Stereo and spaciousness reverberation system using random access memory and multiplex
First Claim
1. A sound reproduction arrangement comprising:
- (a) a listening area;
(b) at least a first primary loudspeaker located in said listening area and connected to be driven in response to a first audio frequency signal;
(c) input means responsive to said first audio frequency signal to provide input signal data as a function thereof;
(d) signal delay means connected to receive said input signal data and provide a plurality of delayed signals each corresponding to the said input signal data delayed by a respective delay constant, said delay means including means conditioned and arranged to multiply each of the said delayed signals by a respective pre-selected gain constant, a plurality of output channels each supplied with at least a respective one of said delayed signals, addressable data storage means for storing successive sampled values of the said input signal data, control means arranged for response to a periodic clock signal to supply a preselected sequence of address instructions to said data storage means so as to produce successive cycles of record/recall operations in each of which at least a respective one of the said successive sampled values is recorded, and a plurality of stored sampled values which sampled values have each been recorded a respective pre-selected numbers of cycles previously, are recalled sequentially, and a demultiplexer means connected for response to the data output by said data storage means and arranged to assign the recalled values to respectively pre-selected ones of said output channels, whereby in use the said data output by said data storage means comprises a plurality of time division multiplexed components each associated with a respective one of the said pre-selected numbers, the said delayed signals being formed by respective ones of the said components and the said delay constants being related, respectively, with associated ones of said pre-selected numbers; and
(e) a plurality of secondary loudspeakers disposed at respective locations spaced around the perimeter of said listening area and each connected to be driven by a respective one of said output channels, the delay constant and secondary loudspeaker for each of said delayed signals being selected so that the delay and direction of the sound produced in the listening area in response thereto substantially corresponds to those of a sound corresponding to said first audio frequency signal reflected from the boundary of an enclosure of substantially greater size than that of the listening area, thus obtaining a sensation of spaciousness.
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Abstract
A sound reproduction arrangement and audio signal delay apparatus suitable for use in such an arrangement, includes, in a listening area, one or more primary sound sources for mono- or multichannel reproduction respectively, and a plurality of secondary sources spaced around the perimeter of the listening area and each providing an acoustic signal corresponding to that from the primary source or sources delayed by a respective and independently selectable delay constant and attenuated by a respective and independently selectable gain constant. Control apparatus is connected with the sound sources to derive a plurality of signals for the respective sound sources from an input signal. The delay constants are substantially greater than the time taken for sound to traverse the listening area, so that the sound from the secondary sources simulates reverberation or reflected sound, and a listener has a sensation of spaciousness normally associated with an enclosure which is larger than the listening area, such as a concert hall, for example. Features of the invention include a random-access memory which stores time-multiplexed data representing sampled input audio and channel-control information.
33 Citations
14 Claims
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1. A sound reproduction arrangement comprising:
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(a) a listening area; (b) at least a first primary loudspeaker located in said listening area and connected to be driven in response to a first audio frequency signal; (c) input means responsive to said first audio frequency signal to provide input signal data as a function thereof; (d) signal delay means connected to receive said input signal data and provide a plurality of delayed signals each corresponding to the said input signal data delayed by a respective delay constant, said delay means including means conditioned and arranged to multiply each of the said delayed signals by a respective pre-selected gain constant, a plurality of output channels each supplied with at least a respective one of said delayed signals, addressable data storage means for storing successive sampled values of the said input signal data, control means arranged for response to a periodic clock signal to supply a preselected sequence of address instructions to said data storage means so as to produce successive cycles of record/recall operations in each of which at least a respective one of the said successive sampled values is recorded, and a plurality of stored sampled values which sampled values have each been recorded a respective pre-selected numbers of cycles previously, are recalled sequentially, and a demultiplexer means connected for response to the data output by said data storage means and arranged to assign the recalled values to respectively pre-selected ones of said output channels, whereby in use the said data output by said data storage means comprises a plurality of time division multiplexed components each associated with a respective one of the said pre-selected numbers, the said delayed signals being formed by respective ones of the said components and the said delay constants being related, respectively, with associated ones of said pre-selected numbers; and (e) a plurality of secondary loudspeakers disposed at respective locations spaced around the perimeter of said listening area and each connected to be driven by a respective one of said output channels, the delay constant and secondary loudspeaker for each of said delayed signals being selected so that the delay and direction of the sound produced in the listening area in response thereto substantially corresponds to those of a sound corresponding to said first audio frequency signal reflected from the boundary of an enclosure of substantially greater size than that of the listening area, thus obtaining a sensation of spaciousness. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification