US20170164095A1 - Microphone Environmental Protection Device - Google Patents
Microphone Environmental Protection Device Download PDFInfo
- Publication number
- US20170164095A1 US20170164095A1 US15/434,499 US201715434499A US2017164095A1 US 20170164095 A1 US20170164095 A1 US 20170164095A1 US 201715434499 A US201715434499 A US 201715434499A US 2017164095 A1 US2017164095 A1 US 2017164095A1
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- United States
- Prior art keywords
- microphone
- chamber
- sensing surface
- ambient environment
- perforation
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- Abandoned
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/12—Sanitary or hygienic devices for mouthpieces or earpieces, e.g. for protecting against infection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/08—Mouthpieces; Microphones; Attachments therefor
- H04R1/083—Special constructions of mouthpieces
- H04R1/086—Protective screens, e.g. all weather or wind screens
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/3827—Portable transceivers
- H04B1/385—Transceivers carried on the body, e.g. in helmets
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
- H04R1/1058—Manufacture or assembly
- H04R1/1075—Mountings of transducers in earphones or headphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2410/00—Microphones
- H04R2410/07—Mechanical or electrical reduction of wind noise generated by wind passing a microphone
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S2/00—Apparel
- Y10S2/905—Electric
- Y10S2/906—Head covering or protector
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S2/00—Apparel
- Y10S2/908—Guard or protector having a hook-loop type fastener
- Y10S2/909—Head protector, e.g. helmet, goggles
Definitions
- This invention relates to devices used to protect microphones from the ambient environment.
- Microphone screens typically incorporate porous materials, such as foamed material and metal mesh, to protect the microphone sensing surface, such as a diaphragm from being damaged by objects, such as fingers, and to prevent wind noise.
- porous materials such as foamed material and metal mesh
- Inventions such as those described in U.S. Pat. No. 7,496,208, U.S. Pat. No. 2,520,706 and U.S. Pat. No. 3,154,171 illustrate such examples.
- porous materials such as foam.
- Foam and other similar porous materials become clogged with water when submerged or subject to rain.
- Porous materials absorb and hold water, dirt and salt crystals which change the nature of the sound sensed by the microphone. High frequency sounds are attenuated; therefore, the microphone signal no longer provides an accurate representation of sound in the ambient acoustic environment.
- Microphones have inherent noise associated with them called “self-noise.” Even in a perfectly quiet ambient environment, microphones will generate electrical noise at their output. This noise is due to the self-noise of electrical amplifier components, such as the “Johnson noise” of resistances and “flicker noise” of transistors. The acoustical and mechanical damping of a microphone diaphragm also contributes to the self-noise of a microphone.
- the “input referenced self-noise” (IRSN) of a microphone is the equivalent sound pressure level (SPL) that would generate the same noise at the electrical leads as the total effective self-noise of the microphone.
- SPL sound pressure level
- the IRSN is typically described as an A-weighted value with units of decibels sound pressure level, or dB SPL, which is a weighted average over a frequency band. However, the IRSN may also be described as a dB SPL value at a single frequency.
- Microphones with high self-noise can mask data, such as speech or music, when the data is at low levels. All other parameters being equal, microphones with lower self-noise are superior to microphones with higher self-noise.
- the present invention protects a microphone from rain, wind, dirt, salt crystals and objects using a chamber having a perforated barrier. Fingers, vegetation, equipment and other objects are kept from contacting and damaging the microphone sensing surface, and a line of sight path from the ambient environment to the microphone is prevented, so that small particles such as sand and dust, water and wind do not impact directly on the microphone sensing surface or on an acoustic vent used to provide a waterproof barrier for the microphone. This provides improved damage protection.
- Acoustic amplification of sound may be provided, which can result in an improvement of the signal-to-noise ratio of the microphone output signal.
- the invention can be attached to a noise-defending headset ear cup.
- the microphone is used to sense the sound outside of the ear cup and the microphone signal is input to an electronic processing circuit that is used to shape the signal and provide amplification and/or attenuation of the signal.
- the processing circuit signal output is input to an amplifier that is connected to a speaker to generate sound in the ear cup.
- An embodiment of the invention may also be incorporated in manikins or other mechanical structures used to mimic the diffraction of sound around the human head.
- FIG. 1 is a view of an embodiment of the invention as it would be incorporated into a vertical outer surface.
- FIG. 2 is a view of the interior of an embodiment of the invention with the perforated cover, screen and screws removed.
- FIG. 3 is a cross-sectional view of an embodiment of the invention along cut line B-B from FIG. 1 .
- FIG. 4 is a cross-sectional view of an embodiment of the invention along cut line A-A from FIG. 1 .
- FIG. 5 is a view of an embodiment of the invention using slot perforations as it could be incorporated in an ear cup of a headset.
- FIG. 6 is a view of an embodiment of the invention using circular perforations as it could be incorporated in an ear cup of a headset.
- FIG. 7 is a view of an embodiment of the invention using a single slot perforation as it could be incorporated in an ear cup from a headset.
- FIG. 8 is a plot of the improvement in acoustic response when an embodiment of the invention with slot perforations is incorporated in an ear cup of a headset.
- FIG. 9 is a cross-sectional view of an embodiment of the invention along cut line C-C from FIG. 7 .
- FIG. 10 is a cross-sectional view of an embodiment of the invention incorporating an auxiliary wind screen and drain tube.
- An embodiment of the invention is a device for protecting microphones against environmental damage which incorporates a special perforated barrier on the outer surface of a chamber, which provides a line of sight from outside the chamber volume to inside the chamber volume.
- the cross-sectional area of the perforations are large enough that water can easily pass through the barrier and the barrier is self-cleaned with rain or can be cleaned deliberately with a spray bottle.
- An outer layer of the barrier can be made of a solid rigid material, such as plastic or metal, with slotted perforations backed by an inner layer of metal mesh material.
- a drainage path can be provided for water and debris that accumulate in the chamber volume.
- the water drain may be a path back through the perforated barrier, or a separated dedicated drain path can be provided. This allows the device to be self-cleaning during rain and easily to clean using a spray bottle.
- the barrier in this embodiment is a rigid perforated surface forming a chamber which creates an effective acoustic mass.
- the total volume of the chamber creates an effective acoustic compliance.
- the combination of these two elements in this embodiment of the invention creates an acoustic resonator that is preferably in the frequency range of 1 kHz to 20 kHz.
- Microphones have electronic and acoustic self noise. If the sound sensed by the microphone is increased, the effective signal-to-noise ratio of the microphone increases and yields an effectively quieter microphone signal for the same ambient acoustic noise signal.
- An equalizer circuit (active or passive) can be connected to the output of the microphone to attenuate the frequency region of boosted signal. Therefore, because the microphone signal is attenuated, the self-noise of the microphone is reduced. However, because the acoustic resonator amplifies the sound through acoustical means, the measured signal strength remains at the same amplitude. Therefore, the signal-to-noise ratio of the microphone output is increased by the resonator of an embodiment of the invention and the effective IRSN is reduced which yields a higher quality microphone.
- the microphone is located in a position relative to the chamber where there is no direct line of sight from the ambient environment outside the chamber to the sensing surface of the microphone.
- no direct line of sight is intended to mean that the sensing surface is located outside of, or spaced apart from, any imaginary sight line passing from the environment through the chamber. In other words, it is the location and conformation of the chamber and its relationship to the sensing surface of the microphone which provides the lack of line-of-sight from the environment to the sensing surface, rather than the prior art arrangement of having the sensing surface facing the environment with only a physical barrier such as a solid or foam or cloth cover providing the protection between the sensing surface and the environment.
- any wind, sand or rain that is blown into the chamber through the perforated barrier makes its first contact with the physical structure of the chamber, instead of the microphone sensing surface, which reduces the kinetic energy compared to an unobstructed path.
- This helps protect the microphone sensing surface, such as a diaphragm, which can be damaged by the force from direct impact of rain or objects.
- Microphones such as condenser, MEMS, dynamic and piezoelectric employ various types of sensing surfaces, such as single and multiple diaphragms and piezoelectric solids among others.
- the microphone used in an embodiment of the invention is preferably waterproof.
- an additional waterproof membrane called an acoustic vent, can be incorporated to block the path to the microphone sensing surface to ensure that the microphone is not damaged by contact with water.
- Acoustic vents may be attached directly to the front face of a microphone or other locations, such as the end of a microphone coupler, which would provide a water tight seal between the ambient environment and the microphone sensing surface.
- FIG. 1 depicts a view of an embodiment of the invention as it would be incorporated into a vertical outer surface with “UP” indicating the direction of higher altitude.
- a perforated cover 2 is attached to an outer surface 10 , using flush-mounted screws 6 .
- screws may be fastened from behind the outer surface so that the screws cannot be seen from the perspective shown.
- the perforated cover 2 incorporates at least one slot perforation 4 having a length u and a height v.
- slot perforations are rounded at the ends and do not have sharp edges to help minimize wind turbulence when wind blows across the outer surface 10 .
- a screen 8 is attached to the back of the perforated cover 2 .
- the screen 8 is preferably made of wire and coated with an oleophobic coating that tends to repel oil and other fluids, although other coatings, such as hydrophobic coatings, may also be used that tend to repel water and other fluids.
- the screen 8 prevents objects longer than slot length u from passing lengthwise through the slots.
- the screen 8 can be attached to the front of the perforated cover 2 to improve wind noise reduction.
- a drain output 12 is located near the bottom of the perforated cover 2 .
- the drain output 12 is incorporated to more easily allow water, dirt and debris to drain out of the interior of an embodiment of the invention.
- the screen 8 does not cover the drain output 12 , so that dirt and other particles that may pass through the screen 8 to exit the interior of an embodiment of the invention.
- FIG. 2 is a view of the interior 24 portion of an embodiment of the invention, with the perforated cover 2 , screen 8 and screws 6 removed. Screw holes 14 are provided to receive the screws 6 that secure the perforated cover 2 .
- a rectangular screen recess 16 is incorporated to provide room for the screen 8 when the perforated cover 2 is attached.
- the coupler 18 is preferably made of elastomeric material such as molded silicone or other compliant material.
- the chamber 20 is enclosed by the interior structure and elements of an embodiment of the invention such that if water enters the chamber through the slot perforations 4 or drain output 12 , the only path for water to drain from the chamber is through slot perforations 4 and drain output 12 .
- a recessed drain channel 22 with width k Within the chamber 20 is a recessed drain channel 22 with width k.
- the recessed drain channel 22 could be located as shown in the figure, or, alternatively could be centered, relative to dimension f, within the chamber 20 .
- the drain channel 22 may incorporate other geometries, such as an “hour glass” design where the drain channel becomes restricted in the middle, relative to dimension d of chamber 20 , while having greater width at the top, where the microphone coupler 18 is located, and at the bottom, where the drain output 12 would be located.
- the “hour glass” design provides for larger diameter microphone couplers and drain diameters while minimizing the total chamber 20 volume.
- FIG. 3 is a cross-sectional view of an embodiment of the invention along the cut line B-B from FIG. 1 , cut through the length u of one of the slots 4 .
- a portion of the chamber has a depth h while the drain channel 22 is recessed further by depth w.
- depth h should be greater than 1 mm to facilitate water drainage and prevent water retention.
- the interior geometry may be curved instead of the sharp edges shown in FIG. 3 .
- the drain channel 22 provides for improved draining of water from the chamber 20 but also allows room for incorporating larger diameter microphones and microphone couplers 18 without increasing the total chamber 20 volume appreciably.
- the drain channel is shown to one side of the chamber 20 but could as well be centered relative to dimension f, or placed in other locations in the chamber 20 .
- the microphone coupler 18 has a coupler sound channel 30 that couples sound to an acoustic vent 26 .
- the microphone coupler 18 in this embodiment is located in the drain channel 22 because it is larger in diameter compared to h.
- a cross-sectional view of the slot perforation 4 can be seen in FIG. 3 with smooth contoured surfaces, such as a contour surface 33 facing the ambient environment instead of sharp edges to minimize wind turbulence and acoustic wind noise.
- the screen 8 has a mesh spacing z and a screen diameter q when the screen 8 incorporates cylindrical webbing such as metal wire and is shown here attached to the back of the perforated cover 2 to protect the screen 8 from damage.
- the screen 8 can be attached to the front of the perforated cover 2 for improved wind noise reduction.
- the perforated cover 2 is attached to an enclosure 32 .
- the perforated cover 2 and enclosure 32 define the chamber 20 volume.
- the enclosure 32 extends to form the outer surface 10 in this embodiment. In another embodiment, the enclosure could be a separate component from the outer surface that attaches to the outer surface.
- FIG. 4 is a cross-sectional view of an embodiment of the invention along cut line A-A from FIG. 1 , through the width v of the slots 4 .
- the slots 4 have a thickness c measured between inner edge 47 and outer surface 51 .
- the slots 4 have smooth outer surfaces 51 instead of sharp edges to reduce turbulence due to wind when wind blows across the perforated cover 2 .
- the slot 4 inner edges 47 do not cause appreciable turbulence because wind is not blowing over this edge.
- the inner edge 47 may be contoured in alternative embodiments.
- This cross-sectional view shows the microphone coupler 18 with a horn-shaped coupler sound channel 30 (although other geometries may be used), attached to a microphone 40 .
- the microphone 40 can be completely or partially installed within the chamber 20 to minimize the length of the coupler sound channel 30 , or if desired the microphone coupler 18 can be eliminated altogether.
- the microphone coupler 18 provides a water tight seal around the microphone 40 .
- the coupler sound channel 30 couples sound from the chamber 20 to the acoustic vent 26 .
- the acoustic vent 26 is gas permeable and couples sound to the microphone 40 .
- the acoustic vent 26 is used to prevent water and dirt from impinging on a microphone sensing surface 42 , such as a fragile diaphragm.
- the acoustic vent 26 is mounted to the microphone 40 with an adhesive 44 to cover a microphone inlet 46 and creates a water-tight seal.
- a “microphone inlet” is a perforation in a microphone housing to allow sound to be coupled to a microphone sensing surface from outside the microphone housing to inside the microphone housing.
- a “microphone sensing surface”, such as a diaphragm, typically vibrates in response to sound excitation, and this vibration is converted into an electrical signal using various means known in the art.
- the slotted perforated cover 2 helps protect the acoustic vent 26 from rain, wind and sand as well as fingers and other foreign objects. Water that penetrates the perforated cover 2 runs down the chamber 20 and back out through the bottom slot perforations 4 and drain output 12 .
- the screen 8 prevents objects smaller than the slot dimensions u and v from entering the chamber 20 . Objects smaller than the mesh spacing z of screen 8 can enter the chamber 20 ; however, they tend to fall to the bottom of the chamber 20 .
- the drain output 12 has diameter k that is larger than the mesh spacing z so that small objects the size of the mesh spacing z can exit the chamber 20 easily without being trapped.
- the drain output 12 is located at the bottom of the chamber 20 so that gravity tends to pull water out of the chamber 20 via the drain output 12 . Thus, if any objects smaller than mesh z do enter the chamber 20 , water will wash the objects out of the chamber 20 through the drain output 12 . In this way, an embodiment of the invention tends to be self-cleaning.
- salt crystals When an embodiment of the invention is used near an environment where salt spray is present, salt crystals will not become trapped as they would if a porous foam material were incorporated. Any salt crystals that form from dried salt spray are also washed down the drain channel 22 during the next rain, and will exit through the drain output 12 .
- the microphone 40 is located at the top of the chamber 20 so that any water which might enter the microphone area will fall out of the coupler sound channel 30 into the chamber 20 and exit out through the drain output 12 . Because there are no porous materials within the chamber 20 such as foam, water is not retained in the chamber 20 .
- the microphone 40 is also located at a position outside of or spaced apart from any imaginary straight line from the ambient environment to the microphone sensing surface 42 or acoustic vent 26 (i.e there is “no line of sight”). That is, the microphone sensing surface 42 or acoustic vent 26 is obscured by the geometry of the microphone coupler 18 , the screen 8 and the slot perforations 4 . This is shown in FIG. 4 as line of sight x. In this way, water spray and small objects cannot impact the microphone sensing surface 42 through a direct path.
- the acoustic vent 26 in this embodiment is also obscured and there is no line of sight from the environment to the vent 26 .
- the acoustic vent 26 may be incorporated in other locations in an embodiment of the invention, such as at the coupler inlet 48 ; however, care must be taken that there is no direct line of sight to the vent.
- a microphone amplifier 36 is connected to microphone leads 38 to provide bias circuitry and amplification.
- a passive or active electronic equalization circuit 34 can be connected to the microphone amplifier 36 to create a generally flat frequency response to ambient sound for sound recording or other purposes.
- the perforated cover 2 and screen 8 are designed so that the acoustic mass of the two, combined with the acoustic compliance of the chamber 20 , form a first acoustic resonance at a frequency between 1 kHz and 20 kHz.
- the acoustic resonance amplifies the sound pressure in the chamber 20 , as compared to the ambient environment at and near the resonance frequency. Boosting the sound pressure has the desired result of improving the effective IRSN of the microphone 40 .
- Dimensions of 20 mm for d, 5 mm for e and 18 mm for f are an example of a desirable geometry which yields a volume of 1.8 cc, and an acoustic compliance of 1.27 ⁇ 10 ⁇ 11 m 5 /N.
- An average chamber depth e of greater than 1 mm is desirable to prevent water from becoming trapped within the chamber volume, and a slot width v of greater than 0.5 mm is desirable to prevent water from becoming trapped in the slots.
- the acoustic mass of the perforated cover 2 and screen 8 will be dominated by the perforated cover 2 when the mesh diameter is small compared to the slot thickness c, and the mesh spacing z is similar in size to the slot width v.
- slot 4 An example of desirable dimensions for slot 4 would be 2 mm for the thickness c, and 18 mm for the length u and 1.5 mm for the width v, where c is the thickness, and there are four slots.
- the diameter of the wires of screen 8 mesh in this embodiment is preferably 0.4 mm while the mesh spacing z is 0.8 mm.
- the acoustic mass of a single slot of this geometry would be approximated as 90 Kg/m 4 .
- the equivalent acoustic mass of a plurality of slots of like geometry is equal to the acoustic mass of one slot divided by the number of slots.
- the acoustic mass in this preferred embodiment would be approximated as 22.5 Kg/m 4 .
- the acoustic resonance frequency of the resonator in Hertz (Hz) can be calculated by the formula:
- the approximate resonance frequency is 9,400 Hertz (9.4 kHz).
- end effects of the slots and the screen result in higher acoustic mass due to the effective mass of the radiation impedance from the slots 4 and the acoustic mass of the screen 8 .
- End effects must be taken into account when the thickness of the slot is not large compared to the square root of the slot area and the calculations become complicated for slots when the wavelength of the sound is not large compared to the slot length.
- the end effects also are affected by how much edge contouring the designer uses for the slots.
- the chamber 20 volume Vol is less than 2.32 cc, so that a larger perforated area is not needed in the perforated cover 2 to achieve higher resonance frequencies.
- a smaller sized perforated area is easier to incorporate in devices such as headsets with earcups that have limited space available.
- An acoustic device is considered in the “lumped-element” region when all its dimensions are small relative to the acoustic wavelength in question.
- a device with resonance frequency below 1 kHz will tend to attenuate high frequencies if the slot or hole perforations are much smaller than a wavelength and the system acts as a lumped-element system at higher frequencies.
- designs with resonances between 1 kHz and 20 kHz will transition out of the lumped-element region and will not attenuate high frequencies so long as the length of the slots is not small in relation to the wavelength of the sound wave.
- the wavelength of a sound wave can be calculated as
- ⁇ is the wavelength in meters
- s is the speed of sound (343 m/sec)
- f is the frequency in Hz.
- a slot of length of 1.8 cm corresponds to a wavelength of 19 kHz. However, the behavior of the slot begins to transition out of the lumped element region at around 1.9 kHz.
- FIG. 5 shows an embodiment of the invention as it can be incorporated into one of the two ear cups 64 of a headset (not shown).
- a second ear cup (not shown), generally similar in geometry to the ear cup 64 shown, is typically employed in headsets, with the two earcups coupled by a headband (not shown) attached to both ear cups.
- Headband attachments 66 are provided on the ear cup 64 to mechanically attach a headband to the ear cup 64 .
- a perforated cover 62 is attached to an outer surface 60 of the earcup, typically using screws (not shown) attached from inside the ear cup 64 . In this way, the screw heads cannot be seen from outside the ear cup 64 .
- the enclosure of an embodiment of the invention in this embodiment also forms the outer surface 60 of the ear cup 64 .
- the perforated cover 62 follows the contour of the outer surface 60 of the ear cup 64 to minimize wind turbulence and wind noise.
- the perforated cover 62 employs slot perforations 76 a screen 72 attached to the front of the perforated cover 62 and a drain output 70 . When worn on the head, the drain output 70 is located below the perforated slots 76 to facilitate water drainage.
- the drain output 70 in this embodiment is located on the perforated cover 62 .
- the screen 72 does not cover the drain in this embodiment.
- a partition can be employed behind the enclosure of an embodiment of the invention and within the ear cup to seal an embodiment of the invention and all related circuitry to achieve a waterproof design. In this way, if the headset is submerged in water, no water will penetrate into the partitioned volume.
- an embodiment of the invention is incorporated in the ear cup of a headset and the headset is used in wet conditions or submerged, no water damage is caused to the microphone or electronics, and because water drains from the chamber of an embodiment of the invention quickly, normal microphone function is restored once the headset is removed from the water.
- FIG. 6 shows another embodiment of an embodiment of the invention as it can be incorporated into one of the two ear cups 64 of a headset (not shown).
- Circle perforations 80 are employed instead of slot perforations in this embodiment.
- a perforated cover 78 is attached to the outer surface 60 of the ear cup 64 using flush-mounted screws 76 .
- a screen is not employed, nor is a drain output in this embodiment. Water drains from the circle perforations 80 if an embodiment of the invention gets wet.
- FIG. 7 shows another embodiment of an embodiment of the invention as it can be incorporated into one of the two ear cups 84 of a headset (not shown).
- FIG. 9 shows a sectional view of the embodiment, cut through lines C-C in FIG. 7 .
- only a single slot perforation 86 is employed.
- the perforated cover in this embodiment is molded into the ear cup 84 body itself.
- the earcup provides an outer surface 82 .
- the enclosure of an embodiment of the invention in this embodiment is a separate component that is attached to the ear cup from inside the ear cup using screws, adhesive, ultrasonic welding or other means.
- a screen 76 is employed to keep larger objects from penetrating into the chamber of an embodiment of the invention. Water drains through the single slot perforation 86 and screen 76 .
- FIG. 9 is a cross-sectional view of an embodiment of the invention along cut line C-C from FIG. 7 , through the slot 86 .
- the microphone coupler 90 incorporates a coupler sound channel 92 that is short and cylindrical in geometry, and the microphone coupler 90 is not much bigger than the microphone 40 in overall size.
- No acoustic vent is employed in this embodiment, and the chamber 94 in this embodiment does not incorporate a recessed drain channel.
- There is no line of sight from the ambient environment to the microphone sensing surface 42 which helps protect the microphone sensing surface 42 from the direct impact of blowing rain, sand and other objects.
- the microphone 40 used does not suffer from detrimental effects from exposure to water (waterproof design). If a non-waterproof design were incorporated in this embodiment, an acoustic vent 26 would be used as a water barrier for the microphone 40 , for example, as shown in FIG. 3 and FIG. 4 . There is a nonlinear unobstructed line of sight yy from the ambient environment to the microphone sensing surface 42 . That is, there are no acoustic foams or other materials in the chamber 94 that would block a path from the ambient environment to the microphone sensing surface 42 and tend to retain water.
- FIG. 10 shows a cross-sectional view of an embodiment of the invention incorporating an auxiliary wind screen 97 , a drain tube 95 and a drain output 99 .
- the auxiliary wind screen 97 can be attached to the outer surface 82 . It may have a geometry that follows the contour of the outer surface 82 or may be bulbous or other geometries that reduce wind noise.
- the auxiliary wind screen 97 can be constructed using mesh screen, cloth, gas-permeable membranes, foam or other materials that reduce wind noise but do not alter the acoustic audio-frequency sound sensed by microphone 40 in a detrimental way.
- the auxiliary wind screen 97 may be thin, for example when employing a single mesh screen or multiple mesh screen layers, or thick, for example when employing foam material with a hollow interior, or solid, for example when employing a solid piece of foam; other wind screen geometries may also be used.
- the drain tube 95 is coupled to the chamber 94 and drain output 99 for draining debris, water and/or other fluids into the ambient environment.
- the drain tube 95 could drain to the interior environment, or other regions, instead of the ambient environment if desired.
- FIG. 8 shows a plot depicting the difference in the response of a microphone mounted flush on the outer surface of an ear cup compared to the response of a microphone used in an embodiment of the invention in an ear cup with four slot perforations and similar aforementioned dimensions, at a range of audio frequencies. That is, the plot in FIG. 8 shows a graph of the improvement in microphone sensitivity when using an embodiment of the invention compared to flush-mounting the microphone.
- the plot is an average of three measurements from three different incidence angles (front, side, back) for a plane pressure wave incident on the ear cup when placed on an acoustic manikin in an anechoic room.
- the response shows a gain in sensitivity in the frequency range from approximately 1 kHz to 8 kHz.
- the signal-to-noise ratio has been improved by an embodiment of the invention because the self-noise of the microphone alone has not changed.
- the first resonance frequency of an embodiment of the invention in this embodiment is approximately 4.7 kHz. There are other resonances and antiresonances due to the headset geometry and invention above 4.7 kHz.
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Abstract
A device for protecting a microphone sensing surface, such as a diaphragm, from the detrimental effects of the ambient environment. The device incorporates a perforated surface to protect the microphone and in conjunction with a chamber volume creates an acoustic resonance in the 1 kHz to 20 kHz spectrum, which improves the microphone signal-to-noise ratio performance. The microphone is acoustically coupled to the chamber volume for sensing pressure of the ambient environment. There is no line of sight to the microphone sensing surface from the ambient environment, so that rain, wind and sand have no direct path to the microphone sensing surface. The perforations of the outer surface are small to prevent objects from contacting the microphone sensing surface via a direct path. Water drains from the chamber volume and does not become trapped if an embodiment of the invention is temporarily submerged so that the microphone returns to normal operation quickly.
Description
- This is a continuation patent application of copending application Ser. No. 14/734,302, filed Jun. 9, 2015, entitled “Microphone Environmental Protection Device”, which was a continuation of application Ser. No. 13/796,579, filed Mar. 12, 2013, now U.S. Pat. No. 9,084,053, issued Jul. 14, 2015, entitled “Microphone Environmental Protection Device”, which claimed benefit under 35 USC §119(e) of provisional application No. 61/751,527, filed Jan. 11, 2013, entitled “Microphone Environmental Protection Device”. The aforementioned applications are hereby incorporated herein by reference.
- Field of the Invention
- This invention relates to devices used to protect microphones from the ambient environment.
- Description of Related Art
- Microphone screens typically incorporate porous materials, such as foamed material and metal mesh, to protect the microphone sensing surface, such as a diaphragm from being damaged by objects, such as fingers, and to prevent wind noise. Inventions such as those described in U.S. Pat. No. 7,496,208, U.S. Pat. No. 2,520,706 and U.S. Pat. No. 3,154,171 illustrate such examples.
- However, there are significant problems with using porous materials such as foam. Foam and other similar porous materials become clogged with water when submerged or subject to rain. Porous materials absorb and hold water, dirt and salt crystals which change the nature of the sound sensed by the microphone. High frequency sounds are attenuated; therefore, the microphone signal no longer provides an accurate representation of sound in the ambient acoustic environment.
- Microphones have inherent noise associated with them called “self-noise.” Even in a perfectly quiet ambient environment, microphones will generate electrical noise at their output. This noise is due to the self-noise of electrical amplifier components, such as the “Johnson noise” of resistances and “flicker noise” of transistors. The acoustical and mechanical damping of a microphone diaphragm also contributes to the self-noise of a microphone.
- The “input referenced self-noise” (IRSN) of a microphone is the equivalent sound pressure level (SPL) that would generate the same noise at the electrical leads as the total effective self-noise of the microphone. The IRSN is typically described as an A-weighted value with units of decibels sound pressure level, or dB SPL, which is a weighted average over a frequency band. However, the IRSN may also be described as a dB SPL value at a single frequency.
- Microphones with high self-noise can mask data, such as speech or music, when the data is at low levels. All other parameters being equal, microphones with lower self-noise are superior to microphones with higher self-noise.
- The present invention protects a microphone from rain, wind, dirt, salt crystals and objects using a chamber having a perforated barrier. Fingers, vegetation, equipment and other objects are kept from contacting and damaging the microphone sensing surface, and a line of sight path from the ambient environment to the microphone is prevented, so that small particles such as sand and dust, water and wind do not impact directly on the microphone sensing surface or on an acoustic vent used to provide a waterproof barrier for the microphone. This provides improved damage protection.
- Acoustic amplification of sound may be provided, which can result in an improvement of the signal-to-noise ratio of the microphone output signal.
- In one embodiment, the invention can be attached to a noise-defending headset ear cup. In this embodiment the microphone is used to sense the sound outside of the ear cup and the microphone signal is input to an electronic processing circuit that is used to shape the signal and provide amplification and/or attenuation of the signal. The processing circuit signal output is input to an amplifier that is connected to a speaker to generate sound in the ear cup. In this way, the user can monitor ambient sounds and modify the amplitude and frequency content of the sounds to suit his/her needs. An embodiment of the invention may also be incorporated in manikins or other mechanical structures used to mimic the diffraction of sound around the human head.
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FIG. 1 is a view of an embodiment of the invention as it would be incorporated into a vertical outer surface. -
FIG. 2 is a view of the interior of an embodiment of the invention with the perforated cover, screen and screws removed. -
FIG. 3 is a cross-sectional view of an embodiment of the invention along cut line B-B fromFIG. 1 . -
FIG. 4 is a cross-sectional view of an embodiment of the invention along cut line A-A fromFIG. 1 . -
FIG. 5 is a view of an embodiment of the invention using slot perforations as it could be incorporated in an ear cup of a headset. -
FIG. 6 is a view of an embodiment of the invention using circular perforations as it could be incorporated in an ear cup of a headset. -
FIG. 7 is a view of an embodiment of the invention using a single slot perforation as it could be incorporated in an ear cup from a headset. -
FIG. 8 is a plot of the improvement in acoustic response when an embodiment of the invention with slot perforations is incorporated in an ear cup of a headset. -
FIG. 9 is a cross-sectional view of an embodiment of the invention along cut line C-C fromFIG. 7 . -
FIG. 10 is a cross-sectional view of an embodiment of the invention incorporating an auxiliary wind screen and drain tube. - An embodiment of the invention is a device for protecting microphones against environmental damage which incorporates a special perforated barrier on the outer surface of a chamber, which provides a line of sight from outside the chamber volume to inside the chamber volume. The cross-sectional area of the perforations are large enough that water can easily pass through the barrier and the barrier is self-cleaned with rain or can be cleaned deliberately with a spray bottle. An outer layer of the barrier can be made of a solid rigid material, such as plastic or metal, with slotted perforations backed by an inner layer of metal mesh material.
- A drainage path can be provided for water and debris that accumulate in the chamber volume. The water drain may be a path back through the perforated barrier, or a separated dedicated drain path can be provided. This allows the device to be self-cleaning during rain and easily to clean using a spray bottle.
- The barrier in this embodiment is a rigid perforated surface forming a chamber which creates an effective acoustic mass. The total volume of the chamber creates an effective acoustic compliance. The combination of these two elements in this embodiment of the invention creates an acoustic resonator that is preferably in the frequency range of 1 kHz to 20 kHz.
- Microphones have electronic and acoustic self noise. If the sound sensed by the microphone is increased, the effective signal-to-noise ratio of the microphone increases and yields an effectively quieter microphone signal for the same ambient acoustic noise signal.
- An equalizer circuit (active or passive) can be connected to the output of the microphone to attenuate the frequency region of boosted signal. Therefore, because the microphone signal is attenuated, the self-noise of the microphone is reduced. However, because the acoustic resonator amplifies the sound through acoustical means, the measured signal strength remains at the same amplitude. Therefore, the signal-to-noise ratio of the microphone output is increased by the resonator of an embodiment of the invention and the effective IRSN is reduced which yields a higher quality microphone.
- The microphone is located in a position relative to the chamber where there is no direct line of sight from the ambient environment outside the chamber to the sensing surface of the microphone. It will be understood that as used herein the phrase “no direct line of sight” is intended to mean that the sensing surface is located outside of, or spaced apart from, any imaginary sight line passing from the environment through the chamber. In other words, it is the location and conformation of the chamber and its relationship to the sensing surface of the microphone which provides the lack of line-of-sight from the environment to the sensing surface, rather than the prior art arrangement of having the sensing surface facing the environment with only a physical barrier such as a solid or foam or cloth cover providing the protection between the sensing surface and the environment.
- In this way, any wind, sand or rain that is blown into the chamber through the perforated barrier makes its first contact with the physical structure of the chamber, instead of the microphone sensing surface, which reduces the kinetic energy compared to an unobstructed path. This helps protect the microphone sensing surface, such as a diaphragm, which can be damaged by the force from direct impact of rain or objects. Microphones, such as condenser, MEMS, dynamic and piezoelectric employ various types of sensing surfaces, such as single and multiple diaphragms and piezoelectric solids among others.
- The microphone used in an embodiment of the invention is preferably waterproof. However, an additional waterproof membrane, called an acoustic vent, can be incorporated to block the path to the microphone sensing surface to ensure that the microphone is not damaged by contact with water. Acoustic vents may be attached directly to the front face of a microphone or other locations, such as the end of a microphone coupler, which would provide a water tight seal between the ambient environment and the microphone sensing surface.
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FIG. 1 depicts a view of an embodiment of the invention as it would be incorporated into a vertical outer surface with “UP” indicating the direction of higher altitude. Aperforated cover 2 is attached to anouter surface 10, using flush-mountedscrews 6. Alternatively, screws may be fastened from behind the outer surface so that the screws cannot be seen from the perspective shown. - The
perforated cover 2 incorporates at least oneslot perforation 4 having a length u and a height v. In a preferred embodiment, slot perforations are rounded at the ends and do not have sharp edges to help minimize wind turbulence when wind blows across theouter surface 10. - Behind the slot perforations, a
screen 8 is attached to the back of theperforated cover 2. Thescreen 8 is preferably made of wire and coated with an oleophobic coating that tends to repel oil and other fluids, although other coatings, such as hydrophobic coatings, may also be used that tend to repel water and other fluids. Thescreen 8 prevents objects longer than slot length u from passing lengthwise through the slots. Alternatively, thescreen 8 can be attached to the front of theperforated cover 2 to improve wind noise reduction. - A
drain output 12 is located near the bottom of theperforated cover 2. Thedrain output 12 is incorporated to more easily allow water, dirt and debris to drain out of the interior of an embodiment of the invention. Thescreen 8 does not cover thedrain output 12, so that dirt and other particles that may pass through thescreen 8 to exit the interior of an embodiment of the invention. -
FIG. 2 is a view of the interior 24 portion of an embodiment of the invention, with theperforated cover 2,screen 8 andscrews 6 removed. Screw holes 14 are provided to receive thescrews 6 that secure theperforated cover 2. Arectangular screen recess 16 is incorporated to provide room for thescreen 8 when theperforated cover 2 is attached. Within the interior 24 there is achamber 20 with average width f and average height d (averages are used here because the interior is irregular). - At the upper end of the interior 24 is located a
microphone coupler 18 which is acoustically coupled to thechamber 20. Thecoupler 18 is preferably made of elastomeric material such as molded silicone or other compliant material. - The
chamber 20 is enclosed by the interior structure and elements of an embodiment of the invention such that if water enters the chamber through theslot perforations 4 or drainoutput 12, the only path for water to drain from the chamber is throughslot perforations 4 and drainoutput 12. - Within the
chamber 20 is a recesseddrain channel 22 with width k. The recesseddrain channel 22 could be located as shown in the figure, or, alternatively could be centered, relative to dimension f, within thechamber 20. Thedrain channel 22 may incorporate other geometries, such as an “hour glass” design where the drain channel becomes restricted in the middle, relative to dimension d ofchamber 20, while having greater width at the top, where themicrophone coupler 18 is located, and at the bottom, where thedrain output 12 would be located. The “hour glass” design provides for larger diameter microphone couplers and drain diameters while minimizing thetotal chamber 20 volume. -
FIG. 3 is a cross-sectional view of an embodiment of the invention along the cut line B-B fromFIG. 1 , cut through the length u of one of theslots 4. In this view of an embodiment of the invention, a portion of the chamber has a depth h while thedrain channel 22 is recessed further by depth w. Preferably, depth h should be greater than 1 mm to facilitate water drainage and prevent water retention. The interior geometry may be curved instead of the sharp edges shown inFIG. 3 . - The
drain channel 22 provides for improved draining of water from thechamber 20 but also allows room for incorporating larger diameter microphones andmicrophone couplers 18 without increasing thetotal chamber 20 volume appreciably. The drain channel is shown to one side of thechamber 20 but could as well be centered relative to dimension f, or placed in other locations in thechamber 20. - The
microphone coupler 18 has acoupler sound channel 30 that couples sound to anacoustic vent 26. Themicrophone coupler 18 in this embodiment is located in thedrain channel 22 because it is larger in diameter compared to h. - A cross-sectional view of the
slot perforation 4 can be seen inFIG. 3 with smooth contoured surfaces, such as acontour surface 33 facing the ambient environment instead of sharp edges to minimize wind turbulence and acoustic wind noise. Thescreen 8 has a mesh spacing z and a screen diameter q when thescreen 8 incorporates cylindrical webbing such as metal wire and is shown here attached to the back of theperforated cover 2 to protect thescreen 8 from damage. Alternatively, thescreen 8 can be attached to the front of theperforated cover 2 for improved wind noise reduction. - The
perforated cover 2 is attached to anenclosure 32. Theperforated cover 2 andenclosure 32 define thechamber 20 volume. Theenclosure 32 extends to form theouter surface 10 in this embodiment. In another embodiment, the enclosure could be a separate component from the outer surface that attaches to the outer surface. -
FIG. 4 is a cross-sectional view of an embodiment of the invention along cut line A-A fromFIG. 1 , through the width v of theslots 4. Theslots 4 have a thickness c measured betweeninner edge 47 andouter surface 51. - Wind turbulence causes undesirable acoustic noise. Preferably, the
slots 4 have smoothouter surfaces 51 instead of sharp edges to reduce turbulence due to wind when wind blows across theperforated cover 2. Theslot 4inner edges 47 do not cause appreciable turbulence because wind is not blowing over this edge. However, theinner edge 47 may be contoured in alternative embodiments. - This cross-sectional view shows the
microphone coupler 18 with a horn-shaped coupler sound channel 30 (although other geometries may be used), attached to amicrophone 40. Alternatively, themicrophone 40 can be completely or partially installed within thechamber 20 to minimize the length of thecoupler sound channel 30, or if desired themicrophone coupler 18 can be eliminated altogether. In the preferred embodiment, themicrophone coupler 18 provides a water tight seal around themicrophone 40. - The
coupler sound channel 30 couples sound from thechamber 20 to theacoustic vent 26. Theacoustic vent 26 is gas permeable and couples sound to themicrophone 40. Theacoustic vent 26 is used to prevent water and dirt from impinging on amicrophone sensing surface 42, such as a fragile diaphragm. Preferably, theacoustic vent 26 is mounted to themicrophone 40 with an adhesive 44 to cover amicrophone inlet 46 and creates a water-tight seal. - As used herein, a “microphone inlet” is a perforation in a microphone housing to allow sound to be coupled to a microphone sensing surface from outside the microphone housing to inside the microphone housing. A “microphone sensing surface”, such as a diaphragm, typically vibrates in response to sound excitation, and this vibration is converted into an electrical signal using various means known in the art.
- Sound impinging on the exterior of the
perforated cover 2 passes through theslots 4 andscreen 8 and into thechamber 20, then throughcoupler inlet 48,coupler sound channel 30,acoustic vent 26 andmicrophone inlet 46, where it is sensed by themicrophone sensing surface 42. - The slotted
perforated cover 2 helps protect theacoustic vent 26 from rain, wind and sand as well as fingers and other foreign objects. Water that penetrates theperforated cover 2 runs down thechamber 20 and back out through thebottom slot perforations 4 and drainoutput 12. Thescreen 8 prevents objects smaller than the slot dimensions u and v from entering thechamber 20. Objects smaller than the mesh spacing z ofscreen 8 can enter thechamber 20; however, they tend to fall to the bottom of thechamber 20. - The
drain output 12 has diameter k that is larger than the mesh spacing z so that small objects the size of the mesh spacing z can exit thechamber 20 easily without being trapped. Thedrain output 12 is located at the bottom of thechamber 20 so that gravity tends to pull water out of thechamber 20 via thedrain output 12. Thus, if any objects smaller than mesh z do enter thechamber 20, water will wash the objects out of thechamber 20 through thedrain output 12. In this way, an embodiment of the invention tends to be self-cleaning. - When an embodiment of the invention is used near an environment where salt spray is present, salt crystals will not become trapped as they would if a porous foam material were incorporated. Any salt crystals that form from dried salt spray are also washed down the
drain channel 22 during the next rain, and will exit through thedrain output 12. - The
microphone 40 is located at the top of thechamber 20 so that any water which might enter the microphone area will fall out of thecoupler sound channel 30 into thechamber 20 and exit out through thedrain output 12. Because there are no porous materials within thechamber 20 such as foam, water is not retained in thechamber 20. - The
microphone 40 is also located at a position outside of or spaced apart from any imaginary straight line from the ambient environment to themicrophone sensing surface 42 or acoustic vent 26 (i.e there is “no line of sight”). That is, themicrophone sensing surface 42 oracoustic vent 26 is obscured by the geometry of themicrophone coupler 18, thescreen 8 and theslot perforations 4. This is shown inFIG. 4 as line of sight x. In this way, water spray and small objects cannot impact themicrophone sensing surface 42 through a direct path. Theacoustic vent 26 in this embodiment is also obscured and there is no line of sight from the environment to thevent 26. - The
acoustic vent 26 may be incorporated in other locations in an embodiment of the invention, such as at thecoupler inlet 48; however, care must be taken that there is no direct line of sight to the vent. - In the embodiment as shown in
FIG. 4 , there are multiple nonlinear unobscured lines of sight paths y from the ambient environment to theacoustic vent 26. Materials, such as many acoustic foams, that do not have straight unobstructed paths through them tend to become clogged with water, dirt and salt crystals and need to be replaced regularly if they are used outdoors, whereas an embodiment of the invention described herein is self-cleaning and, if desired, can be deliberately cleaned by the user easily. In this embodiment, no material is used in thechamber 20, and water easily drains from the chamber. However, highly porous material can also drain water adequately if there are unobstructed paths through the material, for water draining purposes, and the pores are relatively large in size. - A
microphone amplifier 36 is connected to microphone leads 38 to provide bias circuitry and amplification. A passive or activeelectronic equalization circuit 34 can be connected to themicrophone amplifier 36 to create a generally flat frequency response to ambient sound for sound recording or other purposes. - The
perforated cover 2 andscreen 8 are designed so that the acoustic mass of the two, combined with the acoustic compliance of thechamber 20, form a first acoustic resonance at a frequency between 1 kHz and 20 kHz. The acoustic resonance amplifies the sound pressure in thechamber 20, as compared to the ambient environment at and near the resonance frequency. Boosting the sound pressure has the desired result of improving the effective IRSN of themicrophone 40. - The acoustic compliance of the
chamber 20 at room temperature is calculated using the equation Ca=(Vol/1.42×105) m5/N, where Vol is the total volume of thechamber 20 in cubic meters (m3), m stands for meters and N stands for Newtons. The value of Vol is calculated using the equation Vol=edf m3, where e, d and f are the dimensions of the chamber 20 (seeFIGS. 2 and 4 ), measured in meters. - Dimensions of 20 mm for d, 5 mm for e and 18 mm for f are an example of a desirable geometry which yields a volume of 1.8 cc, and an acoustic compliance of 1.27×10−11 m5/N. An average chamber depth e of greater than 1 mm is desirable to prevent water from becoming trapped within the chamber volume, and a slot width v of greater than 0.5 mm is desirable to prevent water from becoming trapped in the slots.
- The acoustic mass of the
perforated cover 2 andscreen 8 will be dominated by theperforated cover 2 when the mesh diameter is small compared to the slot thickness c, and the mesh spacing z is similar in size to the slot width v. - The acoustic mass Ma of an individual slot or hole in kg/m4 is approximated by the formula Ma=1.21L/Area (ignoring end effects), where L is the thickness of the slots in meters, Area is the cross sectional area of the slots in square meters and Kg represents kilograms.
- An example of desirable dimensions for
slot 4 would be 2 mm for the thickness c, and 18 mm for the length u and 1.5 mm for the width v, where c is the thickness, and there are four slots. The diameter of the wires ofscreen 8 mesh in this embodiment is preferably 0.4 mm while the mesh spacing z is 0.8 mm. - Hence, the acoustic mass of a single slot of this geometry would be approximated as 90 Kg/m4. The equivalent acoustic mass of a plurality of slots of like geometry is equal to the acoustic mass of one slot divided by the number of slots. Hence, the acoustic mass in this preferred embodiment would be approximated as 22.5 Kg/m4.
- The acoustic resonance frequency of the resonator in Hertz (Hz) can be calculated by the formula:
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- Using the values calculated above, the approximate resonance frequency is 9,400 Hertz (9.4 kHz). However, end effects of the slots and the screen result in higher acoustic mass due to the effective mass of the radiation impedance from the
slots 4 and the acoustic mass of thescreen 8. End effects must be taken into account when the thickness of the slot is not large compared to the square root of the slot area and the calculations become complicated for slots when the wavelength of the sound is not large compared to the slot length. The end effects also are affected by how much edge contouring the designer uses for the slots. - Measurements of end effects for this geometry with a screen have been made in the Red Tail Hawk Corporation laboratory and yield an effective acoustic mass approximately four times as high as the calculated acoustic mass. Hence, the resulting resonance frequency is approximately 4.7 kHz for the design of this embodiment, rather than the calculated 9.4 kHz.
- In the preferred embodiment, the
chamber 20 volume Vol is less than 2.32 cc, so that a larger perforated area is not needed in theperforated cover 2 to achieve higher resonance frequencies. A smaller sized perforated area is easier to incorporate in devices such as headsets with earcups that have limited space available. - An acoustic device is considered in the “lumped-element” region when all its dimensions are small relative to the acoustic wavelength in question. A device with resonance frequency below 1 kHz will tend to attenuate high frequencies if the slot or hole perforations are much smaller than a wavelength and the system acts as a lumped-element system at higher frequencies. However, designs with resonances between 1 kHz and 20 kHz will transition out of the lumped-element region and will not attenuate high frequencies so long as the length of the slots is not small in relation to the wavelength of the sound wave.
- The wavelength of a sound wave can be calculated as
-
- where λ is the wavelength in meters, s is the speed of sound (343 m/sec) and f is the frequency in Hz. A slot of length of 1.8 cm corresponds to a wavelength of 19 kHz. However, the behavior of the slot begins to transition out of the lumped element region at around 1.9 kHz.
- Acoustic systems that have geometries both small relative to the wavelengths of the acoustic wave and roughly equal to or greater than the size of the acoustic wave are difficult to analyze with simple math and depend on the angle of acoustic wave incidence. A design, such as the design of this embodiment, must be measured in the laboratory and tweaked to achieve the desired results.
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FIG. 5 shows an embodiment of the invention as it can be incorporated into one of the twoear cups 64 of a headset (not shown). A second ear cup (not shown), generally similar in geometry to theear cup 64 shown, is typically employed in headsets, with the two earcups coupled by a headband (not shown) attached to both ear cups.Headband attachments 66 are provided on theear cup 64 to mechanically attach a headband to theear cup 64. - In this embodiment of an embodiment of the invention, a
perforated cover 62 is attached to anouter surface 60 of the earcup, typically using screws (not shown) attached from inside theear cup 64. In this way, the screw heads cannot be seen from outside theear cup 64. The enclosure of an embodiment of the invention in this embodiment also forms theouter surface 60 of theear cup 64. Theperforated cover 62 follows the contour of theouter surface 60 of theear cup 64 to minimize wind turbulence and wind noise. Theperforated cover 62 employs slot perforations 76 ascreen 72 attached to the front of theperforated cover 62 and adrain output 70. When worn on the head, thedrain output 70 is located below theperforated slots 76 to facilitate water drainage. Thedrain output 70 in this embodiment is located on theperforated cover 62. Thescreen 72 does not cover the drain in this embodiment. - A partition can be employed behind the enclosure of an embodiment of the invention and within the ear cup to seal an embodiment of the invention and all related circuitry to achieve a waterproof design. In this way, if the headset is submerged in water, no water will penetrate into the partitioned volume. When an embodiment of the invention is incorporated in the ear cup of a headset and the headset is used in wet conditions or submerged, no water damage is caused to the microphone or electronics, and because water drains from the chamber of an embodiment of the invention quickly, normal microphone function is restored once the headset is removed from the water.
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FIG. 6 shows another embodiment of an embodiment of the invention as it can be incorporated into one of the twoear cups 64 of a headset (not shown).Circle perforations 80 are employed instead of slot perforations in this embodiment. Aperforated cover 78 is attached to theouter surface 60 of theear cup 64 using flush-mountedscrews 76. A screen is not employed, nor is a drain output in this embodiment. Water drains from thecircle perforations 80 if an embodiment of the invention gets wet. -
FIG. 7 shows another embodiment of an embodiment of the invention as it can be incorporated into one of the twoear cups 84 of a headset (not shown).FIG. 9 shows a sectional view of the embodiment, cut through lines C-C inFIG. 7 . - In this embodiment, only a
single slot perforation 86 is employed. The perforated cover in this embodiment is molded into theear cup 84 body itself. The earcup provides anouter surface 82. The enclosure of an embodiment of the invention in this embodiment is a separate component that is attached to the ear cup from inside the ear cup using screws, adhesive, ultrasonic welding or other means. Ascreen 76 is employed to keep larger objects from penetrating into the chamber of an embodiment of the invention. Water drains through thesingle slot perforation 86 andscreen 76. -
FIG. 9 is a cross-sectional view of an embodiment of the invention along cut line C-C fromFIG. 7 , through theslot 86. In this embodiment themicrophone coupler 90 incorporates acoupler sound channel 92 that is short and cylindrical in geometry, and themicrophone coupler 90 is not much bigger than themicrophone 40 in overall size. No acoustic vent is employed in this embodiment, and thechamber 94 in this embodiment does not incorporate a recessed drain channel. There is no line of sight from the ambient environment to themicrophone sensing surface 42 which helps protect themicrophone sensing surface 42 from the direct impact of blowing rain, sand and other objects. (For example, sighting along ray trace xx one cannot see themicrophone sensing surface 42.) In this embodiment, themicrophone 40 used does not suffer from detrimental effects from exposure to water (waterproof design). If a non-waterproof design were incorporated in this embodiment, anacoustic vent 26 would be used as a water barrier for themicrophone 40, for example, as shown inFIG. 3 andFIG. 4 . There is a nonlinear unobstructed line of sight yy from the ambient environment to themicrophone sensing surface 42. That is, there are no acoustic foams or other materials in thechamber 94 that would block a path from the ambient environment to themicrophone sensing surface 42 and tend to retain water. -
FIG. 10 shows a cross-sectional view of an embodiment of the invention incorporating anauxiliary wind screen 97, adrain tube 95 and adrain output 99. Theauxiliary wind screen 97 can be attached to theouter surface 82. It may have a geometry that follows the contour of theouter surface 82 or may be bulbous or other geometries that reduce wind noise. - The
auxiliary wind screen 97 can be constructed using mesh screen, cloth, gas-permeable membranes, foam or other materials that reduce wind noise but do not alter the acoustic audio-frequency sound sensed bymicrophone 40 in a detrimental way. Theauxiliary wind screen 97 may be thin, for example when employing a single mesh screen or multiple mesh screen layers, or thick, for example when employing foam material with a hollow interior, or solid, for example when employing a solid piece of foam; other wind screen geometries may also be used. - The
drain tube 95 is coupled to thechamber 94 anddrain output 99 for draining debris, water and/or other fluids into the ambient environment. Alternatively, thedrain tube 95 could drain to the interior environment, or other regions, instead of the ambient environment if desired. -
FIG. 8 shows a plot depicting the difference in the response of a microphone mounted flush on the outer surface of an ear cup compared to the response of a microphone used in an embodiment of the invention in an ear cup with four slot perforations and similar aforementioned dimensions, at a range of audio frequencies. That is, the plot inFIG. 8 shows a graph of the improvement in microphone sensitivity when using an embodiment of the invention compared to flush-mounting the microphone. - The plot is an average of three measurements from three different incidence angles (front, side, back) for a plane pressure wave incident on the ear cup when placed on an acoustic manikin in an anechoic room. The response shows a gain in sensitivity in the frequency range from approximately 1 kHz to 8 kHz. In this frequency band, the signal-to-noise ratio has been improved by an embodiment of the invention because the self-noise of the microphone alone has not changed. The first resonance frequency of an embodiment of the invention in this embodiment is approximately 4.7 kHz. There are other resonances and antiresonances due to the headset geometry and invention above 4.7 kHz.
- Although there are several higher-frequency ranges where the response is attenuated, there is a significant net gain in output sensitivity due to the resonance characteristics of an embodiment of the invention, which results in a significant net improvement in the IRSN.
- Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.
Claims (27)
1. An environmental protection device for a microphone having a microphone sensing surface, comprising:
a) a chamber enclosing a volume, the chamber comprising a plurality of sides, one of the plurality of sides being formed by an outer surface exposed to an ambient environment, at least part of the outer surface forming a perforated barrier which is perforated by at least one perforation passing through the outer surface from the ambient environment from which sound is to be detected into the chamber;
b) an acoustic vent arranged between the microphone sensing surface and the chamber, configured to restrict water from entering a microphone inlet, the acoustic vent being located such that the sensing surface is outside of any imaginary straight line passing through the chamber from the ambient environment through the perforated barrier to the sensing surface; and
c) a recessed drain channel located inside the chamber and forming part of the side of the chamber which is opposite the perforated barrier, the drain channel having a depth such that a distance from the perforated barrier to the bottom of the drain channel is greater than 1 mm.
2. The device of claim 1 , further comprising a mesh screen covering the at least one perforation.
3. The device of claim 1 , in which there is an unobstructed nonlinear path from the ambient environment to the acoustic vent.
4. The device of claim 1 , wherein the microphone is located above at least one perforation.
5. The device of claim 1 , in which perforated barrier is formed by a plurality of slots passing through the outer surface.
6. The device of claim 5 , in which each of the plurality of slots has a width greater than 0.5 mm.
7. The device of claim 1 , in which the chamber has a volume of less than 2.32 cubic centimeters.
8. The device of claim 1 , further comprising an auxiliary wind screen coupled to an exterior side of the outer surface and extending over the at least one perforation.
9. The device of claim 1 , in which an average depth of the chamber is greater than 1 mm.
10. The device of claim 1 , in which the outer surface is an outer surface of an earcup.
11. The device of claim 1 , in which the microphone is at least partially located within the recessed drain channel.
12. The device of claim 1 , in which the chamber has an upper region, further comprising a microphone located in the upper region of the chamber.
13. An environmental protection device for a microphone having a microphone sensing surface, comprising:
a chamber enclosing a volume acoustically coupled to the microphone sensing surface,
the chamber comprising a plurality of sides,
one of the plurality of sides being formed by an outer surface exposed to an ambient environment from which sound is to be detected by the microphone, at least part of the outer surface forming a perforated barrier which is perforated by at least one perforation passing through the outer surface from the ambient environment into the chamber; and
a recessed drain channel located inside the chamber and forming part of the side of the chamber, the drain channel having a depth such that a distance from the perforated barrier to a bottom of the drain channel is greater than 1 mm.
14. The device of claim 13 , further comprising a mesh screen covering the at least one perforation.
15. The device of claim 13 , further comprising a gas permeable acoustic vent arranged between the microphone sensing surface and the chamber, configured to restrict water from contacting the microphone sensing surface.
16. The device of claim 15 , in which there is an unobstructed nonlinear path from the ambient environment to the gas permeable acoustic vent.
17. The device of claim 13 , in which there is an unobstructed nonlinear path from the ambient environment to the microphone sensing surface.
18. The device of claim 13 , further comprising an elastomeric microphone coupler acoustically coupling the chamber to the microphone sensing surface.
19. The device of claim 18 , in which the elastomeric microphone coupler is at least partially located within the drain channel.
20. The device of claim 13 , wherein the microphone is located above at least one perforation.
21. The device of claim 13 , in which the perforated barrier is formed by a plurality of slots passing through the outer surface.
22. The device of claim 21 , in which each of the plurality of slots has a width greater than 0.5 mm.
23. The device of claim 13 , further comprising an auxiliary wind screen coupled to an exterior side of the outer surface and extending over the at least one perforation.
24. The device of claim 13 , in which the chamber has an average depth of greater than 1 mm.
25. The device of claim 13 , in which the outer surface is an outer surface of an earcup.
26. The device of claim 13 , in which the microphone is at least partially located within the drain channel.
27. The device of claim 13 in which the chamber has an upper region, further comprising a microphone located in the upper region of the chamber.
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US15/434,499 Abandoned US20170164095A1 (en) | 2013-01-11 | 2017-02-16 | Microphone Environmental Protection Device |
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EP (1) | EP2944092A1 (en) |
AU (1) | AU2014205428A1 (en) |
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IL (1) | IL239134A (en) |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109714689A (en) * | 2018-12-21 | 2019-05-03 | 南京理工大学 | A kind of directionality acoustics index acquisition methods based on difference microphone linear array |
US10930261B2 (en) * | 2019-02-04 | 2021-02-23 | Faurecia Emissions Control Technologies, Germany Gmbh | Vehicle outside microphone unit, vehicle acoustical system and vehicle |
Families Citing this family (51)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9529391B2 (en) | 2013-09-27 | 2016-12-27 | Apple Inc. | Button retention, assembly, and water sealing |
US9625944B2 (en) | 2013-09-29 | 2017-04-18 | Apple Inc. | Waterproof port for electronic devices |
WO2015047378A1 (en) | 2013-09-30 | 2015-04-02 | Pearl Capital Developments Llc | Method for clearing water from acoustic port and membrane |
US10659889B2 (en) * | 2013-11-08 | 2020-05-19 | Infineon Technologies Ag | Microphone package and method for generating a microphone signal |
US9573165B2 (en) | 2014-08-22 | 2017-02-21 | Apple Inc. | Hydrophobic mesh cover |
DE102015203542A1 (en) | 2015-02-27 | 2016-09-01 | Sennheiser Electronic Gmbh & Co. Kg | microphone unit |
US9716934B2 (en) | 2015-04-24 | 2017-07-25 | Apple Inc. | Liquid ingress-redirecting acoustic device reservoir |
US11343413B2 (en) * | 2015-07-02 | 2022-05-24 | Gopro, Inc. | Automatically determining a wet microphone condition in a camera |
US9787884B2 (en) * | 2015-07-02 | 2017-10-10 | Gopro, Inc. | Drainage channel for sports camera |
US9627797B2 (en) | 2015-07-21 | 2017-04-18 | Apple Inc. | Ejection assembly with plug feature |
US9780554B2 (en) | 2015-07-31 | 2017-10-03 | Apple Inc. | Moisture sensors |
US10149396B2 (en) | 2015-09-30 | 2018-12-04 | Apple Inc. | Circuit assembly for an electronic device |
US10122904B2 (en) * | 2016-07-11 | 2018-11-06 | Gopro, Inc. | Drain mechanism for camera controller |
USD827696S1 (en) | 2016-08-09 | 2018-09-04 | Gopro, Inc. | Camera housing |
US10784062B2 (en) | 2016-09-08 | 2020-09-22 | Apple Inc. | Ingress prevention for keyboards |
US9807501B1 (en) | 2016-09-16 | 2017-10-31 | Gopro, Inc. | Generating an audio signal from multiple microphones based on a wet microphone condition |
US10595107B2 (en) | 2016-09-20 | 2020-03-17 | Apple Inc. | Speaker module architecture |
US10596604B2 (en) | 2016-09-27 | 2020-03-24 | Texas Instruments Incorporated | Methods and apparatus using multistage ultrasonic lens cleaning for improved water removal |
US10682675B2 (en) | 2016-11-01 | 2020-06-16 | Texas Instruments Incorporated | Ultrasonic lens cleaning system with impedance monitoring to detect faults or degradation |
US11237387B2 (en) | 2016-12-05 | 2022-02-01 | Texas Instruments Incorporated | Ultrasonic lens cleaning system with foreign material detection |
IT201600131334A1 (en) * | 2016-12-27 | 2018-06-27 | Magneti Marelli Spa | ACOUSTIC DEVICE, IN PARTICULAR FOR AUTOMOTIVE APPLICATIONS |
IT201600131329A1 (en) * | 2016-12-27 | 2018-06-27 | Magneti Marelli Spa | ACOUSTIC DEVICE, IN PARTICULAR FOR AUTOMOTIVE APPLICATIONS |
US10695805B2 (en) | 2017-02-03 | 2020-06-30 | Texas Instruments Incorporated | Control system for a sensor assembly |
US10663418B2 (en) | 2017-02-03 | 2020-05-26 | Texas Instruments Incorporated | Transducer temperature sensing |
US11042026B2 (en) | 2017-02-24 | 2021-06-22 | Texas Instruments Incorporated | Transducer-induced heating and cleaning |
US11420238B2 (en) | 2017-02-27 | 2022-08-23 | Texas Instruments Incorporated | Transducer-induced heating-facilitated cleaning |
US11607704B2 (en) | 2017-04-20 | 2023-03-21 | Texas Instruments Incorporated | Methods and apparatus for electrostatic control of expelled material for lens cleaners |
US10780467B2 (en) | 2017-04-20 | 2020-09-22 | Texas Instruments Incorporated | Methods and apparatus for surface wetting control |
US10908414B2 (en) | 2017-05-10 | 2021-02-02 | Texas Instruments Incorporated | Lens cleaning via electrowetting |
US10165694B1 (en) | 2017-09-11 | 2018-12-25 | Apple Inc. | Concealed barometric vent for an electronic device |
IT201800003501A1 (en) * | 2018-03-13 | 2019-09-13 | Magneti Marelli Spa | ACOUSTIC DEVICE, IN PARTICULAR FOR AUTOMOTIVE APPLICATIONS |
EP3824649A4 (en) | 2018-07-19 | 2022-04-20 | Cochlear Limited | Contaminant-proof microphone assembly |
US10986433B2 (en) * | 2018-09-28 | 2021-04-20 | Apple Inc. | Eartips for coupling via wireform attachment mechanisms |
US20220217459A1 (en) * | 2019-05-09 | 2022-07-07 | INVISIO Communications A/S | Waterproof microphone assembly with wind noise filter |
EP3742751A1 (en) * | 2019-05-24 | 2020-11-25 | Axis AB | A weather resistant microphone assembly, and camera arrangement comprising such assembly |
JP2021034775A (en) * | 2019-08-19 | 2021-03-01 | オンキヨーホームエンターテイメント株式会社 | earphone |
USD911412S1 (en) | 2019-09-13 | 2021-02-23 | Gopro, Inc. | Camera housing |
USD911411S1 (en) | 2019-09-13 | 2021-02-23 | Gopro, Inc. | Camera housing |
USD921084S1 (en) | 2019-09-13 | 2021-06-01 | Gopro, Inc. | Camera housing |
US11614716B2 (en) | 2019-09-23 | 2023-03-28 | Apple Inc. | Pressure-sensing system for a wearable electronic device |
USD912120S1 (en) | 2019-09-30 | 2021-03-02 | Gopro, Inc. | Camera housing |
AU2021289548B2 (en) * | 2020-06-09 | 2024-02-08 | 3M Innovative Properties Company | Hearing protection device |
US11860585B2 (en) | 2020-06-17 | 2024-01-02 | Apple Inc. | Wearable electronic device with a compressible air-permeable seal |
US11570546B2 (en) * | 2020-06-22 | 2023-01-31 | Gopro, Inc. | Camera microphone drainage system designed for beamforming |
USD946071S1 (en) | 2020-06-30 | 2022-03-15 | Gopro, Inc. | Camera housing |
USD963016S1 (en) | 2020-07-31 | 2022-09-06 | Gopro, Inc. | Camera housing |
US11381894B2 (en) | 2020-08-05 | 2022-07-05 | Motorola Solutions, Inc. | Device with linear slots for water drainage |
USD946072S1 (en) | 2020-08-10 | 2022-03-15 | Gopro, Inc. | Camera housing |
USD953404S1 (en) | 2020-08-14 | 2022-05-31 | Gopro, Inc. | Camera housing |
US11785375B2 (en) | 2021-06-15 | 2023-10-10 | Quiet, Inc. | Precisely controlled microphone acoustic attenuator with protective microphone enclosure |
CN215453202U (en) * | 2021-06-29 | 2022-01-07 | 影石创新科技股份有限公司 | Microphone subassembly and camera |
Citations (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3043912A (en) * | 1957-07-10 | 1962-07-10 | Laney William J De | Intercom for automobiles |
US4586194A (en) * | 1983-03-09 | 1986-04-29 | Hitachi, Ltd. | Earphone characteristic measuring device |
US5526430A (en) * | 1994-08-03 | 1996-06-11 | Matsushita Electric Industrial Co., Ltd. | Pressure gradient type microphone apparatus with acoustic terminals provided by acoustic passages |
US5812496A (en) * | 1997-10-20 | 1998-09-22 | Peck/Pelissier Partnership | Water resistant microphone |
US20040047486A1 (en) * | 2002-09-06 | 2004-03-11 | Van Doorn Jan Marinus | Microphone with improved sound inlet port |
US20060215863A1 (en) * | 2005-03-16 | 2006-09-28 | Siemens Audiologische Technik Gmbh | Cover fixture for at least one microphone input of a hearing device |
US20070053538A1 (en) * | 2005-09-08 | 2007-03-08 | Oticon A/S | Audio device comprising a microphone |
US20070189563A1 (en) * | 2006-01-30 | 2007-08-16 | Sjursen Walter P | Hearing aid with tuned microphone cavity |
US20070261153A1 (en) * | 2006-05-09 | 2007-11-15 | Wise Robert W | Protective helmet with flush pivoting ear cups |
US20080187150A1 (en) * | 2005-04-29 | 2008-08-07 | Peltor Ab | Ear Cup With Micrphone Device |
DE102007034230A1 (en) * | 2007-07-23 | 2009-01-29 | Siemens Medical Instruments Pte. Ltd. | Hearing device e.g. behind-the-ear hearing aid, has microphone cover to protect microphone and with opening, where plane defines two region halves through microphone opening, and opening of cover is arranged in one region half |
US8009851B2 (en) * | 2006-11-22 | 2011-08-30 | Sony Ericsson Mobile Communications | Noise reduction system and method |
WO2011124250A1 (en) * | 2010-04-06 | 2011-10-13 | Widex A/S | Hearing aid adapted for suppression of wind noise |
US8150082B2 (en) * | 2005-02-22 | 2012-04-03 | Rion Co., Ltd. | Waterproof hearing aid |
US8325951B2 (en) * | 2009-01-20 | 2012-12-04 | General Mems Corporation | Miniature MEMS condenser microphone packages and fabrication method thereof |
JP5216033B2 (en) * | 2010-02-09 | 2013-06-19 | Toa株式会社 | Microphone cover and microphone provided with the same |
US8965001B2 (en) * | 2008-09-22 | 2015-02-24 | Samsung Electronics Co., Ltd. | Mic rubber apparatus for portable electric device |
Family Cites Families (52)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2520706A (en) | 1948-01-30 | 1950-08-29 | Rca Corp | Windscreen for microphones |
US2643729A (en) | 1951-04-04 | 1953-06-30 | Charles C Mccracken | Audio pickup device |
US2946862A (en) | 1955-03-21 | 1960-07-26 | Clark Co Inc David | Ear protector and communication equipment |
US2908772A (en) * | 1957-05-24 | 1959-10-13 | Zenith Radio Corp | Electroacoustical transducer |
US3154171A (en) | 1962-04-02 | 1964-10-27 | Vicon Instr Company | Noise suppressing filter for microphone |
US3683130A (en) | 1967-10-03 | 1972-08-08 | Kahn Res Lab | Headset with circuit control |
US3952158A (en) * | 1974-08-26 | 1976-04-20 | Kyle Gordon L | Ear protection and hearing device |
US3979567A (en) * | 1975-02-18 | 1976-09-07 | Frye G J | Microphone coupler for hearing aid having inverted conical end configuration |
US4006318A (en) | 1975-04-21 | 1977-02-01 | Dyna Magnetic Devices, Inc. | Inertial microphone system |
US4088849A (en) | 1975-09-30 | 1978-05-09 | Victor Company Of Japan, Limited | Headphone unit incorporating microphones for binaural recording |
US4335281A (en) * | 1980-06-24 | 1982-06-15 | Plantronics, Inc. | Post-auricle contoured headset for two-way voice communication |
US4441576A (en) | 1982-04-19 | 1984-04-10 | Allen Clayton H | Nonlinear passive acoustic filtering |
US4570746A (en) | 1983-06-30 | 1986-02-18 | International Business Machines Corporation | Wind/breath screen for a microphone |
US4924502A (en) | 1987-05-08 | 1990-05-08 | Allen Clayton H | Means for stabilizing sound pressure produced at the eardrum under an earpad |
US4972491A (en) | 1988-11-30 | 1990-11-20 | Wilcox Jr Edward R | Ear-mic headset/eardefender |
US5086789A (en) * | 1989-09-13 | 1992-02-11 | Tichy James B | Wind deflector for the ear |
US5305387A (en) | 1989-10-27 | 1994-04-19 | Bose Corporation | Earphoning |
US5333206A (en) | 1992-03-18 | 1994-07-26 | Koss Corporation | Dual element headphone |
US5426719A (en) | 1992-08-31 | 1995-06-20 | The United States Of America As Represented By The Department Of Health And Human Services | Ear based hearing protector/communication system |
US5357585A (en) | 1993-07-09 | 1994-10-18 | Khyber Technologies Corporation | Headphone assembly |
US6567525B1 (en) | 1994-06-17 | 2003-05-20 | Bose Corporation | Supra aural active noise reduction headphones |
US5551090A (en) | 1995-04-20 | 1996-09-03 | Thompson; Janet M. | Ear protecting apparatus |
US6683965B1 (en) | 1995-10-20 | 2004-01-27 | Bose Corporation | In-the-ear noise reduction headphones |
US5675660A (en) | 1996-01-25 | 1997-10-07 | Townsend; Brook Lowell | Apparatus for protecting microphones |
JPH1042017A (en) * | 1996-07-19 | 1998-02-13 | Nec Corp | Transmitting part structure |
US5887286A (en) | 1998-01-22 | 1999-03-30 | Waldron; Carolyn A. | Ear protector |
US6724902B1 (en) | 1999-04-29 | 2004-04-20 | Insound Medical, Inc. | Canal hearing device with tubular insert |
GB2360165A (en) | 2000-03-07 | 2001-09-12 | Central Research Lab Ltd | A method of improving the audibility of sound from a loudspeaker located close to an ear |
US7317802B2 (en) | 2000-07-25 | 2008-01-08 | Lightspeed Aviation, Inc. | Active-noise-reduction headsets with front-cavity venting |
US6445805B1 (en) | 2001-08-06 | 2002-09-03 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Hearing aid assembly |
US8463334B2 (en) * | 2002-03-13 | 2013-06-11 | Qualcomm Incorporated | Apparatus and system for providing wideband voice quality in a wireless telephone |
JP2004328231A (en) * | 2003-04-23 | 2004-11-18 | Matsushita Electric Ind Co Ltd | Microphone with water-proof and wind-proof function, and water-proof and wind-proof screen to be used therefor |
US7352871B1 (en) | 2003-07-24 | 2008-04-01 | Mozo Ben T | Apparatus for communication and reconnaissance coupled with protection of the auditory system |
US7212645B2 (en) | 2003-08-12 | 2007-05-01 | 180S, Inc. | Ear warmer with a speaker system |
JP4336252B2 (en) | 2004-06-02 | 2009-09-30 | 株式会社オーディオテクニカ | Windscreen and microphone |
US20060013409A1 (en) | 2004-07-16 | 2006-01-19 | Sensimetrics Corporation | Microphone-array processing to generate directional cues in an audio signal |
AT500786B1 (en) | 2004-08-19 | 2011-08-15 | Anton Pfanner | HEARING PROTECTION AND / OR SPEAKER ELEMENT |
US7391878B2 (en) | 2005-01-12 | 2008-06-24 | Sheng-Hsin Liao | Earphone device having composite functions |
US7668332B2 (en) * | 2005-10-21 | 2010-02-23 | Motorola, Inc. | Audio porting assembly |
KR100673843B1 (en) * | 2005-10-31 | 2007-01-24 | 주식회사 비에스이 | Condensor microphone including wind screen filter and external frame of building the condensor microphone |
US7457428B2 (en) | 2006-07-27 | 2008-11-25 | Adaptive Technologies, Inc. | Double hearing protection device |
US8688036B2 (en) | 2006-08-31 | 2014-04-01 | Red Tail Hawk Corporation | Wireless communications headset system employing a loop transmitter that fits around the pinna |
US7564989B2 (en) | 2006-11-24 | 2009-07-21 | Schanz Ii, Llc | Concha bowl hearing aid apparatus and method |
GB2445388B (en) | 2007-02-16 | 2009-01-07 | Sonaptic Ltd | Ear-worn speaker-carrying devices |
DE102007037561A1 (en) | 2007-08-09 | 2009-02-19 | Ceotronics Aktiengesellschaft Audio . Video . Data Communication | Sound transducer for the transmission of audio signals |
US7843021B2 (en) * | 2008-02-28 | 2010-11-30 | Shandong Gettop Acoustic Co. Ltd. | Double-side mountable MEMS package |
GB2456846B (en) | 2008-07-31 | 2013-03-13 | Wolfson Microelectronics Plc | Ear simulator |
US20100225461A1 (en) * | 2009-03-05 | 2010-09-09 | Raja Singh Tuli | Apparatus and method for detection of a specified audio signal or gesture |
US8379872B2 (en) | 2009-06-01 | 2013-02-19 | Red Tail Hawk Corporation | Talk-through listening device channel switching |
US8873783B2 (en) * | 2010-03-19 | 2014-10-28 | Advanced Bionics Ag | Waterproof acoustic element enclosures and apparatus including the same |
DE102010062887B4 (en) * | 2010-12-13 | 2014-01-30 | Robert Bosch Gmbh | Microphone package and method for its production |
DK2512152T3 (en) * | 2011-04-13 | 2014-02-03 | Oticon As | Hearing aid with two or more microphones |
-
2013
- 2013-03-12 US US13/796,579 patent/US9084053B2/en active Active
-
2014
- 2014-01-09 CA CA2936175A patent/CA2936175A1/en not_active Abandoned
- 2014-01-09 AU AU2014205428A patent/AU2014205428A1/en not_active Abandoned
- 2014-01-09 EP EP14701261.1A patent/EP2944092A1/en not_active Withdrawn
- 2014-01-09 WO PCT/US2014/010830 patent/WO2014110233A1/en active Application Filing
-
2015
- 2015-06-02 IL IL239134A patent/IL239134A/en active IP Right Grant
- 2015-06-09 US US14/734,302 patent/US9609411B2/en active Active
-
2017
- 2017-02-16 US US15/434,499 patent/US20170164095A1/en not_active Abandoned
Patent Citations (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3043912A (en) * | 1957-07-10 | 1962-07-10 | Laney William J De | Intercom for automobiles |
US4586194A (en) * | 1983-03-09 | 1986-04-29 | Hitachi, Ltd. | Earphone characteristic measuring device |
US5526430A (en) * | 1994-08-03 | 1996-06-11 | Matsushita Electric Industrial Co., Ltd. | Pressure gradient type microphone apparatus with acoustic terminals provided by acoustic passages |
US5812496A (en) * | 1997-10-20 | 1998-09-22 | Peck/Pelissier Partnership | Water resistant microphone |
US20040047486A1 (en) * | 2002-09-06 | 2004-03-11 | Van Doorn Jan Marinus | Microphone with improved sound inlet port |
US8150082B2 (en) * | 2005-02-22 | 2012-04-03 | Rion Co., Ltd. | Waterproof hearing aid |
US20060215863A1 (en) * | 2005-03-16 | 2006-09-28 | Siemens Audiologische Technik Gmbh | Cover fixture for at least one microphone input of a hearing device |
US20080187150A1 (en) * | 2005-04-29 | 2008-08-07 | Peltor Ab | Ear Cup With Micrphone Device |
US20110116671A1 (en) * | 2005-09-08 | 2011-05-19 | Lars Tuborg Jensen | Audio device comprising a microphone |
US7894621B2 (en) * | 2005-09-08 | 2011-02-22 | Oticon A/S | Audio device comprising a microphone |
US20070053538A1 (en) * | 2005-09-08 | 2007-03-08 | Oticon A/S | Audio device comprising a microphone |
US20070189563A1 (en) * | 2006-01-30 | 2007-08-16 | Sjursen Walter P | Hearing aid with tuned microphone cavity |
US20070261153A1 (en) * | 2006-05-09 | 2007-11-15 | Wise Robert W | Protective helmet with flush pivoting ear cups |
US8009851B2 (en) * | 2006-11-22 | 2011-08-30 | Sony Ericsson Mobile Communications | Noise reduction system and method |
DE102007034230A1 (en) * | 2007-07-23 | 2009-01-29 | Siemens Medical Instruments Pte. Ltd. | Hearing device e.g. behind-the-ear hearing aid, has microphone cover to protect microphone and with opening, where plane defines two region halves through microphone opening, and opening of cover is arranged in one region half |
US8965001B2 (en) * | 2008-09-22 | 2015-02-24 | Samsung Electronics Co., Ltd. | Mic rubber apparatus for portable electric device |
US8325951B2 (en) * | 2009-01-20 | 2012-12-04 | General Mems Corporation | Miniature MEMS condenser microphone packages and fabrication method thereof |
JP5216033B2 (en) * | 2010-02-09 | 2013-06-19 | Toa株式会社 | Microphone cover and microphone provided with the same |
WO2011124250A1 (en) * | 2010-04-06 | 2011-10-13 | Widex A/S | Hearing aid adapted for suppression of wind noise |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109714689A (en) * | 2018-12-21 | 2019-05-03 | 南京理工大学 | A kind of directionality acoustics index acquisition methods based on difference microphone linear array |
US10930261B2 (en) * | 2019-02-04 | 2021-02-23 | Faurecia Emissions Control Technologies, Germany Gmbh | Vehicle outside microphone unit, vehicle acoustical system and vehicle |
Also Published As
Publication number | Publication date |
---|---|
US9084053B2 (en) | 2015-07-14 |
AU2014205428A1 (en) | 2015-07-02 |
US20150271587A1 (en) | 2015-09-24 |
US20140198932A1 (en) | 2014-07-17 |
US9609411B2 (en) | 2017-03-28 |
EP2944092A1 (en) | 2015-11-18 |
WO2014110233A1 (en) | 2014-07-17 |
CA2936175A1 (en) | 2014-07-17 |
IL239134A (en) | 2016-06-30 |
IL239134A0 (en) | 2015-07-30 |
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