Patent Application
20250080891
Embodiments of the present disclosure generally relate to a microphone assembly and a microphone system.
Dynamic microphones are commonly used for converting sound waves into electrical signals. They feature a diaphragm that vibrates in response to sound waves, which causes a coil of wire within a magnetic field to generate an electrical current proportional to the sound waves.
Dynamic microphones offer advantages such as durability, ruggedness, affordability, and a wide frequency response, making them well-suited for live performances. However, they are less sensitive when compared to condenser microphones requiring high gain, low noise circuitry to yield a high quality signal. When sound waves hit the diaphragm of a dynamic microphone capsule, vibrations are generated. Without proper isolation, vibrations can also be introduced via external structure-borne motion, such as when handling, moving, or adjusting the device.
To address the challenge of unwanted noise resulting from structure-borne vibrations, dynamic microphones can incorporate suspensions, also known as shock mounts or shock absorbers. These suspensions, or vibration isolators, typically made of rubber or foam, are positioned between the microphone and body, or between the microphone and its stand. Their primary purpose is to isolate the microphone from structure-borne vibrations introduced directly to the microphone body or from the external environment, ensuring a clean audio signal.
However, there are certain areas where current suspensions in dynamic microphones can be improved. Conventional rubber suspensions, while only somewhat effective at isolating vibrations, can be bulky and add weight to the microphone and generally have little damping. This can pose challenges in certain microphone assembly settings where space is limited and weight is a concern. Foam suspensions, on the other hand, offer a lighter alternative but are less effective at isolating vibrations, potentially leading to unwanted noise in the audio signal. External shock mounts can be bulky and costly.
Accordingly, there is a need for an improved suspension apparatus that includes effective vibration isolation, reduced bulkiness, and reduced weight to solve the problems described above.
Embodiments of the disclosure provided herein include microphone capsule suspension assembly, comprising a body. The body will include: an inner surface and an outer surface, wherein the inner surface defines an internal region that is configured to support a microphone capsule; an upper extension extending from the outer surface in a radial direction that extends from a central axis of the body; and a lower extension extending from the outer surface in the radial direction. The upper extension and lower extension are spaced apart in a direction that is parallel to the central axis. The upper extension and lower extension each comprise a wall that has a first wall thickness and comprises an array of indentations that have a second wall thickness formed therein, and the first wall thickness is greater than the second wall thickness.
Embodiments of the disclosure may further provide a microphone assembly that includes a microphone body assembly, a microphone capsule suspension assembly configured to be coupled to the microphone body assembly by a clamp assembly, and a dynamic microphone capsule disposed within the internal region of the body. The microphone capsule suspension assembly may include: a body comprising: an inner surface and an outer surface, wherein the inner surface defines an internal region that is configured to support a microphone capsule; an upper extension extending from the outer surface in a radial direction that extends from a central axis of the body; and a lower extension extending from the outer surface in the radial direction. The upper extension and lower extension are spaced apart in a direction that is parallel to the central axis. The upper extension and lower extension each comprise a wall that has a first wall thickness and comprises an array of indentations that have a second wall thickness formed therein, and the first wall thickness is greater than the second wall thickness.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Embodiments herein are generally directed to a microphone assembly and a microphone system that is configured to support dynamic microphone capsules during use. More particularly, systems that include improved dynamic microphone capsule support structures, which include a microphone capsule suspension assembly.
Dynamic microphone capsules are widely employed for converting sound waves into electrical signals, with a structure akin to loudspeakers, but serving the opposite function. They offer advantages such as durability, ruggedness, affordability, and a wide frequency response, making them ideal for live performances. However, compared to condenser microphone capsule, dynamic microphones exhibit lower sensitivity requiring high gain, low noise circuitry to yield a high quality signal.
During operation, when sound waves hit the diaphragm of a dynamic microphone capsule, vibrations in the diaphragm and supporting structure are often generated, which, if not properly isolated, can introduce noise into the signal generated by the dynamic microphone capsule. To address the challenge of unwanted noise caused by vibrations, supporting structures that include suspensions or vibration isolators, also known as shock mounts or shock absorbers, are integrated into dynamic microphones. These suspensions are placed between the voice coil based dynamic microphone capsule and body of the microphone assembly, aiming to damp and/or isolate the dynamic microphone capsule from vibrations and ensure a clean audio signal.
