Engine Sound Localization Filters for Realistic In-Cabin Synthesis
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Solution Overview
Problem
Modern vehicles, especially those with turbocharged or electric engines, often lack engine noise, leading to an unsatisfying driving experience for drivers, as they may perceive the engine as underpowered due to the absence of typical engine sounds.
Innovation Solution
A vehicle system that synthesizes engine sound by using a controller to generate and project simulated engine noise based on vehicle dynamics and actual engine data, combined with localization filters to create the illusion of sound sources from specific locations within the vehicle, such as the engine compartment or exhaust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sound synthesizers are used to generate sound images from multiple virtual sound sources, then the realism and quality of synthesized engine sound is improved, but the device complexity and computational load increase
Solution Approach 1:
The patent divides the sound synthesis task into multiple independent virtual sound sources, each generating sound images for specific engine components (intake, exhaust, combustion). This segmentation allows parallel processing of different sound elements while maintaining overall system manageability through modular architecture
Solution Approach 2:
A single controller is designed to perform multiple functions: it synthesizes sounds from multiple virtual sources, applies different localization filters to each source, and manages the overall audio output. This multi-functional approach reduces the need for separate dedicated hardware for each sound synthesis task
2Measurement precision
If multiple localization filters are applied to different outputs of a sound synthesizer, then the spatial accuracy and realism of engine sound is improved, but the computational resources and processing time increase
Solution Approach 1:
The patent pre-calculates and stores localization filter characteristics for different virtual sound sources and engine operating conditions. This preliminary preparation allows the controller to quickly apply appropriate filters during real-time operation without performing complex calculations from scratch, reducing processing time
Solution Approach 2:
The system dynamically adjusts localization filter parameters based on engine operating conditions (RPM, load, throttle position). By changing filter parameters rather than recalculating entire filter responses, the system achieves accurate sound localization with reduced computational overhead
3Loss of information
If synthesized engine noise is added to vehicle audio system, then driver perception of engine power and responsiveness is improved, but the risk of masking actual engine sounds or creating unrealistic audio environments increases
Solution Approach 1:
The system continuously monitors actual engine sound levels and adjusts the synthesized sound output accordingly. This feedback mechanism ensures that synthesized sounds complement rather than mask actual engine noises, maintaining audio realism by adapting to changing engine operating conditions in real-time
Solution Approach 2:
Different synthesis techniques and sound characteristics are applied to different engine sound sources (intake, exhaust, combustion) based on their specific acoustic properties. This localized approach ensures each sound element is synthesized with appropriate characteristics, improving overall realism while maintaining distinct identification of individual engine components
Data Source
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AI summary
Synthesizing engine sound in a cabin of a vehicle includes generating a synthesized engine noise audio signal including a plurality of engine order outputs; mixing the engine order outputs in accordance with a first set of gain levels to provide a first channel output; mixing the engine order outputs in accordance with a second set of gain levels to provide a second channel output; using a first localization filter set to provide a first localized output to localize the first channel output as a first sound image at a first location within the cabin, and a second localization filter set to provide a second localized output to localize the second channel output as a second sound image at a second location within the cabin; and mixing the first and second localized outputs into loudspeaker outputs to be applied to the loudspeakers in the cabin.