Speaker Horn With Quartic Curve Sound Path

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Solution Overview

Problem

Horns for speakers have narrow directivity characteristics in specific directions but suffer from sound leakage, which degrades their directivity due to reflected sound from inner walls, leading to inefficient sound distribution.

Innovation Solution

A horn speaker design with a horn body featuring a circular first opening, a quadrilateral second opening, and a quartic curve sound path connecting them, ensuring the inner surface area increases proportionally with distance, enhancing directivity characteristics of mid- to high-frequency ranges by maintaining narrow directivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a horn has narrow directivity characteristics in specific directions, then sound is concentrated in desired directions, but sound leaks from the horn in other directions due to reflection from inner walls

Engineering Contradiction:
Improvedirectivity characteristicsVSAvoidsound leakage
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies acoustic absorption material to the inner walls of the horn to convert harmful sound reflections into beneficial sound absorption. This eliminates the harmful effect of sound leakage and reflection while maintaining the narrow directivity characteristics in desired directions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent selectively applies acoustic absorption material to specific regions of the horn's inner walls where sound reflection problems occur. This localized treatment maintains directivity in critical directions while absorbing sound in other directions to prevent leakage.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If acoustic absorption material is added to the horn, then sound leakage is reduced, but device complexity increases

Engineering Contradiction:
Improvesound leakageVSAvoidhorn structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The acoustic absorption material is applied only to specific inner wall surfaces of the horn where sound reflection occurs, rather than treating the entire structure. This localized approach reduces sound leakage while minimizing the increase in device complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses acoustic absorption material that can be easily applied and replaced, such as foam or fabric materials, rather than integrating complex permanent structures. This reduces overall device complexity while effectively addressing sound leakage.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The design significantly increases directivity characteristics of mid- to high-frequency sound output, reducing side lobes and improving sound distribution by optimizing the shape and length of the horn body.

Implementation Method 1

a sound path (38) connecting the first opening (28) and the second opening (34). In a cross section including a central axis (40) of the horn body (24), an inner surface of the sound path (38) flares out in a quartic curve from the first opening (28) toward the second opening (34)

Methodology Applied
Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

The horn has a reflective curved surface with a parabolic section having the quadrilateral opening as a focal position

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Data Source

PatentEP3713249B1Horn for speakers and horn speaker
Publication Date: 2021.12.22 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3713249B1 patent drawingFigure 1
  • EP3713249B1 patent drawingFigure 2
  • EP3713249B1 patent drawingFigure 3

AI summary

A horn for speakers (6) includes a horn body (24) including: a first opening (28) located in a first end portion (26) and having a circular shape; a second opening (34) located in a second end portion (32) and having a shape different from the circular shape; and a sound path (38) connecting the first opening (28) and the second opening (34). In a cross section including a central axis (40) of the horn body (24), an inner surface of the sound path (38) flares out in a quartic curve from the first opening (28) toward the second opening (34). A length (L2) from the first end portion (24) to the second end portion (32) of the horn body (24) is at least 0.8 times as large as a radius (R) of the first opening (28).