Playback Audio Calibration for Multi-Channel Frequency Response
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Solution Overview
Problem
Existing sound systems face challenges in accurately calibrating sound signals when played through multiple channels due to inter-channel wave cancellations and frequency response changes, requiring frequent recalibration and resulting in an unrealistic user experience in simulators.
Innovation Solution
A method and system that convert sound signals from a logarithmic scale to Pascal scale, subtract background noise, and apply a compensation factor to achieve calibrated sound signals, ensuring accurate playback and improved user experience in simulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If equalization filter is applied on channels while discarding inter-channel wave cancellation, then frequency response is improved when played through one channel, but frequency response becomes unexpected when played through multiple channels
Solution Approach 1:
The patent applies feedback by measuring the actual frequency response of the acoustic environment and using this measurement to adjust the equalization filters. The system plays test signals through the audio channels, records the actual response with microphones, and uses this feedback to calculate compensation filters that account for inter-channel wave cancellations and environmental acoustics.
Solution Approach 2:
The patent introduces an intermediary processing stage that calculates inter-channel cancellation compensation. Before applying equalization filters, the system computes compensation filters based on the measured impulse responses of each channel, creating an intermediary representation of the actual acoustic behavior that mediates between the ideal equalization and the real-world inter-channel interactions.
2Productivity
If experimental calibration is applied to account for interferences, then calibration speed is improved, but the system requires frequent recalibration when frequency distribution changes
Solution Approach 1:
The patent applies preliminary action by performing a comprehensive calibration measurement during the initial setup phase. The system measures the impulse responses of all audio channels in the specific acoustic environment and pre-calculates the equalization and compensation filters. This preliminary calibration accounts for the specific room acoustics and speaker placements, eliminating the need for frequent recalibrations when the frequency distribution changes.
3Adaptability or versatility
If multiple sound models play the same signals, then system versatility is improved, but inter-model interferences occur
Solution Approach 1:
The patent applies local quality by calculating separate equalization and compensation filters for each audio channel and each sound model. Instead of applying a single global filter, the system tailors the filtering to each specific channel's acoustic characteristics and each model's playback requirements. This localized approach ensures that inter-model interferences are compensated for individually, allowing multiple models to play simultaneously without mutual interference.
Data Source
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AI summary
There is described a computer-implemented method for calibrating a sound signal, comprising: receiving (12) an initial sound signal, a recorded background sound signal, a recorded initial sound signal and a target sound signal; subtracting (14) the recorded background sound signal from the recorded initial sound signal, thereby obtaining a denoised sound signal; dividing (16) the target sound signal by the denoised sound signal, thereby obtaining a compensation factor; dividing (18) the initial sound signal by the compensation factor, thereby obtaining a calibrated sound signal; and outputting (20) the calibrated sound signal.