Multiband Noise Gate With Frequency-Bin Attenuation Control

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Solution Overview

Problem

Traditional noise filtering methods struggle to effectively remove noise floors from audio signals across multiple frequencies, often inadvertently suppressing desired audio signals.

Innovation Solution

A multiband noise gate system that transforms audio signals into the frequency domain, separates them into frequency bands, and uses lookup tables to determine bin-specific and overall attenuation multipliers, allowing for targeted noise reduction while preserving desired audio levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional noise filtering methods are used to remove noise floor, then noise reduction is achieved, but desired audio signals are inadvertently suppressed

Engineering Contradiction:

Improvenoise floorVSAvoiddesired audio signal preservation

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The audio signal is divided into multiple frequency bands, with each band processed independently using separate lookup tables. This segmentation allows selective noise reduction in specific frequency ranges while preserving desired signals in other bands, resolving the contradiction between noise removal and signal preservation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different attenuation characteristics are applied to different frequency bands based on their specific noise profiles. Each band has its own lookup table with customized attenuation values, enabling localized noise reduction without uniformly suppressing all audio signals across the entire frequency spectrum.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If frequency domain processing is used to target specific frequency bins, then noise reduction precision is improved, but device complexity increases

Engineering Contradiction:

Improvefrequency-specific noise reductionVSAvoidsignal processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Lookup tables containing pre-calculated attenuation values are generated before processing audio signals. These tables map frequency bin indices to appropriate attenuation factors, allowing the system to quickly apply precise frequency-specific reduction without performing complex real-time calculations, thus reducing processing complexity while maintaining precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Complex iterative noise reduction algorithms are replaced with direct lookup table queries. Instead of performing sophisticated real-time analysis and adjustment, the system substitutes mathematical computation with table-based retrieval, simplifying the processing mechanism while achieving frequency-specific noise reduction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11688409B2Multi-band noise gate

Publication Date: 2023.06.27 GOPRO INC

AI summary

The present disclosure relates to processing a plurality of audio signals. A device receives the plurality of audio signals in the frequency domain and determining an overall attenuation multiplier based on the plurality of audio signals and an overall lookup table that relates decibel values to different overall attenuation multipliers. The device determines an attenuation vector comprising a plurality of bin-specific attenuation multipliers, each bin-specific attenuation multiplier respectively corresponding to a different frequency bin of the plurality of frequency bins. The device scales each bin-specific attenuation value in the attenuation vector with the overall attenuation multiplier, and edits each of the audio signals based on the scaled bin-specific attenuation values in the attenuation vector.