Acoustic Baffle Structure for Compact Sound Source Localization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microphone array systems for voice communications and speech recognition in digital devices face challenges in spatial discrimination and signal-to-noise ratio, requiring multiple microphones and complex processing, which increases cost and complexity, making them unsuitable for smaller devices.
Innovation Solution
A baffle structure is positioned between the microphone and the environment to induce frequency-dependent amplitude and phase differences for sonic waveforms, allowing a processing system to determine the angle of arrival and distance of sound sources using a pair of microphones, mimicking animal hearing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple microphones are used to improve spatial discrimination and signal-to-noise ratio, then measurement precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
A baffle structure is introduced as an intermediary element between the sound source and the microphone. This passive acoustic structure modifies the sound field by creating frequency-dependent amplitude and phase differences for waves arriving from different angles, enabling a single microphone to extract spatial information that would otherwise require multiple microphones. The baffle acts as a mediator that encodes directional information into the acoustic signal itself.
2Measurement precision
If multiple microphones are deployed to achieve accurate sound source localization, then measurement precision is improved, but the device size and volume increase
Solution Approach 1:
The baffle structure serves as a compact intermediary that performs the function of spatial filtering in a passive manner. By positioning the baffle close to the microphone, the system achieves angle-of-arrival discrimination without requiring a large array of widely-spaced microphones. The baffle's acoustic filtering effect is achieved within a compact volume, enabling precise sound source localization in space-constrained mobile devices.
3Measurement precision
If complex audio processing systems are implemented to discern spatial information, then measurement precision is improved, but device complexity and computational requirements increase
Solution Approach 1:
The baffle structure performs preliminary acoustic processing of the sound field before the signal reaches the microphone. By pre-filtering the acoustic signal with frequency-dependent amplitude and phase characteristics that encode spatial information, the system simplifies subsequent digital signal processing. The baffle performs the complex spatial filtering operation in the acoustic domain, reducing the computational burden on the digital processing system.
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 enhances spatial discrimination, increases signal-to-noise ratio, and reduces the number of microphones needed, enabling compact designs suitable for mobile devices while improving sound source localization and noise rejection.
Implementation Method 1
A baffle structure is located between the microphone and the environment. The baffle structure comprises multiple paths for every arriving sonic waveform. The baffle structure is configured to, based at least on an actual angle of arrival for a sonic waveform, induce frequency dependent amplitude differences and phase differences for the sonic waveform
Implementation Method 2
The baffle structure is configured to, based at least on an actual angle of arrival for a sonic waveform, induce frequency dependent amplitude differences and phase differences for the sonic waveform over a range of frequencies
Data Source
AI summary
A computing system comprises an auditory system exposed to an environment. The auditory system comprises a microphone that receives sonic waveforms and outputs audio signals. A baffle structure comprising multiple paths for every arriving sonic waveform is located between the microphone and the environment. The baffle structure is configured to, based at least on an angle of arrival for a sonic waveform, induce frequency dependent amplitude differences and phase differences for the sonic waveform over a range of frequencies. A processing system is communicatively coupled to the microphone. The processing system is configured to receive audio signals from the microphone representing the sonic waveform, to identify a source of the sonic waveform based at least on the received audio signals, and to output an estimated angle of arrival for the sonic waveform based at least on amplitudes and phases of the received audio signals and characteristics of the baffle structure.