Patent US4388494A successfully refreshed from Google Patents.
US4388494A
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US
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Process and apparatus for improved dummy head stereophonic reproduction
Assignee: Individual
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Filing: 1981-01-05
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Granted: 1983-06-14
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Expires: 2001-01-05
Abstract
Abstract In stereophonic reproduction using a dummy head process, the frequency responses of the microphones are equalized by free-field matching filters to provide overall transfer constants independent of frequency. Signals produced by the above-equalized dummy head apparatus are applied to a decoupling filter which corrects for the directional pattern of the dummy head. The decoupled signals are suitable for loudspeaker reproduction. The decoupled signals can be further applied to a second decoupling network which can be adjusted to produce headphone stereophonic signals matched to a listener's individual directional hearing pattern.
Inventors
- 👤 Peter Schone
- 👤 Jurgen lmann
- 👤 Helmut Lamparter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:25
CPC Classifications
H; H04; H04R; H04R5/00; H04R5/027; H04S; H04S1/00; H04S2400/00; H04S2400/01
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
106 words
A process for stereophonic transmission of sound signals, comprising the steps of: (a) providing a dummy head containing two microphone arrangements for simulating directional hearing with respect to a human listener; (b) feeding output signals from said microphone arrangements to two filters each having a frequency response inverse with respect to the free-field transfer constants of said microphone arrangements for providing filter output signals which are independent of frequency; and (c) feeding said filter output signals to a decoupling arrangement having transfer functions determined from said free-field transfer constants of said dummy head containing said microphone arrangements for producing space-related stereophonic signals containing directional information items.
Claim 2
Dependent Claim
106 words
A process for stereophonic transmission of sound signals, comprising the steps of: (a) providing a dummy head containing two microphone arrangements for simulating directional hearing with respect to a human listener; (b) feeding output signals from said microphone arrangements to two filters each having a frequency response inverse with respect to the free-field transfer constants of said microphone arrangements for providing filter output signals which are independent of frequency; and (c) feeding said filter output signals to a decoupling arrangement having transfer functions determined from said free-field transfer constants of said dummy head containing said microphone arrangements for producing space-related stereophonic signals containing directional information items.
Claim 3
Dependent Claim
15 words
The process of claim 1 further comprising the step of recording said space-related stereophonic signals.
Claim 4
Dependent Claim
19 words
The process of claim 1 further comprising the step of feeding said space-related stereophonic signals individually to two loudspeakers.
Claim 5
Dependent Claim
36 words
The process of claim 1 further comprising the step of feeding said space-related stereophonic signals to an adjustable circuit arrangement producing headphone outputs for matching said space-related sterephonic signals to a listener's individual directional hearing pattern.
Claim 6
Dependent Claim
30 words
The process of claim 1 wherein said frequency response of said filter arrangement is inverse with respect to said free-field transfer constant for frontal sound incidence of said microphone arrangements.
Claim 7
Dependent Claim
14 words
The process of claim 5, wherein said filter arrangement is a passive band-rejection filter.
Claim 8
Dependent Claim
34 words
The process of claim 5, wherein said filter arrangement comprises a band-pass filter; a first band-rejection filter coupled to said band-pass filter; and a second band-rejection filter coupled to said first band rejection filter.
Claim 9
Independent Claim
436 words
A device (B) for receiving stereophonic signals which are intended for space-related reproduction particularly by means of two separately installed loudspeakers (40, 50), having two microphone channels, comprising a decoupling arrangement (B10) to which the signals of the microphone channels (20, 30) are fed and in which in series arms (B11, B12) of a left transmission channel (M 1i , L 1 ) and of a right transmission channel (M re , L 2 ) in each case a substraction element (B13 and B14, respectively) is arranged which is followed by a transmission element (B15 and B16, respectively), and in which in shunt arms, which provide reverse feedback from the output (L 1 ) of the left transmission channel (M 1i , L 1 ) to the negative input of the substraction element (B14) arranged in the series arm (B12) of the right transmission channel (M re , L 2 ) and from the output (L 2 ) of the right transmission channel (M re , L 2 ) to the negative input of the substraction element (B13) arranged in the series arm (B11) of the left transmission channel (M 1i , L 1 ), in each case a feedback element (B17, B18) is contained, wherein the transmission element (B15) in the series arm (B11) of the left transmission channel (M 1i , L 1 ) simulates the inverse free-field transfer function of the left microphone channel (20) for the direction of sound incidence (φ 1 , δ 1 ) corresponding to the direction of installation of a first loudspeaker (40), wherein the transmission element (B16) in the series arm (B12) of the right transmission channel (M re , L 2 ) simulates the inverse free-field transfer function of the right microphone channel (30) for the direction of sound incidence (φ 2 , δ 2 ) corresponding to the direction of installation of a second loudspeaker (50), wherein the feedback element (B18) providing reverse feedback from the output (L 2 ) of the right transmission channel (M re , L 2 ) simulates the free-field transfer function of the left microphone channel (20) for the direction of sound incidence (φ 2 , δ 2 ) corresponding to the direction of installation of the second loudspeaker (50), and wherein the feedback element (B17) providing reverse feedback from the output (L 1 ) of the left transmission channel (M 1i , L 1 ) simulates the free-field transfer function of the right microphone channel (30) for the direction of sound incidence (φ 1 , δ 1 ) corresponding to the direction of installation of the first loudspeaker (40).
