Digital Reverberator Startup Control for Echo Interference Reduction

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Solution Overview

Problem

Current methods for rendering reverberation in virtual and augmented reality struggle to minimize interference between late reverberation and early reflections, often requiring complex configurations and increased computational resources, such as running two feedback delay networks in parallel, which can be difficult to configure and computationally expensive.

Innovation Solution

A method and apparatus that control the startup behavior of a digital reverberator using a feedback network with a first echo suppressor, comprising a control delay line and gain filter, to attenuate early echoes and reduce interference with separately rendered early reflections, thereby improving the blending of late reverberation with early reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two feedback delay networks are run in parallel to minimize interference between late reverberation and early reflections, then the quality of reverberation rendering is improved, but the computational complexity and device configuration difficulty increase

Engineering Contradiction:
Improvequality of reverberation renderingVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and suppresses only the problematic early echoes from the feedback delay network output using a dedicated echo suppressor module, rather than running two complete FDNs in parallel. This selective extraction approach maintains reverberation quality while reducing computational complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The echo suppressor acts as an intermediary component between the feedback delay network and the early reflection processing. It mediates the interaction by selectively attenuating early echoes that would otherwise interfere with early reflections, enabling simple configuration while maintaining high rendering quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If two feedback delay networks are run in parallel to minimize interference between late reverberation and early reflections, then the quality of reverberation rendering is improved, but the configuration difficulty increases

Engineering Contradiction:
Improvequality of reverberation renderingVSAvoidconfiguration difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts and suppresses only the problematic early echoes from the feedback delay network output using a dedicated echo suppressor module, rather than running two complete FDNs in parallel. This selective extraction approach maintains reverberation quality while reducing computational complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The echo suppressor acts as an intermediary component between the feedback delay network and the early reflection processing. It mediates the interaction by selectively attenuating early echoes that would otherwise interfere with early reflections, enabling simple configuration while maintaining high rendering quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If late reverberation is allowed to interfere with early reflections, then the computational resources are reduced, but the perception of reverberation quality deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidperception of reverberation quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent converts the harmful interference between late reverberation and early reflections into a beneficial separation by using the echo suppressor to selectively attenuate only the problematic early echoes. This allows the system to maintain high perceptual quality while using fewer computational resources than running two parallel FDNs.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 allows for improved virtual acoustics rendering with reduced computational complexity and easier configuration, enhancing the perception of reverberation by minimizing interference between reflection echoes and late reverberation, resulting in a more realistic audio experience.

Implementation Method 1

applying the at least one delay line to the at least one audio signal to generate at least two echoes

Methodology Applied
Scientific EffectEcho: Echo

Implementation Method 2

generating at least one reverberated audio signal based on at least one output of the at least one digital reverberator

Methodology Applied
Scientific EffectReverberation: Reverberation

Data Source

PatentEP4462423A1Rendering of reverberation with startup control
Publication Date: 2024.11.13 NOKIA TECHNOLOGIES OY
  • EP4462423A1 patent drawingFigure 1
  • EP4462423A1 patent drawingFigure 2
  • EP4462423A1 patent drawingFigure 3

AI summary

A method for applying reverberation to at least one audio signal, the method comprising: obtaining the at least one audio signal; obtaining at least one reverberation parameter; controlling a digital reverberator based on the at least one reverberation parameter; providing at least one control line comprising a delay line and a gain filter, the at least one control line using the at least one reverberation parameter to generate an output from the at least one control line; and generating at least one reverberated audio signal based on at least one output of the at least one digital reverberator and the generated output from the at least one control line, wherein at least a portion of late reverberation in the generated at least one reverberated audio signal interfering with at least one reflection echo is substantially attenuated.