Hybrid Audio Decorrelation Filtering With Timbre Preservation
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Solution Overview
Problem
Existing audio decorrelation methods introduce timbral changes and unintended artifacts, such as negative modifications to the perceived location of virtualized audio sources and timbre, when reducing correlation between audio signals.
Innovation Solution
A method involving the generation of a decorrelation filter with frequency-dependent warping, mixing it with a carrier filter to create a hybrid filter, which processes audio signals while minimizing distortions and preserving timbre, by using a sequence of random numbers, fast Fourier transforms, and inverse FFTs to normalize and warp the phase responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random phase filtering is used to decorrelate audio signals, then correlation between channels is reduced, but timbral changes and artifacts are introduced
Solution Approach 1:
The patent applies frequency-dependent warping to the decorrelation filter, where the warping amount varies with frequency. This parameter change allows the filter to maintain effectiveness across different frequency ranges while minimizing timbral changes, particularly by reducing warping at frequencies where timbre is most sensitive
Solution Approach 2:
The patent combines a decorrelation filter with a carrier filter to create a hybrid filter system. This composite approach integrates the decorrelation function with a carrier signal, allowing the system to achieve effective decorrelation while preserving the natural timbre of the audio signal through the carrier's spectral characteristics
2Reliability
If complex decorrelation filtering is applied, then audio signal decorrelation is achieved, but processor and memory requirements increase
Solution Approach 1:
The patent segments the audio processing into distinct stages: generating a decorrelation filter, applying frequency-dependent warping, and combining with a carrier filter. This segmentation allows each component to be optimized independently, reducing overall computational complexity while maintaining decorrelation effectiveness
Solution Approach 2:
The patent applies partial warping to the decorrelation filter, where the warping is applied selectively rather than uniformly across all frequencies. This partial action approach reduces the computational burden compared to full warping while still achieving the desired decorrelation effect
Data Source
AI summary
Various embodiments relate to a system and method for decorrelating an audio signal with a hybrid filter. The hybrid filter is generated by first generating a decorrelation filter. A frequency-dependent warping is applied to the decorrelation filter. The warped decorrelation filter is then mixed with a carrier filter to generate the hybrid filter. The carrier filter may include filters for spatial processing of an audio signal, filters for upmixing an audio signal, and/or filters for downmixing an audio signal.