Multi-Band Audio Compression for Surround Spread and Low Artifacts
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Solution Overview
Problem
Inexpensive speakers in audio and video systems, such as televisions and computers, often have poor fidelity and perceived sound field spread due to cost constraints, leading to suboptimal audio quality.
Innovation Solution
A multi-band audio compression algorithm with advanced surround processing, including a Soft Clip algorithm, configurable crossover filter order adjustment, compressor maximum gain adjustment, and center gain adjustment, is implemented to enhance sound fidelity and perceived sound field spread, offering various audio enhancement modes for different types of audio material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If small inexpensive speakers are used to minimize cost, then manufacturing cost is reduced, but audio fidelity and perceived sound field spread deteriorate
Solution Approach 1:
The patent applies parameter changes by implementing multi-band compression with different compression ratios, attack times, and release times for different frequency bands (bass, mid, high). This allows optimization of audio fidelity parameters without changing the physical speaker hardware, thereby maintaining low manufacturing cost while improving audio output quality through digital signal processing parameters
2Ease of manufacture
If small inexpensive speakers are used to minimize cost, then manufacturing cost is reduced, but perceived sound field spread deteriorates
Solution Approach 1:
The patent employs Advanced Surround Processing that creates virtual three-dimensional sound positioning from two-dimensional stereo signals. By algorithmically generating height, depth, and surround information, the system expands the perceived sound field in additional spatial dimensions, allowing inexpensive speakers to deliver immersive spatial audio experiences without physical surround speakers
3Power
If audio compression is increased to improve volume, then output level is improved, but artifacts and noise boost increase
Solution Approach 1:
The patent segments the audio signal into multiple frequency bands (bass, mid, high) and applies independent compression control to each band. This segmentation allows optimization of compression parameters for each frequency range, preventing excessive compression artifacts in any single band while maintaining overall output level. The multi-band approach enables granular control that reduces harmful compression effects compared to single-band compression
4Stability of the object's composition
If compressor gain is increased to reduce overshoot, then signal stability is improved, but noise boost increases
Solution Approach 1:
The patent applies local quality by implementing different maximum gain limits and compression ratios for different frequency bands. The bass band can tolerate higher gain adjustments without noise boost, while the high band uses more conservative gain settings to prevent noise amplification. This localized control of compression parameters optimizes signal stability for each band independently while minimizing overall noise boost
Data Source
AI summary
Audio processing architectures are described for implementing a multi-band audio compression algorithm with advanced surround processing. Exemplary architectures can improve the fidelity and perceived sound field spread of inexpensive, cabinet mounted, stereo speakers such as those that might be found in televisions, wireless speaker systems and sound bars. Embodiments of the present disclosure can improve inexpensive, cabinet mounted, stereo speakers by providing, e.g., (i) an Advanced Surround algorithm that adds depth and height to the left/right/center sound field images, (ii) a Soft Clip algorithm to minimize the perceived artifacts caused by compressor overshoot, (iii) configurable crossover filter order adjustment to allow better isolation between bands, (iv) a compressor maximum gain adjustment to reduce overshoot and minimize noise boost, and/or (v) a center gain adjustment to emphasize the perception of the center image (dialog) in high ambient noise situations.