Playback Speaker Calibration Using Moving and Stationary Microphones
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Solution Overview
Problem
Existing media playback systems lack effective calibration methods to adapt to varying acoustic environments and listener positions, leading to suboptimal audio quality and synchronization across multiple playback devices.
Innovation Solution
A calibration process using stationary and moving microphones to detect sound waves emitted by playback devices, analyzing these sounds to determine spectral and spatial calibrations, and applying these calibrations based on conditions such as audio content, content source, and listener presence to optimize audio playback for specific environments and locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple playback devices are used to provide audio in different rooms, then audio coverage and accessibility are improved, but synchronization and calibration across devices become more complex
Solution Approach 1:
The system performs automatic calibration by having each playback device emit test tones that are captured by microphones in the environment. The processor analyzes the captured audio signals to determine transfer functions and automatically adjusts equalization settings, eliminating the need for manual calibration and reducing system complexity despite multiple devices being deployed across different locations
Solution Approach 2:
The system dynamically adjusts audio parameters including equalization filters, transfer functions, and playback settings based on environmental acoustic characteristics measured during calibration. This allows each device to adapt its audio output parameters to match the specific acoustic properties of its location, improving overall system performance while maintaining automated operation
2Measurement precision
If calibration is performed for specific listener positions, then audio quality at those positions is improved, but the system cannot adapt to varying listener locations
Solution Approach 1:
The system transitions from static calibration to dynamic adaptation by continuously measuring acoustic characteristics and adjusting equalization settings in real-time. The processor monitors audio signals and modifies playback parameters dynamically to maintain optimal audio quality regardless of listener position or environmental changes, making the system adaptable to varying conditions
Solution Approach 2:
The system uses microphones to capture audio signals and feeds this information back to the processor, which analyzes the transfer functions and adjusts equalization settings accordingly. This closed-loop feedback mechanism enables the system to automatically compensate for variations in listener position and environmental acoustics, maintaining high audio quality without manual intervention
3Measurement precision
If manual calibration procedures are used, then calibration accuracy can be maintained, but user effort and time consumption increase
Solution Approach 1:
The system performs complete calibration automatically without requiring user intervention. Each playback device autonomously emits test tones, captures its own audio environment through microphones, and the processor automatically calculates transfer functions and applies appropriate equalization settings. This self-calibrating capability maintains high accuracy while eliminating manual calibration effort and time consumption
Solution Approach 2:
The system performs calibration automatically during initial setup and device pairing, completing the calibration process before the user needs to use the device. This preliminary automatic calibration ensures accurate audio output from the start without requiring the user to perform time-consuming manual calibration procedures
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
Enhances audio quality and synchronization by adapting playback devices to environmental acoustics and listener positions, providing improved music playback and home theater experiences across different use cases.
Implementation Method 1
A calibration process using stationary and moving microphones to detect sound waves emitted by playback devices
Data Source
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AI summary
Example techniques may involve multiple calibrations for one or more playback devices. An example implementation may involve detecting, via a microphone, calibration sounds as emitted by one or more playback devices during a calibration sequence, perhaps by recording first samples while the microphone is in motion through a given environment and recording second samples while the microphone is stationary at one or more particular locations. The implementation may also include determining a first calibration for the one or more playback devices based on at least the first samples of the calibrations sounds and determining a second calibration for the one or more playback devices based on at least the second samples of the calibrations sounds. The implementation may further include applying at least one of (a) the first calibration or (b) the second calibration to playback by the one or more playback devices.