Vehicle Audio Phase Shifter for Rear Seat Interference

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Solution Overview

Problem

Conventional sound reproducing apparatuses in vehicles suffer from sound quality deterioration due to sound wave interference, particularly around 100Hz, when output units are placed at the rear seat, leading to worsened gain characteristics.

Innovation Solution

The implementation of a sound reproducing apparatus with phase differences between output units at the front and rear seats, utilizing multiple phase shifters and filters to control and optimize sound wave interference, thereby reducing sound quality degradation across various directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If output units are disposed at the rear seat side, then the sound reproducing apparatus can provide sound output to rear seat passengers, but sound wave interference occurs in the front and rear direction causing worsening of gain characteristic near 100Hz

Engineering Contradiction:

Improvesound output capability to rear seatVSAvoidgain characteristic

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing separate phase shifters (first phase shifter and second phase shifter) that operate independently for front and rear output units. Each phase shifter is configured to compensate for sound wave interference specific to its designated output unit, allowing different phase correction characteristics for front and rear seats. This localized approach enables the system to maintain accurate gain characteristics near 100Hz for both front and rear output units simultaneously.

Inventive Principle:

Principle #3Local quality

2Reliability

If phase shifter is connected to music signal source and output signal is phase-shifted, then specific frequency phase reversal can be prevented, but sound wave interference in front and rear direction cannot be prevented

Engineering Contradiction:

Improvephase reversal preventionVSAvoidsound wave interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the phase shifting function into separate first and second phase shifters, where the first phase shifter processes signals for front output units and the second phase shifter processes signals for rear output units. This segmentation allows each phase shifter to independently compensate for sound wave interference in its specific direction, thereby preventing both phase reversal and sound wave interference effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The phase shifters act as intermediary devices between the music signal source and the output units. By inserting phase shifters in the signal path, the system can compensate for the harmful phase reversal and sound wave interference effects without changing the fundamental architecture of the sound reproducing apparatus. The phase shifters mediate the signal to achieve accurate sound reproduction in both front and rear directions.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration effectively improves sound quality by minimizing interference-related issues, allowing for better sound distribution and quality across the vehicle, with the option to adjust settings via a controller for optimal listening experience.

Implementation Method 1

phase shifter 2 is connected to music signal source 1, and the signal from music signal source 1 is phase-shifted by phase shifter 2

Methodology Applied

Scientific EffectPhase shift:

Implementation Method 2

sound wave interference that occurs in the front and rear direction of vehicle 7

Methodology Applied

Scientific EffectSound wave interference: Interference

Data Source

PatentEP1871142B1Audio reproducing device and vehicle using the audio reproducing device

Publication Date: 2018.02.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

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AI summary

The sound reproducing apparatus comprises a signal source, a first output unit connected to the signal source via a first power amplifier, a first phase shifter connected to the signal source, a second output unit connected to the first phase shifter via a second power amplifier, a second phase shifter connected to the signal source, a third output unit connected to the second phase shifter via a third power amplifier, a fourth phase shifter connected to a third phase shifter, and a fourth output unit connected to the fourth phase shifter via a fourth power amplifier, wherein the first output unit and the second output unit are in right and left relation with each other, the third output unit and the fourth output unit are in right and left relation with each other, a group of the first output unit and the second output unit and a group of the third output unit and the fourth output unit are in front and rear relation with each other. The vehicle is equipped with the sound reproducing apparatus. In this way, it is possible to obtain a sound reproducing apparatus improved in sound quality and a vehicle using the sound reproducing apparatus.