Vehicle Back Door Subwoofer Assembly With Vibration-Canceling Exciter
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Solution Overview
Problem
The operation of a subwoofer on a vehicle's back door causes vibrations, leading to decreased sound pressure, sound quality, and unpleasant chattering sounds.
Innovation Solution
An assembled body comprising a subwoofer attached to the back door with its front face oriented outward and a back face oriented inward, and an exciter generating an output to cancel the vibrations, controlled by a sensor and control unit to reduce door vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a subwoofer is equipped on the back door to reproduce low-pitched sound, then the low-pitched sound reproduction capability is improved, but the back door vibration increases causing decreased sound pressure and sound quality
Solution Approach 1:
The exciter generates a counter-vibration signal in advance to cancel out the vibration caused by the subwoofer operation. The control unit processes the audio signal before it reaches the subwoofer, adding an anti-vibration component that preemptively counteracts the expected door vibration, thereby maintaining sound quality without reducing the subwoofer's power output.
Solution Approach 2:
The exciter acts as an intermediary device between the audio system and the back door structure. It generates controlled vibrations that counterbalance the harmful vibrations from the subwoofer, mediating the interaction between the audio output and the door structure to eliminate the harmful effects while preserving the useful function.
2Power
If a subwoofer is equipped on the back door to reproduce low-pitched sound, then the low-pitched sound reproduction capability is improved, but chattering sounds are generated which are unpleasant for passengers
Solution Approach 1:
The control unit processes the audio signal in advance to generate an anti-chattering signal that counteracts the chattering sounds produced by door vibration. This preliminary anti-action prevents the generation of unpleasant sounds while maintaining the subwoofer's ability to reproduce low-pitched sound effectively.
3Object-affected harmful factors
If vibration cancellation is implemented using an exciter, then back door vibration is reduced, but device complexity increases
Solution Approach 1:
The exciter serves multiple functions: it acts as both a vibration actuator and a signal processing element. By integrating the vibration cancellation function into an existing speaker component (the exciter), the system avoids adding separate dedicated vibration cancellation hardware, thereby reducing overall device complexity while maintaining effective vibration reduction.
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
Reduces back door vibrations effectively, enhancing sound quality and eliminating chattering sounds.
Implementation Method 1
an exciter attached to the back door, the exciter generating an output for cancelling vibration of an installation spot due to the subwoofer
Data Source
AI summary
An assembled body includes: a back door of a vehicle, the back door including an internal space; a subwoofer attached to the back door, a front face of the subwoofer being oriented to the outside of the back door, a back face of the subwoofer being oriented to an internal space side of the back door; and an exciter attached to the back door, the exciter generating an output for cancelling vibration of an installation spot due to the subwoofer.