EARPHONE HAVING SOUND DETOUR PATH

• US 3,586,794 A
• Filed: 11/01/1968
• Issued: 06/22/1971
• Est. Priority Date: 11/04/1967
• Status: Expired due to Term

• Current Assignee: Michaelis Erhard
• Original Assignee: Michaelis Erhard
• Inventors: MICHAELIS ERHARD
• Application Number:
  US04/772,636
• Time in Patent Office: 963 Days
• US Class Current: 381/372
• CPC Class Codes: H04R 1/225 for telephonic receivers
• CPC Class Codes: H04R 9/10 Telephone receivers

Abstract

A dynamic acoustic transducer which is worn in the vicinity of the ear, with sound outlets on both sides of the diaphragm, one of them acting directly on the auditory canal, while one or more others reach the entrance to the auditory canal only via detours is shown. The resonant frequency of the diaphragm lies in the lower transmission range. Means in the form of a spacer are provided which prevent a sealing off of the entrance to the auditory canal with respect to the air space surrounding the head and the acoustic transducer. The spacer is made of acoustically damping material and may be in the form of an acoustic foam cushion. The spacer may be provided with one or more openings on its surface between the diaphragm and the auditory canal. The sound outlet or outlets from the side of the diaphragm facing away from the ear to the air space surrounding the acoustic transducer and the head are conducted via acoustic conduits which are terminated with their characteristic impedance on the end discharging into the air space. The acoustic conduits are so dimensioned that their characteristic impedance coupled to the diaphragm damps the diaphragm.

Claims

1. A dynamic acoustic transducer, suitable for being used as an earphone, comprising a. a diaphragm having a resonant frequency in the lower transmission range, b. at least one front sound outlet on one side of said diaphragm suitable for acting directly on the entrance to the auditory canal, c. at least one year sound outlet on the other side of said diaphragm which provides a detour path for sound, and d. acoustically damping spacer means for preventing the sealing off of the entrance to the auditory canal with respect to the air space surrounding the acoustic transducer, sound reaching said auditory canal by a first path comprising said front sound outlet and acoustically damping spacer means, and by a second path comprising said rear sound outlet and said acoustically damping means.

2. A dynamic acoustic transducer according to claim 1, wherein the acoustic damping material is a foam material.

3. A dynamic acoustic transducer according to claim 2, wherein the acoustic damping material is an acoustic foam cushion.

4. A dynamic acoustic transducer according to claim 1, wherein the acoustically damping spacer means has at least one opening on its surface between the diaphRagm and the entrance to the auditory canal.

5. A dynamic acoustic transducer according to claim 1, wherein at least one rear sound outlet extends from the side of the diaphragm away from the ear to the air space surrounding the acoustic transducer via acoustic conduits which are terminated with their characteristic impedance on the end discharging into the air space.

6. A dynamic acoustic transducer according to claim 5, wherein the acoustic conduits are so dimensioned that their characteristic impedance coupled to the diaphragm damps the diaphragm.

7. A dynamic acoustic transducer according to claim 1, comprising a plurality of rear sound outlets.

8. A dynamic acoustic transducer according to claim 7, wherein the plurality of rear sound outlets comprise four sound outlets.

9. A dynamic acoustic transducer according to claim 7, wherein the plurality of rear sound outlets are distributed substantially uniformly over a circle.

10. A dynamic acoustic transducer according to claim 1, wherein said acoustically damping spacer means covers the outward facing surface of a cover member.

11. A dynamic acoustic transducer according to claim 1, wherein a treble resonator is positioned between said diaphragm and said acoustically damping spacer means.

12. A dynamic acoustic transducer according to claim 1, wherein the acoustically damping spacer means is removable from the earphone.