The suspension acts as a shock absorber, absorbing vibrations and preventing their transmission to the diaphragm of the voice coil based microphone capsule. This effectively enhances sound quality by reducing unwanted noise in the transmitted signal provided to a microphone signal receiving electrical component, such as equipment used in live and recorded audio engineering equipment, sound recording equipment, two-way radios, megaphones, radio and television broadcasting equipment, live streaming audio and/or video equipment, and other similar useful devices.
However, current external suspensions, though effective in isolating vibrations, can be bulky and are not designed or engineered to avoid the effects of resonant frequencies created by the structural design of the microphone assembly, which will lead to distortion in the detectable sounds at one or more frequencies within the audible range detected by the microphone assembly. Further, the often unwanted resonant frequencies disposed within an audible range of a human's hearing, will produce undesirable frequency responses and noticeable distortion in the generated signals produced by the microphone assembly. In general, resonant frequencies of a simple mechanical structure can be determined by:
where k is the spring constant (e.g., stiffness of the supporting system) and m is the mass of the vibrating portion of the supporting system, such as the dynamic microphone and a portion of its supporting structure. This is known as the suspended resonance frequency. Frequencies greater than this suspended resonance frequency are known as the mass controlled region, and are characterized by a high degree of isolation between the capsule and supporting structure. In contrast, frequencies lower than the suspended resonance are known as the stiffness controlled region, and are characterized by a low degree of isolation between the capsule and supporting structure. Since the mass (m) of the a dynamic microphone is typically larger than a condenser microphone, the resonant frequencies of most dynamic microphone containing systems will be in the lower in the audible frequency range versus a condenser microphone type of assembly, due to the smaller mass of the diaphragm coupled components in the condenser microphone designs.
In an effort to maximize the effectiveness of vibration isolation, an important design aspect is to provide the lowest possible suspended resonance, which results in low stiffness and high mass. Since the mass is largely fixed by the design of the capsule, it is necessary to design the suspension stiffness to be as low as possible. The design must offer low stiffness axially, but high stiffness laterally. This is needed to allow good isolation in the direction of diaphragm motion, where the capsule is extremely sensitive to motion, while preventing tilting, rocking, or other unstable motion that might cause collisions with nearby internal structures.
In some embodiments of the disclosure herein, it is desirable to design the suspension structure so that any developed suspended resonant frequencies are less than 100 hertz (Hz), since the audible range of most human voices is greater than 100 Hz. In one example, the suspension structure is designed so that it has a desirable structural shape, as disclosed herein, and is formed from a material that it adapted to damp all resonant frequencies that are greater than 100 Hz, or all resonant frequencies that are greater than 80 Hz, or all resonant frequencies that are greater than 40 Hz, even all resonant frequencies that are greater than 20 Hz. In some embodiments, the suspension structure disclosed herein that is less stiff than conventional dynamic microphone designs and utilizes materials that have higher damping coefficients so that the suspended resonance of the capsule is lower than operating frequency range of the microphone, and a better sound quality can be provided as a signal output by the microphone assembly.
To address these issues, the present disclosure provides a support structure for a dynamic microphone capsule that includes a suspension mounted to a clamp assembly that is used to retain the suspension and facilitate the physical isolation between various regions of the microphone assembly from each other. By surrounding the dynamic microphone capsule with the suspension and isolating the dynamic microphone capsule from other components of the microphone, unwanted vibrations are dampened by the suspension before they are processed by the dynamic microphone capsule, thus reducing noise. This suspension is characterized by low axial stiffness, high lateral stiffness, and built-in shock absorbers to prevent collisions in the case of very large lateral loads.
The microphone capsule suspension assembly 160 is coupled to a housing 112 of the microphone body assembly 110 using an upper clamp 114, a lower clamp 116, the mounting ring 150, and one or more fasteners 152 described further below in reference to
The microphone circuitry 122 may aid in converting acoustic waves received by the dynamic microphone capsule 130 into electrical signals which may then be sent to an external controller (not shown). Such signals may be a signal from the dynamic microphone capsule that includes information relating to sound detected over an audible range. In some embodiments, the audible range includes frequencies between about 20 Hz and 20,000 Hz, such as frequencies between about 80 Hz and 16,000 Hz.
This arrangement of the components within the microphone assembly 100 provides for improved damping as any unwanted vibration, such as vibrations caused from physical impact on the housing 112 of the microphone assembly 100, transmit through the microphone capsule suspension assembly 160 before reaching the dynamic microphone capsule 130. This allows the microphone capsule suspension assembly 160 to dampen the unwanted vibrations to prevent the dynamic microphone capsule 130 from registering the vibrations, and thus reduce the distortion and noise detected and provided in the output signal delivered from the microphone assembly 100.
The scroll wheel 124 is axially aligned with the microphone capsule suspension assembly 160 such that the direction in which the scroll wheel 124 may scroll or rotate is coaxial to a longitudinal center axis (e.g., central axis 202) of the microphone capsule suspension assembly 160. This configuration allows the microphone capsule suspension assembly 160 to effectively dampen vibrations caused by operation of the scroll wheel 124 during use of the microphone assembly 100.
The housing 112 also includes a light aperture 126a on an opposing side 120b of the button aperture 118a and wheel aperture 124a. A light source 126 is disposed within the housing 112 surrounded by a reflector 128. The reflector 128 is configured to direct light emitted from the light source 126 toward the light aperture 126a. The reflector 128 may be any suitable reflector 128, such as a conical reflector 128 as shown in
Further, the scroll wheel 124 and the light source 126 may be used together to indicate a status of the microphone assembly 100. For example, the light source 126 may indicate when the scroll wheel 124 reduces a volume of the microphone assembly 100 below a predetermined volume threshold. The scroll wheel 124 may also include additional light sources (not shown) that may indicate a status of the microphone assembly 100. For example, the additional light sources may indicate that the microphone assembly 100 is muted or off.
The microphone capsule suspension assembly 160 separates the housing 112, including the microphone circuitry 122, the scroll wheel 124, and the light source 126, from the dynamic microphone capsule 130. As a user operates the microphone assembly 100, including manipulating the scroll wheel 124 and the light source 126, the user may cause unwanted internal vibrations, e.g., from scrolling the scroll wheel 124, that may interfere with the desired acoustic signal, e.g., by creating noise. The microphone capsule suspension assembly 160 serves to dampen and reduce vibrations caused by operation of the scroll wheel 124 before the unwanted vibrations are detected by the dynamic microphone capsule 130. The microphone capsule suspension assembly 160 also reduces other acoustic vibrations that are received by the back of the housing 112, e.g., vibrations that enter through the cover 140 and would otherwise reflect off the back of the housing 112 and into the dynamic microphone capsule 130, reducing noise.
In some embodiments, the upper extension 210 has upper protrusions 214 extending upwardly from an outer surface 216 of the upper extension 210. The upper protrusions 214 may be segmented and are disposed along the outer surface 216 of the upper extension 210. The upper protrusions 214 may be arranged in a circular array that is coaxially aligned to the central axis 202 of the body 200. The cross-sectional shape of the upper protrusions 214 may be any suitable shape having a height, width, and thickness. The shape of the upper protrusions 214 in the circular array may be substantially identical or may differ from each other as desired. The number of upper protrusions 214 may be any desired number, such as 24, such as 16, such as 12, such as 6 upper protrusions 214. The upper protrusions 214, in coordination with the upper clamp 114 and lower clamp 116, secure the suspension to the housing 112. In addition, the upper protrusions 214 can act as lateral motion dampers for vibrations traveling through the housing 112, the upper clamp 114, and the lower clamp 116 to the dynamic microphone capsule 130. This configuration allows for a reduction in unwanted noise.
The lower extension 230 is configured similar to the upper extension 210. The lower extension 230 includes lower protrusions 234 extending from an outer surface 236 of the lower extension 230 and lower indentions 238 in an inner surface 240 opposite the outer surface 236 of the lower extension 230. The lower indentions 238 may be arranged in a circular array coaxial to the central axis 202 of the body 200 with a minimum spacing substantially equal to the width 242 of the lower protrusions 234. The number of lower protrusions 234 may be any desired number, such as 24, such as 16, such as 12, such as 6 lower protrusions 234.
The upper indentions 222 and the lower indentions 238 have a thickness less than a thickness 228 of plurality of spoke portions 258 of the upper extension 210 and the lower extension 230, respectively. The ratio of the thickness of the indentions 222 to the thickness of the spoke portions 258, may be less than 1:2, such as 1:3, such as 1:4, such as 1:5 but greater than 1:10. The indentions and spoke portions within the upper extension 210 and the lower extension 230 form a continuous and non-porous layer of material that extends between the body 200 and an outer extent of the upper extension 210 or the lower extension 230 to prevent airflow in the axial direction therethrough. The ratio of the thickness of the indentions 222 to the thickness of the spoke portions 258 will affect the stiffness (e.g., stiffness k of Equation 1) of the microphone capsule suspension assembly 160, and thus can be adjusted to prevent unwanted resonant frequency induced vibrations. For example, indentions at thickness ratios of 1:1.5 may produce tympanic vibrations within the suspension, producing noise within the dynamic microphone capsule 130, and thus thickness ratios of 1:1.2 and greater are used to avoid this problem.
