Feed-Forward Crosstalk Canceller for Stable Spatial Audio
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Solution Overview
Problem
Current stereo spreader designs fail to precisely localize sound in space, and traditional crosstalk canceller designs are difficult to tune for timbre control without affecting spatial characteristics, often leading to instability or signal clipping.
Innovation Solution
A novel crosstalk canceller design combining a minimum-phase equalization filter and a feed-forward crosstalk filter, which allows independent control of timbre and spatial attributes, using a feed-forward cross-talk matrix cascaded with a spectral equalization filter, and implementing crossfading and smoothing techniques in the M-S matrix shuffler topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional feedback crosstalk canceller designs are used, then crosstalk cancellation is achieved, but the system becomes unstable or clips due to ITF constraints
Solution Approach 1:
The patent inverts the traditional feedback-based crosstalk cancellation approach by using a feed-forward topology. Instead of using feedback loops that require ITF < 1.0 constraints, the system applies pre-calculated cancellation signals in advance, eliminating stability constraints while maintaining crosstalk cancellation effectiveness.
Solution Approach 2:
The patent changes the fundamental parameter of the canceller topology from feedback to feed-forward operation. This parameter change removes the ITF constraint limitation, allowing unlimited gain adjustment and timbre control without risking instability or signal clipping.
2Ease of operation
If traditional recursive crosstalk canceller filter designs are used, then crosstalk cancellation is achieved, but tuning spectral response for timbre control is difficult or impractical
Solution Approach 1:
The patent segments the crosstalk cancellation system into independent feed-forward filter components that can be tuned separately. This segmentation allows spectral response adjustment for timbre control without affecting the overall stability or spatial characteristics, making the system easier to operate and tune.
3Adaptability or versatility
If stereo shuffling topology with tuned filters is used, then stereo spreading is achieved, but soundfield localization is imprecise and beyond physical loudspeaker arc
Solution Approach 1:
The patent applies feedback principles in the form of crosstalk cancellation that uses measured or modeled transfer functions to precisely control sound localization. By canceling unwanted crosstalk paths, the system achieves accurate spatial positioning while maintaining stereo spreading capability through the feed-forward M-S matrix processing.
Data Source
AI summary
An audio processing system for processing a single channel audio signal includes a a processor configured to derive a synthetic difference component from the single channel audio input signal a filtering module configured to apply a first filter to the sum signal represented by the single channel signal and to apply a second filter to the synthetic difference signal; and a control module configured to crossfade to control the amount of the resulting audio signal effect by respectively scaling the sum signal and the difference signal.