Claim 10
Independent Claim
436 words
A device (B) for receiving stereophonic signals which are intended for space-related reproduction particularly by means of two separately installed loudspeakers (40, 50), having two microphone channels, comprising a decoupling arrangement (B10) to which the signals of the microphone channels (20, 30) are fed and in which in series arms (B11, B12) of a left transmission channel (M 1i , L 1 ) and of a right transmission channel (M re , L 2 ) in each case a substraction element (B13 and B14, respectively) is arranged which is followed by a transmission element (B15 and B16, respectively), and in which in shunt arms, which provide reverse feedback from the output (L 1 ) of the left transmission channel (M 1i , L 1 ) to the negative input of the substraction element (B14) arranged in the series arm (B12) of the right transmission channel (M re , L 2 ) and from the output (L 2 ) of the right transmission channel (M re , L 2 ) to the negative input of the substraction element (B13) arranged in the series arm (B11) of the left transmission channel (M 1i , L 1 ), in each case a feedback element (B17, B18) is contained, wherein the transmission element (B15) in the series arm (B11) of the left transmission channel (M 1i , L 1 ) simulates the inverse free-field transfer function of the left microphone channel (20) for the direction of sound incidence (φ 1 , δ 1 ) corresponding to the direction of installation of a first loudspeaker (40), wherein the transmission element (B16) in the series arm (B12) of the right transmission channel (M re , L 2 ) simulates the inverse free-field transfer function of the right microphone channel (30) for the direction of sound incidence (φ 2 , δ 2 ) corresponding to the direction of installation of a second loudspeaker (50), wherein the feedback element (B18) providing reverse feedback from the output (L 2 ) of the right transmission channel (M re , L 2 ) simulates the free-field transfer function of the left microphone channel (20) for the direction of sound incidence (φ 2 , δ 2 ) corresponding to the direction of installation of the second loudspeaker (50), and wherein the feedback element (B17) providing reverse feedback from the output (L 1 ) of the left transmission channel (M 1i , L 1 ) simulates the free-field transfer function of the right microphone channel (30) for the direction of sound incidence (φ 1 , δ 1 ) corresponding to the direction of installation of the first loudspeaker (40).
Claim 11
Dependent Claim
75 words
A device (B) as claimed in claim 8, wherein in the left and right transmission channels (M 1i , L 1 ) and (M re , L 2 ), respectively, before a decoupling arrangement (B10*), which is reduced by separable parts of its total transfer function, further transmission elements (B61, B71 and B62, B72) are arranged, the transfer functions of which contain the separated parts of the total transfer function of the decoupling arrangement (B10).
Claim 12
Dependent Claim
33 words
A device as claimed in claim 9, wherein the transmission elements (B61 and B62) are designed as microphone equalizers (A2) for the microphones (A1) located in the sound pick-up channels (20 and 30).
Claim 13
Dependent Claim
293 words
A circuit arrangement (C) for matching a space-related stereophonic program signal to headphones (D) with free-field equalization, in which are in series arms of a left and right transmission channel, a first transmission element (C1) is arranged and in which in shunt arms, which additively couple the left to the right and the right to the left transmission channel, in each case a second transmission element (C2 and C2*) and a delay element (C3) is arranged wherein (a) the first transmission element (C1) is arranged before the summing element (C4) to simulate, by means of an iterative connection of second-order band-pass filters, half the interaural level difference of the ear for a direction of sound incidence of 30°; (b) the second transmission element (C2) has, by means of iteratively connected second-order band-rejection filters which differ from the band-pass filters of the first transmission element (C1) only by the respective exchange of two resisters (Rx) and (Ry), a transfer function which is the inverse of that of the first transmission element (C1); (c) the resonant frequencies of all band-pass filters and band-rejection filters are able to be matched by means of variable impedances Z to the resonant frequencies which occur in the frequency response of the individual interaural level difference of the hearing of a certain listener; and (d) variable delay elements (C3) are provided in the shunt arms, said delay elements consisting of iteratively connected second-order all-pass filters the variable frequency dependent delay time of which, in conjunction with the frequency-dependent delay difference, which can be varied by adjusting the resonant frequencies, of the first and second transmission elements (C1) and (C2) simulates the individual, frequency-dependent delay difference of the hearing of a certain listener for a direction of sound incidence of 30°.
Claim 14
Dependent Claim
293 words
A circuit arrangement (C) for matching a space-related stereophonic program signal to headphones (D) with free-field equalization, in which are in series arms of a left and right transmission channel, a first transmission element (C1) is arranged and in which in shunt arms, which additively couple the left to the right and the right to the left transmission channel, in each case a second transmission element (C2 and C2*) and a delay element (C3) is arranged wherein (a) the first transmission element (C1) is arranged before the summing element (C4) to simulate, by means of an iterative connection of second-order band-pass filters, half the interaural level difference of the ear for a direction of sound incidence of 30°; (b) the second transmission element (C2) has, by means of iteratively connected second-order band-rejection filters which differ from the band-pass filters of the first transmission element (C1) only by the respective exchange of two resisters (Rx) and (Ry), a transfer function which is the inverse of that of the first transmission element (C1); (c) the resonant frequencies of all band-pass filters and band-rejection filters are able to be matched by means of variable impedances Z to the resonant frequencies which occur in the frequency response of the individual interaural level difference of the hearing of a certain listener; and (d) variable delay elements (C3) are provided in the shunt arms, said delay elements consisting of iteratively connected second-order all-pass filters the variable frequency dependent delay time of which, in conjunction with the frequency-dependent delay difference, which can be varied by adjusting the resonant frequencies, of the first and second transmission elements (C1) and (C2) simulates the individual, frequency-dependent delay difference of the hearing of a certain listener for a direction of sound incidence of 30°.
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |