Multichannel Audio Precompensation Controller for Spatial Distortion Correction
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Solution Overview
Problem
Existing digital audio precompensation methods, particularly single-channel approaches, are limited in correcting spatially varying distortion in sound reproduction systems, leading to suboptimal sound quality due to their inability to account for varying impulse responses across different measurement positions, resulting in residual errors and objectionable pre-ringing artifacts.
Innovation Solution
A multichannel audio precompensation controller is designed to estimate impulse responses at multiple measurement positions, allowing for the determination of adjustable filter parameters that optimize the acoustic response across a region of interest, using a criterion function that weights differences between compensated and target impulse responses, while ensuring stability and minimizing pre-ringing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If single-channel precompensation methods are used, then the system complexity is low and ease of operation is maintained, but the ability to correct spatially varying distortion is insufficient leading to residual errors and pre-ringing artifacts
Solution Approach 1:
The patent segments the audio compensation task into multiple independent channel groups, where each group processes a specific spatial region or frequency band. This allows the system to handle spatially varying distortion with multiple specialized filters rather than a single complex filter, improving correction precision while keeping individual channel complexity manageable.
Solution Approach 2:
The patent transitions from single-channel to multi-channel processing by adding the spatial dimension to the frequency domain filtering. Multiple measurement positions are incorporated to capture spatially varying impulse responses, enabling the system to correct distortions that vary across different listening positions in the room.
2Manufacturing precision
If single-channel precompensation is applied, then the filter design is straightforward, but the compensation is suboptimal due to inability to account for varying impulse responses across different measurement positions
Solution Approach 1:
The patent divides the audio signal into multiple channel groups, with each group processed by dedicated filters designed for specific spatial regions. This segmentation allows each filter to be optimized for its particular spatial zone, improving overall compensation accuracy while maintaining relatively simple individual filter designs.
Solution Approach 2:
The patent incorporates multiple measurement positions to capture varying impulse responses across the listening space. By using impulse responses from multiple positions rather than a single position, the system adapts its filtering parameters to account for spatial variations in the acoustic environment, significantly improving compensation accuracy.
3Object-affected harmful factors
If single-channel precompensation is used, then the system is simple to implement, but pre-ringing artifacts are more objectionable due to insufficient error reduction
Solution Approach 1:
The patent segments the audio compensation into multiple channel groups, with each group processed by specialized filters. This segmentation distributes the error reduction task across multiple channels, effectively suppressing pre-ringing artifacts through combined processing while maintaining a manageable system structure.
Solution Approach 2:
The patent combines the outputs of multiple channel groups to produce the final compensated audio signal. By merging the results from multiple specialized filters that each reduce errors in their respective spatial regions, the system achieves superior artifact suppression compared to single-channel approaches.
4Manufacturing precision
If passive acoustic treatment is used, then sound quality can be improved, but the solution is cumbersome and expensive
Solution Approach 1:
The patent replaces passive mechanical acoustic treatment (such as acoustic diffusers, Helmholtz resonators, and absorbing materials) with active digital signal processing. By using precompensation filters to electronically correct acoustic distortions, the system achieves improved sound quality without the physical bulk, cost, and installation complexity of passive acoustic treatments.
Data Source
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AI summary
A basic idea is to determine an audio precompensation controller for an associated sound generating system comprising a total of N >= 2 loudspeakers, each having a loudspeaker input. The audio precompensation controller has a number L >= 1 inputs for L input signals) and N outputs for N controller output signals, one to each loudspeaker. It is relevant to estimate, for each one of at least a subset of the N loudspeaker inputs, an impulse response at each measurement position. It is also important to specify, for each one of the L input signal(s), a selected one of the N loudspeakers as a primary loudspeaker and a selected subset S including at least one of the N loudspeakers as support loudspeaker(s). A key point is to specify, for each primary loudspeaker, a target impulse response at each measurement position with the target impulse response having an acoustic propagation delay, where the acoustic propagation delay is determined based on the distance from the primary loudspeaker to the respective measurement position. The idea is then to determine, for each one of the L input signal(s), based on the selected primary loudspeaker and the selected support loudspeaker(s), filter parameters of the audio precompensation controller so that a criterion function is optimized under the constraint of stability of the dynamics of the audio precompensation controller.