Vehicle Sound Duct for Efficient Low-Frequency Audio Coupling

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Solution Overview

Problem

Automobile interior spaces face challenges in producing high-quality audio at high volumes without distortion, particularly due to road and vehicle noise, especially at highway speeds, where existing systems struggle to efficiently couple low-frequency audio signals to desirable acoustic modes within the passenger compartment.

Innovation Solution

A sound reproduction system featuring a removable module with an electroacoustic transducer and a sound duct that repositions the drive point for low-frequency audio signals from the instrument panel to a more efficient location, such as the intersection of the forward bulkhead and floor, utilizing a waveguide, bass reflex port, and passive radiators to enhance sound coupling and pressure levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electroacoustic transducer is placed in the instrument panel, then the device complexity is reduced and installation is simplified, but the sound pressure levels and acoustic response are insufficient

Engineering Contradiction:

Improveinstallation complexityVSAvoidsound pressure levels

Core Design Contradiction:

Device complexityVSStress or pressure

Solution Approach 1:

A sound duct acts as an intermediary element between the electroacoustic transducer in the instrument panel and the desired acoustic drive point. The duct includes acoustic structures (waveguide, bass reflex port, acoustic volume) that mediate the sound transmission, transforming the insufficient sound pressure at the transducer location into effective sound delivery at the optimized drive point location.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention transitions from a two-dimensional instrument panel mounting to a three-dimensional acoustic pathway. The sound duct extends into the vehicle interior space, utilizing vertical and lateral dimensions to route sound from the front-mounted transducer to optimized drive points at the forward bulkhead or floor intersections, where acoustic modes are more effective.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Stress or pressure

If the sound duct outlet is positioned at the forward bulkhead or floor intersection, then the acoustic response and sound pressure levels are improved, but the device complexity increases due to the ducting required

Engineering Contradiction:

Improvesound pressure levelsVSAvoidducting complexity

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The sound duct is designed to perform multiple functions simultaneously: it routes sound from the transducer, provides acoustic impedance matching through the bass reflex port, creates acoustic volume for resonance, guides sound waves through the waveguide section, and delivers sound to optimized drive points. This multi-functionality reduces the need for separate acoustic components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the sound duct with the instrument panel assembly, integrating the acoustic structures (waveguide, bass reflex port, acoustic volume) into the existing vehicle interior architecture. The duct is contained within or integrated with the instrument panel, combining the mounting function with the acoustic transmission function in a single integrated component.

Inventive Principle:

Principle #5Merging (Combining)

3Power

If high volume audio is produced to overcome road and vehicle noise, then the audio quality is improved, but distortion increases

Engineering Contradiction:

Improveaudio volumeVSAvoidaudio distortion

Core Design Contradiction:

PowerVSLoss of information

Solution Approach 1:

The sound duct is designed with specific acoustic parameters (cross-sectional area variations, length, bass reflex port dimensions, acoustic volume) that optimize sound transmission efficiency. These parameter optimizations allow the system to achieve higher sound pressure levels with reduced distortion by improving the coupling between the transducer and the acoustic modes of the vehicle interior.

Inventive Principle:

Principle #35Parameter changes

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 improves the quality and efficiency of low-frequency audio signal delivery, achieving greater sound pressure levels and improved acoustic response by effectively coupling low-frequency sounds to desirable acoustic modes within the vehicle, even at high speeds.

Implementation Method 1

an electroacoustic transducer and a sound duct that carries the sound from the electroacoustic transducer

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 2

The sound duct includes a waveguide

Methodology Applied

Scientific EffectAcoustic waveguide: Waveguide

Implementation Method 3

The sound duct includes a bass reflex port

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Implementation Method 4

A first passive radiator is attached to the sound duct at the outlet of the duct

Methodology Applied

Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Data Source

PatentUS8144894B2Ducting sound

Publication Date: 2012.03.27 BOSE CORP

AI summary

A sound reproduction system in a vehicle includes an acoustic package including an electroacoustic transducer and a sound duct that carries the sound from the electroacoustic transducer. The sound duct carries the sound to an outlet at a location in the vehicle at which radiated sound efficiently drives selected audio modes of the vehicle.