The upper indentions 222 also includes an upper indention surface area comprising of the total surface area of each of the upper indentions 222 in the circular array 218. Additionally, the plurality of spoke portions 258 includes a spoke surface area comprising the total surface area of each of the plurality of spoke portions 258 disposed between the upper indentions 222 in the circular array 218. The plurality of spoke portions 258 includes a thickness equal to the thickness of the upper extension 210, which is greater than the thickness of the material within each of the upper indentions 222. As such, the overall structural characteristics of the microphone capsule suspension assembly 160 are affected by the ratio of the upper indention surface area 222a of the upper indentions 222 to the spoke surface area 258a of the plurality of spoke portions 258. The ratio of upper indention surface area 222a to spoke surface area 258a can be between about 1:2 and 1:5, such as about 1:3. For example, each of the upper indentions 222 are shaped as a trapezoid with a bottom base length 222b of about 4.3 mm, a top base length 222c of about 3.3 mm, and a height 222d of about 3.9 mm producing a surface area of about 169 mm2 and, for 12 upper indentions 222, a total indention surface area (TISA) of 302 mm2. The spoke surface area 258a covers the remaining surface area, e.g., about 490 mm2, of the inner surface 220 of the upper extension 210. In one example, the ratio of the upper indention surface area 222a to the spoke surface area 258a can be defined as a ratio of about 1:2, which can be calculated by dividing the total indention surface area (TISA) of the upper extension 210 by total extension surface area (TESA) minus the total indention surface area (TISA). The total extension surface area (TESA) being equal to
where R4 equals the extension outer radius R4 and R2 is the outer surface radius R2, and thus the area ratio being
It is believed that maintaining surface area ratios for one or more of the materials described herein allows for an improved damping and resonant frequency characteristics while allowing sufficient structural support to the microphone capsule suspension assembly 160. In general, the area ratio of the upper indention surface area 222a to spoke surface area 258a and the selection of a material used to form the microphone capsule suspension assembly 160, which has desirable mechanical properties is selected to control the structural stiffness to mass ratio of the material structure of the microphone capsule suspension assembly 160.
The lower indentions 238 are configured similarly to the upper indentions 222 and include a lower indention surface area 238a separated by a plurality of spoke portions 258. The ratio of lower indention surface area 238a to the spoke surface area 258a should be between about 1:2 and 1:5, such as about 1:3 and may be equal to the ratio of upper indention surface area 222a to the spoke surface area 258a. Additionally, as noted above, the lower indentions 238 may aligned with the upper indentions 222 such that the cross-sectional area of each of the lower indentions 238 and the upper indentions 222 overlap along an axis parallel to the central axis 202.
Each of the upper extension 210 and the lower extension 230 include a lip, e.g., upper lip 246 and lower lip 248, extending coaxially to the center axis. The upper lip 246 extends downward and from the inner surface 220 of the upper extension 210. The lower lip 248 extends upward and from the inner surface of the lower extension 230. The upper lip 246 and lower lip 248 are configured to interact with the clamp assembly 170 to secure the microphone capsule suspension assembly 160 to the microphone assembly.
The body 200 may also include an annular ridge 250 disposed along the center 204 of the body 200 and coaxial to the central axis 202. The annular ridge 250 includes a protruding portion 252 on an outer surface 206 of the body 200 and a recessed portion 254 in an inner surface 208 of the body 200. The body 200 includes an outer surface 206 that has an outer radius R2, from which the protruding portion 252 extends. The annular ridge 250 may have the same or different thickness as the body 200. The annular ridge 250 is configured to receive a protrusion 256 of the dynamic microphone capsule 130 to secure the dynamic microphone's position within the body 200.
The inner surface 208 of the body 200 has an inner radius R1 that defines an internal region that is configured to support the dynamic microphone capsule 130. In some embodiments, the body 200 includes an annular base 260 configured to additionally support the dynamic microphone capsule 130 when the dynamic microphone capsule 130 is disposed within the body 200. The annular base 260 is disposed along the lower portion 232 on an inner surface 208 of the body 200 on a side opposing the lower extension 230. The annular base 260 includes a base aperture 262 at its center that is configured to allow access to the dynamic microphone capsule 130 from the internal side 125 of the microphone body assembly 110.
In some embodiments, the microphone capsule suspension assembly 160 may be made of a material having a Shore A hardness of between about 30 and about 40, such as about 35. A hardness in these ranges allows for the microphone capsule suspension assembly 160 to be taught enough to support and secure the dynamic microphone capsule 130 while soft enough to provide effective damping through the body 200. For example, the material may be butyl rubber due to the desirable combination of low stiffness and high damping. However, in some configurations, the material may include a polyurethane or silicone material as these materials are convenient, due to the ease of molding, durability, low stiffness, and low cost. However, there are likely a wide variety of other materials that could be used.
In one embodiment, the material used to form the microphone capsule suspension assembly 200 includes a material that has a tensile modulus (Young's modulus) of between about 1 megapascals (MPa) and about 10 MPa, such as about 2 MPa. In some embodiments, the material used to form the microphone capsule suspension assembly 200 includes a material that has a loss factor η of between about 0.5 and about 5. In some embodiments, the material used to form the microphone capsule suspension assembly 200 includes a material that has a glass transition temperature of 20° C. or less, such as less than about 10° C., or less than about −60° C. It has been found that utilizing materials that have the material properties described herein are able to effectively support and dampen the vibrations imparted on the microphone assembly, such that all resonant frequencies were positioned below a 100 Hz, such as less than 80 Hz, or less than 40 Hz. In one example, the material includes butyl rubber.
As shown in
The vibrations received by the dynamic microphone capsule 130 cause oscillations in the diaphragm of the dynamic microphone capsule 130, which are detected by the signal detection components (e.g., diaphragm movement detection components) of the dynamic microphone capsule 130, and thus cause distortion in the sound detected, at one or more frequencies, by the microphone assembly 100. By surrounding the dynamic microphone capsule 130 with the microphone capsule suspension assembly 160 and isolating the dynamic microphone capsule 130 from other components of the microphone, .e.g., the scroll wheel 124, unwanted vibrations are dampened by the suspension before they are processed by the dynamic microphone capsule 130, thus reducing noise.
The lower clamp 116 includes a recessed upper edge 310 configured to receive the upper lip 246 of the upper extension 210 and a recessed lower edge 320 configured to receive the lower lip 248 of the lower extension 230. The lower clamp 116 also include a plurality of angled protrusions 312 extending form an outer surface 314 of the lower clamp 116 adjacent to the recessed upper edge 310. The upper clamp 114 includes a plurality of recesses 316 configured to receive and engage with the plurality of angled protrusions 312.
When engaging the clamp assembly 170, the microphone capsule suspension assembly 160 is coupled to the lower clamp 116 at the recessed upper edge 310 and the recessed lower edge 320. The upper clamp 114 then fits over the suspension and engages the plurality of angled protrusions 312 of the lower clamp 116, such that the angled protrusions slip into the plurality of recesses 316 in the upper clamp 114. Once engaged, the upper clamp 114 imposes a pressure on the suspension and the lower clamp 116 such that the suspension is secured to the upper and lower clamp 116. The annular ring and the fasteners may then be used to secure the clamp assembly 170 to the microphone body assembly 110.
The present disclosure provides a suspension for a dynamic microphone in a microphone assembly that allows for improved dampening of unwanted vibrations, reducing noise in the produced acoustic signal of the microphone. The suspension includes a body with upper protrusions and upper indentions on an upper extension and lower protrusions and lower indentions on a lower extension. The suspension engages with a clamping assembly that serves as the only connection to the microphone housing, effectively isolating the dynamic microphone from all other components of the microphone. In particular, the suspension separates the microphone housing body from the dynamic microphone such that vibrations originating in the housing, including resonant frequencies, are dampened before reaching the dynamic microphone. Isolating the dynamic microphone in this manner prevents undamped mechanical vibration from interfering with the dynamic microphone and producing noise.
When introducing elements of the present disclosure or exemplary aspects or embodiment(s) thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements.
The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, the objects A and C may still be considered coupled to one another—even if objects A and C do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly in physical contact with the second object.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
