In-Vehicle Seat Audio Layout to Prevent Howling and Echoes
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Solution Overview
Problem
In-vehicle communication devices experience howling and echoes due to sound collection and output mechanisms, making it difficult for passengers to hear each other clearly.
Innovation Solution
The device employs strategically positioned microphones and speakers in vehicle seats, with amplifiers and speakers located farther from the head of the passenger to minimize sound re-collection and echoes, and includes a passenger detector to control sound output based on seat occupancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speaker is positioned close to the sound collector to improve sound transmission efficiency, then the sound can be heard more clearly, but howling and echoes occur making it difficult to hear
Solution Approach 1:
The speaker is repositioned from a location near the sound collector to a different spatial dimension - specifically, in or near the headrest and more outward than the head position. This dimensional relocation breaks the direct acoustic path between speaker and sound collector, eliminating the feedback loop that causes howling and echoes while maintaining sound transmission through the passenger's head as an intermediary medium.
Solution Approach 2:
The passenger's head serves as an intermediary medium for sound transmission. The sound travels from the speaker, through the passenger's head (which acts as a natural acoustic waveguide), to the other side where it can be heard clearly without directly returning to the sound collector. This intermediary approach solves the contradiction by using the passenger's body as part of the acoustic path.
2Ease of operation
If the speaker is positioned to output sound clearly to the passenger, then conversation quality improves, but sound re-collection by the sound collector increases causing echoes
Solution Approach 1:
The speaker positioning in or near the headrest, more outward than the head position relative to the sound collector, creates a geometric relationship where sound radiating toward the passenger does not directly return to the sound collector. This spatial arrangement in another dimension allows clear sound output while avoiding re-collection.
3Device complexity
If speakers are positioned in standard locations for general audio output, then device complexity is reduced, but howling occurs making conversation difficult
Solution Approach 1:
The speaker positioning is optimized for the specific local condition of in-seat conversation rather than general audio playback. By placing the speaker in or near the headrest at a specific location more outward than the head position, the system achieves high conversation quality without howling, while accepting that this specific positioning may not be optimal for other audio functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Minimizes howling and echoes, enabling clear and smooth conversations between front and back seat passengers by reducing sound re-collection and selectively outputting sound only when passengers are present.
Implementation Method 1
a front row sound collector provided at a position that is in front of and between the front row left seat and the front row right seat, and is configured to collect a sound uttered by the passenger
Implementation Method 2
a front row sound amplifier configured to amplify the sound collected by the front row sound collector
Implementation Method 3
a front row left seat speaker provided in or near a headrest of the front row left seat
Data Source
AI summary
An in-vehicle conversation device amplifies a sound of a passenger collected by a front row microphone by a front row sound amplifier and outputs the sound from speakers and provided more outward than a head position of a passenger of a back row seat relative to the microphone, amplifies a sound of a passenger collected by a back row microphone by a back row sound amplifier and outputs the sound from speakers and provided more outward than a head position of a passenger of a front row seat relative to the microphone.