Patent US3824342A successfully refreshed from Google Patents.
US3824342A
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Omnidirectional sound field reproducing system
Assignee: RCA Licensing Corp
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Filing: 1972-05-09
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Granted: 1974-07-16
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Expires: 1992-05-09
Abstract
Abstract Systems for producing a sound field in a region surrounding a listener wherein three information channels are utilized for conveying a first signal representative of total sound pressure (A) at a point in space, and two additional signals, A cos theta and A sin theta , for describing the directional characteristics of the sound field. An array of microphones having, for example, equal cardioidal response characteristics are arranged in the original sound field for detecting sound information. Linear, additive signal combining networks are coupled to the microphones for producing the three signals. A plurality of loudspeakers (e.g., four) are coupled to the three information channels by additional linear signal combining networks for reproduction of the sound field. Systems for synthesizing the three signals by electronic devices are also described.
Inventors
- 👤 R Christensen
- 👤 J Gibson
- 👤 Roy A Le
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:42
CPC Classifications
H; H04; H04S; H04S3/00; H04S3/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
116 words
Apparatus for producing signals representative of a sound field in a spatial region comprising: a plurality of transducers responsive to audio information signals for converting said information signals into a corresponding plurality of electrical signals, first means for additively combining said plurality of electrical signals to produce a signal A proportional to the sum thereof, seconds means for additively combining said plurality of electrical signals to produce a signal proportional to A cos theta , wherein theta is the angular disposition of a sound source with respect to a reference direction in said spatial region, and third means for additively combining said plurality of electrical signals to produce a signal proportional to A sin theta .
Claim 2
Dependent Claim
116 words
Apparatus for producing signals representative of a sound field in a spatial region comprising: a plurality of transducers responsive to audio information signals for converting said information signals into a corresponding plurality of electrical signals, first means for additively combining said plurality of electrical signals to produce a signal A proportional to the sum thereof, seconds means for additively combining said plurality of electrical signals to produce a signal proportional to A cos theta , wherein theta is the angular disposition of a sound source with respect to a reference direction in said spatial region, and third means for additively combining said plurality of electrical signals to produce a signal proportional to A sin theta .
Claim 3
Dependent Claim
38 words
Apparatus according to claim 1 wherein: said plurality of transducers comprise four like microphones disposed about a point in a sound field, said microphones being equally angularly spaced around said point and each exhibiting a cardioidal response characteristic.
Claim 4
Dependent Claim
102 words
Apparatus according to claim 2 wherein: said first additive combining means comprises a summing circuit providing a relative gain of one-half for each of signals supplied by said four microphones, said second and third additive combining means providing relative gains of Square Root 2/2 for each of said signals from said four microphones, said second combining means further providing inversion of signals from two adjacent ones of said microphones and said third combining means providing inversion of signals from one of said two adjacent ones of said microphones and of signals from a third one of said microphones adjacent to said one.
Claim 5
Dependent Claim
49 words
Apparatus according to claim 1 wherein: said transducers comprise a plurality of magnetic pickup devices, each associated with a corresponding magnetic sound recording track, said apparatus further comprising a like plurality of sine-cosine potentiometers coupled in ciRcuit between each said pickup device and said second and third combining means.
Claim 6
Dependent Claim
144 words
In a system for reproducing a sound field surrounding a listener wherein said sound field is represented by three signals A, A cosine theta , and A sine theta , the quantity A being representative of total sound pressure at a point in space and the parameter theta being representative of a spatial orientation of a sound source with respect to a reference direction, a sound reproducing system comprising: first, second and third audio signal transmission channels for said three signals; four sound reproducing means; and first, second, third and fourth linear additive signal combining means for coupling said transmission channels to said sound reproducing means to produce, by means of said three signals, four output signals representative of a sound field surrounding a spatial region suitable for reproduction by synthesis of said four signals from said three signals in additive and subtractive combinations.
Claim 7
Dependent Claim
144 words
In a system for reproducing a sound field surrounding a listener wherein said sound field is represented by three signals A, A cosine theta , and A sine theta , the quantity A being representative of total sound pressure at a point in space and the parameter theta being representative of a spatial orientation of a sound source with respect to a reference direction, a sound reproducing system comprising: first, second and third audio signal transmission channels for said three signals; four sound reproducing means; and first, second, third and fourth linear additive signal combining means for coupling said transmission channels to said sound reproducing means to produce, by means of said three signals, four output signals representative of a sound field surrounding a spatial region suitable for reproduction by synthesis of said four signals from said three signals in additive and subtractive combinations.
Claim 8
Dependent Claim
131 words
A sound reproducing system according to claim 5 wherein: signal A, proportional to total sound pressure, is defined by the expression: A K(Lf + Rf + Rr + Lr) wherein Lf, Rf, Rr and Lr correspond respectively to sound sources disposed at left front, right front, right rear and left rear locations in a sound field; signal A cosine theta is porportional to the difference between the front and rear sound sources defined by the expression: A cosine theta Square Root 2 K(Lf + Rf - Rr -Lr); and signal A sine theta is proportional to the difference between the left side and right side sound sources defined by the expression: A sine theta Square Root 2 K(Lf - Rf - Rr + Lr), the quantity K representing a numerical constant.
References Cited (Backward Citations)
US3746792A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-15 | 1978-01-14 | 1978-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-15 | 1982-01-14 | 1982-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-15 | 1986-01-14 | 1986-07-16 | $7700.00 | Window Closed / Lapsed |