Acoustic Processing Device for In-Vehicle Sound Leakage Control
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Solution Overview
Problem
Conventional in-vehicle acoustic processing devices fail to accurately reproduce sound signals with a wide frequency band, leading to altered acoustic images and increased sound leakage between front and rear seats, affecting audibility in vehicles with multiple listening positions.
Innovation Solution
An acoustic processing device that separates sound source signals into common and other components, using interaction calculation and sound level adjustment processors to output the common components to speakers near the listeners' heads, reducing sound leakage and maintaining the original acoustic image by adjusting sound levels based on measured characteristics and masking amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional in-vehicle acoustic processing devices reproduce sound signals with wide frequency band, then sound leakage between front and rear seats increases, but if they attenuate high and low frequencies, then the original acoustic image is altered
Solution Approach 1:
The patent divides the sound source signal into multiple frequency bands (high, midrange, low frequencies) and processes each band separately through different signal paths. The common signal component is extracted and processed differently from the other components, allowing selective attenuation of specific frequency ranges to reduce sound leakage while preserving the acoustic image through the headrest speakers that are positioned closer to the listener's head
Solution Approach 2:
The patent applies different signal processing characteristics to different spatial locations by directing processed signals to specific speakers (front speakers vs. headrest speakers). The headrest speakers receive signals with specific frequency attenuation applied, creating a localized acoustic environment that reduces sound leakage to rear seats while maintaining accurate acoustic imaging for front seat listeners
2Reliability
If different sound sources are simultaneously reproduced for front and rear seats, then audibility for each position is improved, but then sound leakage between positions increases
Solution Approach 1:
The patent segments the audio system into separate signal paths for front and rear seats, with independent signal processing for each. By extracting the common signal component and routing it through headrest speakers with frequency attenuation, the system can provide different sound sources to front and rear seats simultaneously while reducing the harmful sound leakage between these positions through selective frequency attenuation
Solution Approach 2:
The headrest speakers act as an intermediary element that receives the common signal component and applies frequency attenuation before reproducing the sound. This intermediary processing step allows the system to simultaneously serve multiple listening positions while reducing sound leakage, as the attenuated high and low frequencies from headrest speakers are less likely to be heard clearly by listeners in other positions
Data Source
AI summary
An acoustic processing device performs acoustic processing in a space having a first listening position and a second listening position apart from the first listening position. The acoustic processing device includes a first input unit, a first output unit, and a signal processing circuit. The first input unit receives a first sound source signal to be reproduced at the first listening position. The first sound source signal includes a first left-channel signal and a first right-channel signal. The first output unit outputs the first sound source signal to a first speaker group including a first speaker disposed near a place of a head of a listener at the first listening position. The signal processing circuit draws out a first common signal common to both the first left-channel signal and the first right-channel signal and outputs the first common signal to the first speaker.