Loudspeaker Position Estimation Using Microphone Array Signal Processing
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Solution Overview
Problem
Surround sound systems require cumbersome manual calibration, as listeners must physically place a multi-element microphone at a sweet spot to achieve optimal loudspeaker placement, which can be hindered by room constraints and result in distorted audio experiences.
Innovation Solution
An apparatus and method using a microphone array with two microphones to estimate loudspeaker positions by determining time differences of arrival and direct path components in audio signals, comparing angles to detect abnormal conditions such as obstruction or incorrect orientation, and notifying users or adjusting compensation parameters for optimal playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-element microphone is physically placed at the sweet spot for calibration, then accurate loudspeaker position estimation is achieved, but the calibration process becomes cumbersome and difficult to operate
Solution Approach 1:
The patent uses a virtual microphone array created through signal processing to copy the function of a physical multi-element microphone placed at the sweet spot. The virtual array is synthesized from signals captured by a single omnidirectional microphone, eliminating the need for physical placement while maintaining position estimation accuracy
Solution Approach 2:
The patent replaces the mechanical system of physically placing and positioning a multi-element microphone with an acoustic signal processing system. By using beamforming and virtual array synthesis techniques, the system achieves the same measurement capability without the mechanical complexity of handling multiple microphones and positioning equipment
2Reliability
If a multi-element microphone is tethered to an A/V receiver via a long cable for calibration, then the system can receive test signals from each loudspeaker, but the setup becomes physically cumbersome and complex
Solution Approach 1:
The patent merges the functions of multiple microphones and their associated cables into a single omnidirectional microphone. This consolidation eliminates the need for multiple cable connections to the A/V receiver while maintaining the ability to capture test signals from all loudspeakers through signal processing
Solution Approach 2:
The patent extracts the essential function of the multi-element microphone array (capturing spatial audio information) and implements it through a single microphone combined with virtual array synthesis. This removes the unnecessary physical components (multiple microphones and long cables) while preserving the core functionality
3Manufacturing precision
If manual calibration is performed to achieve optimal listening position, then audio quality is improved, but the calibration process requires significant time and effort from listeners
Solution Approach 1:
The patent enables the audio system to perform self-calibration by automatically determining loudspeaker positions and generating appropriate compensation parameters without user intervention. The system uses the omnidirectional microphone to capture test signals, processes them through virtual array synthesis, and automatically adjusts audio rendering based on the determined geometry
Solution Approach 2:
The patent performs preliminary automatic calibration before the user begins using the system. By pre-determining the loudspeaker positions and configuring the audio processing parameters automatically, the system eliminates the need for time-consuming manual calibration sessions, allowing users to immediately experience optimized audio quality
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
Enables accurate and automated loudspeaker position estimation, reducing manual intervention and distortion, while compensating for non-ideal placements and obstructions for improved audio quality.
Implementation Method 1
a microphone array including a first microphone and a second microphone, the first microphone to generate a first audio signal in response to the loudspeaker outputting a test signal, the second microphone to generate a second audio signal
Implementation Method 2
determine a time difference of arrival estimate based on the first audio signal and the second audio signal
Data Source
AI summary
Embodiments of systems and methods are described for estimating a position of a loudspeaker and notifying a listener if an abnormal condition is detected, such as an incorrect loudspeaker orientation or an obstruction in a path between the loudspeaker and a microphone array. For example, a front component of a multi-channel surround sound system may include the microphone array and a position estimation engine. The position estimation engine may estimate the distance between the loudspeaker and the microphone array. In addition, the position estimation engine may estimate an angle of the loudspeaker using a first technique. The position estimation engine may also estimate an angle of the loudspeaker using a second technique. The two angles can be processed to determine whether the abnormal condition exists. If the abnormal condition exists, a listener can be notified and be provided with suggestions for resolving the issue in a graphical user interface.