IIR Audio Equalization Using Genetic Algorithms for Room Adaptation
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Solution Overview
Problem
Existing audio systems, such as those in televisions, face challenges in adapting to varying room environments due to limited processing bandwidth and the need for efficient equalization across different frequency ranges, particularly in non-ideal acoustic conditions like those found in homes with furniture and windows.
Innovation Solution
The use of a genetic algorithm-based method to adapt Infinite Impulse Response (IIR) filters, which iteratively adjusts the equalization parameters to match an ideal frequency response, utilizing a population of chromosomes representing parametric equalizer settings and incorporating Gray coding for faster convergence, allows for efficient equalization across the entire audio system bandwidth while preserving factory-calibrated responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FIR filters are used for audio frequency response equalization, then the equalization accuracy is improved, but the processor bandwidth requirement increases significantly
Solution Approach 1:
The patent changes the fundamental parameter of the filter type from FIR (Finite Impulse Response) to IIR (Infinite Impulse Response). This parameter change allows achieving similar equalization accuracy with significantly lower computational complexity and processor bandwidth requirements, as IIR filters use feedback mechanisms to achieve frequency shaping with fewer coefficients.
Solution Approach 2:
The patent substitutes the direct mathematical computation approach of FIR filters with a recursive feedback mechanism characteristic of IIR filters. This substitution replaces the need for extensive processor bandwidth with a more efficient computational structure that uses feedback loops to achieve the same equalization goal.
2Use of energy by moving object
If IIR filters are used for audio frequency response equalization, then the processor bandwidth requirement is reduced, but the stability and complexity of filter design increases
Solution Approach 1:
The patent employs feedback mechanisms inherent in IIR filter structures, where the output of the filter is fed back into the input through feedback coefficients. This feedback approach allows the system to achieve stable frequency response with fewer computational resources, as the recursive structure naturally shapes the frequency response while maintaining stability through proper pole placement.
Solution Approach 2:
The patent carefully manages the parameters of the IIR filter (zeros and poles) to ensure stability. By controlling the placement of poles within the unit circle and optimizing the feedback coefficients, the system achieves both reduced processor bandwidth requirements and maintained filter stability.
3Use of energy by moving object
If IIR filters are used for audio frequency response equalization, then the filter order is reduced, but the mathematical complexity of deriving the solution increases
Solution Approach 1:
The patent uses feedback-based optimization techniques to automatically determine the optimal IIR filter coefficients. This approach simplifies the design process by using iterative methods that converge to stable solutions, reducing the need for complex manual mathematical manipulation of zeros and poles while maintaining low filter order.
Data Source
AI summary
Systems and methods utilize a modified genetic algorithm for adapting an off-the-shelf audio system, such as in a high-end television, to a given, particular room or other physical location presenting a specific or unique auditory environment with a set of acoustic properties. An audio system is adapted to a given room by determining an IIR based EQ solution via iterative techniques, including an iterative technique based upon a genetic algorithm adapted for an audio frequency response equalization application. In a variant, an audio system is adapted to a particular room, adjust the EQ across a microphone's bandwidth while preserving the factory-calibrated EQ response across the remaining bandwidth.