Patent ID: 12262174

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.1-5illustrate an exemplary microphone array assembly100comprising a housing102and an array microphone104, in accordance with embodiments. More specifically,FIG.1depicts a front perspective view of the microphone array assembly100,FIG.2depicts a rear perspective view of the microphone array assembly100,FIG.3depicts an exploded view of the microphone array assembly100, showing various components of the housing102and the microphone array104included therein,FIG.4depicts a side cross-sectional view of the microphone array assembly100, andFIG.5depicts the microphone 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 the microphones106. In some embodiments, the microphones106may be unidirectional microphones that are primarily sensitive in one direction. In other embodiments, the microphones106may have other directionalities or polar patterns, such as cardioid, subcardioid, or omnidirectional, as desired.

The microphones106may 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, the microphones106are micro-electrical mechanical system (MEMS) microphones. In other embodiments, the microphones106may be condenser microphones, balanced armature microphones, electret microphones, dynamic microphones, and/or other types of microphones.

The microphones106can be coupled to, or included on, a substrate107. In the case of MEMS microphones, the substrate107may be one or more printed circuit boards (also referred to herein as “microphone PCB”). For example, inFIG.5, the microphones106are surface mounted to the microphone PCB107and included in a single plane. In other embodiments, for example, where the microphones106are condenser microphones, the substrate107may be made of carbon-fiber, or other suitable material.

As shown inFIGS.1and2, the housing102is configured to fully encase the microphone array104in order to protect and structurally support the array104. More specifically, a first or front face of the housing102includes a sound-permeable screen or grill108, and a second or rear face of the housing102includes a back panel or support110. As shown inFIG.1, the screen108can 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, the screen108may have a substantially solid surface made of sound-permeable film or fabric. As shown inFIG.3, the housing102also includes a membrane111, made of foam or other suitable material, positioned between the screen108and the microphone array104to protect the microphone array104from external elements, as will be appreciated by those skilled in the pertinent art. As also shown inFIG.3, the housing102further includes side rails112for securing each side of the back support110, the foam membrane111, and the screen108together to form the housing102. The housing102may further include standoffs105and spacers (not shown) to mechanically support the microphone array104away from other components of the housing102and/or the assembly100.

Referring additionally toFIG.6, shown is an example ceiling600with the microphone array assembly100installed therein. The ceiling600may 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 the ceiling600, or more specifically, below the microphone array assembly100, although other physical configurations and placements of the audio sources and/or the microphone array assembly100are contemplated and possible. In embodiments, the microphone array104may 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, the ceiling600may 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, the drop ceiling600comprises a grid of metal channels602that 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 or panel604that, for example, can be removed to provide access for repair or inspection of the area above the tiles. In a preferred embodiment, the ceiling tiles604are drop-in tiles that can be easily installed or removed without disturbing the grid or other tiles604. Each ceiling tile604is 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, the housing102can be sized and shaped for installation in the drop ceiling600in place of at least one of the ceiling tiles604. For example, the housing102can have length and width dimensions that are substantially equivalent to the cell size of the grid forming the drop ceiling600. In one embodiment, the housing102is substantially square-shaped with dimensions of approximately two feet by two feet (e.g., each of the side rails112is about 2 feet long), so that the housing102can replace any one of the ceiling tiles604in a standard U.S. drop ceiling. In other embodiments, the housing102may be sized and shaped to replace two or more of the ceiling tiles604. For example, the housing102may be shaped as an approximately four feet by four feet square to replace any group of four adjoining ceiling tiles604that form a square. In other embodiments, the housing102can 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 the microphone array assembly100in place of a ceiling tile604of the drop ceiling600, the assembly100can 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 the housing102to be compatible with drop ceilings that have a cell size that is larger than the housing102. For example, the adapter frame may be an aluminum frame that can be coupled around a perimeter of the housing102and has a width that extends the dimensions of the housing102to fit a predetermined cell size. In such cases, a housing102that is sized for standard U.S. ceilings can be adapted to fit, for example, a standard Asian ceiling. In other cases, the housing102may 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 the housing102to 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 the housing102may be made of a lightweight, sturdy aluminum or any other material that is light enough to allow the microphone array assembly100to be supported by the grid of the drop ceiling600and strong enough to enable the housing102to support the microphone array104mounted therein. For example, in certain embodiments, at least the back panel110comprises 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, the back portion110, the screen108, the microphone array104, etc.) can be configured to easily fit together for assembly and easily taken apart for disassembly. This feature allows the housing102to be customizable according to the end user's specific needs, including, for example, replacing the screen108with 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 the housing102, as described above; replacing the side rails112to match a color or material of the metal channels602in the drop ceiling600; replacing or adjusting the array microphone104(e.g., in order to provide an array with more or fewer microphones106); etc.

Referring additionally toFIGS.7and8, in embodiments, the housing102can be configured to provide alternative mounting options, for example, to accommodate environments that have a ceiling700that is not a drop ceiling. In some cases, the microphone array assembly100can include the rear mounting plate101, as shown inFIG.2. The rear mounting plate101can be coupled to a mounting post702, using a standard VESA mounting hole pattern, the mounting post702being configured for attachment to the ceiling700, as shown inFIG.7. As shown inFIG.8, in some cases, the microphone array assembly100can be mounted to the ceiling700by coupling drop-down ceiling cables704to the cable mounting hooks103attached to the back support110of the housing102, as shown inFIG.2. In still other embodiments, the housing102can 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, the microphone array assembly100includes a control box114mounted on the back support110. As shown inFIGS.3and4, the control box114houses a printed circuit board116(also referred to herein as “audio PCB”) that is electrically coupled to the microphone array104. For example, the audio PCB116can be coupled to the microphone array104, or more specifically, the substrate107, through a board-to-board connector118that extends vertically from the microphone array104through an opening120in the back support110, as shown inFIGS.3and4. In embodiments, the audio PCB116can be configured as an audio processor (e.g., through hardware and/or software elements) to process audio signals received from and captured by the microphone array104and to produce a corresponding audio output, as discussed in more detail herein. As illustrated, the control box114can include a removable cover122to provide access to the audio PCB116and/or other components within the control box114.

In embodiments, the microphone array assembly100includes an external port124mechanically coupled to the control box114and configured to electrically couple a cable (not shown) to the audio PCB116. The cable may be a data, audio, and/or power cable, depending on the type of information being conveyed through the port124. For example, upon coupling the cable thereto, the external port124can 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 the audio PCB116. Further, the port124can be configured to transmit or output, to the external control device, audio signals received at the audio PCB116from the microphone array104. In some cases, the external port124can be configured to provide power from an external power supply (e.g., a battery, wall outlet, etc.) to the audio PCB116and/or the microphone array104. In a preferred embodiment, the external port124is an Ethernet port configured to receive an Ethernet cable (e.g., CAT5, CAT6, etc.) and to provide power, audio, and control connectivity to the microphone array assembly100. In other embodiments, the external port124can 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.1and3, the microphone array assembly100further includes an indicator126that 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, the indicator126can be integrated into the screen108, so that the indicator126is visible on an exterior of the front face of the housing102, to externally indicate the operating mode of the microphone array104to 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 the array microphone assembly100. In some embodiments, the light indicator126can turn on a first light source to indicate a first operating mode (e.g., power on) of the microphone 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, the indicator126includes at least one LED (not shown) mounted to a PCB126a(also referred to herein as “LED PCB”) and a light guide126bconfigured to optically direct the light from the LED to outside the screen108, as shown inFIG.3. The LED can be electrically coupled to the microphone array104via a cable128that connects the LED PCB126ato a connector129on the microphone PCB107, as shown inFIGS.3and5.

Referring now toFIGS.3and5, in embodiments, the substrate107of the microphone array assembly100can include a central PCB107aand one or more peripheral PCBs107bpositioned around the central board to increase an available space for mounting the microphones106. For example, a portion of the microphones106may be mounted on the central PCB107aand a remainder of the microphones106may be mounted on the peripheral PCBs107b, as will be explained in more detail below. Each of the peripheral PCBs107bcan be coupled to the central PCB107ausing one or more board-to-board connectors130. In a preferred embodiment, the microphones106are all mounted in one plane of the substrate107, as shown inFIG.4.

The number, size, and shape of the one or more peripheral PCBs107bcan vary depending on, for example, a number of sides132, size and/or shape of the central PCB107a, as well as an overall shape of the substrate107. For example, in the illustrated embodiment, the central PCB107ais a polygon with seven uniform sides132, and the substrate107includes seven peripheral PCBs107brespectively coupled to each side132at an inner end134of each peripheral PCB107b. As illustrated, the inner ends134are flat surfaces uniformly sized to match any one of the seven sides132. Each peripheral PCB107bcan further include an outer end136that is opposite the inner end134. In the illustrated embodiment, the substrate107is shaped as a circle, and therefore, the outer end136of each peripheral PCB107bis curved.

In other embodiments, the central 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 ends134of the peripheral PCBs107bmay be sized and shaped according to the size and shape of the sides132of the central PCB107a. For example, in one embodiment, the central PCB107may have a circular shape such that each of the sides132is curved, and therefore, the inner ends134of the peripheral PCBs107bmay also be curved. Likewise, in other embodiments, the substrate107can have other overall shapes, including, for example, an oval or a polygon, and the outer ends136of the peripheral PCB107bcan be shaped accordingly. In still other embodiments, the substrate107can include a donut-shaped peripheral PCB107bsurrounding a circular central PCB107a, or a single, continuous board107comprising all of the microphone transducers106.

As shown inFIG.5, in embodiments, the plurality of microphones106includes a central microphone106apositioned at a central point of the central PCB107aand a remaining set of the microphones106bthat are arranged in a fractal, or self-similar, configuration surrounding the central microphone106aand positioned on either the central PCB107aor the peripheral PCB107b. Due, at least in part, to the fractal-like placement of the microphones106, the array microphone104can 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, the microphone array104can 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 the array104to 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, the microphones106can 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 the central 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 remaining microphones106b, and each subset of microphones106bcan be positioned at predetermined intervals along a circumference of the corresponding ring. The predetermined interval or spacing between neighboring microphones106bwithin a given ring can depend on a size or diameter of the ring, a number of microphones106bincluded in the subset assigned to that ring, and/or a desired sensitivity or overall sound pressure for the microphones106bin the ring. Increasing the number of microphones106and 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.5only shows an exemplary embodiment of the array microphone104and other configurations of the microphones106are contemplated in accordance with the principles disclosed herein. For example, in some embodiments, the plurality of microphones106may be arranged in concentric rings around a central point, but without any microphone positioned at the central point (e.g., without the central microphone106a). In still other embodiments, only a portion of the microphones106may be arranged in concentric rings, and the remaining portion of the microphones106may 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.9graphically depicts an exemplary microphone configuration900that may be found in an array microphone in accordance with certain embodiments. The microphone configuration900may be substantially similar to the self-similar configuration of microphones106included the microphone array104, except for the number of microphones106bincluded in an innermost ring of the array104. As shown, the microphone configuration900includes one microphone902(e.g., the central microphone106a) located at a center of the configuration900and a plurality of microphones906(e.g., the remaining set of microphones106b) arranged in seven concentric rings910-922. For ease of explanation and illustration, a circle has been drawn through each group of microphones906that forms the rings of the microphone configuration900.

In order to accommodate the microphones906, the microphone configuration900may be mounted on a plurality of printed circuit boards (not shown), similar to the central PCB107aand the plurality of peripheral PCBs107b. For example, referring now toFIG.5as well, the microphones906may include (i) a first subset of the microphones906mounted on the central PCB107ato form a first ring910surrounding the central microphone902, (ii) a second subset of the microphones906mounted on the central PCB107ato form a second ring912surrounding the first ring910, (iii) a third subset of the microphones906that are mounted on the central PCB107ato form a third ring914surrounding the second ring912, (iv) a fourth subset of the microphones906mounted on the central PCB107ato form a fourth ring916surrounding the third ring914, (v) a fifth subset of the microphones906mounted on the peripheral PCBs107bto form a fifth ring918surrounding the fourth ring916, (vi) a sixth subset of the microphones906mounted on the peripheral PCBs107bto form a sixth ring920surrounding the fifth ring918, and (vii) a seventh subset of the microphones906mounted on, and near an edge of, the peripheral PCBs107bto form a seventh ring922surrounding the sixth ring920.

In embodiments, the number of rings910-922included 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 the outermost ring922can 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, the outermost ring922may 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, including more microphones906within 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 rings910-922may be at least slightly rotated relative to a central axis930that 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 rings910-922can be rotationally offset from each other, for example, by rotating each ring a different number of degrees, so that no more than any two microphones906are 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 the peripheral PCBs107bcan be uniformly designed to streamline manufacturing and assembly. For example, as shown inFIG.5, each peripheral PCB107bcan have a uniform shape, and the microphones106bcan be placed in identical locations on each board107b. In this manner, any one of the peripheral PCBs107bcan be coupled to any one of the connectors130in order to electrically couple the peripheral PCB107bto the central PCB107a. For example, in the illustrated embodiment, the microphone PCB107includes seven peripheral PCBs107bso that each of the peripheral PCBs107bcan include eight microphones in uniform locations. The remaining 64 microphones are included on the central PCB107a, so that the microphone array104includes a total of 120 microphones.

In embodiments, the total number of microphones106and/or the number of microphones106bon the central PCB107aand/or each of the peripheral PCBs107bmay vary depending on, for example, the configuration of the harmonic nests, a preset operating frequency range of the array104, an overall size of the microphone array104, as well as other considerations. For example, inFIG.9, the microphone configuration900includes only 113 microphones, or more specifically, one central microphone902surrounded by112microphones906, because the ring910includes seven fewer microphones906than the corresponding ring of the microphone array104inFIG.5. In certain embodiments, removing these seven microphones from the first or innermost ring910can be achieved with little to no loss in frequency coverage or microphone sensitivity.

In embodiments, the number of microphones906included in each of the rings910-922can be selected to create a self-similar or repeating pattern in the microphone configuration900. This can allow the microphone configuration900to 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.5and9, a fractal or self-similar configuration is formed by placing 7, 14, or 21 microphones106b/906(e.g., a multiple of 7) in each of the seven rings910-922. Other embodiments may include other repeatable arrangements of the microphones106b/906, such as, for example, multiples of another integer greater than one, or any other pattern that can simplify manufacturing of the array microphone104. For example and without limitation, in one embodiment, the number of microphones906in each of the inner rings910-920may alternate between two numbers (e.g., 8 and 16), while the outermost ring922may include any number of microphones906(e.g., 20).

As will be appreciated, in other embodiments, the microphones106/906may 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 of microphones106/906, and/or have a different number of microphones106/906in each of the rings910-922depending on, for example, a desired distance between each ring, an overall size of the substrate107, a total number of microphones106in the array104, a preset audio frequency range covered by the array104, as well as other performance- and/or manufacturing-related considerations.

FIG.10illustrates a block diagram of an exemplary audio system1000comprising an array microphone system1030and a control device1032. The array microphone system1030may be configured similar to the array microphone assembly100shown inFIGS.1-5, or in other configurations. For example, the array microphone system1030may include an array microphone1034that is similar to the array microphone104. The array microphone system1030may also include an audio component1036that receives audio signals from the array microphone1034and is configured as an audio recorder, audio mixer, amplifier, and/or other component for processing of audio signals captured by the microphone array1034. In such embodiments, the audio component1036may be at least partially included on a printed circuit board (not shown), such as, e.g., the audio PCB116. In other embodiments, the audio component1036is located in the audio system1000independently of the array microphone system1030, and the array microphone system1030(e.g., within the control device1032) may be in wired or wireless communication with the audio component1036. The array microphone system1030may further include an indicator1038similar to the indicator126to visually indicate an operating mode of the microphone array1034on a front exterior of the array microphone system1030.

The control device1032may be in wired or wireless communication with the array microphone system1030to control the audio component1036, the microphone array1034, and/or the indicator1038. For example, the control device1036may include controls to activate or deactivate the microphone array1034and/or the indicator1038. Controls on the control device1036may further enable the adjustment of parameters of the microphone array1034, such as directionality, gain, noise suppression, pickup pattern, muting, frequency response, etc. In embodiments, the control device1036may be a laptop computer, desktop computer, tablet computer, smartphone, proprietary device, and/or other type of electronic device. In other embodiments, the control device1036may include one or more switches, dimmer knobs, buttons, and the like.

In some embodiments, the microphone array system1030includes a wireless communication device1040(e.g., a radio frequency (RF) transmitter and/or receiver) for facilitating wireless communication between the system1030and the control device1036and/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 the microphone array1034and/or control signals received from the control device1036. In some embodiments, the wireless communication device1040may 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, the array microphone system1030includes an external port (not shown) similar to the external port124, and the system1030is in wired communication with the control device1036via a cable1042coupled to the port124. In one such embodiment, the audio system1000further includes a power supply1044that is also coupled to the array microphone system1030via the cable1042, such that the cable1042carries power, control, and/or audio signals between various components of the audio system1000. In a preferred embodiment, the cable1042is an Ethernet cable (e.g., CAT5, CAT6, etc.). In other embodiments, the power supply1044is coupled to the array microphone system1030via a separate power cable.

As illustrated, the indicator1038can include a first light source1046and a second light source1048. The first light source1046may be configured to indicate a first operating mode or status of the microphone array1034by turning the light on or off, and likewise, the second light source1048may be configured to indicate a second operating mode of the microphone array1034. For example, the first light source1046may indicate whether or not the microphone array system1030has power (e.g., the light1046turns on if the system1030is turned on), and the second light source1048may indicate whether or not the microphone array1034has been muted (e.g., the light1048turns on if the system1030has been set to a mute setting). In other cases, at least one of the light sources1046,1048may indicate whether or not audio is being received from an outside audio source (e.g., during web conferencing). In a preferred embodiment, the first light source1046is a first LED with a first light color, and the second light source1048is a second LED with a second light color that is different from the first light color (e.g., blue, green, red, white, etc.). The indicator1038can be in electronic communication with and controlled by the control device1032and/or the audio component1036, for example, to determine which operating mode(s) can be indicated by the indicator1038and which color(s), LED(s), or other forms of indication are assigned to each operating mode.

In embodiments, the audio component1036can be configured (e.g., via computer programming instructions) to enable adjustment of parameters of the microphone array1034, such as directionality, gain, noise suppression, pickup pattern, muting, frequency response, etc. Further, the audio component1036may 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 the microphone array1034, automatically select an appropriate (e.g., best) lobe formed by the microphone array1034for 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), the microphone array1034can be configured to simultaneously form up to eight lobes at any angle around the microphone array1034, for example, to emulate up to eight seated positions at a table. Due to its microphone configuration (e.g., the microphone configuration900), the microphone array1034can 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 the array1034. For example, the audio component1036may 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 the microphone array1034can be electronically steered without physically moving the array1034.

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 the microphone array1034and being generated by combining the inputs received from all microphones in the microphone array1034. The audio mixer may also provide a ninth auto-mixed output to capture all other audio signals. As will be appreciated, the microphone array1034can be configured to have any number of lobes.

According to embodiments, the lobes of the microphone array1034can be configured to have an adjustable beamwidth that allows the audio component1036to effectively track, and capture audio from, human speakers as they move within the environment. In some cases, the microphone array system1030and/or the control device1032may 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 the audio component1036and/or the control device1032.

In environments where multiple microphone array systems1030are included, for example, to cover a very large conference room, the audio system1000may include an audio mixer that receives the outputs from the audio components1036included in each microphone array system1030and outputs a mixed output based on the received audio signals.

The audio component1036may 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 the environment600, or to a remote environment via a wired or wireless connection.

The connections between the components shown inFIG.10are 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, the microphone array1034includes 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, the microphone array1034includes 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 the microphone array1034, the audio component1036may require less programming and other software-based configuration. More specifically, because MEMS microphones produce audio signals in a digital format, the audio component1036need 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, the microphone array1034may 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.11is a diagram of an example microphone polar pattern1100in accordance with embodiments. The polar pattern1100represents the directionality of a given microphone array (e.g., the microphone array1034/104or 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, the polar pattern1100shows polar responses of the microphone array at each of frequencies 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz, with the microphone array being configured to form a lobe1102, or a directional beam, at each of these frequencies and the lobe1102being steered to an elevation of 60 degrees relative to the plane of the array. As will be appreciated, while the polar plot1100shows the polar responses of a single lobe1102at 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 the polar pattern1100, at the 1000 Hz frequency, side lobes1104are formed at 10 decibels (dB) below the main 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.12illustrates an example method1200of assembling an array microphone in accordance with embodiments. The array microphone may be substantially similar to the array microphone104shown inFIG.5and/or may include a plurality of microphones arranged in a configuration that is substantially similar to the microphone configuration900shown 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., the central PCB107a) and a plurality of peripheral or satellite boards (e.g., the peripheral PCBs107b). In such cases, the method1200can include step1204, where the peripheral boards are electrically coupled to the central board, for example, using board-to-board connectors (e.g., connectors130).

In some embodiments, the method1200includes, at step1206, selecting a total number of microphones (e.g., the microphones106b/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.5and9, 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, the method1200includes, at step1208, arranging a first plurality of microphones in a first configuration on the substrate. The method1200also includes, at step1210, arranging a second plurality of microphones in a second configuration on the substrate, the second configuration concentrically surrounding the first configuration. In some embodiments, the method1200can additionally include, at step1212, 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 the innermost ring910, the second ring912, and third ring914, the second configuration comprises at least the fourth ring916and the fifth ring918, and the third configuration comprises at least the sixth ring920and the outermost 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, the method1200can include, at step1214, 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. The method1200can also include, at step1216, 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.