Electroacoustic devices with noise-reducing capability

• US 7,466,838 B1
• Filed: 12/08/2004
• Issued: 12/16/2008
• Est. Priority Date: 12/10/2003
• Status: Expired due to Fees

• Current Assignee: William T. Moseley
• Original Assignee: William T. Moseley
• Inventors: Moseley, William T.
• Primary Examiner(s): Ensey; Brian
• Application Number:
  US11/007,397
• Time in Patent Office: 1,469 Days
• Field of Search: 381/71, 381/71.6, 381/71.7, 381/72, 381/74, 381/370, 381/26, 381/309, 381/371, 381/372, 381/375
• US Class Current: 381/370
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17861 using additional means for damping sound, e.g. using sound absorbing panels
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: H04R 1/1008 Earpieces of the supra-aural or circum-aural type
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06

Abstract

New and improved electroacoustic devices each including at least one transducer assembly having one or more microphones typically mounted on a baffle plate and disposed in substantially the same acoustic plane as a speaker or speakers. In the various embodiments, at least one microphone and at least one speaker face the same or opposite directions. Each microphone may be parallel to or oriented at an angle with respect to the speaker. In other embodiments, the speaker includes a central opening or cavity in which a microphone having one of various orientations is provided. The orientations of the microphone or microphones with respect to the speaker or speakers minimize adverse noise reduction effects associated with the differences in sensitivities, frequency responses and phase responses and acoustic time delays between the microphones and the speaker or speakers, as well as minimize sound reflections that are picked up by the microphone or microphones.

Claims

1. An electroacoustic device having at least one transducer assembly comprising:

a generally planar baffle plate having inner cavity and outer cavity surfaces, and a microphone recess for positioning a microphone adjacent to the baffle plate surface;

a speaker having a speaker diaphragm for converting input electrical signals into sound waves, wherein the speaker is positioned facing the outer cavity baffle plate surface;

a microphone having a microphone diaphragm for converting sound waves into electrical signals, wherein the microphone is positioned adjacent to the baffle plate, the microphone faces generally the baffle plate surface, optional microphone acoustic foam overlays the microphone face and is positioned generally between the microphone face and the baffle plate surface, and the speaker diaphragm and the microphone diaphragm are positioned in substantially a common acoustic plane; and

a circuit operably connected to the speaker and the microphone for modifying the electrical signals from the microphone and transmitting the electrical signals to the speaker.

2. The device of claim 1 wherein the microphone and the speaker face generally opposite directions.

3. The device of claim 1 wherein the microphone and the speaker face generally the same direction.

4. The device of claim 1 further comprising a second microphone positioned adjacent to the baffle plate, wherein the microphone and the speaker face generally a first direction, the second microphone faces generally a second direction substantially opposite the first direction, and optional microphone acoustic foam overlays the second microphone face.

5. The device of claim 1 further comprising a second microphone positioned adjacent to the baffle plate, wherein the microphone faces a first direction, the speaker faces a second direction substantially opposite the first direction, the second microphone faces generally the second direction but is oriented at a non-perpendicular angle relative to the speaker, and optional microphone acoustic foam overlays the second microphone face.

6. The device of claim 1 further comprising a second microphone positioned adjacent to the baffle plate, wherein the microphone and the speaker face substantially the same direction, the second microphone faces generally the same direction but is oriented at a non-perpendicular angle relative to the speaker, and optional microphone acoustic foam overlays the second microphone face.

7. The device of claim 1 wherein the microphone is positioned adjacent to the baffle plate, and wherein the microphone faces an angle that is not perpendicular relative to the speaker.

8. The device of claim 7 wherein the microphone and the speaker face generally opposite directions.

9. The device of claim 8 further comprising a second microphone positioned adjacent to the baffle plate, wherein the second microphone and the speaker face generally the same direction, and optional microphone acoustic foam overlays the second microphone face.

10. The device of claim 8 further comprising a second microphone positioned adjacent to the baffle plate, and wherein the second microphone and the speaker face generally opposite directions, and optional microphone acoustic foam overlays the second microphone face.

11. The device of claim 7 wherein the microphone and the speaker face generally the same direction.

12. The device of claim 11 further comprising a second microphone positioned adjacent to the baffle plate, and wherein the second microphone and the speaker face substantially the same direction, and optional microphone acoustic foam overlays the second microphone face.

13. An electroacoustic device having at least one transducer assembly comprising:

a speaker comprising a housing, a speaker diaphragm for converting input electrical signals into sound waves, and a central cavity provided in the speaker, wherein the cavity has an opening to the front or to the rear of the speaker;

a microphone having a microphone diaphragm for converting sound waves into electrical signals, wherein the microphone is positioned within a central cavity of the speaker, the microphone faces generally a sound-reflecting surface, optional microphone acoustic foam overlays the microphone face and is positioned generally between the microphone face and the surface, and the speaker diaphragm and the microphone diaphragm are positioned in substantially a common acoustic plane; and

a circuit operably connected to the speaker and the microphone for modifying the electrical signals and transmitting the electrical signals to the speaker.

14. The device of claim 13 wherein the microphone and the speaker face substantially the same direction.

15. The device of claim 13 wherein the microphone and the speaker face substantially opposite directions.

16. The device of claim 13 wherein the microphone further is positioned at an angle that is neither perpendicular nor parallel relative to the speaker face.

17. The device of claim 16 wherein the microphone and the speaker face generally the same direction.

18. The device of claim 16 wherein the microphone and the speaker face generally opposite directions.

19. A method for minimizing undesirable noise reduction acoustic properties associated with differences in at least one of sensitivity, frequency response, and phase response or acoustic time delay between a microphone and a speaker in a transducer assembly, the method comprising orienting the microphone face generally toward an adjacent surface to minimize direct sound reflections that originate from the speaker and are received by the microphone from at least one of an inner or outer cavity of the transducer assembly.

20. The method of claim 19 wherein the surface is a baffle plate.