Synthetic Engine Sound Synthesis with Room Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for synthesizing combustion engine sound are not suitable for low-cost applications in the automotive industry, as they require powerful digital signal processors and do not accurately replicate the sound experienced by drivers in electric or hybrid vehicles, which can pose safety issues due to the absence of aural cues.
Innovation Solution
A system that uses a model parameter database to generate synthetic engine sound signals, compensating for the listening room's effect through an equalizer filter, allowing for the reproduction of realistic engine sounds using pre-defined sets of model parameters and guide signals, such as rotational speed and engine load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known methods and algorithms for synthesizing sound signals are used, then sound synthesis capability is achieved, but computational complexity and processing power requirements increase
Solution Approach 1:
The patent segments the engine sound synthesis into multiple independent components: excitation signal generation, filter bank processing, and spectral envelope shaping. Each component is handled separately through dedicated modules, allowing the system to achieve complex sound synthesis without requiring a single powerful processor to handle all computations simultaneously.
Solution Approach 2:
The patent uses pre-recorded engine sound samples to create spectral templates that are then synthesized through filtering and modulation. Instead of generating engine sounds from scratch using complex physical models, the system copies the essential spectral characteristics from recorded samples and reproduces them through simpler computational processes.
2Reliability
If synthetic engine sound is generated to warn surrounding traffic participants, then safety is improved, but the sound may not accurately replicate real combustion engine sound
Solution Approach 1:
The patent dynamically adjusts multiple sound parameters including spectral envelope, filter frequencies, and excitation signal characteristics based on engine operating conditions such as RPM and load. This allows the synthesized sound to accurately reflect real engine behavior across different operating states while maintaining sufficient volume and clarity for safety warnings.
Solution Approach 2:
The system incorporates feedback loops that continuously monitor engine sensor data and adjust the synthesized sound parameters in real-time. This ensures the acoustic output accurately represents the current engine state, providing both safety warnings and realistic sound reproduction.
3Measurement precision
If model parameters are modified to compensate for listening room effects, then sound accuracy at listening position is improved, but processing complexity increases
Solution Approach 1:
The patent performs room compensation calculations in advance by measuring the listening room's acoustic characteristics and pre-computing compensation filters. These pre-computed filters are then applied to the synthesized sound without requiring real-time complex calculations, thus improving sound accuracy at the listening position while avoiding excessive processing complexity during operation.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A system for reproducing synthetic engine sound in at least one listening position of a listening room is described. In accordance with an example of the invention, the system comprises a model parameter database including various pre-defined sets of model parameters. An engine sound synthesizer receives at least one guide signal and is configured to select one set of model parameters in accordance with the guide signal(s). The engine sound synthesizer generates a synthetic engine sound signal in accordance with the selected set of model parameters. At least one loudspeaker is used for reproducing the synthetic engine sound by generating a corresponding acoustic signal. Moreover, the system comprises one of the following: (1) an equalizer that receives the synthetic engine sound signal and that is configured to filter the synthetic engine sound signal in accordance with a filter transfer function, which is set such that the effect of the listening room on the resulting acoustic engine sound signal is approximately compensated at the listening position(s); and (2) a model parameter tuning unit, which is configured to modify the pre-defined sets of model parameters in the model parameter database in accordance with an equalizer filter parameter set such that, when the resulting synthetic engine sound signal is generated from a modified set of model parameters, the effect of the listening room on the resulting acoustic signal is approximately compensated at the listening position(s).