External Microphone Headset for HRTF Inference
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Solution Overview
Problem
Existing methods for determining head-related transfer functions (HRTFs) require uncomfortable and inconvenient microphone placement inside the ear canal, which limits user experience in spatial sound systems.
Innovation Solution
An audio system for a headset that remotely infers low sound frequencies by using a microphone assembly positioned external to the ear canal but within a threshold distance, allowing for the detection of audio signals that are similar to those at the ear canal, enabling the determination of HRTFs without direct canal insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microphone is placed inside the ear canal to determine HRTFs, then measurement precision is improved, but ease of operation deteriorates due to uncomfortable and inconvenient user experience
Solution Approach 1:
The patent introduces an intermediary approach by placing the microphone assembly on the headset frame in a detection region external to the ear canal, rather than directly inside it. This intermediate position allows the microphone to detect audio signals that are sufficiently similar to those at the ear canal entrance, serving as a mediator between the ideal measurement location and the comfortable user experience location
Solution Approach 2:
The patent creates a copy of the ear canal sound pressure signal by detecting audio signals at an external location. The detected audio signal at the detection region is within a threshold degree of similarity of the sound pressure wave at the ear canal, effectively creating a surrogate measurement that replicates the essential characteristics without requiring direct ear canal insertion
2Ease of operation
If a microphone is placed external to the ear canal for comfort, then ease of operation is improved, but measurement precision deteriorates due to reduced similarity to ear canal sound pressure
Solution Approach 1:
The patent applies parameter changes by establishing specific thresholds for distance and signal similarity. The detection region is positioned within a threshold distance from the ear canal entrance, and the detected audio signal must be within a threshold degree of similarity to the ear canal sound pressure wave. These parameter thresholds ensure that external microphone placement maintains sufficient measurement precision while preserving user comfort
3Reliability
If direct microphone placement in ear canal is used, then reliability of HRTF determination is improved, but device complexity increases due to insertion and positioning requirements
Solution Approach 1:
The patent extracts the microphone assembly from the ear canal environment and positions it on the headset frame instead. This extraction eliminates the need for insertion procedures, positioning adjustments within the ear canal, and associated cleaning/maintenance requirements, thereby reducing device complexity while maintaining HRTF determination reliability through the external detection region approach
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 provides a comfortable and convenient method for determining personalized HRTFs, enhancing spatial sound quality by accurately inferring sound pressure at the ear canal without the need for direct microphone placement, thus improving user experience in audio content delivery.
Implementation Method 1
The microphone assembly is configured to detect an audio signal emitted from an audio source
Data Source
AI summary
A headset comprises a frame and an audio system. The audio system includes a microphone assembly positioned on the frame in a detection region, the detection region external to an ear of a user wearing the headset, and within a threshold distance from an ear canal of the ear, the microphone assembly configured to detect an audio signal emitted from an audio source, wherein the audio signal detected at the detection region is within a threshold degree of similarity of a sound pressure wave at the ear canal of the user, and an audio controller configured to determine a set of head-related transfer functions (HRTFs) based in part on the detected audio signal.