Pseudo Bass Harmonic Filtering for Low-Noise Bass Perception
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Solution Overview
Problem
Existing pseudo bass generating systems produce noise and fail to generate high-quality pseudo bass due to limitations in low-frequency reproduction capabilities of speakers and headphones, which are unable to reproduce frequencies below 50 Hz or 100 Hz.
Innovation Solution
A pseudo bass generating apparatus is designed with a 4th-order low pass filter, absolute value circuit, clip circuit, multipliers, and adders to process input signals, generating even and odd harmonics while suppressing high-frequency components and noise, using higher-order filters to enhance signal quality and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional pseudo bass generation methods are used, then bass perception is achieved, but significant noise is generated
Solution Approach 1:
The patent segments the pseudo bass generation process into multiple independent filtering stages: a first 4th-order low pass filter processes the input signal, and a second 4th-order low pass filter processes the noise component. This segmentation allows each filter to be optimized for its specific function, effectively separating bass perception from noise generation.
Solution Approach 2:
The patent applies different filtering characteristics to different signal components. The first 4th-order low pass filter is configured with specific cutoff frequency characteristics optimized for bass generation, while the second 4th-order low pass filter is configured with different characteristics optimized for noise reduction. This local optimization of filter qualities achieves both bass perception and noise reduction.
2Object-affected harmful factors
If higher-order filters are used to reduce noise, then noise is reduced, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or analog filtering systems with digital signal processing implementations of 4th-order low pass filters. This substitution maintains the high-order filtering capability for noise reduction while simplifying the physical device structure and reducing manufacturing complexity.
3Reliability
If multiple processing stages are added to improve quality, then pseudo bass quality is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary noise filtering by applying the first 4th-order low pass filter to the input signal before the main pseudo bass generation process. This preliminary action removes high-frequency components that would otherwise require more extensive processing later, thereby reducing total processing time while maintaining quality.
Solution Approach 2:
The patent implements continuous processing through parallel filter operations where the first and second 4th-order low pass filters operate simultaneously on different signal components. This continuous parallel processing maintains high quality output without sequential delays that would increase processing time.
Data Source
AI summary
A pseudo bass generating apparatus includes a first 4th-order LPF, an absolute value circuit, a clip circuit, a multiplier, a first adder for subtracting an output signal of the multiplier from an output signal of the clip circuit, a second adder for adding an output signal of the first adder and an output signal of the absolute value circuit, a second 4th-order LPF, and a third adder for adding the input signal and an output signal of the second 4th-order LPF.