Wearable Loudspeaker Head Position Compensation
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Solution Overview
Problem
Wearable loudspeaker devices that are not in direct contact with the ears experience variable acoustic transfer functions due to head movement, leading to changes in sound quality and spatial representation, causing discomfort and impairing audio playback.
Innovation Solution
A method and system that use sensor data to determine the current head position and adapt the filter transfer function of the loudspeaker device, ensuring a consistent audio output by compensating for head movements and positional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the loudspeaker device is worn at a distance from the ears to avoid physical discomfort, then the user experiences less physical pressure and fatigue, but the acoustic transfer function becomes variable due to head movement, causing changes in sound quality and spatial representation
Solution Approach 1:
The system dynamically adapts the filter transfer function based on real-time sensor data about head position and movement. The filter characteristics are continuously adjusted to compensate for changes in the acoustic transfer function, maintaining consistent sound quality despite head movements. This dynamic adaptation resolves the contradiction by making the system responsive to changing conditions rather than relying on a fixed configuration.
Solution Approach 2:
The system uses sensor data to provide feedback about head position and movement, which is then used to adjust the filter transfer function. This closed-loop feedback mechanism allows the system to detect changes in the acoustic transfer function and compensate for them automatically, maintaining reliable audio output while allowing the device to be worn comfortably at a distance from the ears.
2Reliability
If headphones are worn directly on the ears to maintain stable acoustic transfer function, then sound quality and spatial representation remain consistent, but the user experiences physical pressure on the ear canal or pinna and muscle fatigue
Solution Approach 1:
Instead of requiring a fixed physical connection between the loudspeaker and ear, the system uses dynamic filter adjustment to maintain acoustic stability. The filter transfer function is continuously adapted based on sensor feedback, allowing the device to be worn comfortably at a distance while maintaining consistent sound quality through active compensation rather than passive physical contact.
Solution Approach 2:
The system introduces an intermediary processing layer (the adaptive filter) between the loudspeaker output and the user's ear. This intermediary compensates for variations in the acoustic transfer function caused by head movement, allowing the physical distance between the loudspeaker and ear to be increased for comfort while maintaining acoustic stability through the mediating filter adjustment.
3Reliability
If the filter transfer function is adapted dynamically based on head position, then sound quality and spatial representation remain consistent during head movement, but the device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The sensor system serves multiple functions: it detects head position for filter adaptation, tracks head movement for spatial audio processing, and provides data for both compensation algorithms and potential user interface functions. This multi-functionality justifies the added complexity by extracting maximum utility from the sensor subsystem, reducing the overall system complexity relative to the benefits gained.
Solution Approach 2:
The system changes the parameters of the filter transfer function dynamically based on sensor data. By adjusting filter coefficients, cutoff frequencies, and other parameters in response to head position and movement, the system maintains consistent audio output. This parameter adaptation approach is more efficient than complete system reconfiguration, reducing the effective complexity of the control mechanism.
Data Source
AI summary
A method for operating a wearable loudspeaker device that is worn on the upper part of the body of a user distant to the user's ears and head comprises determining sensor data, based on the sensor data, and determining at least one parameter related to the current position of the user's head in relation to the wearable loudspeaker device. The method further includes adapting a filter transfer function of at least one filter unit for the current position of the user's head based on the at least one parameter, and an audio output signal that is output to at least one loudspeaker of the wearable loudspeaker device depends on the filter transfer function.