Patent US4504704A successfully refreshed from Google Patents.
US4504704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loudspeaker system
Assignee: Pioneer Corp
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Filing: 1983-08-30
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Granted: 1985-03-12
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Expires: 2003-08-30
Abstract
Abstract A dynamic loudspeaker unit having a voice coil formed with two windings in which a capacitor is connected in series to a parallel circuit, one circuit arm being composed of a series circuit of one of the two windings and an inductor and the other circuit arm being composed of the remaining winding. The dynamic loudspeaker unit thus constructed is housed in a bass-reflex type cabinet, whereby a shoulder characteristic having a large Q in a bass zone can be obtained, and due to a combination of the inductor and the capacitor, a desired lowest resonance frequency lower than an actual lowest resonance frequency can be selected. Thus, the reproducible bass range can be extended.
Inventors
- 👤 Takashi Ohyaba
- 👤 Minoru Kamishima
- 👤 Shozo Kinoshita
- 👤 Tetsuo Kawamura
- 👤 Hiroaki Matsuhisa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:49
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/04; H04R3/08; H04R3/12; H04R3/14; H04R2209/00; H04R2209/041; H04R9/00; H04R9/06; H04R9/063
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
63 words
A loudspeaker system including a dynamic loudspeaker unit, said loudspeaker unit comprising: a bobbin; a voice coil having first and second windings both wound around said bobbin, said first winding being connected in series to an inductor to form a series circuit, said series circuit and said second winding forming a parallel circuit; and a capacitor connected in series to said parallel circuit.
Claim 2
Dependent Claim
63 words
A loudspeaker system including a dynamic loudspeaker unit, said loudspeaker unit comprising: a bobbin; a voice coil having first and second windings both wound around said bobbin, said first winding being connected in series to an inductor to form a series circuit, said series circuit and said second winding forming a parallel circuit; and a capacitor connected in series to said parallel circuit.
Claim 3
Dependent Claim
38 words
A loudspeaker system as claimed in claim 1, further comprising a first variable resistor interposed between said first winding and said inductor of said series circuit, and a second variable resistor connected in series to said second winding.
Claim 4
Dependent Claim
19 words
A loudspeaker system as claimed in claim 1, wherein said loudspeaker unit is housed in a bass-reflex type cabinet.
Claim 5
Dependent Claim
19 words
A loudspeaker system as claimed in claim 1, wherein said loudspeaker unit is housed in a closed type cabinet.
Claim 6
Dependent Claim
19 words
A loudspeaker system as claimed in claim 2, wherein said loudspeaker unit is housed in a bass-reflex type cabinet.
Claim 7
Dependent Claim
19 words
A loudspeaker system as claimed in claim 2, wherein said loudspeaker unit is housed in a closed type cabinet.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-11 | 1988-09-10 | 1989-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-11 | 1992-09-10 | 1993-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-11 | 1996-09-10 | 1997-03-12 | $7700.00 | Window Closed / Lapsed |