Patent US3909531A successfully refreshed from Google Patents.
US3909531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic transducer system
Assignee: Custom Electronics Inc
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Filing: 1974-03-25
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Granted: 1975-09-30
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Expires: 1994-03-25
Abstract
Abstract Equal-sized speaker cones are housed in equal-sized closed compartments in a system of loudspeakers, a housing therefor and electrical crossover circuits which system results in substantially equal acoustic treatment for the midrange of acoustic frequencies and the lower or bass range of acoustic frequencies. The effective resonant frequency for both the bass and midrange speaker cones is primarily determined by the compliance of entrapped air within the respectively corresponding speaker enclosures, thus insuring that both the midrange and bass frequencies are produced with minimum distortion. Other combined features of the overall acoustic system assist in providing substantially equal acoustic treatment for the midrange and bass frequencies.
Inventors
- 👤 Jan P Plummer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:39
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/26; H04R1/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
218 words
An acoustic transducer system for use with an audio frequency electrical signal amplifier, said system comprising: a cabinet structure having separate closed upper and lower speaker housing chambers of substantially equal volume, electrical input connections adapted for connection to the electrical output of an audio frequency electrical signal amplifier, a bass loudspeaker housed in said lower chamber and having a speaker cone of a first predetermined diameter, said bass loudspeaker being adapted for transducing electrical signals into acoustic signals within a first lower frequency range, a midrange loudspeaker housed in said upper chamber and having a speaker cone of a second predetermined diameter equal to said first predetermined diameter, said midrange loudspeaker being adapted for transducing electrical signals into acoustic signals within a second middle frequency range which, at its lower frequency portion, overlaps the upper frequency portion of the first lower frequency range, each of said chambers beiNg defined by solid, nonapertured walls on all but a front side, which front side is also solid except for an aperture therein directly behind which the respectively associated loudspeaker is mounted, electrical circuit means for electrically connecting said electrical input connections to said bass and midrange loudspeakers including an electrical crossover network which effectively prevents electrical signals below a predetermined crossover frequency from being applied to said midrange loudspeaker.
Claim 2
Dependent Claim
218 words
An acoustic transducer system for use with an audio frequency electrical signal amplifier, said system comprising: a cabinet structure having separate closed upper and lower speaker housing chambers of substantially equal volume, electrical input connections adapted for connection to the electrical output of an audio frequency electrical signal amplifier, a bass loudspeaker housed in said lower chamber and having a speaker cone of a first predetermined diameter, said bass loudspeaker being adapted for transducing electrical signals into acoustic signals within a first lower frequency range, a midrange loudspeaker housed in said upper chamber and having a speaker cone of a second predetermined diameter equal to said first predetermined diameter, said midrange loudspeaker being adapted for transducing electrical signals into acoustic signals within a second middle frequency range which, at its lower frequency portion, overlaps the upper frequency portion of the first lower frequency range, each of said chambers beiNg defined by solid, nonapertured walls on all but a front side, which front side is also solid except for an aperture therein directly behind which the respectively associated loudspeaker is mounted, electrical circuit means for electrically connecting said electrical input connections to said bass and midrange loudspeakers including an electrical crossover network which effectively prevents electrical signals below a predetermined crossover frequency from being applied to said midrange loudspeaker.
Claim 3
Dependent Claim
38 words
An acoustic transducer system as in claim 1 further comprising: a pedestal structure of predetermined dimensions attached to the underside of said cabinet structure for maintaining the lower chamber at a predetermined height above an underlying floor surface.
Claim 4
Dependent Claim
63 words
An acoustic transducer system as in claim 1 wherein the internal surfaces of both of said chambers are lined with a predetermined thickness of porous, resilient material for displacing a predetermined volume of air within the chambers and wherein the lower chamber also contains a further quantity of the porous, resilient material for displacing an additional volume of air within the lower chamber.
Claim 5
Dependent Claim
20 words
An acoustic transducer system as in claim 3 wherein said porous, resilient material comprises a layer of fiberglass insulation material.
Claim 6
Dependent Claim
25 words
An acoustic tranducer system as in claim 1 wherein said electrical crossover network comprises a capacitor for producing a 3 db per octave crossover rate.
Claim 7
Dependent Claim
48 words
An acoustic transducer system as in claim 1 wherein the crossover network has a 3 db crossover frequency at approximately 125 Hz and wherein the bass loudspeaker continues to effectively operate up to approximately 600 Hz thus producing an overlapping range from approximately 125 Hz to 600 Hz.
Claim 8
Dependent Claim
50 words
An acoustic transducer system as in claim 1 further comprising a high frequency range transducer housed directly behind a second aperture in said upper chamber and another electrical crossover network which effectively prevents electrical signals below a second predetermined crossover frequency from being applied to said high frequency range transducer.
Claim 9
Dependent Claim
122 words
A stereo acoustic transducer system comprising a pair of systems as defined in claim 7 wherein one such system is intended to be placed on the left side of a listener for use with signals representing left-side sounds and the other such system is intended to be placed on the right side of a listener for use with signals representing right-side sounds, wherein: the second aperture is disposed at the upper right-hand corner of the front side of the upper chamber in the system intended for the right side of a listener, and the second aperture is disposed at the upper left-hand corner of the front side of the upper chamber in the system intended for the left side of a listener.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |