vibrations and a speaker element that generates anti-phase sound waves. These intermediary components mediate between the occluding earpiece and the ear canal, actively counteracting the occlusion effect without requiring the earpiece to be modified structurally.
2Object-generated harmful factors
If vents or through-holes are added to the earpiece to reduce the occlusion effect, then low-frequency own-voice elements are removed, but noise from the environment leaks into the ear and bass sensitivity is reduced
Solution Approach 1:
The patent replaces the mechanical venting system with an active electronic control system. Instead of using physical holes to relieve pressure, the system uses a vibration sensor to detect bone-conducted vibrations and a speaker element to generate anti-phase sound waves, actively canceling the occlusion effect without creating physical openings in the earpiece.
Solution Approach 2:
The patent changes the acoustic parameters in the ear canal by generating sound waves with specific phase and amplitude characteristics. The signal generator modifies the electrical signal to control the speaker element, creating sound waves that are 180 degrees out of phase with the occlusion effect, thereby canceling it through parameter manipulation rather than structural modification.
3Loss of information
If an electric sidetone path is introduced to restore air-conducted sound, then own-voice perception is improved, but the balance between low, mid and high frequencies differs from normal and distortion remains
Solution Approach 1:
Instead of adding sound waves to restore own-voice perception (as in traditional sidetone paths), the patent inverts the approach by generating anti-phase sound waves to cancel the harmful bone-conducted vibrations. This inversion strategy eliminates the need for frequency balancing and avoids the distortion issues inherent in additive approaches.
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 solution effectively reduces the occlusion effect, restoring a more natural sound balance and improving the user's experience by canceling unwanted bone-conducted sound waves, thus providing a more comfortable and familiar sound perception.
Implementation Method 1
vibrations formed by the user speaking and conducted by the user's head to the vibration sensor
Implementation Method 2
generate sound waves to counteract the occlusion effect by canceling bone-conducted vibrations
Implementation Method 3
the occluded ear canal defines a small enclosed volume which has a large acoustic impedance
Implementation Method 4
When the ear canal is blocked, i.e. occluded, the vibrations are instead reflected back towards the eardrum
Data Source
AI summary
A system and method are provided for controlling the own-voice experience of a user who talks while an earpiece is mounted to occlude an ear of the user. A vibration sensor is engaged with the user's head to sense vibrations formed by the user speaking and conducted by the user's head to the vibration sensor. A signal generator operates a speaker element, which is integrated with the earpiece, to generate sound waves in the ear canal of the user, based on the output signal of the vibration sensor. The signal generator generates the sound waves to at least partially cancel other sound waves that are generated by at least part of said vibrations entering the ear canal from surrounding bone and/or tissue. The system and method counteracts the occlusion effect and are applicable in connection with in-ear headsets, earphones, in-ear headphones, in-ear monitors, circumaural headphones, hearing aids, earplugs and earmuffs.