Loudspeaker Calibration Filters That Avoid Acoustic Null Overdriving
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Solution Overview
Problem
Existing loudspeaker systems face challenges in compensating for interference effects in acoustic environments, which can lead to overdriving and damage due to the application of conventional filters.
Innovation Solution
A method for calibrating loudspeaker systems by applying an audio test signal, recording the response, identifying exclusion frequency ranges with acoustic nulls, and implementing calibration filters to correct the frequency response without overdriving the speakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional filters are applied to compensate for interference effects, then frequency response compensation is improved, but loudspeaker reliability deteriorates due to overdriving
Solution Approach 1:
The patent applies different processing to different frequency ranges by identifying exclusion frequency ranges where acoustic nulls occur. Instead of uniformly applying filters across all frequencies, the method selectively excludes problematic frequency ranges from filter application, thereby preventing overdriving in specific regions while maintaining compensation in safe regions.
Solution Approach 2:
The frequency spectrum is segmented into exclusion frequency ranges and non-exclusion frequency ranges. The patent divides the overall frequency response compensation task into separate处理 paths: one for excluded ranges (where filters are not applied) and another for non-excluded ranges (where filters are applied), thus preventing the harmful effect of overdriving while maintaining beneficial compensation.
2Measurement precision
If filters are applied to correct frequency response, then frequency response accuracy is improved, but energy efficiency deteriorates due to overdriving and wasted power
Solution Approach 1:
The patent extracts and removes the problematic frequency components (exclusion frequency ranges with acoustic nulls) from the filter processing path. By taking out these specific frequency ranges where filter application would be counterproductive, the system avoids wasting energy on ineffective compensation attempts while maintaining accurate compensation in the remaining frequency ranges.
3Measurement precision
If filters are applied to compensate interference effects, then frequency response compensation is improved, but harmful effects worsen due to overdriving and potential damage
Solution Approach 1:
The patent performs preliminary identification of exclusion frequency ranges before applying filters. By detecting acoustic nulls in advance and marking these frequency ranges for exclusion, the system takes preventive action to avoid the harmful effects of overdriving. This preliminary anti-action ensures that filters are never applied to frequency ranges where they would cause damage or ineffective compensation.
Data Source
AI summary
The invention relates to a method for calibrating a loudspeaker system in an acoustic environment. The method comprises steps of providing a local frequency response based on a recorded test signal and providing a target frequency response. A difference frequency response is established based on a difference between the local frequency response and the target frequency response. A list of exclusion frequency ranges associated with minima of the local frequency response is generated and one or more filter frequency ranges which are non-overlapping with the exclusion frequency ranges are identified. A target filter frequency is selected from the identified filter frequency ranges and a calibration filter related to the target filter frequency is implemented in an equalizer of the loudspeaker system. The invention further relates to a loudspeaker system arranged to carry out the above method for calibrating a loudspeaker system.