Bone Conduction Transducers for Stereo Audio Crosstalk Cancellation
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Solution Overview
Problem
Near-eye displays, such as head-mounted displays, face challenges in implementing stereophonic audio due to crosstalk between bone conduction audio channels, which impede sound localization and make it difficult to provide accurate audio to each ear.
Innovation Solution
A method for a wearable computing device, like a head-mounted display, that receives audio signals and applies transforms based on wearer-specific parameters to cancel crosstalk by using bone conduction transducers to vibrate the skull, ensuring that the intended sound is heard by the correct ear and not the contralateral ear, using a crosstalk cancellation processor to generate out-of-phase signals for simultaneous vibration of transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bone conduction transducers are used to provide audio to each ear, then audio can be delivered through the skull, but crosstalk occurs where sound intended for one ear is heard by the contralateral ear
Solution Approach 1:
The system preemptively applies anti-phase signals through bone conduction transducers to cancel crosstalk before it reaches the contralateral ear. The crosstalk cancellation processor generates anti-phase versions of audio signals and delivers them through BCTs, preventing the harmful crosstalk effect from occurring at the destination ear.
Solution Approach 2:
The system converts the crosstalk phenomenon into a beneficial effect by using the same bone conduction path that causes crosstalk to deliver anti-phase cancellation signals. The harmful skull transmission pathway is repurposed to deliver therapeutic anti-phase signals that eliminate the original harm.
2Object-generated harmful factors
If crosstalk cancellation signals are generated and delivered through additional bone conduction transducers, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The bone conduction transducers serve dual functions: delivering primary audio signals and delivering crosstalk cancellation signals. The same physical transducers and skull conduction pathway are used for both purposes, eliminating the need for separate cancellation hardware and reducing overall device complexity.
Solution Approach 2:
The system merges the audio delivery function and crosstalk cancellation function into a single integrated system. The crosstalk cancellation processor and audio processor work together, and both audio and cancellation signals are delivered through the same bone conduction transducers, combining multiple functions into unified hardware and software components.
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 approach effectively cancels crosstalk between bone conduction audio channels, enhancing the ability to localize sound and providing accurate stereo audio by ensuring that the intended sound is heard by the correct ear, thereby improving the overall audio experience in wearable computing devices.
Implementation Method 1
causing a first bone conduction transducer (BCT) coupled to the wearable computing device to vibrate so as to provide the first sound to the first ear
Implementation Method 2
receiving a second audio signal that is out of phase with the first audio signal and effective to substantially cancel at least a portion of the first audio signal
Data Source
AI summary
Methods, apparatus, and computer-readable media are described herein related to implementing stereo audio using bone conduction transducers (BCTs). A wearable computing device can receive audio signals effective to cause the wearable computing device to provide stereo sound to a first ear and a second ear opposite the first ear. The wearable computing device can also apply a transform to the audio signals so as to determine other audio signals that are out of phase with the audio signals and effective to substantially cancel crosstalk signals resulting from the audio signals, where the transform may be based on one or more wearer-specific parameters. The wearable computing device may then cause two BCTs to vibrate substantially simultaneous to each other so as to provide the stereo sound to the first ear and the second ear and substantially cancel the crosstalk signals.