# US 11,451,891 B2 · Moving coil microphone transducer with secondary port

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- Number: US 11,451,891 B2
- Document ID: US11451891B2
- Status: Granted
- Kind: B2
- Application number: 16/746,044
- Filed: 2020-01-17
- Published: 2020-08-13
- Granted: 2022-09-20
- Earliest claimed: 2017-07-18
- Assignees: Shure Acquisition Holdings, Inc.
- Applicants: Shure Acquisition Holdings, Inc.
- Inventors: Roger Stephen Grinnip, III
- Web page: https://patentgrep.com/patent/US11451891B2

## CPC

- H04R 1/02: Casings; Cabinets {; Supports therefor;} Mountings therein (H04R1/28 takes precedence {; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075})
- B65D 81/18: providing specific environment for contents, e.g. temperature above or below ambient (with thermal insulation B65D81/38)
- H04R 1/028: {associated with devices performing functions other than acoustics, e.g. electric candles}
- H04R 1/2807: {Enclosures comprising vibrating or resonating arrangements (for the reduction of undesired resonances or vibrations H04R1/2869)}
- H04R 1/38: in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone
- H04R 9/08: Microphones
- H04R 1/083: {Special constructions of mouthpieces}
- H04R 1/2869: {Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself}
- H04R 3/007: {Protection circuits for transducers}
- H04R 7/127: {dome-shaped}
- H04R 2201/029: Manufacturing aspects of enclosures transducers
- H04R 2410/01: Noise reduction using microphones having different directional characteristics
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)
- B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES

## Abstract

A microphone transducer is provided, the microphone transducer comprising a housing and a transducer assembly supported within the housing and defining an internal acoustic space. The transducer assembly includes a magnet assembly, a diaphragm disposed adjacent the magnet assembly and having a front surface and a rear surface, and a coil attached to the rear surface of the diaphragm and capable of moving relative to the magnet assembly in response to acoustic waves impinging on the front surface. The transducer assembly further includes a primary port establishing acoustic communication between the internal acoustic space and an external cavity at least partially within the housing, and a secondary port located at the front surface of the diaphragm.

## Claims

### Claim 1

A microphone, comprising:
a microphone body;
a first microphone transducer assembly disposed in the microphone body the first microphone transducer assembly comprising:
a first diaphragm having at least one aperture passing through the first diaphragm, and
an internal cavity defining an internal acoustic volume, the internal cavity configured such that an external acoustic delay associated with the at least one aperture is substantially equal to zero;
an external acoustic volume located outside the first transducer assembly, the external acoustic volume in acoustic communication with the internal acoustic volume; and
a second microphone transducer assembly comprising a second diaphragm having one or more second apertures passing through the second diaphragm, wherein the first microphone transducer assembly is disposed within a second internal acoustic volume of the second microphone transducer assembly.

### Claim 2 (depends on 1)

The microphone of claim 1, wherein the first transducer assembly further includes a primary tuning port for establishing acoustic communication between the external acoustic volume and the internal acoustic volume.

### Claim 3 (depends on 2)

The microphone of claim 2, wherein an acoustic resistance associated with the primary tuning port is greater than a critical damping resistance of the first diaphragm.

### Claim 4 (depends on 2)

The microphone of claim 2, wherein a first acoustic path formed by the primary tuning port and a second acoustic path formed by the at least one aperture are disposed substantially parallel to a central axis of the first diaphragm.

### Claim 5 (depends on 1)

The microphone of claim 1, wherein the at least one aperture is disposed through a center of the first diaphragm.

### Claim 6 (depends on 1)

The microphone of claim 1, wherein the at least one aperture includes a plurality of apertures configured to create acoustic flow resistance through the first diaphragm.

### Claim 7 (depends on 1)

The microphone of claim 1, wherein the at least one aperture is covered by a perforated material configured to create acoustic flow resistance through the first diaphragm.

### Claim 8 (depends on 1)

The microphone of claim 1, wherein a total series resistance associated with the transducer is configured to be equal to or less than a critical damping resistance of the diaphragm, the total series resistance being equal to a parallel equivalent resistance through the at least one aperture and an acoustic path for establishing the acoustic communication between the external acoustic volume and the internal acoustic volume.

### Claim 9

A microphone, comprising:
a microphone transducer assembly comprising:
a diaphragm,
at least one aperture passing through the diaphragm, and
an internal cavity defining an internal acoustic volume;
an external acoustic volume located outside the microphone transducer assembly; and
a primary tuning port for establishing acoustic communication between the internal acoustic volume and the external acoustic volume,
wherein the internal cavity is configured such that an external acoustic delay between the primary tuning port and the at least one aperture is substantially equal to zero, and
wherein the primary tuning port is associated with a first acoustic resistance, R1, the at least one aperture is associated with a second acoustic resistance, Rf, and a total series resistance associated with the microphone transducer assembly is equal to a parallel equivalent resistance of the first and second resistances, or R1∥Rf.

### Claim 10 (depends on 9)

The microphone of claim 9, wherein the first acoustic resistance, R1, associated with the primary tuning port is greater than a critical damping resistance of the diaphragm.

### Claim 11 (depends on 9)

The microphone of claim 9, wherein the at least one aperture is disposed through a center of the diaphragm.

### Claim 12 (depends on 9)

The microphone of claim 9, wherein the at least one aperture is covered by a perforated material configured to create acoustic flow resistance through the diaphragm.

### Claim 13 (depends on 9)

The microphone of claim 9, wherein the at least one aperture includes a plurality of apertures configured to create acoustic flow resistance through the diaphragm.

### Claim 14 (depends on 9)

The microphone of claim 9, wherein a first acoustic path formed by the primary tuning port and a second acoustic path formed by the at least one aperture are disposed substantially parallel to a central axis of the diaphragm.

### Claim 15 (depends on 9)

The microphone of claim 9, wherein the primary tuning port is located under a resilient brim of the diaphragm.

### Claim 16 (depends on 9)

The microphone of claim 9, wherein the microphone transducer assembly further comprises a magnet assembly disposed adjacent the diaphragm and a coil attached to a rear surface of the diaphragm, the coil being capable of moving relative to the magnet assembly in response to acoustic waves impinging on a front surface of the diaphragm, wherein the primary tuning port is an aperture disposed within a top portion of the magnet assembly adjacent the rear surface of the diaphragm.

### Claim 17 (depends on 9)

The microphone of claim 9, further comprising a second microphone transducer assembly in acoustic communication with the microphone transducer assembly.

### Claim 18 (depends on 9)

The microphone of claim 9, further comprising a second microphone transducer assembly, wherein the microphone transducer assembly is disposed within an internal acoustic volume of the second microphone transducer assembly.

### Claim 19 (depends on 9)

The microphone of claim 9, wherein the total series resistance associated with the microphone transducer assembly is configured to be equal to or less than a critical damping resistance of the diaphragm.

### Claim 20

A microphone, comprising:
a microphone body;
a first microphone transducer assembly disposed in the microphone body, the first microphone transducer assembly comprising:
a first diaphragm having at least one aperture passing through the first diaphragm, and
an internal cavity defining an internal acoustic volume, the internal cavity configured such that an external acoustic delay associated with the at least one aperture is substantially equal to zero;
an external acoustic volume located outside the first transducer assembly, the external acoustic volume in acoustic communication with the internal acoustic volume; and
a second microphone transducer assembly disposed within the internal acoustic volume of the first microphone transducer assembly, the second microphone transducer assembly including a second diaphragm having one or more second apertures passing through the second diaphragm.

### Claim 21 (depends on 20)

The microphone of claim 20, wherein the first transducer assembly further includes a primary tuning port for establishing acoustic communication between the external acoustic volume and the internal acoustic volume.

### Claim 22 (depends on 21)

The microphone of claim 21, wherein an acoustic resistance associated with the primary tuning port is greater than a critical damping resistance of the first diaphragm.

### Claim 23 (depends on 21)

The microphone of claim 21, wherein a first acoustic path formed by the primary tuning port and a second acoustic path formed by the at least one aperture are disposed substantially parallel to a central axis of the first diaphragm.

### Claim 24 (depends on 20)

The microphone of claim 20, wherein the at least one aperture is disposed through a center of the first diaphragm.

### Claim 25 (depends on 20)

The microphone of claim 20, wherein the at least one aperture includes a plurality of apertures configured to create acoustic flow resistance through the first diaphragm.

### Claim 26 (depends on 20)

The microphone of claim 20, wherein the at least one aperture is covered by a perforated material configured to create acoustic flow resistance through the first diaphragm.

### Claim 27 (depends on 20)

The microphone of claim 20, wherein a total series resistance associated with the transducer is configured to be equal to or less than a critical damping resistance of the diaphragm, the total series resistance being equal to a parallel equivalent resistance through the at least one aperture and an acoustic path for establishing the acoustic communication between the external acoustic volume and the internal acoustic volume.