CEILING MICROPHONE ASSEMBLY
First Claim
1. A microphone assembly, comprising:
- an L-shaped structure formed by a first planar surface perpendicularly attached to a second planar surface;
a first microphone element disposed at the intersection of the first and second planar surfaces;
a second microphone element disposed along a line bisecting an angle formed by the first and second planar surfaces, the second microphone element being a predetermined distance from both the first and second planar surfaces;
a first subtractor configured to subtract an output of the first microphone element from an output of the second microphone element; and
a first equalizer configured to equalize the output of the first subtractor, the first equalizer having a frequency response of Heq,wherein a quarter toroid sensitivity pattern for the microphone assembly is generated by acoustical interaction of the two planar surfaces with the two microphone elements and subtraction of the microphone element outputs.
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Accused Products
Abstract
A video teleconferencing directional microphone has two surfaces joined with an angle of 90° relative to each other, a first omni directional microphone element arranged adjacent to the intersection between the two surfaces. The ceiling microphone assembly also includes a second omni directional microphone element arranged at a predetermined distance (d) from both surfaces. A subtractor subtracts the output of the first microphone element from the output of the second microphone element, and the output of the subtractor is equalized by an equalizer (Heq) to generate an equalized output. The surfaces and subtractor generates a quarter toroid directivity pattern for the ceiling microphone assembly. The quarter toroid sensitivity pattern increases sensitivity in the direction of a sound source of interest, but reduces sensitivity to any sound waves generated by noise sources at other locations or reverberations.
56 Citations
21 Claims
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1. A microphone assembly, comprising:
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an L-shaped structure formed by a first planar surface perpendicularly attached to a second planar surface; a first microphone element disposed at the intersection of the first and second planar surfaces; a second microphone element disposed along a line bisecting an angle formed by the first and second planar surfaces, the second microphone element being a predetermined distance from both the first and second planar surfaces; a first subtractor configured to subtract an output of the first microphone element from an output of the second microphone element; and a first equalizer configured to equalize the output of the first subtractor, the first equalizer having a frequency response of Heq, wherein a quarter toroid sensitivity pattern for the microphone assembly is generated by acoustical interaction of the two planar surfaces with the two microphone elements and subtraction of the microphone element outputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A microphone assembly, comprising:
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an L-shaped structure formed by a first planar surface perpendicularly attached to a second planar surface; a bidirectional microphone element having a front acoustic input port and a rear acoustic input port; a first waveguide having an output port associated with the rear acoustic input port of the bidirectional microphone, an input port of the first waveguide being disposed adjacent to an intersection of the first and second planar surfaces; a second waveguide having an output port associated with the front acoustic input port of the bidirectional microphone element, an input port of the second waveguide being arranged at a predetermined distance (d) from the first and second planar surfaces; and a equalizer filter configured to equalize an output of the bidirectional microphone element, the equalizer having a frequency response (Heq), wherein a quarter toroid sensitivity pattern for the microphone assembly is generated by acoustical interaction of the two planar surfaces, the two waveguides and the bidirectional microphone element. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method for creating an quarter toroid directivity pattern in a microphone assembly, comprising:
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joining two planar surfaces to form an L-shaped structure; converting audio waves received at a first microphone into first audio data, the first microphone being arranged adjacent to an intersection of the two planar surfaces; converting audio waves received at a second microphone into second audio data, the second microphone being arranged at a predetermined distance (d) from each of the two planar surfaces; subtracting, in a subtractor, the first audio data from the second audio data; and equalizing, in an equalizer, an output of the subtractor. - View Dependent Claims (18, 19, 20, 21)
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Specification