Patent US3739096A successfully refreshed from Google Patents.
US3739096A
Expired / Lapsed
US
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Loudspeaker system having a cardioid directional response pattern
Assignee: US Philips Corp
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Filing: 1971-01-12
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Granted: 1973-06-12
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Expires: 1991-01-12
Abstract
Abstract A loudspeaker system, preferably in the form of a straight or concavely bent column in the or each lateral wall of which at least one slit has been formed which acts only as an acoustic resistor. This ensures that the cardioid directional response pattern remains constant over a wide frequency range. The directional response pattern may be influenced by varying the location and/or the width of the or each slit.
Inventors
- 👤 W Iding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:08
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/32; H04R1/34; H04R1/345; H04R1/347
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
132 words
A loudspeaker system having a cardioid directional response pattern comprising, at least one loudspeaker mounted at the front face of a substantially closed enclosure having lateral walls, at least one slit-shaped opening located in at least one of the lateral walls, the direction of length of said opening being substantially at right angles to the direction of the axis of the loudspeaker, acoustic damping material covering each slit, each slit being located so that the shortest distance of the slit from the most effectively active part of the diaphragm of the loudspeaker is about equal to the diameter of said diaphragm, whereby the upper limit of the frequency at which the cardioid effect still holds is about equal to the frequency associated with a wavelength equal to the circumference of the loudspeaker.
Claim 2
Dependent Claim
132 words
A loudspeaker system having a cardioid directional response pattern comprising, at least one loudspeaker mounted at the front face of a substantially closed enclosure having lateral walls, at least one slit-shaped opening located in at least one of the lateral walls, the direction of length of said opening being substantially at right angles to the direction of the axis of the loudspeaker, acoustic damping material covering each slit, each slit being located so that the shortest distance of the slit from the most effectively active part of the diaphragm of the loudspeaker is about equal to the diameter of said diaphragm, whereby the upper limit of the frequency at which the cardioid effect still holds is about equal to the frequency associated with a wavelength equal to the circumference of the loudspeaker.
Claim 3
Dependent Claim
31 words
A loudspeaker system as claimed in claim 1, characterized in that there is formed in said one lateral wall behind and parallel to each slit a second slit of equal shape.
Claim 4
Dependent Claim
20 words
A loudspeaker system as claimed in claim 1 wherein each slit may be displaced in the direction of its width.
Claim 5
Dependent Claim
16 words
A loudspeaker system as claimed in claim 1 wherein the width of each slit is adjustable.
Claim 6
Dependent Claim
22 words
A loudspeaker system as claimed in claim 1 characterized in that each slit comprises a large number of linearly disposed adjoining holes.
Claim 7
Dependent Claim
100 words
A loudspeaker system as claimed in claim 1 further comprising a plurality of other loudspeakers mounted at said front face in a line with said one loudspeaker, and a plurality of other slit-shaped openings located in said one lateral wall each with its direction of length substantially at right angles to the axial direction of its respective loudspeaker, acoustic damping material covering at least some of said other openings, and wherein the shortest distance of said other slits from the most effectively active part of the diaphragm of its respective loudspeaker is about equal to the diameter of said diaphragm.
Claim 8
Dependent Claim
63 words
A loudspeaker system as claimed in claim 6 wherein a like number of slit-shaped openings are located in a second lateral wall of the enclosure opposite said one lateral wall and in a mirror relationship to the openings in said one wall and to their respective loudspeakers, and acoustic damping material covering at least some of the openings in said second lateral wall.
Claim 9
Dependent Claim
23 words
A loudspeaker system as claimed in claim 6 wherein all of said openings are positioned with their longitudinal axes arranged in a line.
Claim 10
Dependent Claim
48 words
A loudspeaker system as claimed in claim 1 wherein said enclosure comprises a hollow cylinder with the loudspeaker mounted at one end wall and further comprising a plurality of other slit-shaped openings which, along with said one opening, are linearly aligned in a circle about the cylinder wall.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |