Patent US4468806A successfully refreshed from Google Patents.
US4468806A
Expired / Lapsed
US
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Stero speaker mixer
Assignee: Individual
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Filing: 1983-05-13
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Granted: 1984-08-28
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Expires: 2003-05-13
Abstract
Abstract A stereo speaker mixer is disclosed for coupling a plurality of pairs of stereo speakers to the output of an amplifier. A plurality of manually operable selection switches is provided for selecting and coupling in parallel a particular number of speaker pairs. The position of the these switches is detected and decoded by digital logic circuitry which is utilized to couple an appropriate value impedance matching device between the amplifier and the selected number of speaker pairs in response to the actual number of speaker pairs selected. A safety circuit is provided which ensures that at least one pair of speakers is always coupled to the amplifier output without regard to the position of the selection switches, thereby preventing the sudden and unexpected application of amplifier output to a speaker pair.
Inventors
- 👤 Joe L. Gaulden
- 👤 Perry L. Compton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:38
CPC Classifications
H; H04; H04R; H04R3/00; H04R3/12; H04R2420/00; H04R2420/03
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
90 words
Apparatus for coupling a plurality of speaker pairs to the output of an amplifier comprising: switching means having multiple selectable states for coupling in parallel a selected number of speaker pairs from said plurality of speaker pairs; a plurality of pairs of impedance matching resistive devices; and digital logic means coupled to said switching means for automatically coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the states of said switching means.
Claim 2
Dependent Claim
90 words
Apparatus for coupling a plurality of speaker pairs to the output of an amplifier comprising: switching means having multiple selectable states for coupling in parallel a selected number of speaker pairs from said plurality of speaker pairs; a plurality of pairs of impedance matching resistive devices; and digital logic means coupled to said switching means for automatically coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the states of said switching means.
Claim 3
Dependent Claim
16 words
The apparatus according to claim 1 wherein said plurality of speaker pairs comprises four speaker pairs.
Claim 4
Dependent Claim
22 words
The apparatus according to claim 2 wherein said plurality of pairs of impedance matching resistive devices comprises three pairs of precision resistors.
Claim 5
Dependent Claim
20 words
The apparatus according to claim 1 wherein said digital logic means includes a digital decoder coupled to said switching means.
Claim 6
Dependent Claim
48 words
The apparatus according to claim 4 wherein said digital logic means includes relay devices for coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the output of said digital decoder.
Claim 7
Dependent Claim
21 words
The apparatus according to claim 1 wherein said switching means comprises a plurality of double pole double throw manually operable switches.
Claim 8
Dependent Claim
117 words
Apparatus for coupling a plurality of speaker pairs to the output of an amplifier comprising: switching means having multiple selectable states for coupling in parallel a selected number of speaker pairs from said plurality of speaker pairs; a plurality of pairs of impedance matching resistive devices; digital logic means coupled to said switching means for automatically coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the states of said switching means; and safety means for coupling at least one of said plurality of speaker pairs to the output of said amplifier in response to said selected number equaling zero.
Claim 9
Dependent Claim
117 words
Apparatus for coupling a plurality of speaker pairs to the output of an amplifier comprising: switching means having multiple selectable states for coupling in parallel a selected number of speaker pairs from said plurality of speaker pairs; a plurality of pairs of impedance matching resistive devices; digital logic means coupled to said switching means for automatically coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the states of said switching means; and safety means for coupling at least one of said plurality of speaker pairs to the output of said amplifier in response to said selected number equaling zero.
Claim 10
Dependent Claim
16 words
The apparatus according to claim 7 wherein said plurality of speaker pairs comprises four speaker pairs.
Claim 11
Dependent Claim
22 words
The apparatus according to claim 8 wherein said plurality of pairs of impedance matching resistive devices comprises three pairs of precision resistors.
Claim 12
Dependent Claim
20 words
The apparatus according to claim 7 wherein said digital logic means includes a digital decoder coupled to said switching means.
Claim 13
Dependent Claim
48 words
The apparatus according to claim 10 wherein said digital logic means includes relay devices for coupling a selected pair of impedance matching resistive devices between the output of said amplifier and said selected number of parallel coupled speaker pairs in response to the output of said digital decoder.
Claim 14
Dependent Claim
21 words
The apparatus according to claim 7 wherein said switching means comprises a plurality of double pole double throw manually operable switches.
References Cited (Backward Citations)
US3370125A
Cited
US3694764A
Cited
US3881058A
Cited
US4004095A
Cited
US3959736A
Cited
US4176251A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |