METHOD AND APPARATUS TO CREATE A SOUND FIELD
First Claim
1. A method of creating a sound field using an array of output transducers, said array comprising first transducers spanning a first portion of said array and second transducers spanning a second portion of said array smaller than said first portion, said method comprising:
- dividing an input signal into at least a low frequency component and a high frequency component;
using said first portion of the array to output said low frequency component;
selecting a delay value for transducers of said array in at least said second portion; and
using said second portion of said array to output said high frequency component, wherein said high frequency component for each transducer is delayed by said respective delay value;
whereby a beam of at least high frequency sound is directed in a particular direction.
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Accused Products
Abstract
The invention generally relates to a method and apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focused beam or a simulated origin. In a first aspect, delays are added to sound channels to remove the effects of different travelling distances. In a second aspect, a delay is added to a video signal to account for the delays added to the sound channels. In a third aspect, different window functions are applied to each channel to give improved flexibility of use. In a fourth aspect, a smaller extent of transducers is used top output high frequencies than are used to output low frequencies. An array having a larger density of transducers near the center is also provided. In a fifth aspect, a line of elongate transducers is provided to give good directivity in a plane. In a sixth aspect, sound beams are focused in front or behind surfaces to give different beam widths and simulated origins. In a seventh aspect, a camera is used to indicate where sound is directed.
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Citations
17 Claims
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1. A method of creating a sound field using an array of output transducers, said array comprising first transducers spanning a first portion of said array and second transducers spanning a second portion of said array smaller than said first portion, said method comprising:
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dividing an input signal into at least a low frequency component and a high frequency component; using said first portion of the array to output said low frequency component; selecting a delay value for transducers of said array in at least said second portion; and using said second portion of said array to output said high frequency component, wherein said high frequency component for each transducer is delayed by said respective delay value; whereby a beam of at least high frequency sound is directed in a particular direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Apparatus for creating a sound field comprising:
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an array of output transducers, wherein in a first area of the array the output transducers are more densely packed than in the remainder of said array; said apparatus being arranged to apply delays to a signal provided to the output transducers so as to provide a beam of sound in a particular direction. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification