Audio Equalizer Preset Switching Without Click Noise
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Solution Overview
Problem
Audio equalizers (AEQs) often produce a noise sound like 'Click' when switching preset sets during audio signal playback, discomforting users due to deviations in actual frequency response from the design principle caused by quantization errors in high-order IIR filters.
Innovation Solution
A parameter processing method that linearly adjusts parameters of the AEQ by ramping down and ramping up gains of filter and bypass branches, replacing all-pass filter factors, and adjusting gains to match target preset settings, ensuring smooth transitions without noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If parameters of audio equalizer are switched directly between preset sets during audio signal playback, then switching speed is improved, but noise sound like 'Click' is generated due to sudden changes in frequency response
Solution Approach 1:
The patent applies preliminary action by ramping down the gain of the filter branch and ramping up the gain of the bypass branch before switching parameters. This preparatory adjustment of gains prevents sudden frequency response changes that would cause click noise, while still enabling relatively fast parameter switching between preset sets.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the gains of filter and bypass branches during the parameter switching process. Instead of static direct switching, the system continuously modifies gain values to smoothly transition between different frequency responses, eliminating noise while maintaining switching functionality.
2Manufacturing precision
If high-order IIR filter is used to achieve accurate frequency response, then manufacturing precision is improved, but quantization error causes deviation from design principle
Solution Approach 1:
The patent applies segmentation by dividing the high-order IIR filter into multiple low-order filters connected in series. This decomposition reduces quantization errors in each individual filter stage while maintaining the overall frequency response characteristics, thereby resolving the contradiction between manufacturing precision and measurement precision.
Data Source
AI summary
A parameter processing method, an audio signal playing method and device of an audio equalizer, and an audio equalizer are provided. The parameter processing method includes: acquiring a current parameter preset set and a predetermined target parameter preset set of the audio equalizer, linearly processing at least a part of parameters in the current parameter preset set, to enable the parameters processed linearly to be identical to target parameters in the target parameter preset set.