Multi-band Bass Management for Spatial Audio Accuracy

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Solution Overview

Problem

Conventional bass management systems face challenges in accurately reproducing low-frequency audio signals due to limitations in speaker configurations, leading to spatial distortion and 'bass build-up' issues, as they fail to effectively distribute low-frequency information across multiple loudspeakers.

Innovation Solution

The proposed solution involves a multi-band bass management method that applies high-pass, low-pass, and band-pass filters to audio signals based on the capabilities of different loudspeakers, dynamically adjusting filter settings to minimize spatial artifacts and optimize low-frequency reproduction by panning signals to appropriate speakers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional bass management systems direct low frequencies to a single or limited number of loudspeakers, then the system complexity is reduced, but spatial distortion and bass build-up occur due to ineffective distribution of low-frequency information

Engineering Contradiction:
Improvesystem complexityVSAvoidspatial accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments low-frequency audio information into multiple frequency bands (e.g., 20-60Hz, 60-120Hz, 120-250Hz) and distributes each band to different capable loudspeakers based on their individual frequency response characteristics. This segmentation allows effective distribution of low-frequency information across multiple speakers, improving spatial accuracy while avoiding bass build-up at any single location.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple filters (high-pass, low-pass, band-pass) are applied to audio signals based on speaker capabilities, then spatial resolution and accuracy of low-frequency reproduction is enhanced, but the processing complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary analysis of each loudspeaker's frequency response capabilities before audio playback, storing this information in a database. During playback, the system retrieves pre-determined filter settings and routing information based on the stored speaker characteristics, avoiding real-time complex calculations and reducing processing complexity while maintaining high spatial resolution.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts filter parameters (cutoff frequencies, Q-factors) and signal routing based on the specific capabilities of available loudspeakers and the characteristics of the audio content. This dynamic adaptation allows optimal distribution of low-frequency bands to different speakers, enhancing spatial resolution while the system automatically manages the processing complexity through adaptive algorithms.

Inventive Principle:
Principle #15Dynamics

3Object-generated harmful factors

If low-frequency signals are distributed across multiple loudspeakers, then bass build-up is reduced, but the requirements for speaker configuration and coordination increase

Engineering Contradiction:
Improvebass build-upVSAvoidspeaker configuration flexibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameters of audio signals (frequency content, amplitude, phase) dynamically based on the capabilities of available loudspeakers. By analyzing each speaker's frequency response and adjusting signal parameters accordingly, the system can distribute low-frequency content across various speaker configurations (home theater, car audio, portable devices) without causing bass build-up, thereby maintaining high adaptability to different speaker configurations.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the spatial resolution and accuracy of low-frequency sound reproduction, reducing distortion and 'bass build-up' by tailoring the processing to the specific capabilities of each speaker, resulting in a more immersive audio experience.

Implementation Method 1

applying a high-pass filter to at least some of the speaker feed signals, to produce high-pass-filtered speaker feed signals

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Implementation Method 2

applying a bass extraction process involving low-pass filters to the audio object signals, to produce extracted low-frequency audio signals

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Implementation Method 3

applying high-pass, low-pass, and band-pass filters to audio signals based on the capabilities of different loudspeakers

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Data Source

PatentEP3868129B1Methods and devices for bass management
Publication Date: 2023.10.11 DOLBY LABORATORIES LICENSING CORP
  • EP3868129B1 patent drawingFigure 1
  • EP3868129B1 patent drawingFigure 2
  • EP3868129B1 patent drawingFigure 3

AI summary

Some disclosed methods involve multi-band bass management. Some such examples may involve applying multiple high-pass and low-pass filter frequencies for the purpose of bass management. Some disclosed methods treat at least some low-frequency signals as audio objects that can be panned. Some disclosed methods involve panning low and high frequencies separately. Following high-pass rendering, a power audit may determine a low-frequency deficit factor that is to be reproduced by subwoofers or other low-frequency-capable loudspeakers.