Arrangements and methods for active noise cancelling
First Claim
1. A loudspeaker arrangement comprising:
- a first loudspeaker configured to radiate an acoustical signal; and
a first microphone that is acoustically coupled to the first loudspeaker via a secondary path and that is electrically coupled to the first loudspeaker via an active noise control processing unit, wherein, during use of the loudspeaker arrangement,the first loudspeaker is arranged at a first distance from a first active noise control target position, wherein the first active noise control target position is a position at which noise is to be suppressed, and wherein the first distance is a length of a shortest path between the first loudspeaker and the first active noise control target position through free air,the first microphone is arranged at a second distance from the first loudspeaker, wherein the second distance is a length of a shortest path between the first loudspeaker and the first microphone through free air,the first distance equals the second distance, andthe position of the first microphone is remote from the first active noise target position,the loudspeaker arrangement further comprising a second loudspeaker, wherein;
a distance between the first loudspeaker and the first microphone approximately equals a distance between the second loudspeaker and the first microphone; and
the distance between the second loudspeaker and the first microphone equals a distance between the second loudspeaker and at least one of the first active noise control target position and a second active noise control target position, andwherein at least one of;
the first loudspeaker and the second loudspeaker form a feedback loop, the feedback loop further comprising the first microphone, wherein the first and second loudspeakers are controlled by a first and second control signal emitted by the active noise control processing unit, the first and second control signals being equal at least over a limited frequency range;
the first loudspeaker forms a feedback loop with the first microphone, wherein the feedback loop further comprises at least one active noise control processing unit; and
the second loudspeaker forms a feedback loop with the first microphone, wherein the feedback loop further comprises at least one active noise control processing unit.
1 Assignment
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Accused Products
Abstract
A loudspeaker arrangement comprises a first loudspeaker configured to radiate an acoustical signal, and a first microphone that is acoustically coupled to the first loudspeaker via a secondary path and that is electrically coupled to the first loudspeaker via an active noise control processing unit. During the use of the loudspeaker arrangement, the first loudspeaker is arranged at a first distance from a first active noise control target position, wherein the first active noise control target position is a position at which noise is to be suppressed, and wherein the first distance is a length of the shortest path between the first loudspeaker and the first active noise control target position through free air. The first microphone is arranged at a second distance from the first loudspeaker that equals the first distance, and the position of the first microphone differs from the first active noise target position.
9 Citations
16 Claims
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1. A loudspeaker arrangement comprising:
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a first loudspeaker configured to radiate an acoustical signal; and a first microphone that is acoustically coupled to the first loudspeaker via a secondary path and that is electrically coupled to the first loudspeaker via an active noise control processing unit, wherein, during use of the loudspeaker arrangement, the first loudspeaker is arranged at a first distance from a first active noise control target position, wherein the first active noise control target position is a position at which noise is to be suppressed, and wherein the first distance is a length of a shortest path between the first loudspeaker and the first active noise control target position through free air, the first microphone is arranged at a second distance from the first loudspeaker, wherein the second distance is a length of a shortest path between the first loudspeaker and the first microphone through free air, the first distance equals the second distance, and the position of the first microphone is remote from the first active noise target position, the loudspeaker arrangement further comprising a second loudspeaker, wherein; a distance between the first loudspeaker and the first microphone approximately equals a distance between the second loudspeaker and the first microphone; and the distance between the second loudspeaker and the first microphone equals a distance between the second loudspeaker and at least one of the first active noise control target position and a second active noise control target position, and wherein at least one of; the first loudspeaker and the second loudspeaker form a feedback loop, the feedback loop further comprising the first microphone, wherein the first and second loudspeakers are controlled by a first and second control signal emitted by the active noise control processing unit, the first and second control signals being equal at least over a limited frequency range; the first loudspeaker forms a feedback loop with the first microphone, wherein the feedback loop further comprises at least one active noise control processing unit; and the second loudspeaker forms a feedback loop with the first microphone, wherein the feedback loop further comprises at least one active noise control processing unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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radiating an acoustical signal at a first position, wherein a first active noise control target position is arranged at a first distance from the first position, wherein the first active noise control target position is a position at which noise is to be suppressed, and wherein the first distance is a length of a shortest path of the acoustical signal to the first active noise control target position through free air; and detecting sound at a second position, wherein the second position is arranged at a second distance from the first position, wherein the second distance is a length of a shortest path of the sound to the second position through free air, wherein the first distance equals the second distance, and the first active noise control target position is remote from the second position, and the detected sound is a sum signal comprising a desired acoustical signal as well as an unwanted signal, the method further comprising; subtracting the sum signal from the desired acoustical signal to obtain information about the unwanted signal at the second position, wherein the unwanted signal has an amplitude and a phase. - View Dependent Claims (12, 13, 14, 15)
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16. A loudspeaker system comprising:
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a first loudspeaker configured to radiate an acoustical signal; a first microphone that is acoustically coupled to the first loudspeaker via a secondary path and that is electrically coupled to the first loudspeaker via an active noise control processing unit; and the active noise control processing unit configured to generate a sum signal comprising a desired acoustical signal as well as an unwanted signal derived from sound detected by the first microphone, subtract the sum signal from the desired acoustical signal to generate a difference signal, filter the difference signal to generate a filtered difference signal, and apply the filtered difference signal as a driving signal to the first loudspeaker, wherein, during use of the loudspeaker system, the first loudspeaker is arranged at a first distance from a first active noise control target position, wherein the first active noise control target position is a position at which noise is to be suppressed, and wherein the first distance is a length of a shortest path between the first loudspeaker and the first active noise control target position through free air, the first microphone is arranged at a second distance from the first loudspeaker, wherein the second distance is a length of a shortest path between the first loudspeaker and the first microphone through free air, the first distance equals the second distance, and the position of the first microphone is remote from the first active noise target position, wherein the active noise control processing unit is further configured to add a first sound signal detected by the first microphone to a second sound signal detected at a second microphone to generate the sum signal, and subtracting the sum signal from the desired acoustical signal to obtain the difference signal, the second microphone being arranged at a third distance from the first loudspeaker, the third distance being equal to the first distance and the second distance, and the second microphone being remote from the first active noise control target position and the first microphone.
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Specification