Acoustically transparent waveguide

Patent metadata

Field	Value
Publication number	US-2016192062-A1
Application number	US-201414584517-A
Country	US
Kind code	A1
Filing date	Dec 29, 2014
Priority date	Dec 29, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

The invention provides a high-frequency acoustic waveguide for use in coaxial loudspeaker systems. The waveguide is made up of a plurality of walls that define a conduit with an input end and an output end. Each of the walls includes a mask layer and a perforation layer. The mask layer has a plurality of holes sized and shaped to make the mask layer acoustically transparent to sound waves below a crossover frequency. The perforation layer has a plurality of micro-perforations sized and shaped to make the perforation layer acoustically opaque to sound waves above the crossover frequency. The waveguide directs sound waves above the crossover frequency, and is acoustically transparent to sound waves below the crossover frequency.

First claim

1 . A high-frequency acoustic waveguide for use in coaxial loudspeaker systems, the waveguide comprising:
a plurality of walls defining a conduit having an input end and an output end, the plurality of walls including a mask layer and a perforation layer; wherein the mask layer includes a plurality of openings sized and shaped to make the mask layer acoustically transparent to sound waves below a crossover frequency, the perforation layer has a plurality of micro-perforations sized and shaped to make the perforation layer acoustically opaque to sound waves above the crossover frequency, and the waveguide directs sound waves above the crossover frequency, and is acoustically transparent to sound waves below the crossover frequency.

2 . The waveguide of claim 1 , wherein the perforation layer is positioned on an inner surface of the mask layer and covers the plurality of openings.

3 . The waveguide of claim 1 , wherein the perforation layer is positioned on an outer surface of the mask layer and covers the plurality of openings.

4 . The waveguide of claim 1 , wherein the perforation layer includes a plurality of screens, each of the plurality of screens having a plurality of micro-perforations sized and shaped to make the screen acoustically opaque to sound waves above the crossover frequency, and each of the plurality of screens is positioned to cover one of the plurality of openings in the mask layer.

5 . The waveguide of claim 4 , wherein the plurality of screens are positioned on an inner surface of the mask layer.

6 . The waveguide of claim 4 , wherein the plurality of screens are positioned on an outer surface of the mask layer.

7 . The waveguide of claim 1 , wherein the mask layer and the perforation layer are formed from a single layer of material.

8 . A coaxial loudspeaker system, the system comprising:
a low-frequency section having at least one low-frequency transducer coupled to a low-frequency waveguide, the at least one low-frequency transducer emitting sound at frequencies below a crossover frequency; and a high-frequency section including at least one high-frequency transducer emitting sound at frequencies above the crossover frequency; a high-frequency waveguide having a plurality of walls defining a conduit having an input end and an output end, the plurality of walls including a mask layer and a perforation layer, wherein the mask layer includes a plurality of openings sized and shaped to make the mask layer acoustically transparent to sound waves below the crossover frequency, the perforation layer has a plurality of micro-perforations sized and shaped to make the perforation layer acoustically opaque to sound waves above the crossover frequency; wherein the at least one high-frequency transducer is coupled to the high-frequency waveguide; wherein the high-frequency section is positioned within the low-frequency section, the high-frequency waveguide directs sound waves above the crossover frequency, and is acoustically transparent to sound waves below the crossover frequency.

9 . The system of claim 8 , wherein the perforation layer is positioned on an inner surface of the mask layer and covers the plurality of openings.

10 . The system of claim 8 , wherein the perforation layer is positioned on an outer surface of the mask layer and covers the plurality of openings.

11 . The system of claim 8 , wherein the perforation layer includes a plurality of screens, each of the plurality of screens having a plurality of micro-perforations sized and shaped to make the screen acoustically opaque to sound waves above the crossover frequency, and each of the plurality of screens is positioned to cover one of the plurality of openings in the mask layer.

12 . The system of claim 11 , wherein the plurality of screens are positioned on an inner surface of the mask layer.

13 . The system of claim 11 , wherein the plurality of screens are positioned on an outer surface of the mask layer.

14 . The system of claim 8 , wherein the mask layer and the perforation layer are formed from a single layer of material.

Assignees

• Bosch Gmbh Robert

Inventors

• Delay Mark Thomas
• Carlson David Edward

Classifications

• H04R1/20 Primary

  Arrangements for obtaining desired frequency or directional characteristics (for stereophonic purpose H04R5/00) · CPC title

• H04R1/30

  Combinations of transducers with horns, e.g. with mechanical matching means {, i.e. front-loaded horns}(horns in general G10K; {transducer enclosures or mountings using a back-loaded horn H04R1/2861; application of horns as guiding means to obtain a predetermined directivity characteristic H04R1/345}) · CPC title

• H04R1/26

  Spatial arrangements of separate transducers responsive to two or more frequency ranges · CPC title

• H04R1/24 Primary

  Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges · CPC title

• G10K13/00

  Cones, diaphragms, or the like, for emitting or receiving sound in general (for electromechanical transducers H04R7/00) · CPC title