Patent US1031214A successfully refreshed from Google Patents.
EP0075615A1
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EP
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Sound field simulation system and method for calibrating same
Assignee: Individual
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Filing: 1981-09-24
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Granted: —
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Expires: 2001-09-24
Abstract
Abstract System for generating within a relatively small enclosed space a sound field corresponding to that in a relatively large enclosed space having specific acoustic characteristics, said system including an input unit adapted to receive at least one primary electric audio signal, the output of which is connected to the input of a signal processing unit having a number (N) of secondary channels, each provided with signal processing means with selectable delay time and selectable gain constant, the N outputs of said channels being intended to produce N secondary electric audio signals, each to be supplied to one of N secondary loudspeaker units placed in said relatively small enclosed space in preselected positions. The system comprises a programmable memory for storing parameter groups representative of a number of various relatively large enclosed spaces, i.e. each comprising N delay times and N gain constants, and selecting means for selectively just that part of the memory, in which the parameter group representative of a desired enclosed space is stored.
Inventors
- 👤 Hok Lioe Han
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 23:18
CPC Classifications
H; H04; H04R; H04R29/00; G; G10; G10K; G10K15/00; G10K15/08; G10K15/12; H03; H03G; H03G5/00; H03G5/02; H03G5/025; H04R3/00; H04R3/12; H04S; H04S7/00; H04S7/30; H04S7/301; H04R29/007
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
164 words
A system for generating within a relatively small enclosed space a sound field corresponding to that in a relatively large enclosed space having specific acoustic characteristics, including an input unit to receive at least one primary electric audio signal, the output of which is connected to the input of a signal processing unit having a number (N) secondary channels, each provided with signal processing means with selectable delay time and selectable gain constant, the N outputs of said channels being intended to produce N secondary electric audio signals, each to be supplied to one of N secondary loudspeaker units placed in said relatively small enclosed space in preselected positions, characterized by (1) a programmable memory for storing parameter groups representative of a number of various relatively large enclosed spaces, i.e. each comprising N delay-times and N gain constants, and (2) selecting means for selectively activating just that portion of the memory, in which the parameter group, representative of a desired enclosed space is stored.
Claim 2
Independent Claim
164 words
A system for generating within a relatively small enclosed space a sound field corresponding to that in a relatively large enclosed space having specific acoustic characteristics, including an input unit to receive at least one primary electric audio signal, the output of which is connected to the input of a signal processing unit having a number (N) secondary channels, each provided with signal processing means with selectable delay time and selectable gain constant, the N outputs of said channels being intended to produce N secondary electric audio signals, each to be supplied to one of N secondary loudspeaker units placed in said relatively small enclosed space in preselected positions, characterized by (1) a programmable memory for storing parameter groups representative of a number of various relatively large enclosed spaces, i.e. each comprising N delay-times and N gain constants, and (2) selecting means for selectively activating just that portion of the memory, in which the parameter group, representative of a desired enclosed space is stored.
Claim 3
Dependent Claim
62 words
The system as recited in claim 1, characterized by a demultiplexer (93) with its input « connected to the output of a digital to analog converter (83) of the multiplying type, having an input for receiving time- multiplexed audio information signals and a number of inputs connected to the programmable memory (69) for receiving signals representative of just one selected parameter group.
Claim 4
Dependent Claim
55 words
The system as recited in claim 1 or 2, characterized by digital detection means for discriminating between signal levels over or under a preselected value, and for choosing, depending upon the result of detection, a full or a scaled down signal processing range in order to achieve an increase of the effectively usable dynamic range.
Claim 5
Dependent Claim
170 words
The system as recited in claim 3, including an analog to digital converter comprising: (1) a comparator with its input connected to the input terminal of the analog to digital converter; (2) a successive approximation register (SAR) connected to the output of the comparator; and (3) a digital to analog converter connected to the outputs of said register, and having an output connected to the second input of the comparator; characterized by (1) a number of AND gates corresponding to the desired scale down ratio, incorporated in the same number of the register's output lines corresponding to the most significant bits, that serve to perform successive approximations; (2) a control unit operating at command of the register and adapted to apply a logic "0" to the second input of each of the AND gates during conversion of the SCALE bit; (3) a two-position step attenuator controlled by the control unit, said attenuator being connected at one end to the input terminal, and at the other end to the comparator's input.
Claim 6
Dependent Claim
60 words
The system as recited in claim 4, characterized in that the full signal processing processing scale corresponds to the Binary number "11111111" (analog: 255), and the scaled down signal processing scale to binary number 00011111 (analog: 31) in such manner that said chosen value is equal to 255/31 of full scale, and that said number of AND gates is 3.
Claim 7
Independent Claim
43 words
The system as recited in one of the previous claims, characterized in that the program unit is configured and connected to generate logic zeros ("0") during the write cycle of the random access memory (RAM 64), forming part of said signal processing means.
Claim 8
Independent Claim
115 words
A method for calibrating a sound field simulation system as recited in one of the previous claims, characterized by the following steps: (1) switching off the secondary loudspeaker units, and driving at least one sound source, eventually positioned in a place representative of the primary source(s), for the emission of a broad band, e.g. at least predominantly corresponding to pink noise, acoustic signal; (2) measuring the sound pressure level as thereby produced in the listening room; and (3) switching on the secondary loudspeakers and adjusting same in such manner that the sound pressure level produced thereby is equal to the sound pressure level produced by the primary source or differs therefrom in a chosen amount.
Claim 9
Dependent Claim
34 words
The system as recited in one of the claims 1 through 6, characterized by a pink noise generator for generating an electric pink noise signal for performing a calibration as recited in claim 7.
Claim 10
Independent Claim
88 words
The system as recited in one of the claims 1 through 6, 8 using an amplifier for driving at least one loudspeaker unit serving as primary source, said amplifier including a volume control, which can be manually operated with a knob, characterized by a remote controlled adjustment unit (381 including an electric motor, the shaft of which, eventually via a gearwheel reduction unit, is adapted to transmit via a transmission device, an adjusting force to the knob, in such manner that the volume control can be remotely controlled.
Claim 11
Independent Claim
36 words
The system as recited in one of the claims l through 6, 8, 9 characterized by means for connecting between 'the input unit and the signal processing unit an equalizer unit for equalizing the frequency response.
Claim 12
Independent Claim
37 words
The system as recited in one of the claims 1 - 6, 8 - 13, characterized by mixing means for mixing two or more secondary channels at will, eventually by employing more than one signal processing unit.
Claim 13
Independent Claim
136 words
The system as recited in one of the claims 1 - 6, 8 - 14, with safeguarding means to protect the secondary loudspeaker units against a DC voltage above a preselected threshold value, characterized by a summing network (132), the inputs of which are each connected to an output of a power amplifier forming part of a secondary channel, and the output of which is connected to a low pass filter having a crossover frequency in the order of 1 Hz, the output signal of which is supplied to a level detecting circuit, which on exceeding a preselected level activates a power supply shutoff unit in such manner that the power amplifiers forming part of the secondary channels are switched off, display means being present to visually indicate the activation of the power supply shutoff unit.
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