Waveguide for shaping sound waves

• US 9,392,358 B2
• Filed: 10/28/2014
• Issued: 07/12/2016
• Est. Priority Date: 10/28/2014
• Status: Active Grant

• Current Assignee: Bosch Security Systems Incorporated (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH
• Inventors: DeLay, Mark, Carlson, David
• Primary Examiner(s): Phillips, Forrest M
• Application Number:
  US14/525,874
• Publication Number:
  US 20160119711A1
• Time in Patent Office: 623 Days
• Field of Search: 181/196, 181/185, 181/192, 181/187, 181/188, 181/155
• US Class Current: 1/1
• CPC Class Codes: G10K 11/22 for conducting sound through hollow pipes, e.g. speaking tubes
• CPC Class Codes: G10K 11/30 using refraction, e.g. acoustic lenses
• CPC Class Codes: G10K 13/00 Cones, diaphragms, or the like, for emitting or receiving sound in general for electromechanical transducers H04R7/00
• CPC Class Codes: H04R 1/345 for loudspeakers
• CPC Class Codes: H04R 2400/13 Use or details of compression drivers

Abstract

An acoustic waveguide includes a plurality of projections to redirect sound waves to obtain a desired wave front, such as a flat plane wave front or an asymmetric curved wave front. The waveguide includes two waveguide members that are mirror images of each other. The waveguide members have corresponding vanes and projections. The waveguide includes an essentially circular input opening for alignment with a compression driver and provides a substantially rectangular output opening from the waveguide.

Claims

1. An acoustic waveguide for shaping waves comprising:

walls defining a chamber having an input end and an output end with the chamber defined therebetween;

an opening at the input end for receiving sound waves from an acoustic transducer;

an opening at the output end for outputting sound waves;

the chamber opening in a first direction from the input end to the output end, the first direction being transverse to a path from the input end to the output end, the chamber defining a first inner face and a second inner face opposing and facing the first inner face;

a plurality of projections provided on the first inner face and projecting outwardly therefrom; and

at least two vanes disposed on the first inner face of the chamber, the vanes extending from proximate the opening at the input end and generally toward the output end.

2. The waveguide of claim 1, wherein the vanes have a substantially constant thickness along the length thereof.

3. The waveguide of claim 1, wherein the opening at the input end comprises a circular opening and the opening at the output end comprises a generally rectangular opening.

4. The waveguide of claim 1, wherein the vanes and the projections extend substantially across the entirety of the cavity from the first inner face to the second inner face.

7. The waveguide of claim 1, wherein the plurality of projections comprises at least twenty cylindrical projections.

9. The waveguide of claim 7, wherein at least four of the cylindrical projections are disposed on the inner face a distance from the output opening that is closer than a distance from a closest end of the vane from the output opening.

10. The waveguide of claim 1, wherein the projections comprise cylindrical projections and the cylindrical projections are disposed to output an asymmetric curved wavefront.

11. The waveguide of claim 1, wherein the projections comprise cylindrical projections and the cylindrical projections are disposed to output a flat plane wave front.

12. The waveguide of claim 1, further comprising a horn disposed at the output end of the waveguide.

13. The waveguide of claim 1, wherein a majority of the projections are disposed closer to the output end than to the input end of the waveguide.

5. An acoustic waveguide for shaping waves comprising:

walls defining a chamber having an input end and an output end with the chamber defined therebetween;

an opening at the input end for receiving sound waves from an acoustic transducer;

an opening at the output end for outputting sound waves;

the chamber opening in a first direction from the input end to the output end, the first direction being transverse to a path from the input end to the output end, the chamber defining a first inner face and a second inner face opposing and facing the first inner face;

a plurality of projections provided on the first inner face and projecting outwardly therefrom;

at least two vanes disposed on the first inner face of the chamber, the vanes extending from proximate the opening at the input end and generally toward the output end;

a plurality of projections provided on the second inner face and projecting outwardly therefrom, the projections on the second inner face being in alignment with the projections on the first inner face; and

at least two vanes disposed on the second inner face of the chamber, the vanes on the second inner face of the chamber being in alignment with the vanes on the first face of the chamber,

wherein the waveguide comprises two waveguide members that are mirror images of each other, wherein the first inner face is associated with a first one of the waveguide members and the second inner face is associated with a second one of the waveguide members.

6. The waveguide of claim 5, further comprising a gasket provided between the first waveguide member and the second waveguide member, the gasket providing a seal between the vanes on the first inner face and the second inner face, and the gasket providing a seal between the projections provided on the first inner face and the projections provided on the second inner face.

8. The waveguide of claim 6, wherein the plurality of cylindrical projections comprise at least thirty cylindrical projections and the at least two vanes comprises at least three vanes, wherein one of the vanes is centrally oriented along an axis of the waveguide beginning proximate the input opening and ending near the output opening.

14. An acoustic waveguide for shaping waves comprising:

walls defining a chamber having an input end and an output end with a chamber defined therebetween;

an opening at the input end for receiving sound waves from an acoustic transducer;

a substantially rectangular opening at the output end for outputting sound waves;

the chamber opening in a first direction from the input end to the output end, the first direction being transverse to a path from the input end to the output end, the chamber defining a first inner face and a second inner face opposing and facing the first inner face, and the opening chamber in the first direction defining the height of the rectangular opening at the output end;

a plurality of projections provided on the first inner face and projecting outwardly therefrom; and

at least one vane disposed on the first inner face of the chamber, the vane extending from proximate the opening at the input end and generally toward the output end.

15. The acoustic waveguide of claim 14, wherein the plurality of projections are disposed away from the input end of the waveguide, wherein sound travels at least about 40% of the distance from the input end to the output end of the waveguide before contacting one of the projections.

16. The acoustic waveguide of claim 14, wherein the at least one vane comprises one of at least three vanes extending from proximate the opening at the input end and generally toward the output end.

17. The waveguide of claim 14, wherein the plurality of projections comprise at least thirty projections and the at least one vane comprises at least three vanes, wherein one of the vanes is centrally oriented along an axis of the waveguide beginning proximate the input opening and ending near the output opening.