Omnidirectional surround microphone

Abstract

Methods and apparatus for acquiring and encoding omnidirectional surround sound are described herein. An exemplary omnidirectional surround microphone may include a first microphone capsule oriented substantially toward a first vertex of a conceptual tetrahedron, a second microphone capsule oriented substantially toward a second vertex of the conceptual tetrahedron, a third microphone capsule oriented substantially toward a third vertex of the conceptual tetrahedron and a fourth microphone capsule oriented substantially toward a fourth vertex of the conceptual tetrahedron.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 576,446, filed April 28, 2023, and U.S. Patent Application No. 18 / 644,251, filed April 24, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The various aspects described herein generally relate to an omnidirectional surround sound microphone and / or related hardware and software. More specifically, one or more aspects of this document provide a microphone capsule array for acquiring omnidirectional surround sound. Background Technology

[0004] Omnidirectional surround sound refers to a global form of surround sound used in many virtual reality and / or other immersive applications. Omnidirectional surround sound is encoded according to the Ambisonics B-format, which encodes four A-format signals from four microphone capsules in an omnidirectional surround microphone into four independent channels labeled W, X, Y, and Z. The W channel corresponds to the mono output of the omnidirectional microphone, while the X, Y, and Z channels correspond to the directional components of the sound signal. As various services and applications utilizing omnidirectional surround sound become increasingly prevalent, the demand for improvements to omnidirectional surround microphones is growing, and these improvements are expected to be achieved through relatively simple processes and relatively low-cost equipment. Summary of the Invention

[0005] To provide a basic understanding of some aspects of this disclosure, a brief summary is given below. This summary is not a broad overview of the invention. It is not intended to identify key or essential elements of the invention or to define the scope of the invention. The following summary presents only some concepts of the disclosure in a simplified form as an introduction to the more detailed description provided below.

[0006] Acquiring omnidirectional surround sound typically requires significant financial investment, complex cabling, external equipment, and a deep understanding of A-to-B format conversion technology to obtain high-quality omnidirectional surround sound signals. Furthermore, with the increasing prevalence and portability of podcasting, live streaming, and other recording equipment, users can create in various acoustic environments. However, depending on the application scenario, users may lack sufficient time, expertise, and / or equipment to properly acquire omnidirectional surround sound, making it difficult to achieve the desired audio quality.

[0007] As detailed herein, this application proposes apparatus and methods for acquiring omnidirectional surround sound, employing a microphone capsule array architecture with stable high-frequency polar coordinate consistency and reduced acoustic masking effects. These apparatus and methods enable consumers to quickly and easily acquire high-quality omnidirectional surround sound, convert it to desired formats, and / or utilize this audio technology in a variety of applications, including immersive music recording, surround sound coding, podcasts, video game audio design, stereo-tracking virtual reality / augmented reality experiences, and multi-channel mixing.

[0008] An exemplary omnidirectional surround microphone may comprise a plurality of microphone capsules that reduce acoustic masking effects caused by structural interference through geometric arrangement and reduce phase correlation errors through compact nesting. The plurality of microphone capsules may include: a first microphone capsule generally oriented toward a first vertex of a conceptual tetrahedron, a second microphone capsule oriented toward a second vertex of a conceptual tetrahedron, a third microphone capsule generally oriented toward a third vertex of a conceptual tetrahedron, and a fourth microphone capsule generally oriented toward a fourth vertex of a conceptual tetrahedron.

[0009] An exemplary method may include arranging a first microphone capsule on a first face of a conceptual tetrahedron, with the first face of the first microphone capsule substantially orthogonal to the first face of the conceptual tetrahedron. The method may further include arranging a second microphone capsule on a second face of the conceptual tetrahedron, with the second face of the second microphone capsule substantially orthogonal to the second face of the conceptual tetrahedron and oriented accordingly; and nesting the first microphone capsule and the second microphone capsule such that a first minimum sensitivity axis of the first microphone capsule intersects a second minimum sensitivity axis of the second microphone capsule at a first coincident point.

[0010] These and other novel advantages, details, examples, features, and purposes of this disclosure will be apparent to those skilled in the art from the detailed description, appended claims, and drawings listed herein, which can be used to explain the concepts discussed herein. Attached Figure Description

[0011] Some features are shown in the accompanying drawings by way of example rather than limitation. In the drawings, the same reference numerals denote similar elements.

[0012] Figure 1 An example network architecture that can be used to implement one or more of the illustrative aspects described herein is shown.

[0013] Figure 2 A perspective view of an example omnidirectional surround microphone that can be used to implement one or more of the illustrative aspects described herein is shown.

[0014] Figure 3aThis document illustrates one or more illustrative aspects that can be used to implement the descriptions herein. Figure 2 The instance geometry of multiple microphone capsules of an omnidirectional surround microphone.

[0015] Figure 3b This document illustrates one or more illustrative aspects that can be used to implement the descriptions herein. Figure 2 Another example of a geometric representation of multiple microphone capsules of an omnidirectional surround microphone.

[0016] Figure 4a It shows Figure 1 The right-side view of an example omnidirectional surround microphone.

[0017] Figure 4b It shows Figure 1 The front view of an example omnidirectional surround microphone.

[0018] Figure 4c It shows Figure 1 A top view of an example omnidirectional surround microphone.

[0019] Figure 4d It shows Figure 1 Another perspective view of an example of an omnidirectional surround microphone.

[0020] Figure 5 An example system architecture is shown that can be used to implement one or more of the illustrative aspects described herein.

[0021] Figure 6 An example flowchart is shown that can be executed to implement one or more of the illustrative aspects described herein. Detailed Implementation

[0022] In the following description of various examples, reference will be made to the accompanying drawings, which form part of the following description and illustrate various examples in which aspects can be practiced by way of example. References to “embodiment,” “example,” etc., indicate that the embodiments or examples of the invention described herein may include specific features, structures, or characteristics, but not every embodiment or example is required to include specific features, structures, or characteristics. Furthermore, it is contemplated that some embodiments or examples may have some, all, or none of the features described for other examples. And it should be understood that other embodiments and examples may be utilized, and structural and functional modifications may be made without departing from the scope of this disclosure.

[0023] Unless otherwise stated, the use of sequential adjectives such as “first,” “second,” “third,” etc., to describe components is only to indicate different components, which may be similar components. However, the use of such sequential adjectives does not mean that components must be provided in a given order (temporally, spatially, in rank, or in any other way).

[0024] Furthermore, while the terms “front,” “rear,” “side,” etc., may be used in this specification to describe various exemplary features and elements, these terms are used herein for convenience, for example, based on the exemplary orientations shown in the figures and / or the orientations in typical use. Nothing in this specification should be construed as requiring a specific three-dimensional or spatial orientation of the structure to fall within the scope of the claims.

[0025] Figure 1Examples of network architectures that can be used to implement one or more of the illustrative aspects described herein in standalone and / or networked environments are shown. Device 100 may be an omnidirectional surround microphone. Device 102 may be one or more computing devices, such as a desktop computer, laptop computer, one or more cloud computing devices, one or more servers, etc. Device 104 may be a smartphone or tablet. Device 100 may be connected to and / or communicate with one or more of devices 102 and / or 104 (wired or wireless). Device 100 may be connected to and / or communicate with one or more other devices (not shown) (wired or wireless), including but not limited to hybrid consoles, recording consoles, etc. Any one or more of devices 100, 102, 104, and 106 may be any type of known computer or server. In one or more examples, device 102 and / or device 104 may include a user interface, such as a graphical user interface, to allow a user to interact with the system. In one or more examples, device 106 may include a data server, such as a cloud data server. Devices 100, 102, 104, and / or 106 can be interconnected via a wide area network (WAN) such as the Internet and / or via any other network. For example, one or more other networks, such as a local area network (LAN), wireless network, personal network (PAN), etc., can also be used. Devices 100, 102, 104, and / or 106 and / or other devices (not shown) can be communicatively connected to one or more networks via or without twisted-pair cables, coaxial cables, fiber optic cables, radio waves, and / or other communication media. In one or more examples, device 100 can be communicatively connected to devices 102 and / or 104 via connections 108a and / or 108b, respectively. Devices 102 and / or 104 can connect to device 100 via connectors 108a and / or 108b using any one or more of a variety of different connectors, such as LEMO connectors, XLR connectors, Lightning® connectors, TQG connectors, TRS connectors, USB connectors (including but not limited to USB type A, type B, type C, Mini B, Micro B type) and / or one or more RCA connectors. Connectors 108a and / or 108b can be wireless and can connect to device 100 using one or more of the following protocols: WiMAX, LTE, Bluetooth, Bluetooth Broadcast, GSM, 3G, 4G, 5G, 6G, Zigbee, 60GHz Wi-Fi, Wi-Fi (e.g., compliant with IEEE 802.11 a / b / g / n / ac / ad / af / ah / ai / aj / aq / ax / ay / ba / be standards), one or more proprietary wireless connectivity protocols, one or more NFC protocols, and / or any other protocol.When the connection is wireless, devices 102 and 104 (and / or their respective transmitters, receivers, or transceivers) may include a wireless communication interface with device 100. In one or more examples, device 102 may be communicatively connected to device 106 via connection 110, and / or device 104 may be communicatively connected to device 106 via connection 112.

[0026] Figure 2 A perspective view of an omnidirectional surround microphone 200 (hereinafter referred to as "microphone 200"), an example that can be used to implement one or more illustrative aspects described herein, is shown. Microphone 200 may comprise microphone capsules 200a-200d (collectively referred to as "microphone capsules"). Microphone 200 may comprise any number of microphone capsules, for example, more or fewer than microphone capsules 200a to 200d. Microphone capsules may be any type of capsule, such as condenser (e.g., including large and small diaphragms and electret capacitors), dynamic (e.g., including dynamic and ribbon microphones), and / or microelectromechanical systems (MEMS), etc. Microphone capsules may be constructed according to one or more geometries (e.g., circular, oval, elliptical, rectangular, etc.).

[0027] Microphone 200 may include a yoke 202. The yoke 202 may be constructed according to one or more shapes and / or geometries. The yoke 202 may include a protruding member 206. The protruding member 206 may be constructed according to one or more shapes or geometries. Member 206 may be substantially columnar. One or more microphone capsules may be coupled to the yoke 202 along the protruding member 206. One or more microphone capsules may be electrically connected to the yoke 202 and / or the protruding member 206. The protruding member 206 may define an axis along which the microphone capsule is positioned, which is substantially vertical (further described with reference to FIG3). The microphone capsule may be integrally molded to member 206 or detachably coupled to member 206. The microphone capsule may be rotatably and / or pivotally coupled to member 206, allowing a user to variably rotate and / or pivot the orientation of the microphone capsule.

[0028] Microphone 200 may include a handle 204. The handle 204 may include a neck 208. A yoke 202 may be coupled to the handle 204 at the neck 208. The yoke 202 may be electrically connected to the handle 204 and / or the neck 208. The yoke 202 may be integrally molded to the handle 204. The yoke 202 may be detachably coupled to the handle 204. The yoke 202 may include legs 202a and 202b. Legs 202a and 202b may be integrally molded to the handle 204 and may be electrically connected to the handle 204. Legs 202a and 202b may be detachably coupled to the handle 204. Legs 202a and / or 202b may be rotatably and / or pivotally coupled to the handle 204, which allows a user to rotate and / or pivot the orientation of one or more microphone capsules about the neck 208 of the handle 204. The yoke 202 can be configured to rotate on the neck 208 of the handle 204. The yoke 202 and / or component 206 can accommodate some or all of the electronic components described and discussed herein.

[0029] The handle 204 and / or neck 208 can be constructed according to any number of shapes or geometries. The handle 204 can be adapted for handheld use and can be constructed according to a variety of ergonomic geometries. The handle 204 and / or neck 208 can accommodate some or all of the electronic components described and discussed herein (e.g., conversion module 500). The handle 204 can be adapted as a mounting clamp compatible with one or more cameras or brackets, including tripods (for...). Figure 4d (Discussed in more detail). The handle 204 can be adapted for handheld use and as a mounting clamp. The handle 204 and / or neck 208 may include electrical connections to an n-channel D / A converter 511, a memory 503, and / or a processor 504 (also for...). Figure 5 The output port 512 (for discussion) Figure 5 discuss).

[0030] Microphone capsule 200a can be positioned in the direction indicated by line 200a'. Microphone capsule 200b can be positioned in the direction indicated by line 200b'. Microphone capsule 200c can be positioned in the direction indicated by line 200c'. Microphone capsule 200d can be positioned in the direction indicated by line 200d'. For microphone capsules 200a, 200b, 200c, and 200d, lines 200a', 200b', 200c', and 200d' can respectively represent their maximum sensitivity axis (i.e., the axis passing through the center of the microphone capsule and extending infinitely in the positive direction) and minimum sensitivity axis (i.e., the axis extending infinitely in the negative or opposite direction). The minimum sensitivity axes of microphone capsules 200a and 200d (i.e., lines 200a' and 200d', respectively) may or may not intersect at a point in space (i.e., lines 200a' and 200d' may share at least one coincident intersection point). The minimum sensitivity axes of microphone capsules 200b and 200c (i.e., lines 200b' and 200c', respectively) may or may not intersect at a point in space (i.e., lines 200b' and 200c' may share at least one coincident intersection point).

[0031] Microphone capsules 200a-200d can be geometrically arranged and compactly nested within each other, thereby enabling these microphone capsules to exhibit a consistent and / or stable polar coordinate response at high frequencies. This compact nesting helps minimize phase correlation errors and / or contributes to higher spatial / positioning accuracy. These microphone capsules can be geometrically oriented according to the various aspects described herein to mitigate acoustic masking caused by structural interference from one or more adjacent microphone capsules. That is, the geometric orientation of the microphone capsules can mitigate acoustic masking by reducing the obstruction cross-sectional area created by adjacent microphone capsules, which may contribute to improved high-frequency response.

[0032] Figure 3a An example geometry of the orientation of the microphone capsules 200a-200d of the omnidirectional surround microphone 200 around the conceptual tetrahedron 300 is shown. The conceptual tetrahedron 300 can take the geometry of any type of tetrahedron. The conceptual tetrahedron 300 can be a regular tetrahedron in which all four triangular faces are equilateral triangles and all edges are of equal length. The conceptual tetrahedron 300 can also be an irregular tetrahedron, an isosceles tetrahedron, or a triangular tetrahedron, etc.

[0033] like Figure 3aAs shown, each microphone capsule can be disposed on one of the four triangular faces of the conceptual tetrahedron 300. For example, microphone capsule 200a can be disposed at the centroid of face 304 of the conceptual tetrahedron 300 (i.e., the intersection of the three medians of a triangular face of the tetrahedron). Microphone capsule 200a can also be disposed at any number of points on face 304. Face 304 is defined by vertices 300a', 300b', and 300c'. Microphone capsule 200a can include an outer edge 302 that defines the outer contour of microphone capsule 200a. The edge 302 of microphone capsule 200a can be tangent to face 304 of tetrahedron 300. The orientation of microphone capsule 200a can be such that the capsule faces approximately the direction of vertex 300a' (represented by line 200a'). Line 200a' may not intersect vertex 300a'. A face of microphone capsule 200a may define a plane that is substantially (e.g., ±10 degrees) orthogonal (i.e., perpendicular) to the plane defined by the corresponding face of conceptual tetrahedron 300 (i.e., the face defined by vertices 300a', 300b', and 300c'). In other words, line 200a' may be substantially parallel (e.g., ±10 degrees) to the plane defined by that face of conceptual tetrahedron 300. In one example, the face of microphone capsule 200a may not be orthogonal to face 304. The face of microphone capsule 200a may be parallel to face 304. The face of microphone capsule 200a may be parallel and substantially tangential to face 304. Microphone capsule 200a may also be positioned on face 304 of conceptual tetrahedron 300 such that the plane defined by face 304 intersects one or more points of capsule 200a (i.e., the edge 302 of capsule 200a may not be tangential to face 304).

[0034] Microphone capsule 200b may or may not be located at the centroid of face 306. Microphone capsule 200b may be located at any number of points on face 306. Face 306 may be defined by vertices 300a', 300b', and 300d'. Microphone capsule 200c may or may not be located at the centroid of face 308. Capsule 200c may be located at any number of points on face 308. Face 308 may be defined by vertices 300a', 300c', and 300d'. Capsule 200d may or may not be located at the centroid of face 310. Capsule 200d may be located at any number of points on face 310. Face 310 may be defined by vertices 300b', 300c', and 300d'. Capsules 200b-200d may include corresponding edges tangent to faces 306, 308, and 310 of the conceptual tetrahedron 300, respectively. Microphone capsule 200b may be positioned on face 306 of the conceptual tetrahedron 300 such that the plane defined by face 306 intersects one or more points of capsule 200b (i.e., the edge of capsule 200b may not be tangent to face 306). Microphone capsule 200c may be positioned on face 308 of the conceptual tetrahedron 300 such that the plane defined by face 308 intersects one or more points of capsule 200c (i.e., the edge of capsule 200c may not be tangent to face 308). Microphone capsule 200d may be positioned on face 310 of the conceptual tetrahedron 300 such that the plane defined by face 310 intersects one or more points of capsule 200d (i.e., the edge of capsule 200d may not be tangent to face 310).

[0035] Microphone capsule 200b can be oriented substantially toward vertex 300b' (represented by line 200b'). Capsule 200c can be oriented substantially toward vertex 300c' (represented by line 200c'). Capsule 200d can be oriented substantially toward vertex 300d' (represented by line 200d'). The faces of microphone capsules 200b, 200c, and 200d (i.e., the sides of the microphone capsules corresponding to maximum acoustic sensitivity) can each define a plane that is substantially (e.g., ±10 degrees) orthogonal (i.e., perpendicular) to the plane defined by the corresponding faces of conceptual tetrahedron 300 (i.e., face 304 of capsule 200a, face 306 of capsule 200b, face 308 of capsule 200c, and face 310 of capsule 200d). In this example, the faces of microphone capsules 200b, 200c, and / or 200d may not be orthogonal to faces 306, 308, and / or 310, respectively. The faces of microphone capsules 200b, 200c, and / or 200d may be oriented parallel to faces 306, 308, and / or 310, respectively. The faces of microphone capsules 200b, 200c, and / or 200d may be oriented parallel to and substantially tangent to faces 306, 308, and / or 310, respectively.

[0036] As already discussed, microphone capsules 200a-200d can be nested compactly relative to each other, which helps ensure a consistent polarity response of the microphone capsules at high frequencies and helps reduce phase correlation errors. Microphone capsules 200a-200d can be geometrically arranged to help reduce acoustic masking experienced by any one microphone capsule from the other microphone capsules. While microphone capsules can generally be oriented or arranged as described above, the distance between any two given microphone capsules can vary (e.g., can vary considerably).

[0037] For example, such as Figure 3b As shown, the center a of microphone capsule 200a and the center b of capsule 200b are horizontally spaced apart by a distance ab (represented by line 200ab). The center c of microphone capsule 200c and the center d of capsule 200d are horizontally spaced apart by a distance cd (represented by line 200cd). The distances ab and cd can be determined by the specific geometry of the conceptual tetrahedron 300 (i.e., whether the conceptual tetrahedron is a regular tetrahedron, an irregular tetrahedron, an isosceles tetrahedron, etc.). The distance ab can be approximately twice the radius (or width, as appropriate) of microphone capsule 200a or 200b measured from its respective center to its respective outer diameter (or perimeter). The distance cd can be approximately twice the radius (or width) of microphone capsule 200c or 200d measured from its respective center to its respective outer diameter (or perimeter). The distances ab and / or cd can be approximately twice the radius (or width) of the microphone capsules 200a or 200b and 200c or 200d, respectively.

[0038] Microphone capsules 200a and 200b can be offset by a distance d from microphone capsules 200c and 200d along the z-axis of yoke 206 (e.g., Figure 2 As shown, by Figure 3a (Represented by line 206' in the diagram). The distance d can be determined by the specific geometry of the conceptual tetrahedron 300 (i.e., whether the conceptual tetrahedron is a regular tetrahedron, an irregular tetrahedron, an isosceles tetrahedron, etc.). The distance d can be approximately twice the radius (or width) of the microphone capsules 200a, 200b, 200c, or 200d, said radius being measured from their respective centers to their respective outer diameters (or circumferences, as appropriate). The distance d can be greater than or less than approximately twice the radius (or width) of the microphone capsules 200a, 200b, 200c, or 200d, measured from their respective centers to their respective outer diameters (or circumferences).

[0039] As already discussed, the conceptual tetrahedron 300 can take the shape of an irregular tetrahedron (i.e., a tetrahedron without four equal sides). In one example, microphone capsules 200a, 200b, 200c, and 200d can typically be arranged on the surface of the conceptual tetrahedron 300 with a constant radius relative to the center point, such that the microphone capsule array is radially symmetrical when projected onto a plane. The faces of capsules 200a, 200b, 200c, and 200d can be equally spaced relative to each other and can form an angle of approximately 90 degrees relative to adjacent capsules. Capsules 200a, 200b, 200c, and 200d can be arranged in first and second vertical planes such that each vertical plane contains two microphone capsules sharing a common intersecting axis. Each pair of microphone capsules can be rotated about a respective shared axis such that the respective axes of maximum sensitivity are orthogonal. The second vertical plane can be rotated approximately 90 degrees and mirrored about its axis of rotation. Therefore, microphone capsules 200a, 200b, 200c, and 200d can be substantially outward-facing. The axes of maximum sensitivity for microphone capsules 200a, 200b, 200c, and 200d may not overlap. The upper pair of microphone capsules may face mostly upwards, and the lower pair of microphone capsules may face mostly downwards.

[0040] Figure 4a , 4b Figures 4c and 4d show various side and perspective views of the microphone 200. Figure 4a A right-side view of the omnidirectional surround microphone 200 is shown. The faces of microphone capsules 200c and 200d (i.e., the sides of microphone capsules 200c and 200d corresponding to their maximum acoustic sensitivity) can be oriented substantially downwards. The faces of capsules 200c and 200d can be oriented relative to each other to form an angle of approximately 70 degrees (as shown by angle 400cd). The faces of capsules 200c and 200d can be oriented relative to each other to form an angle greater than or less than 70 degrees (i.e., angle 400cd can be in the range of, for example, 65 degrees to 95 degrees).

[0041] Figure 4b A front view of an omnidirectional surround microphone 200 is shown. The faces of microphone capsules 200a and 200b (i.e., the sides of microphone capsules 200a and 200b corresponding to their maximum acoustic sensitivity) are substantially upward-facing. The faces of capsules 200a and 200b can be oriented relative to each other to form an angle of approximately 70 degrees (as shown by angle 400ab). The faces of capsules 200a and 200b can be oriented relative to each other to form an angle greater than or less than 70 degrees (i.e., angle 400ab can be in the range of, for example, 65 degrees to 95 degrees).

[0042] Figure 4c A top view of the omnidirectional surround microphone 200 is shown.

[0043] about Figure 4d The handle 204 can be adapted as a mounting clamp compatible with one or more cameras or brackets (not shown). The microphone 200 can be used in combination with cameras and / or camera arrays that can be configured to produce a 360-degree field of view (e.g., cameras and / or camera arrays for virtual reality applications and / or 360-degree video). The handle 204 may include a coupling mechanism 410 adapted to be coupled to any number of camera mounts, brackets, etc. in any manner. The coupling mechanism 410 may be threaded. The coupling mechanism 410 may be configured with ball bearings, etc., to allow the microphone 200 to rotate when engaged with a camera mount or bracket. The coupling mechanism 410 may include a ratchet assembly (not shown) to allow the user to variably and securely position the microphone 200 in a desired orientation relative to the camera array and / or camera bracket.

[0044] Figure 5Examples of system architectures that can be used to implement one or more of the illustrative aspects described herein are shown. One or more of microphones 100 and / or 200 (collectively referred to below as “microphone 200”) may include and / or be communicatively connected to processor 504 for controlling the overall operation of the microphones. Microphone 200 may include microphone capsules 200a, 200b, 200c, 200d, and 200n. Microphone 200 may include and / or be communicatively connected to an n-channel analog-to-digital (“A / D”) converter 502. In one or more instances, n may be greater than or equal to 2, 3, 4, or 5. The number of n microphone capsules may correspond to the number of n channels of the A / D converter 502 (i.e., the number of microphone capsules and the number of channels in the A / D converter 502, both represented as integers n, may be the same). Microphone 200 may include and / or be communicatively connected to memory 503. Memory 503 may store operating system software 506 for controlling the overall operation of microphone 200 and / or control logic 507 for instructing microphone 200 to perform the aspects described herein. The function of control logic 507 may refer to operations or decisions made automatically based on rules encoded in control logic 507, operations or decisions made manually by the user providing input to the system, and / or a combination of automatic processing based on user input (e.g., queries, data updates, user-selected modes, lists of input devices previously set by a software application, etc.). Memory 503 may store data used in performing one or more aspects described herein, including in at least one database 508. Memory may store other data. For example, where memory 503 is, for example, part of microphone 200, memory may store its operating system and / or software applications performing the aspects described herein, user preferences (e.g., preferred modes), lists of input devices (e.g., microphone 200, etc.) previously set by a software application, communication protocol settings, and / or any other functional data supporting the microphone.

[0045] One or more aspects may be embodied in computer-usable or readable data and / or computer-executable instructions, for example in one or more program modules, executed by one or more computers or other devices (e.g., microphone 200) described herein. Typically, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type when executed by a processor in a computer or other device. Modules may be written in a source code programming language subsequently compiled for execution, or may be written in a scripting language such as (but not limited to) Python, Perl, PHP, Ruby, JavaScript, etc. Computer-executable instructions may be stored on a computer-readable medium such as a non-volatile storage device. Any suitable computer-readable storage medium may be utilized, including hard disks, CD-ROMs, optical storage devices, magnetic storage devices, solid-state storage devices, and / or any combination thereof. Furthermore, various transmission (non-storage) media representing data or events as described herein may be transmitted between a source and a destination in the form of electromagnetic waves traveling through signal conduction media such as metal wires, optical fibers, and / or wireless transmission media (e.g., air and / or space). The aspects described herein may be embodied as methods, data processing systems, or computer program products. Therefore, various functions can be embodied, in whole or in part, in software, firmware, and / or hardware or hardware equivalents, such as integrated circuits, field-programmable gate arrays (FPGAs), etc. Specific data structures can be used to more efficiently implement one or more aspects described herein, and such data structures are considered to be within the scope of the computer-executable instructions and computer-available data described herein.

[0046] Further reference Figure 1 and 5An omnidirectional surround microphone 200 may be implemented in device 100. An n-channel A / D converter 502, a memory 203, a processor 504, an n-channel digital-to-audio (“D / A”) converter 511, and an output port 512 may be implemented in microphone 200 and / or any one or more of devices 102, 104, and / or 106, and (or alternatively) in one or more additional devices (not shown). The aspects described herein can operate with many other general-purpose and / or special-purpose computing system environments or configurations. Examples of other computing systems, environments, and / or configurations to which the aspects described herein may be applied include, but are not limited to, personal computers, server computers, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, networked personal computers (PCs), minicomputers, mainframe computers, supercomputers configured to run online application programming interfaces (APIs), distributed computing environments including any of the aforementioned systems or devices, etc. The aspects of microphone 200 may be implemented as embedded software running, for example, in device 100. Various aspects of the microphone 200 can be implemented as external signal processors, such as hardware DSP modules, real-time software processors, offline software processors, or software plugins (including VST, AU, and AAX formats). This omnidirectional surround microphone 200 is compatible with software or plugins for a variety of video communication or video streaming platforms.

[0047] Microphone capsules 200a-200d can be configured to receive acoustic signals emitted from various directions within an acoustic environment. The microphone capsules can acquire a set of audio signals in format A. The duration of this set of audio signals can vary considerably (e.g., from less than one second to more than 1000 seconds). The microphone capsules can provide the set of format A audio signals to external devices. Onboard processing of the microphone 200 (e.g., conversion module 500, processor 504) can encode the set of format A audio signals into formats B, C (or stereo reverb UHJ, such as nested multichannel output formats), D (e.g., 3.1, 5.1, 5.1.n, 7.1, 7.1.n and / or other surround sound formats, including custom speaker array formats and other formats with pre-encoded channels), G, mono, stereo, and / or binaural audio formats for use with headphones (hereinafter referred to as...). Figure 5 (Further description). Processor 504 can render audio signals in A, B, C, D, and / or G formats for use by external devices. Microphone 200 can provide a set of rendered mono, stereo, binaural, B, C, D, and / or G format audio signals to external devices.

[0048] like Figure 5As shown, the omnidirectional surround microphone 200 may include a conversion module 500 and / or be communicatively connected to the conversion module 500. The conversion module 500 may include a device controller 501. The device controller 501 facilitates interaction between various components from microphone capsules 200a-200n to the conversion module 500. Analog and / or digital audio can be transmitted from the microphone 200 to the device controller 501. Digital data can be transmitted bidirectionally (from the microphone 200 to the device controller 501, and / or from the device controller 501 to the microphone 200). The microphone 200 may include, for example, one or more Universal Serial Bus (USB) connectors, one or more XLR connectors, one or more power connectors, and / or any other type of data and / or power connector suitable for transmitting signals to and from the microphone 200, such as power, digital data (including digital audio signals), and / or analog audio signals. In the case of a wired connection, the device controller 501 may also include a data interface (not shown) for communicating with the microphone 200. For example, the data interface may include a USB interface and / or an XLR interface. While several wired connections between device controller 501 and microphone 200 have been discussed, other types of wired or wireless connections can be used. For example, the connection between device controller 501 and microphone 200 can alternatively be a wireless connection, such as a Wi-Fi connection or other proprietary wireless connection protocol, a Bluetooth connection, a near field connection (NFC), and / or an infrared connection. In the case of a wireless connection, device controller 501 and microphone 200 may include a wireless communication interface.

[0049] In operation, device controller 501 can receive a set of A-format audio signals acquired by microphone capsules 200a-200n. Device controller 501 can route this set of A-format audio signals to A / D converter 502, which can provide a set of digital A-format audio signals to processor 504 for further processing. Processor 504 can provide this set of digital A-format audio signals to digital-to-analog (D / A) converter 511 for output to output device 514 via output port 512. The number of n channels of D / A converter 511 can correspond to the number of channels n of analog-to-digital (A / D) converter and / or the number of n microphone capsules (i.e., the number of channels in D / A converter 511, represented by the integer n, can be the same as the number of channels and / or the number of microphone capsules in A / D converter 502). Output device 514 can be any of devices 102 and 104, and / or other devices, such as a mixing console, recording console, headphones, in-ear headphones, etc.

[0050] The converter module 500 may include an encoder / decoder 510. The encoder 510 may be configured to encode (or convert) the set of digital A-format audio signals into a set of B-format audio signals. The encoder 510 may be configured to decode (or render) the set of B-format audio signals to a D / A converter 511 and via port 512 for use in an output device 514. As already discussed, the orientation and arrangement of the microphone capsules 200a-200d according to the aspects described herein can minimize A-to-B format conversion errors and positioning inaccuracies that are typically caused by the non-overlapping of microphone capsules in an omnidirectional surround microphone. Therefore, the B-format stability (or bidirectional breakdown point) of the microphone capsules can be improved at higher frequencies. That is, the directional pattern and frequency response pattern of the microphone capsules can remain stable while acquiring audio signals with frequencies occupying a range of approximately 4-20 kHz. The encoder 510 may employ any number of time-domain processing techniques when performing A-to-B format encoding of the set of audio signals. Encoder 510 and / or processor 504 may employ any number of pure time-domain processing techniques when performing A-to-B format encoding of the audio signal set. That is, encoder 510 and / or processor 504 may not need to perform a Fast Fourier Transform on the A-format audio signal set before encoding it into B format. Instead, encoder 510 and / or processor 504 may analyze one or more waveforms of the audio signal set. Encoder 510 and / or processor 504 may not convert the audio signal set into spectral components and may not analyze those spectral components. In one or more examples, frequency response correction filters, equalization filters, and / or other correction measures may be unnecessary. Encoder 510 and / or processor 504 may encode the A-format audio signal set into B-format audio signal by adopting the following convention:

[0051] W = FLU + FRD + BLD + BRU

[0052] X = FLU + FRD – BLD – BRU

[0053] Y = FLU – FRD + BLD – BRU

[0054] Z = FLY – FRD – BLD + BRU

[0055] Where W represents an omnidirectional microphone channel, and X, Y, and Z represent bidirectional (or figure-eight) microphone channels; and where FLU can represent the signal acquired by microphone capsule 200a, FRD can represent the signal acquired by microphone capsule 200c, BLD can represent the signal acquired by microphone capsule 200d, and BRU can represent the signal acquired by microphone capsule 200b. Channel W can be attenuated by approximately 3dB (i.e., factor is...). (or 0.707). Due to the use of time-domain processing technology, processing latency is reduced, enabling microphone 200 to provide real-time A-format or decoded B-format audio signals for latency-sensitive applications such as live streaming. Encoder / decoder 510 supports various B-format export standards, including but not limited to FuMa and Ambix.

[0056] The encoder / decoder 510 can be configured to decode the set of B-format audio signals into a set of D-format audio signals. The converter module 500 may include an interface controller 505 communicatively connected to the user interface 515. The interface controller 505 can facilitate communication between the user interface 515 and the converter module 500. For example, the interface controller 505 may receive user instructions and / or queries from the user interface 515 and provide these instructions and / or queries to the converter module for further actions as described herein. The user interface 515 may include, for example, a capacitive touch interface or a graphical user interface that can be controlled by the user via touch. Accompanying software applications (not shown) installed on device 102 and / or device 104 provide the user interface 515 and can perform some or all of the processing and decoding of the audio signals described herein.

[0057] Interface 515 may work in conjunction with some or all of the hardware and / or software components described herein to help simplify the workflow of acquiring spatial audio using microphone 200 and providing it to end users. User interface 515 may present users with a variety of audio acquisition and conversion options. For example, interface 515 may provide options allowing users to output acquired audio signals to external devices in mono, stereo, binaural, A, B, C, D, and / or G format audio standards. Interface 515 may provide users with additional pre- and / or post-recording processing options, such as filtering, equalization, compression, and a controllable virtual microphone with independent position / directivity and gain adjustment. Interface 515 may provide users with a graphical representation of the sound field and allow users to create any number of virtual microphones and manipulate the polarity of said virtual microphones. Interface 515 may include a video stream window, allowing users to monitor the synchronization status of the input audio signal with real-time or pre-recorded video data.

[0058] Figure 5Any circuit described herein can be implemented as, for example, a programmable gate array (PGA), a MOS integrated circuit (IC) chip, an application-specific integrated circuit (ASIC), a complex programmable logic device (CPLD), a field-programmable gate array (FPGA) chip, or an analog circuit. An ASIC may contain transistors, such as FETs. Any operation described herein can be implemented in hardware, software, and / or a combination thereof.

[0059] Figure 6 An example flowchart of method 600, which can be executed to implement one or more illustrative aspects described herein, is shown. Some or all of the steps of method 600 may be performed by microphone 200. Some or all of the steps of method 600 may be performed by a device (such as device 102 and / or 104) connected to microphone 200. Processor 504, coupled to memory 503, may control the overall operation of microphone 200 while microphone 200 performs steps 601-614. Although method 600 shows specific steps in a particular order, the method may be further subdivided into additional sub-steps, steps may be combined, steps may be performed in a different order, and some steps may be omitted without departing from the concepts described herein.

[0060] In operation, according to the aspects described herein, one or more microphone capsules may be arranged or oriented relative to the conceptual tetrahedron in a first direction. For example, a first microphone capsule may be arranged on a first face of the conceptual tetrahedron in a direction generally toward a first vertex of the conceptual tetrahedron (step 602). The faces of the microphone capsules may be oriented relative to (or about) the faces of the conceptual tetrahedron (e.g., orthogonally, substantially orthogonally, parallel, substantially parallel) (step 604). The first microphone capsule may be oriented relative to a second microphone capsule such that the minimum sensitivity axis of the first capsule may share a coincidence point with the minimum sensitivity axis of the second capsule (i.e., the axes may intersect at a point in space). The axes of maximum sensitivity of the first and second microphone capsules may not share a coincidence point with each other. A third and fourth microphone capsule may be oriented relative to each other such that the minimum sensitivity axis of the third capsule may share a coincidence point with the minimum sensitivity axis of the fourth capsule (i.e., the axes may intersect at a point in space). The first, second, third, and / or fourth microphone capsules may be oriented relative to each other to reduce structural interference and associated acoustic masking that may be caused by adjacent microphone capsules.

[0061] According to the aspects described herein, the first microphone capsule may be nested with one or more other microphone capsules to help reduce phase correlation errors (step 606). The microphone capsule may be configured to acquire audio signals (step 608). The user may wish to convert the audio signals acquired by the group (e.g., A-format audio signals) into any number of different audio standards (e.g., B-format, C-format, D-format, G-format, mono, stereo, binaural, etc.). The user may indicate via an interface (such as interface 515) and / or microphone 200 that such conversion is desired and may specify the desired format. Based on receiving the conversion instruction (step 610: Yes), conversion module 500 may employ time-domain processing techniques as described herein to convert the A-format audio signal into the desired format (step 612) for further processing and / or output to, for example, output device 514 (step 614). In one or more examples, the output audio signal may be synchronized with a video stream (including live streams, broadcast signals, etc.). The user may wish to output the raw A-format audio signal to an external device. Based on the received instruction to output the raw A-format audio signal (step 610: No), the conversion module 500 can provide the A-format audio signal to the output port 512 for conversion and / or further processing by, for example, the output device 514 (step 614). The microphone capsule can automatically continue to acquire audio signals indefinitely (step 616: Yes). The conversion module 500 can receive an instruction to stop acquiring audio signals (step 616: No), at which point method 600 can terminate.

[0062] The aspects described herein can be performed by a variety of device configurations. For example, a user can connect, for instance, microphones 100 and 200 to devices 102, 104 and / or other devices that operate software applications capable of performing the operations described herein. In another example, the aspects described herein can be performed by a smartphone, desktop computer, laptop computer and / or other devices with an internal microphone and software applications capable of performing the operations described herein. No additional audio devices may be required to perform the operations described herein.

[0063] An omnidirectional surround microphone may include multiple microphone capsules. The multiple microphone capsules may be geometrically arranged to reduce acoustic masking effects from structural interference. The multiple microphone capsules may be compactly nested to reduce phase correlation errors. The multiple microphone capsules may include a first microphone capsule oriented in a first direction, a second microphone capsule oriented in a second direction, a third microphone capsule, and a fourth microphone capsule. The first direction may be substantially oriented towards a first vertex of the conceptual tetrahedron, and the second direction may be substantially oriented towards a second vertex of the conceptual tetrahedron. The third microphone capsule may be oriented in a third direction. The third direction may be substantially oriented towards a third vertex of the conceptual tetrahedron. The fourth microphone capsule may be oriented in a fourth direction. The fourth direction may be substantially oriented towards a fourth vertex of the conceptual tetrahedron. The first microphone capsule may include a first capsule face arranged in a first orientation relative to the first direction; the second microphone capsule may include a second capsule face arranged in a second orientation relative to the second direction; the third microphone capsule may include a third capsule face arranged in a third orientation relative to the third direction; and the fourth microphone capsule may include a fourth capsule face arranged in a fourth orientation relative to the fourth direction. The first orientation, second orientation, third orientation, and / or fourth orientation may be at least one of a group consisting of substantially orthogonal or substantially parallel orientations. The first microphone capsule may be positioned on a first face of the conceptual tetrahedron. A second microphone capsule may be mounted on the second face of the conceptual tetrahedron. A third microphone capsule may be mounted on the third face of the conceptual tetrahedron. A fourth microphone capsule may be mounted on the fourth face of the conceptual tetrahedron. An omnidirectional surround microphone may include one or more processors and a 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 into at least one of an A-format audio standard, a B-format audio standard, a C-format audio standard, a D-format audio standard, or a G-format audio standard. The memory stores instructions that, when executed by the one or more processors, cause the microphone to encode the set of audio signals using time-domain processing techniques. The omnidirectional surround microphone may include an output port to provide a set of audio signals formatted according to at least one of the A-format audio standard, a B-format audio standard, a C-format audio standard, a D-format audio standard, or a G-format audio standard to an external device. The omnidirectional surround microphone may further include a mounting clamp configured to be removably coupled to at least one camera. The mounting clamp may be positioned above or below the plurality of microphone capsules.

[0064] A device may include one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the device to receive a set of audio signals from an omnidirectional surround microphone and encode the set of audio signals using time-domain processing techniques. The device may include a first microphone capsule disposed on a first face of the conceptual tetrahedron. The first microphone capsule may include a first microphone capsule face disposed in a first orientation relative to the first face of the conceptual tetrahedron. The device may include a second microphone capsule disposed on a second face of the conceptual tetrahedron. The second microphone capsule may include a second microphone capsule face disposed in a second orientation relative to the second face of the conceptual tetrahedron. The device may include a third microphone capsule disposed on a third face of the conceptual tetrahedron. The third microphone capsule may include a third microphone capsule face disposed in a third orientation relative to the third face of the conceptual tetrahedron. The device may include a fourth microphone capsule disposed on a fourth face of the conceptual tetrahedron. The fourth microphone capsule may include a fourth microphone capsule face disposed in a fourth orientation relative to the fourth face of the conceptual tetrahedron. The first orientation, second orientation, third orientation, and / or fourth orientation may be at least one of a group consisting of substantially orthogonal or substantially parallel orientations. The audio signal set can be encoded according to at least one of the following audio standards: A format, B format, C format, D format, or G format. The device can receive the audio signal set from the omnidirectional surround microphone via wireless transmission. The memory stores instructions that, when executed by the at least one processor, cause the device to convert the audio signal set into at least one of the following audio standards: B format, C format, D format, or G format. The omnidirectional surround microphone may include the one or more processors and the memory. The device may also include a mounting clamp configured to be removably coupled to at least one camera.

[0065] A method for acquiring audio may include arranging a first microphone capsule on a first face of a conceptual tetrahedron, and orienting the first face of the first microphone capsule substantially orthogonal to the first face of the conceptual tetrahedron. The method may further include arranging a second microphone capsule on a second face of the conceptual tetrahedron, orienting the second face of the second microphone capsule substantially orthogonal to the second face of the conceptual tetrahedron, and nesting the first and second microphone capsules such that the first minimum sensitivity axis of the first microphone capsule and the second minimum sensitivity axis of the second microphone capsule intersect at a first coincidence point. The method may further include encoding the first set of audio signals using time-domain processing techniques and providing the second set of audio signals to an output device, wherein the second set of audio signals is encoded according to at least one of an A-format audio standard, a B-format audio standard, a C-format audio standard, a D-format audio standard, or a G-format audio standard. The method may also include obtaining a set of audio signals and wirelessly transmitting the set of audio signals to an output device. The set of audio signals may be encoded according to at least one of an A-format audio standard, a B-format audio standard, a C-format audio standard, a D-format audio standard, or a G-format audio standard.

[0066] In the foregoing description, this disclosure has been described with reference to specific exemplary examples. Although the invention has been described with reference to preferred embodiments, those skilled in the art will recognize that various modifications, embodiments, or variations of the invention can be practiced within the spirit and scope of the invention as set forth in the appended claims. Therefore, the description and drawings are to be considered illustrative rather than restrictive. Consequently, the invention is not intended to be limited except as may be necessary according to the appended claims.

Claims

1. An omnidirectional surround microphone, comprising: Multiple microphone capsules, including: The multiple microphone capsules are geometrically arranged to reduce the acoustic masking effect caused by structural interference; and The multiple microphone capsules reduce phase correlation errors through compact nesting.

2. The omnidirectional surround microphone according to claim 1, wherein the plurality of microphone capsules comprises: A first microphone capsule oriented in a first direction, wherein the first direction is substantially toward the first vertex of the conceptual tetrahedron; and A second microphone capsule oriented in a second direction, wherein the second direction is substantially toward the second vertex of the conceptual tetrahedron.

3. The omnidirectional surround microphone according to claim 2, further comprising: A third microphone capsule oriented upwards, the third orientation being substantially toward the third vertex of the concept tetrahedron; and A fourth microphone capsule oriented in a fourth direction, which is substantially toward the fourth vertex of the conceptual tetrahedron.

4. The omnidirectional surround microphone according to claim 3, wherein: The first microphone capsule includes a first capsule surface arranged in a first orientation relative to the first direction; The second microphone capsule includes a second capsule surface arranged in a second orientation relative to the second direction; The third microphone capsule includes a third capsule surface arranged in a third orientation relative to the third third orientation; The fourth microphone capsule includes a fourth capsule surface 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 at least one of a group consisting of substantially orthogonal or substantially parallel orientations.

5. The omnidirectional surround microphone according to claim 3, wherein: The first microphone capsule includes a first minimum sensitivity axis, the second microphone capsule includes a second minimum sensitivity axis, and wherein the first axis and the second axis intersect at a first point in space; and The third microphone capsule includes a third minimum sensitivity axis, and the fourth microphone capsule includes a fourth minimum sensitivity axis, wherein the third axis and the fourth axis intersect at a second point in space.

6. The omnidirectional surround microphone according to claim 3, wherein: The first microphone capsule is positioned on the first face of the conceptual tetrahedron; The second microphone capsule is positioned on the second face of the conceptual tetrahedron; The third microphone capsule is positioned on the third face of the conceptual tetrahedron; and The fourth microphone capsule is positioned on the fourth face of the conceptual tetrahedron.

7. The omnidirectional surround microphone according to claim 1, further comprising: One or more processors; and A 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 into at least one of a group consisting of format A, format B, format C, format D, format G, or binaural format.

8. The omnidirectional surround microphone according to claim 1, further comprising: One or more processors; and A memory storing instructions that, when executed by the one or more processors, cause the microphone to encode the set of audio signals using time-domain processing techniques.

9. The omnidirectional surround microphone of claim 1, further comprising an output port for providing a set of audio signals formatted according to at least one of the group consisting of format A, format B, format C, format D, format G or binaural format to an external device.

10. The omnidirectional surround microphone of claim 1, further comprising a mounting clamp configured to be removably coupled to at least one camera.

11. The omnidirectional surround microphone of claim 10, wherein the mounting clamp is disposed below the plurality of microphone capsules.

12. An omnidirectional surround microphone, comprising: A first microphone capsule oriented in a first direction, wherein the first direction is substantially toward the first vertex of the conceptual tetrahedron; and A second microphone capsule oriented in a second direction, wherein the second direction is substantially toward the second vertex of the conceptual tetrahedron.

13. The omnidirectional surround microphone according to claim 12, further comprising: A third microphone capsule oriented upwards, the third orientation being substantially toward the third vertex of the concept tetrahedron; and A fourth microphone capsule oriented in a fourth direction, which is substantially toward the fourth vertex of the conceptual tetrahedron.

14. The omnidirectional surround microphone according to claim 13, wherein: The first microphone capsule is positioned on the first face of the conceptual tetrahedron; The second microphone capsule is positioned on the second face of the conceptual tetrahedron; The third microphone capsule is positioned on the third face of the conceptual tetrahedron; and The fourth microphone capsule is positioned on the fourth face of the conceptual tetrahedron.

15. The omnidirectional surround microphone according to claim 13, wherein: The first microphone capsule includes a first minimum sensitivity axis, the second microphone capsule includes a second minimum sensitivity axis, and wherein the first axis and the second axis intersect at a first point in space; and The third microphone capsule includes a third minimum sensitivity axis, and the fourth microphone capsule includes a fourth minimum sensitivity axis, wherein the third axis and the fourth axis intersect at a second point in space.

16. The omnidirectional surround microphone according to claim 13, wherein: The first microphone capsule includes a first capsule surface arranged in a first orientation relative to the first direction; The second microphone capsule includes a second capsule surface arranged in a second orientation relative to the second direction; The third microphone capsule includes a third capsule surface arranged in a third orientation relative to the third third orientation; The fourth microphone capsule includes a fourth capsule surface 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 at least one of a group consisting of substantially orthogonal or substantially parallel orientations.

17. The omnidirectional surround microphone of claim 13, further comprising: One or more processors; and A memory storing instructions that, when executed by the one or more processors, cause the omnidirectional surround 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 into at least one of the following: format A, format B, format C, format D, format G, or binaural format.

18. The omnidirectional surround microphone of claim 17, further comprising an output port for providing the set of audio signals formatted according to at least one of the group consisting of format A, format B, format C, format D, format G or binaural format to an external device.

19. The omnidirectional surround microphone of claim 12, further comprising a mounting clamp configured to be removably coupled to at least one camera.

20. The omnidirectional surround microphone of claim 19, wherein the mounting clamp is disposed below the first microphone capsule and the second microphone capsule.

Images