Audio Filter Bell-Curve Control for Asymmetric Frequency Response
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Solution Overview
Problem
Conventional peaking filters, whether analog or digital, have the same amplitude characteristics and operability, making it difficult to achieve an asymmetrically shaped amplitude characteristic without altering the user's familiar sound quality and operability.
Innovation Solution
A control method and device that independently or conjointly adjusts high-frequency and low-frequency parameters to control the slopes of a bell-shaped amplitude characteristic, mimicking the behavior of Biquad filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional Biquad filters are used, then the same operability and sound quality are maintained, but the amplitude characteristic cannot be made asymmetric
Solution Approach 1:
The filter parameters are segmented into high-frequency parameter and low-frequency parameter, allowing independent control of each side of the frequency response. This segmentation enables asymmetric amplitude characteristics while maintaining familiar operability through separate parameter adjustment.
Solution Approach 2:
The invention introduces asymmetric control by allowing the high-frequency parameter and low-frequency parameter to be adjusted independently, breaking the symmetry constraint of conventional Biquad filters. This enables the creation of asymmetric amplitude characteristics while preserving the familiar bell-shaped curve structure.
2Adaptability or versatility
If FIR filter with independent bandwidth control is used, then asymmetric amplitude characteristic is achieved, but the operability and amplitude characteristic of Biquad filter are lost
Solution Approach 1:
The invention applies local quality by allowing different parameters (high-frequency parameter and low-frequency parameter) to control different regions of the frequency response independently. This enables asymmetric shaping in specific frequency regions while maintaining overall familiarity with Biquad filter operation.
Solution Approach 2:
The filter structure maintains universality by preserving the bell-shaped amplitude characteristic and familiar parameter adjustment interface of Biquad filters, while adding the capability for asymmetric control through independent high-frequency and low-frequency parameter adjustment.
3Adaptability or versatility
If additional parameters are added to Biquad filter, then asymmetric amplitude characteristic may be achieved, but the algorithmic constraints of Biquad filters prevent it
Solution Approach 1:
The invention achieves asymmetric amplitude characteristics by changing the parameters of the existing Biquad filter structure rather than modifying the algorithm itself. By introducing high-frequency parameter and low-frequency parameter variations, asymmetric control is achieved while maintaining the simplicity of the Biquad filter algorithm.
Data Source
AI summary
A method for controlling a frequency response having a bell-shaped amplitude characteristic of a filter that is configured to process an audio signal includes preparing a high-frequency parameter related to a high-frequency side characteristic on a high-frequency side of the frequency response, and a low-frequency parameter related to a low-frequency side characteristic on a low-frequency side of the frequency response, independently changing the high-frequency parameter or the low-frequency parameter in accordance with a first change instruction, changing both of the high-frequency parameter and the low-frequency parameter in conjunction with each other in accordance with a second change instruction, and controlling a slope on the high-frequency side and a slope on the low-frequency side of the bell-shaped amplitude characteristic of the frequency response, by using the high-frequency parameter and the low-frequency parameter.