Audio Transducer Position Compensation via HRTF Filtering
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Solution Overview
Problem
Existing audio delivery systems, such as headphones and earphones, experience a significant decrease in audio quality and realism when transducers are positioned off-center relative to the ear canal, leading to distortions caused by reflections from the user's physical structures.
Innovation Solution
Applying a head-related transfer function (HRTF) and a transducer position compensation filter to audio signals, which adjusts the frequency response to match the spectral characteristics of sounds emitted from a transducer positioned at the ear canal entrance, even when the transducer is spaced apart from the ear, thereby mitigating spectral coloring and enhancing frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transducers are positioned off-center relative to the ear canal, then device comfort and wearability are improved, but audio quality and realism deteriorate due to spectral coloring and distortions
Solution Approach 1:
The system applies HRTF filtering and transducer position compensation filters to the audio signal before it reaches the off-center transducer. This preliminary signal processing pre-compensates for the expected spectral coloring and distortions that will occur during sound transmission, ensuring accurate frequency response even when the transducer is positioned away from the ear canal entrance.
Solution Approach 2:
The system dynamically adjusts audio signal parameters by applying frequency-dependent filtering based on the transducer's position relative to the ear canal. The compensation filter modifies the spectral characteristics of the audio signal to counteract the distorting effects of off-center positioning, thereby maintaining audio quality while allowing flexible transducer placement.
2Adaptability or versatility
If transducers are positioned away from the ear canal entrance, then device design flexibility is improved, but frequency response accuracy deteriorates due to reflections from physical structures
Solution Approach 1:
The HRTF filter and transducer position compensation filter act as intermediary signal processing elements between the audio source and the off-center transducer. These filters mediate the distorting effects of the acoustic path by pre-equalizing the frequency response, allowing the system to maintain accurate frequency representation despite the intermediate physical structures (head, pinnae, ear canal) that would otherwise cause reflections and spectral coloring.
3Device complexity
If conventional audio delivery systems are used with off-center transducers, then device simplicity is maintained, but spatial audio realism deteriorates
Solution Approach 1:
The system performs preliminary signal processing by applying HRTF filtering and position compensation filters to the audio signal before transmission through the off-center transducer. This pre-compensation ensures that the spatial audio characteristics and frequency response remain accurate and realistic, maintaining high audio fidelity without requiring complex physical adjustments to transducer positioning.
Data Source
AI summary
Systems and methods of providing an audio signal are disclosed herein. In one embodiment, a method of delivering an audio signal from a device toward a user's ear includes, for example, transmitting a filtered audio signal from a transducer positioned at a location on the device that is longitudinally spaced apart from an entrance of an auditory canal of the user's ear when the device is worn on the user's head.