Numerically Optimized Binaural Room Impulse Responses for Headphones
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Solution Overview
Problem
Conventional binaural room impulse responses (BRIRs) designed to match actual room acoustics can sound colored and muddy when auditioned in inconsistent listening environments, and their application is computationally expensive due to large memory requirements.
Innovation Solution
Design BRIRs through a numerical optimization method that incorporates perceptual cues and acoustic constraints, using a stochastic room/head model to minimize coloration and time-smearing artifacts, and apply them using feedback delay networks (FDNs) for efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional BRIRs are designed to match actual room acoustics, then spatial perception accuracy is improved, but audio quality deteriorates (colored and muddy sound)
Solution Approach 1:
The patent transforms the BRIR design from matching physical room acoustics to optimizing perceptual parameters. The impulse responses are designed by adjusting parameters such as early reflection timing, level, and spectral content to achieve natural-sounding spatial perception without the coloration inherent in measured room responses.
Solution Approach 2:
The patent replaces expensive, complex measured room impulse responses with simplified, synthesized perceptual BRIRs that achieve the same spatial perception goal without the harmful coloration. These optimized BRIRs are computationally lighter and avoid the muddy sound of conventional approaches.
2Measurement precision
If conventional BRIRs are applied, then spatial perception is achieved, but computational cost increases due to large memory requirements
Solution Approach 1:
The patent extracts only the essential spatial perception components from full room impulse responses. By focusing on key perceptual cues (early reflections, interaural time differences, interaural level differences) and discarding redundant information, the BRIRs achieve spatial perception with reduced computational and memory requirements.
Solution Approach 2:
The patent segments the BRIR into distinct functional components (direct sound, early reflections, late reverberation) and optimizes each segment independently for perceptual effectiveness. This segmentation allows for more efficient processing and storage while maintaining spatial perception quality.
Data Source
AI summary
Methods and systems for designing binaural room impulse responses (BRIRs) for use in headphone virtualizers, and methods and systems for generating a binaural signal in response to a set of channels of a multi-channel audio signal, including by applying a BRIR to each channel of the set, thereby generating filtered signals, and combining the filtered signals to generate the binaural signal, where each BRIR has been designed in accordance with an embodiment of the design method. Other aspects are audio processing units configured to perform any embodiment of the inventive method. In accordance with some embodiments, BRIR design is formulated as a numerical optimization problem based on a simulation model (which generates candidate BRIRs) and at least one objective function (which evaluates each candidate BRIR), and includes identification of a best one of the candidate BRIRs as indicated by performance metrics determined for the candidate BRIRs by each objective function.