Sound field offset device
First Claim
1. A sound field offset device having two channels, each of which comprises:
- a frequency selection filter for dividing a stereophonic input signal into first and second frequency bands by a given frequency falling within an audio frequency, said first frequency band being higher than said given frequency, said second frequency band being lower than said given frequency;
analog-to-digital converter means for converting a second frequency band output from said frequency selection filter into a digital signal;
at least one digital filter for performing sound field offsetting with respect to an output of said analog-to-digital converter means;
digital-to-analog converter means for converting an output of said digital filter into an analog signal;
delay means for delaying a first frequency band output from said frequency selection filter;
adder means for summing an output of said digital-to-analog converter means and an output of said delay means; and
at least one loudspeaker assembly having a sharp directivity pattern for defining an area to which acoustic power is emitted within said first frequency band with a substantially uniform sound pressure level, the one loudspeaker assembly having an axis of directivity, wherein selection of said given frequency is substantially dictated by a sound pressure difference between a first listening point located on the axis of directivity and a second listening point off the axis of directivity and outside of said area.
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Accused Products
Abstract
A sound field offset device having two channels, each of which includes a frequency selection filter for dividing a stereophonic input signal into two frequency bands by a given frequency falling within an audio frequency, at least one digital filter for performing sound field offsetting within a lower frequency band, and at least one loudspeaker assembly for a higher frequency band having a sharp directivity pattern and capable of defining an area to which acoustic power is emitted. This device allows a sound field to be offset in a cost effective and simple manner, by improving the frequency characteristic of a sound field space and by clarifying the sense of locality of acoustic images.
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Citations
17 Claims
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1. A sound field offset device having two channels, each of which comprises:
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a frequency selection filter for dividing a stereophonic input signal into first and second frequency bands by a given frequency falling within an audio frequency, said first frequency band being higher than said given frequency, said second frequency band being lower than said given frequency; analog-to-digital converter means for converting a second frequency band output from said frequency selection filter into a digital signal; at least one digital filter for performing sound field offsetting with respect to an output of said analog-to-digital converter means; digital-to-analog converter means for converting an output of said digital filter into an analog signal; delay means for delaying a first frequency band output from said frequency selection filter; adder means for summing an output of said digital-to-analog converter means and an output of said delay means; and at least one loudspeaker assembly having a sharp directivity pattern for defining an area to which acoustic power is emitted within said first frequency band with a substantially uniform sound pressure level, the one loudspeaker assembly having an axis of directivity, wherein selection of said given frequency is substantially dictated by a sound pressure difference between a first listening point located on the axis of directivity and a second listening point off the axis of directivity and outside of said area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification