Patent US4264790A successfully refreshed from Google Patents.
US4264790A
Expired / Lapsed
US
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Directional microphone
Assignee: AKG Acoustics GmbH
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Filing: 1979-11-20
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Granted: 1981-04-28
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Expires: 1999-11-20
Abstract
Abstract A directional microphone of the interference type comprising a single elongated tube having one or more longitudinal slots or side apertures therein, at least one electroacoustic transducer provided at one end of the tube and an acoustic reflector assembly provided at an opposite free end zone of the tube, by which, preferably, sound waves of the upper audio frequency range are concentrated toward the sound inlet of the interference tube at the opposite free end zone thereof. A directional microphone which is easy to handle and unites the advantages of an interference microphone with that of a reflector microphone is thus obtained.
Inventors
- 👤 Alfred Zlevor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:45
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/32; H04R1/34; H04R1/342
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
66 words
A directional microphone comprising a single elongated interference tube having at least one aperture in the side thereof and two ends, at least one electroacoustic transducer connected in one end of said tube, and a concave acoustic reflector connected to the opposite end of said tube whereby sound waves of the upper audio frequency range are concentrated and directed into the opposite end of the tube.
Claim 2
Dependent Claim
66 words
A directional microphone comprising a single elongated interference tube having at least one aperture in the side thereof and two ends, at least one electroacoustic transducer connected in one end of said tube, and a concave acoustic reflector connected to the opposite end of said tube whereby sound waves of the upper audio frequency range are concentrated and directed into the opposite end of the tube.
Claim 3
Dependent Claim
55 words
A directional microphone according to claim 1, wherein said reflector is cup-shaped and has a central opening in the base thereof of a diameter substantially equal to that of said opposite end of said interference tube, said cup-shaped reflector being connected to said interference tube in the vicinity of said operating end at its base.
Claim 4
Dependent Claim
46 words
A directional microphone according to claim 2, wherein said reflector further includes a sleeve member extending from the base thereof, said sleeve member disposed over said interference tube in the vicinity of said opposite end and affixed thereto at a selected position on said interference tube.
Claim 5
Dependent Claim
13 words
A directional microphone according to claim 1, wherein said reflector is parabolically shaped.
Claim 6
Dependent Claim
37 words
A directional microphone according to claim 1, wherein said reflector has a different curved shape symmetrical about at least two intersecting planes passing through a principal apex of said elongated interference tube of different radaii of curvature.
Claim 7
Dependent Claim
52 words
A directional microphone according to claim 1, wherein said reflector has a central opening of a diameter larger than that of said interference tube in the vicinity of said opposite end, and at least one bracing element connected between said reflector and said interference tube in the vicinity of said opposite end.
Claim 8
Dependent Claim
48 words
A directional microphone according to claim 6 further including a sleeve provided over said interference tube in the vicinity of said opposite end connected to said brace, said sleeve positionable at a selected position on said intermediate tube in the vicinity of said opposite end and affixed thereto.
Claim 9
Dependent Claim
22 words
A directional microphone according to claim 6, wherein said reflector is in the shape of an annular section of a parabolic surface.
Claim 10
Dependent Claim
33 words
A directional microphone according to claim 6, wherein said reflector is of an oval shape symmetrical in curvature about two different intersecting planes passing through a principal axis of said elongated interference tube.
Claim 11
Dependent Claim
62 words
A directional microphone according to claim 1, further including a second smaller reflector than said first mentioned reflector concave toward said opposite end of said interference tube disposed concentric with said first mentioned reflector and interference tube whereby sound waves are first collected by said first mentioned reflector and deflected by said smaller reflector into said opposite end of said interference tube.
Claim 12
Dependent Claim
17 words
A directional microphone according to claim 1, wherein said reflector is detachably connected to said interference tube.
Claim 13
Dependent Claim
18 words
A directional microphone according to claim 1, wherein said reflector forms an integral part of said interference tube.
Claim 14
Dependent Claim
30 words
A directional microphone according to claim 4, wherein said parabolically shaped reflector is positioned so that its focus is in the plane of said opposite end of said interference tube.
References Cited (Backward Citations)
US2228886A
Cited
US3305043A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-04-27 | 1984-10-27 | 1985-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-27 | 1988-10-27 | 1989-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-27 | 1992-10-27 | 1993-04-28 | $7700.00 | Window Closed / Lapsed |