Ambisonic microphone
Methods and apparatuses for capturing and encoding ambisonic audio are described herein. An example ambisonic microphone may comprise a first microphone capsule oriented substantially toward a first vertex of a notional tetrahedron, a second microphone capsule oriented substantially toward a second vertex of the notional tetrahedron, a third microphone capsule oriented substantially toward a third vertex of the notional tetrahedron, and a fourth microphone capsule oriented substantially toward a fourth vertex of the notional tetrahedron.
1 . An ambisonic microphone, comprising:
a yoke comprising a protruding member defining an axis; and
a plurality of microphone capsules coupled to the yoke along the protruding member, wherein:
the plurality of microphone capsules is geometrically arranged to reduce an acoustic shading effect from a structural interference introduced by adjacent ones of the plurality of microphone capsules; and
the plurality of microphone capsules is compactly nested along the axis defined by the protruding member to reduce a phase-related error.
2 . The ambisonic microphone of claim 1 , wherein the plurality of microphone capsules comprises:
a first microphone capsule oriented in a first direction that is substantially toward a first vertex of a notional tetrahedron; and
a second microphone capsule oriented in a second direction that is substantially toward a second vertex of the notional tetrahedron.
3 . The ambisonic microphone of claim 2 , further comprising:
a third microphone capsule oriented in a third direction that is substantially toward a third vertex of the notional tetrahedron; and
a fourth microphone capsule oriented in a fourth direction that is substantially toward a fourth vertex of the notional tetrahedron.
4 . The ambisonic microphone of claim 3 , wherein:
the first microphone capsule comprises a first capsule face that is arranged in a first orientation relative to the first direction,
the second microphone capsule comprises a second capsule face that is arranged in a second orientation relative to the second direction,
the third microphone capsule comprises a third capsule face that is arranged in a third orientation relative to the third direction,
the fourth microphone capsule comprises a fourth capsule face that is arranged in a fourth orientation relative to the fourth direction, and
the first orientation, the second orientation, the third orientation, and the fourth orientation are each substantially orthogonal or substantially parallel.
5 . The ambisonic microphone of claim 3 , wherein:
the first microphone capsule comprises a first axis of minimum sensitivity,
the second microphone capsule comprises a second axis of minimum sensitivity,
the first axis and the second axis intersect at a first point in space,
the third microphone capsule comprises a third axis of minimum sensitivity,
the fourth microphone capsule comprises a fourth axis of minimum sensitivity, and
the third axis and the fourth axis intersect at a second point in space.
6 . The ambisonic microphone of claim 3 , wherein:
the first microphone capsule is disposed on a first face of the notional tetrahedron,
the second microphone capsule is disposed on a second face of the notional tetrahedron,
the third microphone capsule is disposed on a third face of the notional tetrahedron, and
the fourth microphone capsule is disposed on a fourth face of the notional tetrahedron.
7 . The ambisonic microphone of claim 1 further comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the microphone to encode a set of audio signals generated by the plurality of microphone capsules to one or more of an A-format, a B-format, a C-format, a D-format, a G-format, or a binaural format.
8 . The ambisonic microphone of claim 7 ,
wherein the instructions, when executed by the one or more processors, cause the microphone to encode the set of audio signals using time-domain processing.
9 . The ambisonic microphone of claim 1 , further comprising:
an output port configured to provide a set of audio signals formatted according to one or more of an A-format, a B-format, a C-format, a D-format, a G-format, or a binaural format, to an external device.
10 . The ambisonic microphone of claim 1 , further comprising:
a mounting fixture configured to be removably coupled to at least one camera such that the mounting fixture is disposed beneath the plurality of microphone capsules.
11 . The ambisonic microphone of claim 1 , wherein:
a first pair of microphone capsules from among the plurality of microphone capsules comprise a first set of axes of minimum sensitivity that intersect at a first point in space,
a second pair of microphone capsules from among the plurality of microphone capsules comprise a second set of axes of minimum sensitivity that intersect at a second point in space, and
the first point in space is offset from the second point in space.
12 . An ambisonic microphone, comprising:
a yoke comprising a protruding member defining an axis;
a first microphone capsule coupled to the yoke along the protruding member, the first microphone capsule being oriented in a first direction that is substantially toward a first vertex of a notional tetrahedron; and
a second microphone capsule coupled to the yoke along the protruding member, the second microphone capsule being oriented in a second direction that is substantially toward a second vertex of the notional tetrahedron,
wherein the first and second microphone capsules are compactly nested along the axis defined by the protruding member to reduce a phase-related error.
13 . The ambisonic microphone of claim 12 , further comprising:
a third microphone capsule oriented in a third direction that is substantially toward a third vertex of the notional tetrahedron; and
a fourth microphone capsule oriented in a fourth direction that is substantially toward a fourth vertex of the notional tetrahedron.
14 . The ambisonic microphone of claim 13 , wherein:
the first microphone capsule is disposed on a first face of the notional tetrahedron,
the second microphone capsule is disposed on a second face of the notional tetrahedron,
the third microphone capsule is disposed on a third face of the notional tetrahedron, and
the fourth microphone capsule is disposed on a fourth face of the notional tetrahedron.
15 . The ambisonic microphone of claim 13 , wherein:
the first microphone capsule comprises a first axis of minimum sensitivity,
the second microphone capsule comprises a second axis of minimum sensitivity,
the first axis and the second axis intersect at a first point in space,
the third microphone capsule comprises a third axis of minimum sensitivity,
the fourth microphone capsule comprises a fourth axis of minimum sensitivity, and
the third axis and the fourth axis intersect at a second point in space.
16 . The ambisonic microphone of claim 13 , wherein:
the first microphone capsule comprises a first capsule face that is arranged in a first orientation relative to the first direction,
the second microphone capsule comprises a second capsule face that is arranged in a second orientation relative to the second direction,
the third microphone capsule comprises a third capsule face that is arranged in a third orientation relative to the third direction,
the fourth microphone capsule comprises a fourth capsule face that is arranged in a fourth orientation relative to the fourth direction, and
the first orientation, the second orientation, the third orientation, and the fourth orientation are each substantially orthogonal or substantially parallel.
17 . The ambisonic microphone of claim 13 , further comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the ambisonic microphone to encode a set of audio signals generated by the first microphone capsule, the second microphone capsule, the third microphone capsule, and the fourth microphone capsule to one or more of an A-format, a B-format, a C-format, a D-format, a G-format, or a binaural format.
18 . The ambisonic microphone of claim 17 , further comprising:
an output port configured to provide the set of audio signals to an external device.
19 . The ambisonic microphone of claim 12 , further comprising:
a mounting fixture configured to be removably coupled to at least one camera such that the mounting fixture is disposed beneath the first microphone capsule and the second microphone capsule.
20 . The ambisonic microphone of claim 12 , wherein the first microphone capsule is oriented in the first direction within a range of 20 degrees towards the first vertex of the notional tetrahedron, and
wherein the second microphone capsule is oriented in the second direction within a range of 20 degrees towards the second vertex of the notional tetrahedron.