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Patent US3818136A successfully refreshed from Google Patents.
US3818136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Four-channel front-to-back balance control
Assignee: Zenith Electronics LLC
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Filing: 1972-04-27
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Granted: 1974-06-18
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Expires: 1992-04-27
Abstract
Abstract A front-to-back balance control circuit in a quadraphonic playback system for adjusting the sound output levels of a front pair of speakers relative to a back pair while simultaneously varying the phase differential between the back speakers. The balance control utilizes a ganged potentiometer arrangement wherein a potentiometer is serially-connected with each front speaker to concurrently adjust the sound output of each speaker to corresponding levels. The ganged potentiometer arrangement also provides a variable impedance signal path common to the back speakers for varying their sound output levels inversely in response to adjustments in the sound output level of the front speakers. The common signal path is further effective to serve as a variable coefficient matrixing means for applying portions of a first and a second input signal to each of the back speakers.
Inventors
- 👤 W Schott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:07
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; H04H20/89; H04S; H04S3/00; H04S3/02
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
353 words
A control circuit for use in an audio playback system which includes an amplifier stage having right and left outputs issuing respective right and left output signals, a right front sound reproducer and a right back sound reproducer each having a first terminal coupled to said right output, a left front sound reproducer and a left back sound reproducer each having a first terminal coupled to said second output, said control circuit comprising: a pair of potentiometers individually associated with an assigned one of said front sound reproducers, each of said potentiometers having a first terminal coupled to a second terminal of its assigned front sound reproducers, each potentiometer also having a second terminal coupled to a junction and each potentiometer further having a wiper arm coupled to a plane of reference potential to constitute a first segment of each potentiometer between its first terminal and its wiper arm as a series impedance for coupling its assigned front sound reproducer to reference potential; impedance means intercoupling a second terminal of said right back sound reproducer and a second terminal of said left back sound reproducer; a matrix network comprising second segments of said potentiometers disposed between their wiper arms and said junction and a matrixing impedance coupled between said junction and said intercoupling impedance means, said potentiometer second Segments, said matrixing impedance and said intercoupling impedance means establishing a common signal path coupling said second terminals of said back sound reproducers to reference potential to permit application of portions of said first and second output signals to each of said back sound reproducers; and control means coupled to said potentiometer wiper arms for varying the impedance of said potentiometer second segments included in said matrix network to adjust the output levels of said back sound reproducers as well as the magnitude of said first and second output signals applied to said left back and right back sound reproducers, respectively, while simultaneously varying the impedance of said potentiometer first segments forming said series impedances to adjust the output level of said front sound reproducers relative to the output level of said back sound reproducers.
Claim 2
Dependent Claim
353 words
A control circuit for use in an audio playback system which includes an amplifier stage having right and left outputs issuing respective right and left output signals, a right front sound reproducer and a right back sound reproducer each having a first terminal coupled to said right output, a left front sound reproducer and a left back sound reproducer each having a first terminal coupled to said second output, said control circuit comprising: a pair of potentiometers individually associated with an assigned one of said front sound reproducers, each of said potentiometers having a first terminal coupled to a second terminal of its assigned front sound reproducers, each potentiometer also having a second terminal coupled to a junction and each potentiometer further having a wiper arm coupled to a plane of reference potential to constitute a first segment of each potentiometer between its first terminal and its wiper arm as a series impedance for coupling its assigned front sound reproducer to reference potential; impedance means intercoupling a second terminal of said right back sound reproducer and a second terminal of said left back sound reproducer; a matrix network comprising second segments of said potentiometers disposed between their wiper arms and said junction and a matrixing impedance coupled between said junction and said intercoupling impedance means, said potentiometer second Segments, said matrixing impedance and said intercoupling impedance means establishing a common signal path coupling said second terminals of said back sound reproducers to reference potential to permit application of portions of said first and second output signals to each of said back sound reproducers; and control means coupled to said potentiometer wiper arms for varying the impedance of said potentiometer second segments included in said matrix network to adjust the output levels of said back sound reproducers as well as the magnitude of said first and second output signals applied to said left back and right back sound reproducers, respectively, while simultaneously varying the impedance of said potentiometer first segments forming said series impedances to adjust the output level of said front sound reproducers relative to the output level of said back sound reproducers.
Claim 3
Dependent Claim
42 words
A control circuit as set forth in claim 1 in which said wiper arms are interconnected through said control means so that when the impedance of said matrix segments is increased, the impedance of said series segments is decreased, and vice versa.
Claim 4
Dependent Claim
22 words
A control circuit as set forth in claim 1 in which said matrix segments of said potentiometers are effectively connected in parallel.
Claim 5
Dependent Claim
122 words
A control circuit as set forth in claim 1 in which said impedance means intercoupling said right back and left back sound reproducers comprises an adjustable resistor having one terminal coupled to said second terminal of one of said back sound reproducers and a wiper arm coupled to said second terminal of said other back sound reproducer and, through said matrixing impedance, to said junction, for changing the phase difference between said first and second output signals applied to said rear sound reproducers to substantially zero as the output level of said rear sound reproducers approaches a maximum, and in which said wiper arm of said intercoupling impedance is mechanically coupled to said wiper arms of said potentiometers for conjoint displacement therewith.
References Cited (Backward Citations)
US3735047A
Cited
US3697692A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |