US20180338205A1 - Array microphone system and method of assembling the same - Google Patents

Abstract

Embodiments include a microphone assembly comprising an array microphone and a housing configured to support the array microphone and sized and shaped to be mountable in a drop ceiling in place of at least one of a plurality of ceiling tiles included in the drop ceiling. A front face of the housing includes a sound-permeable screen having a size and shape that is substantially similar to the at least one of the plurality of ceiling tiles. Embodiments also include an array microphone system comprising a plurality of microphones arranged, on a substrate, in a number of concentric, nested rings of varying sizes around a central point of the substrate. Each ring comprises a subset of the plurality of microphones positioned at predetermined intervals along a circumference of the ring.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 15/631,310, filed on Jun. 23, 2017, which is a continuation of U.S. patent application Ser. No. 15/403,765, filed on Jan. 11, 2017, which is a continuation of U.S. patent application Ser. No. 14/701,376, filed on Apr. 30, 2015, now U.S. Pat. No. 9,565,493. The contents of each application are fully incorporated herein by reference.
TECHNICAL FIELD
• This application generally relates to an array microphone system and method of assembling the same. In particular, this application relates to an array microphone capable of fitting into a ceiling tile of a drop ceiling and providing 360-degree audio pickup with an overall directivity index that is optimized across the voice frequency range.
BACKGROUND
• Conferencing environments, such as boardrooms, video conferencing settings, and the like, can involve the use of microphones for capturing sound from audio sources. The audio sources may include human speakers, for example. The captured sound may be disseminated to an audience through speakers in the environment, a telecast, and/or a webcast.
• In some environments, the microphones may be placed on a table or lectern near the audio source in order to capture the sound. However, such microphones may be obtrusive or undesirable, due to their size and/or the aesthetics of the environment in which the microphones are being used. In addition, microphones placed on a table can detect undesirable noise, such as pen tapping or paper shuffling. Microphones placed on a table may also be covered or obstructed, such as by paper, cloth, or napkins, so that the sound is not properly or optimally captured.
• In other environments, the microphones may include shotgun microphones that are primarily sensitive to sounds in one direction. The shotgun microphones can be located farther away from an audio source and be directed to detect the sound from a particular audio source by pointing the microphone at the area occupied by the audio source. However, it can be difficult and tedious to determine the direction to point a shotgun microphone to optimally detect the sound coming from its audio source. Trial and error may be needed to adjust the position of the shotgun microphone for optimal detection of sound from an audio source. As such, the sound from the audio source may not be ideally detected unless and until the position of the microphone is properly adjusted. And even then, audio detection may be less than optimal if the audio source moves in and out of a pickup range of the microphone (e.g., if the human speaker shifts in his/her seat while speaking).
• In some environments, microphones may be mounted to a ceiling or wall of the conference room to free up table space and provide human speakers with the freedom to move around the room, thereby resolving at least some of the above concerns with tabletop and shotgun microphones. Most existing ceiling-mount microphones are configured to be secured directly to the ceiling or hanging from drop-down cables that are mounted to the ceiling. As a result, these products require complex installation and tend to become a permanent fixture. Further, while ceiling microphones may not pick up tabletop noises given their distance from the table, such microphones have their own audio pickup challenges due to a closer proximity to loudspeakers and HVAC systems, a further distance from audio sources, and an increased sensitivity to air motion or white noise.
• Accordingly, there is an opportunity for systems that address these concerns. More particularly, there is an opportunity for systems including an array microphone that is unobtrusive, easy to install into an existing environment, and can enable the adjustment of the microphone array to optimally detect sounds from an audio source, e.g., a human speaker, and reject unwanted noise and reflections.
SUMMARY
• The invention is intended to solve the above-noted problems by providing systems and methods that are designed to, among other things: (1) provide an array microphone assembly that is sized and shaped to be mountable in a drop ceiling in place of a ceiling tile; and (2) provide an array microphone system comprising a concentric configuration of microphones that achieves improved directional sensitivity over the voice frequency range and an optimal main to side lobe ratio over a prescribed steering angle range.
• In an embodiment, an array microphone system comprises a substrate and a plurality of microphones arranged, on the substrate, in a number of concentric, nested rings of varying sizes. In said embodiment, each ring comprises a subset of the plurality of microphones positioned at predetermined intervals along a circumference of the ring.
• In another embodiment, a microphone assembly comprises an array microphone comprising a plurality of microphones and a housing configured to support the array microphone. In said embodiment, the housing is sized and shaped to be mountable in a drop ceiling in place of at least one of a plurality of ceiling tiles included in the drop ceiling. Further, a front face of the housing includes a sound-permeable screen having a size and shape that is substantially similar to the at least one of the plurality of ceiling tiles.
• In another embodiment, a method of assembling an array microphone comprises arranging a first plurality of microphones to form a first configuration on a substrate and arranging a second plurality of microphones to form a second configuration on the substrate, where the second configuration concentrically surrounds the first configuration. The method further comprises electrically coupling each of the first and second pluralities of microphones to an audio processor for processing audio signals captured by the microphones.
• These and other embodiments, and various permutations and aspects, will become apparent and be more fully understood from the following detailed description and accompanying drawings, which set forth illustrative embodiments that are indicative of the various ways in which the principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a front perspective view of an exemplary array microphone assembly in accordance with certain embodiments.
• FIG. 2 is a rear perspective view of the array microphone assembly ofFIG. 1 in accordance with certain embodiments.
• FIG. 3 is an exploded view of the array microphone assembly ofFIG. 1 in accordance with certain embodiments.
• FIG. 4 is a side cross-sectional view of the array microphone assembly ofFIG. 3 in accordance with certain embodiments.
• FIG. 5 is a top plan view of the array microphone included in the array microphone assembly ofFIG. 3 in accordance with certain embodiments.
• FIG. 6 is an exemplary environment including the array microphone assembly ofFIG. 1 in accordance with certain embodiments.
• FIG. 7 is another exemplary environment including the array microphone assembly ofFIG. 2 in accordance with certain embodiments.
• FIG. 8 is another exemplary environment including the array microphone assembly ofFIG. 2 in accordance with certain embodiments.
• FIG. 9 is a graph showing microphone placement in another example array microphone in accordance with certain embodiments.
• FIG. 10 is a block diagram depicting an example array microphone system in accordance with certain embodiments.
• FIG. 11 is a polar plot showing select polar responses of the array microphone ofFIG. 9 in accordance with certain embodiments.
• FIG. 12 is a flow diagram illustrating an example process for assembling an array microphone in accordance with certain embodiments.
DETAILED DESCRIPTION
• The description that follows describes, illustrates and exemplifies one or more particular embodiments of the invention in accordance with its principles. This description is not provided to limit the invention to the embodiments described herein, but rather to explain and teach the principles of the invention in such a way to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiments described herein, but also other embodiments that may come to mind in accordance with these principles. The scope of the invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents.
• It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers, such as, for example, in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. Such labeling and drawing practices do not necessarily implicate an underlying substantive purpose. As stated above, the specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood to one of ordinary skill in the art.
• With respect to the exemplary systems, components and architecture described and illustrated herein, it should also be understood that the embodiments may be embodied by, or employed in, numerous configurations and components, including one or more systems, hardware, software, or firmware configurations or components, or any combination thereof, as understood by one of ordinary skill in the art. Accordingly, while the drawings illustrate exemplary systems including components for one or more of the embodiments contemplated herein, it should be understood that with respect to each embodiment, one or more components may not be present or necessary in the system.
• Systems and methods are provided herein for an array microphone assembly that (1) is configured to be mountable in a drop ceiling of, for example, a conferencing or boardroom environment, in place of an existing ceiling panel, and (2) includes a plurality of microphone transducers selectively positioned in a self-similar or fractal-like configuration, or constellation, to create a high performance array with, for example, an optimal directivity index and a maximal main-to-side-lobe ratio. In embodiments, this physical configuration can be achieved by arranging the microphones in concentric rings, which allows the array microphone to have equivalent beamwidth performance at any given look angle in a three-dimensional (e.g., X-Y-Z) space. As a result, the array microphone described herein can provide a more consistent output than array microphones with linear, rectangular, or square constellations. Further, each concentric ring within the constellation of microphones can have a slight, rotational offset from every other ring in order to minimize side lobe growth, giving the array microphone lower side lobes than existing arrays with co-linearly positioned elements. This offset configuration can also tolerate further beam steering, which allows the array to cover a wider pick up area. Moreover, the microphone constellation can be harmonically nested to optimize beamwidth over a given set of distinct frequency bands.
• In embodiments, the array microphone may be able to achieve maximal side lobe rejection across the voice frequency range and over a broad range of array focus (e.g., look) angles due, at least in part, to the use of micro-electrical mechanical system (MEMS) microphones, which allows for a greater microphone density and improved rejection of vibrational noise, as compared to existing arrays. The microphone density of the array constellation can permit varying beamwidth control, whereas existing arrays are limited to a fixed beamwidth. In other embodiments, the microphone system can be implemented using alternate transduction schemes (e.g., condenser, balanced armature, etc.), provided the microphone density is maintained.
• FIGS. 1-5 illustrate an exemplarymicrophone array assembly100 comprising ahousing102 and anarray microphone104, in accordance with embodiments. More specifically,FIG. 1 depicts a front perspective view of themicrophone array assembly100,FIG. 2 depicts a rear perspective view of themicrophone array assembly100,FIG. 3 depicts an exploded view of themicrophone array assembly100, showing various components of thehousing102 and themicrophone array104 included therein,FIG. 4 depicts a side cross-sectional view of themicrophone array assembly100, andFIG. 5 depicts themicrophone array104, in accordance with embodiments. For the sake of simplicity and illustration, several structural support elements, such as, e.g., screws, washers,rear mounting plate101, and cable mounting hooks103,standoffs105, have been at least partially removed from select views, such as, e.g.,FIGS. 3-5.
• The array microphone104 (also referred to herein as “microphone array”) comprises a plurality of microphone transducers106 (also referred to herein as “microphones”) configured to detect and capture sounds in an environment, such as, for example, speech spoken by speakers sitting in chairs around a conference table. The sounds travel from the audio sources (e.g., human speakers) to themicrophones106. In some embodiments, themicrophones106 may be unidirectional microphones that are primarily sensitive in one direction. In other embodiments, themicrophones106 may have other directionalities or polar patterns, such as cardioid, subcardioid, or omnidirectional, as desired.
• Themicrophones106 may be any suitable type of transducer that can detect the sound from an audio source and convert the sound to an electrical audio signal. In a preferred embodiment, themicrophones106 are micro-electrical mechanical system (MEMS) microphones. In other embodiments, themicrophones106 may be condenser microphones, balanced armature microphones, electret microphones, dynamic microphones, and/or other types of microphones.
• Themicrophones106 can be coupled to, or included on, a substrate107. In the case of MEMS microphones, the substrate107 may be one or more printed circuit boards (also referred to herein as “microphone PCB”). For example, inFIG. 5, themicrophones106 are surface mounted to the microphone PCB107 and included in a single plane. In other embodiments, for example, where themicrophones106 are condenser microphones, the substrate107 may be made of carbon-fiber, or other suitable material.
• As shown inFIGS. 1 and 2, thehousing102 is configured to fully encase themicrophone array104 in order to protect and structurally support thearray104. More specifically, a first or front face of thehousing102 includes a sound-permeable screen orgrill108, and a second or rear face of thehousing102 includes a back panel orsupport110. As shown inFIG. 1, thescreen108 can have a perforated surface comprising a plurality of small openings, and can be made of aluminum, plastic, wire mesh, or other suitable material. In other embodiments, thescreen108 may have a substantially solid surface made of sound-permeable film or fabric. As shown inFIG. 3, thehousing102 also includes amembrane111, made of foam or other suitable material, positioned between thescreen108 and themicrophone array104 to protect themicrophone array104 from external elements, as will be appreciated by those skilled in the pertinent art. As also shown inFIG. 3, thehousing102 further includes side rails112 for securing each side of theback support110, thefoam membrane111, and thescreen108 together to form thehousing102. Thehousing102 may further includestandoffs105 and spacers (not shown) to mechanically support themicrophone array104 away from other components of thehousing102 and/or theassembly100.
• Referring additionally toFIG. 6, shown is anexample ceiling600 with themicrophone array assembly100 installed therein. Theceiling600 may be part of a conferencing environment, such as, for example, a boardroom where microphones are utilized to capture sound from audio sources or human speakers. In the exemplary environment ofFIG. 6, human speakers (not shown) may be seated in chairs at a table below theceiling600, or more specifically, below themicrophone array assembly100, although other physical configurations and placements of the audio sources and/or themicrophone array assembly100 are contemplated and possible. In embodiments, themicrophone array104 may be configured for optimal performance at a certain height, or range of heights, above a floor of the environment, for example, in accordance with standard ceiling heights (e.g., eight to ten feet high), or any other appropriate height range.
• As shown inFIG. 6, theceiling600 may be a drop ceiling (a.k.a. dropped ceiling or suspended ceiling), or a secondary ceiling hung below a main, structural ceiling. As is conventional, thedrop ceiling600 comprises a grid ofmetal channels602 that are suspended on wires (not shown) from the main ceiling and form a pattern of regularly spaced cells. Each cell can be filled with a lightweight ceiling tile orpanel604 that, for example, can be removed to provide access for repair or inspection of the area above the tiles. In a preferred embodiment, theceiling tiles604 are drop-in tiles that can be easily installed or removed without disturbing the grid orother tiles604. Eachceiling tile604 is typically sized and shaped according to a “cell size” of the grid. In the United States, for example, the cell size is typically a square of approximately two feet by two feet, or a rectangle of approximately two feet by four feet. As another example, in Europe, the cell size is typically a square of approximately 600 millimeters (mm) by 600 mm. As yet another example, in Asia, the cell size is typically a square of approximately 625 mm by 625 mm.
• In embodiments, thehousing102 can be sized and shaped for installation in thedrop ceiling600 in place of at least one of theceiling tiles604. For example, thehousing102 can have length and width dimensions that are substantially equivalent to the cell size of the grid forming thedrop ceiling600. In one embodiment, thehousing102 is substantially square-shaped with dimensions of approximately two feet by two feet (e.g., each of the side rails112 is about 2 feet long), so that thehousing102 can replace any one of theceiling tiles604 in a standard U.S. drop ceiling. In other embodiments, thehousing102 may be sized and shaped to replace two or more of theceiling tiles604. For example, thehousing102 may be shaped as an approximately four feet by four feet square to replace any group of four adjoiningceiling tiles604 that form a square. In other embodiments, thehousing102 can be sized to fit into a standard European drop ceiling (e.g., 600 mm by 600 mm), or a standard Asian drop ceiling (e.g., 625 mm by 625 mm). By mounting themicrophone array assembly100 in place of aceiling tile604 of thedrop ceiling600, theassembly100 can gain acoustic benefits, similar to that of mounting a speaker in a speaker cabinet (such, for example, infinite baffling).
• In some cases, an adapter frame (not shown) may be provided to retro-fit or adapt thehousing102 to be compatible with drop ceilings that have a cell size that is larger than thehousing102. For example, the adapter frame may be an aluminum frame that can be coupled around a perimeter of thehousing102 and has a width that extends the dimensions of thehousing102 to fit a predetermined cell size. In such cases, ahousing102 that is sized for standard U.S. ceilings can be adapted to fit, for example, a standard Asian ceiling. In other cases, thehousing102 may be designed to fit a minimum cell size (such as, for example, a 600 mm by 600 mm square), and the adapter frame may be provided in multiple sizes or widths that can extend the dimensions of thehousing102 to fit various different cell sizes (such as, for example, a two feet by two feet square, a 625 mm by 625 mm square, etc.), as needed.
• In embodiments, all or portions of thehousing102 may be made of a lightweight, sturdy aluminum or any other material that is light enough to allow themicrophone array assembly100 to be supported by the grid of thedrop ceiling600 and strong enough to enable thehousing102 to support themicrophone array104 mounted therein. For example, in certain embodiments, at least theback panel110 comprises a flat, aerospace-grade, aluminum board comprising a honeycomb core (e.g., as manufactured by Plascore®). Further, according to certain embodiments, the components of the housing102 (e.g., the side rails112, theback portion110, thescreen108, themicrophone array104, etc.) can be configured to easily fit together for assembly and easily taken apart for disassembly. This feature allows thehousing102 to be customizable according to the end user's specific needs, including, for example, replacing thescreen108 with a different material (e.g., fabric) or color (e.g., to match the color of the ceiling tiles604); adding or removing an adapter frame to change an overall size of thehousing102, as described above; replacing the side rails112 to match a color or material of themetal channels602 in thedrop ceiling600; replacing or adjusting the array microphone104 (e.g., in order to provide an array with more or fewer microphones106); etc.
• Referring additionally toFIGS. 7 and 8, in embodiments, thehousing102 can be configured to provide alternative mounting options, for example, to accommodate environments that have aceiling700 that is not a drop ceiling. In some cases, themicrophone array assembly100 can include therear mounting plate101, as shown inFIG. 2. Therear mounting plate101 can be coupled to a mountingpost702, using a standard VESA mounting hole pattern, the mountingpost702 being configured for attachment to theceiling700, as shown inFIG. 7. As shown inFIG. 8, in some cases, themicrophone array assembly100 can be mounted to theceiling700 by coupling drop-down ceiling cables704 to the cable mounting hooks103 attached to theback support110 of thehousing102, as shown inFIG. 2. In still other embodiments, thehousing102 can be configured to provide a wall-mounting option and/or for placement in front of a performance area, such as a stage.
• Referring now toFIGS. 2-4, themicrophone array assembly100 includes acontrol box114 mounted on theback support110. As shown inFIGS. 3 and 4, thecontrol box114 houses a printed circuit board116 (also referred to herein as “audio PCB”) that is electrically coupled to themicrophone array104. For example, theaudio PCB116 can be coupled to themicrophone array104, or more specifically, the substrate107, through a board-to-board connector118 that extends vertically from themicrophone array104 through anopening120 in theback support110, as shown inFIGS. 3 and 4. In embodiments, theaudio PCB116 can be configured as an audio processor (e.g., through hardware and/or software elements) to process audio signals received from and captured by themicrophone array104 and to produce a corresponding audio output, as discussed in more detail herein. As illustrated, thecontrol box114 can include aremovable cover122 to provide access to theaudio PCB116 and/or other components within thecontrol box114.
• In embodiments, themicrophone array assembly100 includes anexternal port124 mechanically coupled to thecontrol box114 and configured to electrically couple a cable (not shown) to theaudio PCB116. The cable may be a data, audio, and/or power cable, depending on the type of information being conveyed through theport124. For example, upon coupling the cable thereto, theexternal port124 can be configured to receive control signals from an external control device (e.g., an audio mixer, an audio recorder/amplifier, a conferencing processor, a bridge, etc.) and provide the control signals to theaudio PCB116. Further, theport124 can be configured to transmit or output, to the external control device, audio signals received at theaudio PCB116 from themicrophone array104. In some cases, theexternal port124 can be configured to provide power from an external power supply (e.g., a battery, wall outlet, etc.) to theaudio PCB116 and/or themicrophone array104. In a preferred embodiment, theexternal port124 is an Ethernet port configured to receive an Ethernet cable (e.g., CAT5, CAT6, etc.) and to provide power, audio, and control connectivity to themicrophone array assembly100. In other embodiments, theexternal port124 can include a number of ports and/or can include any other type of data, audio, and/or power port including, for example, a Universal Serial Bus (USB) port, a mini-USB port, a PS/2 port, an HDMI port, a serial port, a VGA port, etc.
• Referring now toFIGS. 1 and 3, themicrophone array assembly100 further includes anindicator126 that visually indicates an operating mode or status of the microphone array104 (e.g., power on, power off, mute, audio detected, etc.). As shown inFIG. 1, theindicator126 can be integrated into thescreen108, so that theindicator126 is visible on an exterior of the front face of thehousing102, to externally indicate the operating mode of themicrophone array104 to human speakers or others in the conferencing environment. In embodiments, the indicator126 (also referred to herein as “external indicator”) comprises at least one light source (not shown), such as, for example, a light emitting diode (LED), that is turned on or off in accordance with an operating mode (e.g., power on or off) of thearray microphone assembly100. In some embodiments, thelight indicator126 can turn on a first light source to indicate a first operating mode (e.g., power on) of themicrophone array assembly100, turn on a second light source to indicate a second operating mode (e.g., audio detected), such that, in some instances, both light sources may be on at the same time. In a preferred embodiment, theindicator126 includes at least one LED (not shown) mounted to aPCB126a(also referred to herein as “LED PCB”) and alight guide126bconfigured to optically direct the light from the LED to outside thescreen108, as shown inFIG. 3. The LED can be electrically coupled to themicrophone array104 via acable128 that connects theLED PCB126ato aconnector129 on the microphone PCB107, as shown inFIGS. 3 and 5.
• Referring now toFIGS. 3 and 5, in embodiments, the substrate107 of themicrophone array assembly100 can include acentral PCB107aand one or moreperipheral PCBs107bpositioned around the central board to increase an available space for mounting themicrophones106. For example, a portion of themicrophones106 may be mounted on thecentral PCB107aand a remainder of themicrophones106 may be mounted on theperipheral PCBs107b, as will be explained in more detail below. Each of theperipheral PCBs107bcan be coupled to thecentral PCB107ausing one or more board-to-board connectors130. In a preferred embodiment, themicrophones106 are all mounted in one plane of the substrate107, as shown inFIG. 4.
• The number, size, and shape of the one or moreperipheral PCBs107bcan vary depending on, for example, a number ofsides130, size and/or shape of thecentral PCB107a, as well as an overall shape of the substrate107. For example, in the illustrated embodiment, thecentral PCB107ais a polygon with sevenuniform sides132, and the substrate107 includes sevenperipheral PCBs107brespectively coupled to eachside132 at aninner end134 of eachperipheral PCB107b. As illustrated, the inner ends134 are flat surfaces uniformly sized to match any one of the sevensides132. Eachperipheral PCB107bcan further include anouter end136 that is opposite theinner end134. In the illustrated embodiment, the substrate107 is shaped as a circle, and therefore, theouter end136 of eachperipheral PCB107bis curved.
• In other embodiments, thecentral PCB107acan have other overall shapes, including, for example, other types of polygons (e.g., square, rectangle, triangle, pentagon, etc.), a circle, or an oval. In such cases, the inner ends134 of theperipheral PCBs107bmay be sized and shaped according to the size and shape of thesides132 of thecentral PCB107a. For example, in one embodiment, the central PCB107 may have a circular shape such that each of thesides132 is curved, and therefore, the inner ends134 of theperipheral PCBs107bmay also be curved. Likewise, in other embodiments, the substrate107 can have other overall shapes, including, for example, an oval or a polygon, and the outer ends136 of theperipheral PCB107bcan be shaped accordingly. In still other embodiments, the substrate107 can include a donut-shapedperipheral PCB107bsurrounding a circularcentral PCB107a, or a single, continuous board107 comprising all of themicrophone transducers106.
• As shown inFIG. 5, in embodiments, the plurality ofmicrophones106 includes acentral microphone106apositioned at a central point of thecentral PCB107aand a remaining set of themicrophones106bthat are arranged in a fractal, or self-similar, configuration surrounding thecentral microphone106aand positioned on either thecentral PCB107aor theperipheral PCB107b. Due, at least in part, to the fractal-like placement of themicrophones106, thearray microphone104 can achieve improved directional sensitivity across the voice frequency range and maximal main-to-side-lobe ratio over a prescribed steering angle range. As a result, themicrophone array104 can more precisely “listen” for signals coming from a single direction and reject unwanted noise and/or interference sounds, and can more effectively differentiate between adjacent human speakers. In addition, the fractal nature of the microphone configuration allows the directivity of thearray104 to be easily extensible to a wider frequency range (e.g., lower and/or higher frequencies) by adding more microphones and/or creating a larger-sized microphone array104.
• More specifically, in embodiments, themicrophones106 can be arranged in concentric, circular rings of varying sizes, so as to avoid undesired pickup patterns (e.g., due to grating lobes) and accommodate a wide range of audio frequencies. As used herein, the term “ring” may include any type of circular configuration (e.g., perfect circle, near-perfect circle, less than perfect circle, etc.), as well as any type of oval configuration or other oblong loop. As shown inFIG. 5, the rings can be positioned at various radial distances from thecentral microphone106a, or a central point of the substrate107, to form a nested configuration that can handle progressively lower audio frequencies, with the outermost ring being configured to optimally operate at the lowest frequencies in the predetermined operating range. Using harmonic nesting techniques, the concentric rings can be used to cover a specific frequency bands within a range of operating frequencies.
• In embodiments, each ring contains a different subset of the remainingmicrophones106b, and each subset ofmicrophones106bcan be positioned at predetermined intervals along a circumference of the corresponding ring. The predetermined interval or spacing between neighboringmicrophones106bwithin a given ring can depend on a size or diameter of the ring, a number ofmicrophones106bincluded in the subset assigned to that ring, and/or a desired sensitivity or overall sound pressure for themicrophones106bin the ring. Increasing the number ofmicrophones106 and a microphone density of the rings (e.g., due to nesting of the rings) can help remove grating lobes and thereby, produce an improved beamwidth with a near constant frequency response across all frequencies within the preset range.
• As will be appreciated,FIG. 5 only shows an exemplary embodiment of thearray microphone104 and other configurations of themicrophones106 are contemplated in accordance with the principles disclosed herein. For example, in some embodiments, the plurality ofmicrophones106 may be arranged in concentric rings around a central point, but without any microphone positioned at the central point (e.g., without thecentral microphone106a). In still other embodiments, only a portion of themicrophones106 may be arranged in concentric rings, and the remaining portion of themicrophones106 may be positioned at various points outside of, or in between, the discrete rings, at random locations on the substrate107, or in any other suitable arrangement.
• FIG. 9 graphically depicts anexemplary microphone configuration900 that may be found in an array microphone in accordance with certain embodiments. Themicrophone configuration900 may be substantially similar to the self-similar configuration ofmicrophones106 included themicrophone array104, except for the number ofmicrophones106bincluded in an innermost ring of thearray104. As shown, themicrophone configuration900 includes one microphone902 (e.g., thecentral microphone106a) located at a center of theconfiguration900 and a plurality of microphones906 (e.g., the remaining set ofmicrophones106b) arranged in seven concentric rings910-922. For ease of explanation and illustration, a circle has been drawn through each group ofmicrophones906 that forms the rings of themicrophone configuration900.
• In order to accommodate themicrophones906, themicrophone configuration900 may be mounted on a plurality of printed circuit boards (not shown), similar to thecentral PCB107aand the plurality ofperipheral PCBs107b. For example, referring now toFIG. 5 as well, themicrophones906 may include (i) a first subset of themicrophones902 mounted on thecentral PCB107ato form afirst ring910 surrounding thecentral microphone906, (ii) a second subset of themicrophones906 mounted on thecentral PCB107ato form asecond ring912 surrounding thefirst ring910, (iii) a third subset of themicrophones906 that are mounted on thecentral PCB107ato form athird ring914 surrounding thesecond ring912, (iv) a fourth subset of themicrophones906 mounted on thecentral PCB107ato form afourth ring916 surrounding thethird ring914, (v) a fifth subset of themicrophones906 mounted on theperipheral PCBs107bto form afifth ring918 surrounding thefourth ring916, (vi) a sixth subset of themicrophones906 mounted on theperipheral PCBs107bto form asixth ring920 surrounding thefifth ring918, and (vii) a seventh subset of themicrophones906 mounted on, and near an edge of, theperipheral PCBs107bto form aseventh ring922 surrounding thesixth ring920.
• In embodiments, the number of rings910-922 included in the microphone array, a diameter of each ring, and/or the radial distance between neighboring rings can vary depending on the desired frequency range over which the array microphone is configured to operate and what percentage of that range will be covered by each ring. In embodiments, the diameter of each ring in the microphone array defines the lowest frequency at which the subset of microphones within that ring can operate without picking up unwanted signals (e.g., due to grating lobes). As such, the diameter of theoutermost ring922 can determine a lower end of the operational frequency range of the microphone array, and the remaining ring diameters can be determined by subdividing the remaining frequency range. For example and without limitation, in some embodiments, the microphone array can be configured to cover an operational frequency range of at least 100 hertz (Hz) to at least 10 kilohertz (KHz), with each ring covering, or contributing to coverage of, a different octave or other frequency band within this range. As a further example, in such embodiments, theoutermost ring922 may be configured to cover the lowest frequency band (e.g., 100 Hz), and the remaining rings910-920, either alone or in combination with one or more other rings, may contribute to coverage of the remaining octaves or bands (e.g., frequency bands starting at 200 Hz, 400 Hz, 800 Hz, 1600 Hz, 3200 Hz, and/or 6400 Hz).
• As will be appreciated, side lobes may be present in a polar response of a microphone array, in addition to a main lobe of the array beam, the result of undesired, extraneous pick-up sensitivity at angles other than the desired beam angle. Because side lobes can change in magnitude and frequency sensitivity as the array beam is steered, a beam that typically has very small side lobes relative to a main lobe can have a much larger side lobe response once the beam is steered to a different direction. In some cases, the side lobe sensitivity can even rival the main lobe sensitivity at certain frequencies. However, in embodiments, includingmore microphones906 within the microphone array can strengthen the main lobe of a given beam and thereby, reduce the ratio of side lobe sensitivity to main lobe sensitivity.
• In embodiments, the rings910-922 may be at least slightly rotated relative to acentral axis930 that passes through a center of the array (e.g., the central microphone902) in order to optimize the directivity of the microphone array. In such cases, the microphone array can be configured to constrain microphone sensitivity to the main lobes, thereby maximizing main lobe response and reducing side lobe response. In some embodiments, the rings910-922 can be rotationally offset from each other, for example, by rotating each ring a different number of degrees, so that no more than any twomicrophones906 are axially aligned. For example, in microphone arrays with a smaller number of microphones, this rotational offset may be beneficial to reduce an undesired acoustic signal pickup that can occur when more than two microphones are aligned. In other embodiments, for example, in arrays with a large number of microphones, the rotational offset may be more arbitrarily implemented, if at all, and/or other methods may be utilized to optimize the overall directivity of the microphone array.
• Referring back toFIG. 5, in embodiments, each of theperipheral PCBs107bcan be uniformly designed to streamline manufacturing and assembly. For example, as shown inFIG. 5, eachperipheral PCB107bcan have a uniform shape, and themicrophones106bcan be placed in identical locations on eachboard107b. In this manner, any one of theperipheral PCBs107bcan be coupled to any one of theconnectors130 in order to electrically couple theperipheral PCB107bto thecentral PCB107a. For example, in the illustrated embodiment, the microphone PCB107 includes sevenperipheral PCBs107bso that each of theperipheral PCBs107bcan include eight microphones in uniform locations. The remaining 64 microphones are included on thecentral PCB107a, so that themicrophone array104 includes a total of 120 microphones.
• In embodiments, the total number ofmicrophones106 and/or the number ofmicrophones106bon thecentral PCB107aand/or each of theperipheral PCBs107bmay vary depending on, for example, the configuration of the harmonic nests, a preset operating frequency range of thearray104, an overall size of themicrophone array104, as well as other considerations. For example, inFIG. 9, themicrophone configuration900 includes only 113, or more specifically, one central microphone surrounded by 112microphones906, because thering910 includes sevenfewer microphones906 than the corresponding ring of themicrophone array104 inFIG. 5. In certain embodiments, removing these seven microphones from the first orinnermost ring910 can be achieved with little to no loss in frequency coverage or microphone sensitivity.
• In embodiments, the number ofmicrophones906 included in each of the rings910-922 can be selected to create a self-similar or repeating pattern in themicrophone configuration900. This can allow themicrophone configuration900 to be easily extended by adding one or more rings, in order to cover more audio frequencies, or easily reduced by removing one or more rings, in order to cover fewer frequencies. For example, in the illustrated embodiments ofFIGS. 5 and 9, a fractal or self-similar configuration is formed by placing 7, 14, or 21microphones106b/906 (e.g., a multiple of 7) in each of the seven rings910-922. Other embodiments may include other repeatable arrangements of themicrophones106b/906, such as, for example, multiples of another integer greater than one, or any other pattern that can simplify manufacturing of thearray microphone104. For example and without limitation, in one embodiment, the number ofmicrophones906 in each of the inner rings910-920 may alternate between two numbers (e.g., 8 and 16), while theoutermost ring922 may include any number of microphones906 (e.g., 20).
• As will be appreciated, in other embodiments, themicrophones106/906 may be arranged in other configuration shapes, such as, for example, ovals, squares, rectangles, triangles, pentagons, or other polygons, have more or fewer subsets or rings ofmicrophones106/906, and/or have a different number ofmicrophones106/906 in each of the rings910-922 depending on, for example, a desired distance between each ring, an overall size of the substrate107, a total number ofmicrophones106 in thearray104, a preset audio frequency range covered by thearray104, as well as other performance- and/or manufacturing-related considerations.
• FIG. 10 illustrates a block diagram of anexemplary audio system1000 comprising anarray microphone system1030 and acontrol device1032. Thearray microphone system1030 may be configured similar to thearray microphone assembly100 shown inFIGS. 1-5, or in other configurations. For example, thearray microphone system1030 may include anarray microphone1034 that is similar to thearray microphone104. Thearray microphone system1030 may also include anaudio component1036 that receives audio signals from thearray microphone1034 and is configured as an audio recorder, audio mixer, amplifier, and/or other component for processing of audio signals captured by themicrophone array1034. In such embodiments, theaudio component1036 may be at least partially included on a printed circuit board (not shown), such as, e.g., theaudio PCB116. In other embodiments, theaudio component1036 is located in theaudio system1000 independently of thearray microphone system1030, and the array microphone system1030 (e.g., within the control device1032) may be in wired or wireless communication with theaudio component1036. Thearray microphone system1030 may further include anindicator1038 similar to theindicator126 to visually indicate an operating mode of themicrophone array1034 on a front exterior of thearray microphone system1030.
• Thecontrol device1032 may be in wired or wireless communication with thearray microphone system1030 to control theaudio component1036, themicrophone array1034, and/or theindicator1038. For example, thecontrol device1036 may include controls to activate or deactivate themicrophone array1034 and/or theindicator1038. Controls on thecontrol device1036 may further enable the adjustment of parameters of themicrophone array1034, such as directionality, gain, noise suppression, pickup pattern, muting, frequency response, etc. In embodiments, thecontrol device1036 may be a laptop computer, desktop computer, tablet computer, smartphone, proprietary device, and/or other type of electronic device. In other embodiments, thecontrol device1036 may include one or more switches, dimmer knobs, buttons, and the like.
• In some embodiments, themicrophone array system1030 includes a wireless communication device1040 (e.g., a radio frequency (RF) transmitter and/or receiver) for facilitating wireless communication between thesystem1030 and thecontrol device1036 and/or other computer devices (e.g., by transmitting and/or receiving RF signals). For example, the wireless communication may be in the form of an analog or digital modulated signal and may contain audio signals captured by themicrophone array1034 and/or control signals received from thecontrol device1036. In some embodiments, thewireless communication device1040 may include a built-in web server for facilitating web conferencing and other similar features through communication with a remote computer device and/or server.
• In some embodiments, thearray microphone system1030 includes an external port (not shown) similar to theexternal port124, and thesystem1030 is in wired communication with thecontrol device1036 via acable1042 coupled to theport124. In one such embodiment, theaudio system1000 further includes apower supply1044 that is also coupled to thearray microphone system1030 via thecable1042, such that thecable1042 carries power, control, and/or audio signals between various components of theaudio system1000. In a preferred embodiment, thecable1042 is an Ethernet cable (e.g., CAT5, CAT6, etc.). In other embodiments, thepower supply1044 is coupled to thearray microphone system1030 via a separate power cable.
• As illustrated, theindicator1038 can include afirst light source1046 and a secondlight source1048. Thefirst light source1046 may be configured to indicate a first operating mode or status of themicrophone array1034 by turning the light on or off, and likewise, the secondlight source1048 may be configured to indicate a second operating mode of themicrophone array1034. For example, thefirst light source1046 may indicate whether or not themicrophone array system1030 has power (e.g., the light1046 turns on if thesystem1030 is turned on), and the secondlight source1048 may indicate whether or not themicrophone array1034 has been muted (e.g., the light1048 turns on if thesystem1030 has been set to a mute setting). In other cases, at least one of thelight sources1046,1048 may indicate whether or not audio is being received from an outside audio source (e.g., during web conferencing). In a preferred embodiment, thefirst light source1046 is a first LED with a first light color, and the secondlight source1048 is a second LED with a second light color that is different from the first light color (e.g., blue, green, red, white, etc.). Theindicator1038 can be in electronic communication with and controlled by thecontrol device1032 and/or theaudio component1036, for example, to determine which operating mode(s) can be indicated by theindicator1038 and which color(s), LED(s), or other forms of indication are assigned to each operating mode.
• In embodiments, theaudio component1036 can be configured (e.g., via computer programming instructions) to enable adjustment of parameters of themicrophone array1034, such as directionality, gain, noise suppression, pickup pattern, muting, frequency response, etc. Further, theaudio component1036 may include an audio mixer (not shown) to enable mixing of the audio signals captured by the microphone array1034 (e.g., combining, routing, changing, and/or otherwise manipulating the audio signals). The audio mixer may continuously monitor the received audio signals from each microphone in themicrophone array1034, automatically select an appropriate (e.g., best) lobe formed by themicrophone array1034 for a given human speaker, automatically position or steer the selected lobe directly towards the human speaker, and output an audio signal that emphasizes the selected lobe while suppressing signals from the other audio sources.
• In embodiments, in order to accommodate the possibility of several human speakers speaking simultaneously (e.g., in a boardroom environment), themicrophone array1034 can be configured to simultaneously form up to eight lobes at any angle around themicrophone array1034, for example, to emulate up to eight seated positions at a table. Due to its microphone configuration (e.g., the microphone configuration900), themicrophone array1034 can form relatively narrow lobes (e.g., as shown inFIG. 11) to pick up less of the unwanted audio signals (e.g., noise) in an environment. The lobes can be steerable so as to provide audio pick-up coverage of human speakers positioned at any point 360 degrees around thearray1034. For example, theaudio component1036 may be configured (e.g., using computer programming instructions) to allow the lobes to be steered or adjusted to any point in a three-dimensional space covering azimuth, elevation, and distance or radius. In embodiments, the beam pattern of themicrophone array1034 can be electronically steered without physically moving thearray1034.
• Further, the audio mixer may be configured to simultaneously provide up to eight individually-routed outputs or channels (not shown), each output corresponding to a respective one of the eight lobes of themicrophone array1034 and being generated by combining the inputs received from all microphones in themicrophone array1034. The audio mixer may also provide a ninth auto-mixed output to capture all other audio signals. As will be appreciated, themicrophone array1034 can be configured to have any number of lobes.
• According to embodiments, the lobes of themicrophone array1034 can be configured to have an adjustable beamwidth that allows theaudio component1036 to effectively track, and capture audio from, human speakers as they move within the environment. In some cases, themicrophone array system1030 and/or thecontrol device1032 may include a user control (not shown) that allows manual beamwidth adjustment. For example, the user control may be a knob, slider, or other manual control that can be adjusted between three settings: normal beamwidth, wide beamwidth, and narrow beamwidth. In other cases, the beamwidth control can be configured using software running on theaudio component1036 and/or thecontrol device1032.
• In environments where multiplemicrophone array systems1030 are included, for example, to cover a very large conference room, theaudio system1000 may include an audio mixer that receives the outputs from theaudio components1036 included in eachmicrophone array system1030 and outputs a mixed output based on the received audio signals.
• Theaudio component1036 may also include an audio amplifier/recorder (not shown) that is in wired or wireless communication with the audio mixer. The audio amplifier/recorder may be a component that receives the mixed audio signals from the audio mixer and amplifies the mixed audio signals for output to a loudspeaker, headphones, live radio or TV feeds, etc., and/or records the received signals onto a medium, such as flash memory, hard drives, solid state drives, tapes, optical media, etc. For example, the audio amplifier/recorder may disseminate the sound to an audience through loudspeakers located in theenvironment600, or to a remote environment via a wired or wireless connection.
• The connections between the components shown inFIG. 10 are intended to depict the potential flow of control signals, audio signals, and/or other signals over wired and/or wireless communication links. Such signals may be in digital and/or analog formats.
• In embodiments, themicrophone array1034 includes a plurality of MEMS microphones (e.g., the microphones906) arranged in a self-similar or repeating configuration comprising concentric, nested rings of microphones (e.g., the rings910-922) surrounding a central microphone (e.g., the microphone902). MEMS microphones can be very low cost and very small sized, which allows a large number of microphones to be placed in close proximity in a single microphone array. For example, in embodiments, themicrophone array1034 includes between 113 and 120 microphones and has a diameter of less than two feet (e.g., to fit in place of a two feet by two feet ceiling tile). Further, by using MEMS microphones in themicrophone array1034, theaudio component1036 may require less programming and other software-based configuration. More specifically, because MEMS microphones produce audio signals in a digital format, theaudio component1036 need not include analog-to-digital conversion/modulation technologies, which reduces the amount of processing required to mix the audio signals captured by the microphones. In addition, themicrophone array1034 may be inherently more capable of rejecting vibrational noise due to the fact that MEMS microphones are good pressure transducers but poor mechanical transducers, and have good radio frequency immunity compared to other microphone technologies.
• FIG. 11 is a diagram of an example microphonepolar pattern1100 in accordance with embodiments. Thepolar pattern1100 represents the directionality of a given microphone array (e.g., themicrophone array1034/104 or a microphone array having the microphone configuration900), or more specifically, indicates how sensitive the microphone array is to sounds arriving at different angles about a central axis of the microphone array. In particular, thepolar pattern1100 shows polar responses of the microphone array at each offrequencies 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz, with the microphone array being configured to form alobe1102, or a directional beam, at each of these frequencies and thelobe1102 being steered to an elevation of 60 degrees relative to the plane of the array. As will be appreciated, while thepolar plot1100 shows the polar responses of asingle lobe1102 at selected frequencies, the microphone array is capable of creating multiple simultaneous lobes in multiple directions, each with equivalent, or at least substantially similar, polar response.
• As shown by thepolar pattern1100, at the 1000 Hz frequency,side lobes1104 are formed at 10 decibels (dB) below themain lobe1102. Further, as shown inFIG. 11, the low frequency response at 500 Hz has a large beamwidth, representing lower directivity, while the higher frequency responses at 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz each have a narrow beamwidth, representing high directivity. Thus, in embodiments, the microphone array can provide a high overall directivity index (e.g., 19 dB) across the voice frequency range with a high level of side lobe rejection and an optimal main-to-side-lobe ratio (e.g., 10 dB) over a prescribed steering angle range.
• FIG. 12 illustrates anexample method1200 of assembling an array microphone in accordance with embodiments. The array microphone may be substantially similar to thearray microphone104 shown inFIG. 5 and/or may include a plurality of microphones arranged in a configuration that is substantially similar to themicrophone configuration900 shown inFIG. 9. The array microphone may be arranged on a substrate, such as, for example, a printed circuit board, a carbon-fiber board, or any other suitable substrate. In some embodiments, the substrate includes a central board (e.g., thecentral PCB107a) and a plurality of peripheral or satellite boards (e.g., theperipheral PCBs107b). In such cases, themethod1200 can includestep1204, where the peripheral boards are electrically coupled to the central board, for example, using board-to-board connectors (e.g., connectors130).
• In some embodiments, themethod1200 includes, atstep1206, selecting a total number of microphones (e.g., themicrophones106b/906) to include in each configuration that will be placed on the substrate. Where the configuration includes a number of concentric rings, the number of microphones in each ring may be selected based on a desired frequency range of the array, a frequency band assigned to the ring, a desired microphone density for the array, as well as other considerations, as discussed herein. In one embodiment, the total number may be selected from a group consisting of numbers that are a multiple of an integer greater than one. For example, for the rings shown inFIGS. 5 and 9, the integer is seven, and each ring includes 7, 14, or 21 microphones. Other patterns or arrangements may drive the selection of the total number of microphones for each configuration, as described herein.
• As illustrated, themethod1200 includes, atstep1208, arranging a first plurality of microphones in a first configuration on the substrate. Themethod1200 also includes, atstep1210, arranging a second plurality of microphones in a second configuration on the substrate, the second configuration concentrically surrounding the first configuration. In some embodiments, themethod1200 can additionally include, atstep1212, arranging a third plurality of microphones in a third configuration on the substrate, the third configuration concentrically surrounding the second configuration.
• In embodiments, each of the first, second, and/or third configurations comprises a number of concentric rings positioned at different radial distances from a central point of the substrate to form a nested configuration. In some cases, the first configuration includes a different number of concentric rings than at least one of the second configuration and the third configuration. For example, in the illustrated embodiment ofFIG. 9, the first configuration comprises at least theinnermost ring910, thesecond ring912, andthird ring914, the second configuration comprises at least thefourth ring916 and thefifth ring918, and the third configuration comprises at least thesixth ring920 and theoutermost ring922. In each of the configurations, arranging the microphones can include, for each concentric ring, arranging a subset of the microphones at predetermined intervals along a circumference of that ring. In some embodiments, the first configuration further includes the central point of the substrate, and at least one of the first plurality of microphones is positioned at the central point. Further, in some embodiments, at least one of the rings included in the second configuration may be positioned on the peripheral boards. Further, in some embodiments, the third configuration may be positioned entirely on the peripheral boards.
• In some embodiments, themethod1200 can include, atstep1214, rotating at least one of the first, second, and third fourth configurations relative to a central axis (e.g., the central axis930) of the array microphone so that the configurations are at least slightly rotationally offset from each other, to improve the overall directivity of the array microphone. Themethod1200 can also include, atstep1216, electrically coupling each of the microphones to an audio processor for processing audio signals captured by the microphones.
• In embodiments, the first, second, and/or third pluralities of microphones are configured to cover different preset frequency ranges, or in some cases, octaves within an overall operating range of the array microphone (for example and without limitation, 100 Hz to 10 KHz). According to embodiments, a diameter of each concentric ring can be defined by a lowest operating frequency assigned to the microphones forming the ring. In some cases, the concentric rings included in the first, second, and/or third configurations are harmonically nested. In a preferred embodiment, the microphone array includes a plurality of MEMS microphones.
• Any process descriptions or blocks in figures should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included within the scope of the embodiments of the invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those having ordinary skill in the art.
• This disclosure is intended to explain how to fashion and use various embodiments in accordance with the technology rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to be limited to the precise forms disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) were chosen and described to provide the best illustration of the principle of the described technology and its practical application, and to enable one of ordinary skill in the art to utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the embodiments as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.

Claims (21)

1-40. (canceled)

41. An array microphone system comprising:

a plurality of microphones arranged in a number of concentric, nested configurations, each configuration comprising a subset of the plurality of microphones positioned at predetermined intervals from each other to form the configuration, wherein the configurations are rotationally offset from each other relative to a central axis of the array microphone system.

42. The array microphone system ofclaim 41, wherein each configuration is rotationally offset from the central axis by a different number of degrees.

43. The array microphone system ofclaim 41, wherein each configuration is positioned at a different radial distance from the central axis to form the nested arrangement.

44. The array microphone system ofclaim 41, further comprising at least one microphone arranged at a central point of the concentric, nested configurations.

45. The array microphone system ofclaim 41, wherein each configuration forms a circular shape with a diameter that is selected based on a lowest operating frequency assigned to the subset of microphones included in that configuration.

46. The array microphone system ofclaim 41, wherein each configuration comprises a predetermined number of microphones, the predetermined number being selected from a group consisting of numbers that are multiples of an integer greater than one.

47. The array microphone system ofclaim 46, wherein the predetermined number is an odd number.

48. The array microphone system ofclaim 41, further comprising a substrate, the plurality of microphones being arranged on said substrate.

49. The array microphone system ofclaim 48, wherein the substrate includes at least one printed circuit board (PCB), and the plurality of microphones are micro-electrical mechanical system (MEMS) microphones coupled to the PCB.

50. The array microphone system ofclaim 48, wherein the substrate comprises a central printed circuit board (PCB) and a plurality of peripheral printed circuit boards (PCBs) radially positioned around, and electrically connected to, the central PCB, at least one of the concentric, nested configurations being positioned on the plurality of peripheral PCBs.

51. A method of assembling an array microphone, comprising:

arranging a first plurality of microphones to form a first configuration;

arranging a second plurality of microphones to form a second configuration, the second configuration concentrically surrounding the first configuration;

rotating at least one of the first and second configurations relative to a central axis of the array microphone, and

electrically coupling each of the first and second pluralities of microphones to an audio processor for processing audio signals captured by the microphones.

52. The method ofclaim 51, wherein rotating at least one of the first and second configurations includes rotating each configuration by a different number of degrees relative to the central axis.

53. The method ofclaim 51, wherein:

arranging the first plurality of microphones includes: positioning the first configuration at a first radial distance from the central axis; and

arranging the second plurality of microphones includes: positioning the second configuration at a second radial distance from the central axis,

the second radial distance being greater than the first radial distance to form a concentric, nested arrangement.

54. The method ofclaim 51, further comprising: arranging at least one microphone at a central point of the first configuration.

55. The method ofclaim 51, wherein arranging the first plurality of microphones includes: arranging the first plurality of microphones at predetermined intervals from each other to form the first configuration.

56. The method ofclaim 51, wherein:

arranging the first plurality of microphones to form the first configuration includes: arranging the first plurality of microphones in a circular shape with a first diameter to form the first configuration; and

arranging the second plurality of microphones to form the second configuration includes: arranging the second plurality of microphones in a circular shape with a second diameter to form the second configuration,

the first and second diameters being defined by a lowest operating frequency assigned to the microphones forming the corresponding configuration.

57. The method ofclaim 51, further comprising:

selecting a predetermined number of microphones for each of the first and second configurations from a group consisting of numbers that are multiples of an integer greater than one.

58. The method ofclaim 57, wherein the predetermined number is an odd number.

59. The method ofclaim 51, wherein the first and second pluralities of microphones are arranged on a substrate, and electrically coupling each of the microphones to the audio processor includes: electrically connecting each of the microphones to the substrate, and electrically connecting the substrate to the audio processor.

60. The method ofclaim 59, wherein the substrate includes at least one printed circuit board (PCB), and the plurality of microphones are micro-electrical mechanical system (MEMS) microphones coupled to the PCB.

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