Bass Extraction Routing for Multi-Speaker Build-Up Control

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Solution Overview

Problem

Current audio processing methods face challenges in efficiently managing low-frequency audio signals in complex playback environments with multiple speakers and channels, leading to bass build-up issues during amplitude panning and array processing.

Innovation Solution

A method involving bass extraction using low-pass filters to produce extracted low-frequency audio signals, followed by routing these signals to appropriate speakers, and applying high-pass filters to other audio signals, with a bass management process that limits amplitudes and combines signals to mitigate bass build-up, while considering the playback environment's speaker layout and channel configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If array processing methods duplicate signals in phase into nearby speakers, then sound coverage is improved, but bass build-up occurs

Engineering Contradiction:
Improvesound coverageVSAvoidbass build-up
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts low-frequency signals from the audio signal before array processing is applied. By separating the bass content and routing it through a dedicated low-frequency management path rather than duplicating it with the full-band signal, the harmful bass build-up is prevented while maintaining the beneficial sound coverage from array processing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The audio signal is segmented into different frequency bands, with low-frequency signals being processed separately from the rest of the audio spectrum. This segmentation allows the low-frequency content to be managed independently, preventing the bass build-up that occurs when full-band signals are duplicated in phase across multiple speakers.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the number of speakers is increased to improve audio reproduction quality, then sound coverage and immersion are enhanced, but bass build-up issues worsen

Engineering Contradiction:
Improveaudio reproduction qualityVSAvoidbass build-up
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The low-frequency signals are extracted from the overall audio signal before distribution to multiple speakers. This extraction creates a separate management path for bass content, allowing the system to utilize multiple speakers for improved sound coverage and immersion without causing bass build-up, as the low-frequency content is controlled independently.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If low-pass filters are applied to extract bass signals, then bass management control is improved, but processing complexity increases

Engineering Contradiction:
Improvebass management controlVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The low-frequency signal extraction is performed as a preliminary step before the main array processing and signal distribution. By applying the low-pass filter and separating the bass content early in the processing chain, the system achieves precise bass management control while simplifying subsequent processing steps, as the low-frequency management is already handled.

Inventive Principle:
Principle #10Preliminary action

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 effectively reduces bass build-up and improves sound reproduction by accurately routing low-frequency signals, enhancing the audio processing efficiency and quality in multi-channel, multi-speaker setups.

Implementation Method 1

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

Methodology Applied
Scientific EffectLow-pass filtering: Filter (electronic)

Implementation Method 2

applying high-pass filter to at least some of the audio object signals, to produce high-pass filtered audio signals

Methodology Applied
Scientific EffectHigh-pass filtering: Filter (electronic)

Data Source

PatentEP3011764B1Bass management for audio rendering
Publication Date: 2018.11.21 DOLBY LABORATORIES LICENSING CORP
  • EP3011764B1 patent drawingFigure 1
  • EP3011764B1 patent drawingFigure 2
  • EP3011764B1 patent drawingFigure 3A~3B

AI summary

Improved methods and devices for processing low-frequency audio data are provided. A bass extraction process may involve applying low-pass filters to received audio object signals, to produce extracted low-frequency audio signals. The bass extraction process may be performed prior to a process of rendering audio objects into speaker feed signals. A bass management process may involve routing the extracted low-frequency audio signals to the one or more speakers capable of reproducing low-frequency audio signals.