Multi-Speaker Audio Delay Filtering for Spatial Aliasing Reduction
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Solution Overview
Problem
Auditory spatial aliasing occurs when multiple speakers output the same sound with differing path lengths to a listener's ear, causing constructive or destructive interference at various frequencies, leading to audio distortion.
Innovation Solution
A system incorporating a tablet computer with multiple speakers, delay filters, and an inertial measurement unit (IMU) adjusts audio signal delays based on the device's orientation and attachment state to reduce spatial aliasing by applying specific delay profiles to each speaker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple speakers output the same audio signal simultaneously, then audio coverage is improved, but spatial aliasing distortion occurs due to path length differences
Solution Approach 1:
The system applies delay filters to audio signals before they reach speakers with longer path lengths, pre-compensating for the expected time of flight differences. This preliminary timing adjustment ensures that sound waves from multiple speakers arrive at the listener's ear simultaneously, eliminating spatial aliasing while maintaining multi-speaker audio coverage
Solution Approach 2:
The system dynamically adjusts the delay parameter (duration) of audio signals based on speaker position and listener orientation. By changing the time delay parameter for different speakers and audio sources, the system optimizes sound arrival timing to prevent constructive and destructive interference patterns that cause spatial aliasing
2Object-affected harmful factors
If delay filters are applied to compensate for path length differences, then spatial aliasing is reduced, but system complexity increases
Solution Approach 1:
The system uses the device's own IMU sensor data to automatically determine listener orientation and calculate appropriate delay compensations. By leveraging existing onboard sensors rather than requiring external measurement equipment, the system achieves spatial aliasing reduction without proportionally increasing complexity
Solution Approach 2:
The delay filter parameters are dynamically adjusted based on real-time IMU data reflecting device orientation and usage context. The system transitions between different delay profiles (e.g., docked vs. handheld modes) to adapt to changing spatial relationships between speakers and listener, maintaining effectiveness without requiring complex manual configuration
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
The system effectively minimizes audio distortion by compensating for path length differences and reflections, ensuring coherent audio output regardless of the device's position or orientation.
Implementation Method 1
The audio source may include a delay filter that delays output of the audio signal by a duration to a speaker compared to another speaker
Implementation Method 2
The system may comprise a tablet computer comprising a first plurality of magnets. The system may comprise a dock that removably attaches with the tablet computer using a second plurality of magnets that magnetically couple with the first plurality of magnets
Implementation Method 3
The tablet computer may further comprise an inertial measurement unit (IMU). The speakers that output audio from the first audio source and the second audio source may vary based on an orientation determined based on a measurement by the IMU
Data Source
AI summary
Various arrangements for reducing auditory spatial aliasing for a user are detailed herein. A first delay filter may be set that delays output of a first same audio signal by a first duration to a speaker of a first set of multiple speakers of a device compared to a second speaker of the first set of multiple speakers. A second delay filter may also be set that delays output of a second same audio signal by a second duration to a speaker of a second set of multiple speakers of the device compared to a second speaker of the second set of multiple speakers. The first same audio signal can be output using the first set of multiple speakers and the second same audio signal can be output using the second set of multiple speakers.