# US 2019/0174228 A1 · Dual-Use Bilateral Microphone Array

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- Number: US 2019/0174228 A1
- Document ID: US20190174228A1
- Status: Published application
- Kind: A1
- Application number: 16/272,013
- Filed: 2019-02-11
- Published: 2019-06-06
- Earliest claimed: 2016-11-09
- Assignees: Bose Corporation
- Applicants: Bose Corporation
- Inventors: Ryan terMeulen; Andrew Jackson Stockton, X
- Web page: https://patentgrep.com/patent/US20190174228A1

## CPC

- H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)}
- G10L 21/028: using properties of sound source
- H04R 1/1083: {Reduction of ambient noise (active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06)}
- H04R 1/406: {microphones}
- H04R 5/033: Headphones for stereophonic communication {(details thereof, e.g. relating to batteries, cables or control elements H04R1/10)}
- G10L 2021/02166: {Microphone arrays; Beamforming}
- H04R 1/1016: {Earpieces of the intra-aural type}
- H04R 1/1075: {Mountings of transducers in earphones or headphones}
- H04R 2201/107: Monophonic and stereophonic headphones with microphone for two-way hands free communication
- H04R 2410/07: Mechanical or electrical reduction of wind noise generated by wind passing a microphone
- H04R 2430/21: Direction finding using differential microphone array [DMA]
- 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)
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

A pair of earphones have microphone arrays each including a front microphone and a rear microphone. A processor uses a first set of filters to combine the four microphone signals to generate a far-field signal that is more sensitive to sounds originating a short distance away from the earphones than to sounds close to the apparatus, and provides the far-field signal to the speakers for output. The processor also uses a second set of filters to combine the four microphone signals to generate a near-field signal that is more sensitive to voice signals from a person wearing the earphones than to sounds originating away from the earphones, and provides the near-field signal to a communication system.

## Claims

### Claim 1

An apparatus comprising:
a first earphone having a first microphone array, providing a first set of microphone signals, and a first speaker;
a second earphone having a second microphone array, providing a second set of microphone signals, and a second speaker; and
a processor receiving the first set of microphone signals and second set of microphone signals, and configured to:
apply a first set of filters to combine the microphone signals to generate a first signal that is more sensitive to sounds originating at a first location relative to the apparatus than to sounds originating at a second location relative to the apparatus;
provide the first signal to a first output;
apply a second set of filters to combine the microphone signals to generate a second signal that is more sensitive to sounds from the second location relative to the apparatus than to sounds originating at the first location relative to the apparatus; and
provide the second signal to a second output.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the first microphone array and second microphone array are physically arranged to optimize detection of sounds a short distance away from the apparatus.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the processor is further configured to:
use a third set of filters, different from the second set of filters, to combine the microphone signals to generate a third signal that is more sensitive to sounds from the second location relative to the apparatus than to sounds originating at the first location relative to the apparatus; and
provide the third signal to a third output.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein applying the first set of filters comprises:
applying separate filters to each signal from each of the first and second sets of microphone signals to produce a first set of filtered signals;
summing the signals of the first set of filtered signals to produce a first summed signal; and
applying an equalization filter to the first summed signal to generate the first signal.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the processor is further configured to generate the first signal and provide the first signal to the first output by:
combining the microphone signals, using a third set of filters, different from the first set of filters, to generate a third signal that is more sensitive to sounds originating at the first location relative to the apparatus than to sounds originating at the second location relative to the apparatus;
providing the first signal to a first channel of the first output; and
providing the third signal to a second channel of the first output.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the processor comprises a first array sub-processor for applying the first set of filters, and a second array sub-processor for applying the second set of filters, and wherein the sub-processors are configured to generate the first signal by:
in the first array sub-processor,
summing signals corresponding to a first one of the microphones in the first array and a first one of the microphones in the second array to form a combined front microphone signal, and
summing signals corresponding to a second one of the microphones in the first array and a second one of the microphones in the second array to form a combined rear microphone signal; and
in the second array sub-processor,
filtering the combined front microphone signal to form a filtered combined front microphone signal,
filtering the combined rear microphone signal to form a filtered combined rear microphone signal, and
combining the filtered combined front microphone signal and the filtered combined rear microphone signal to form a directional microphone signal;
the second signal comprising the directional microphone signal.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the processor is further configured to operate the first and second sets of filters simultaneously.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein:
the first signal is more sensitive to sounds originating in a first direction than to sounds originating in other directions, and
the processor is further configured to:
apply a third set of filters to combine at least the first set of microphone signals to generate a first anti-noise signal that will cancel sounds at the first earphone when output by the first speaker; and
apply a fourth set of filters to combine at least the second set of microphone signals to generate a second anti-noise signal that will cancel sounds at the second earphone when output by the second speaker.

### Claim 9

A method comprising, in a processor:
receiving, from a first earphone having a first microphone array, a first set of microphone signals;
receiving, from a second earphone having a second microphone array, a second set of microphone signals; and
combining the microphone signals, using a first set of filters, to generate a first signal that is more sensitive to sounds originating at a first location relative to the first and second earphones than to sounds originating at a second location relative to the first and second earphones;
providing the first signal to a first output;
combining the microphone signals, using a second set of filters, to generate a second signal that is more sensitive to sounds originating at the second location relative to the first and second earphones than to sounds originating at the first location relative to the first and second earphones; and
providing the second signal to a second output.

### Claim 10 (depends on 9)

The method of claim 9, further comprising, in the processor:
combining the microphone signals using a third set of filters, different from the second set of filters, to generate a third signal that is more sensitive to sounds from the second location relative to the first and second earphones than to sounds originating at the first location relative to the first and second earphones; and
providing the third signal to a third output.

### Claim 11 (depends on 9)

The method of claim 9, wherein applying the first set of filters comprises:
applying separate filters to each signal from each of the first and second sets of microphone signals to produce a first set of filtered signals;
summing the signals of the first set of filtered signals to produce a first summed signal; and
applying an equalization filter to the first summed signal to generate the first signal.

### Claim 12 (depends on 9)

The method of claim 9, wherein generating the first signal and providing the first signal to the output comprises, in the processor:
using a third set of filters, different from the first set of filters, to combine the microphone signals to generate a third signal that is more sensitive to sounds originating at the first location relative to the first and second earphones than to sounds originating at the second location relative to the first and second earphones;
providing the first signal to a first channel of the first output; and
providing the third signal to a second channel of the first output.

### Claim 13 (depends on 9)

The method of claim 9, wherein generating the near-field signal comprises:
in a first array sub-processor,
summing signals corresponding to a first one of the microphones in the first array and a first one of the microphones in the second array to form a combined front microphone signal, and
summing signals corresponding to a second one of the microphones in the first array and a second one of the microphones in the second array to form a combined rear microphone signal; and
in a second array sub-processor,
filtering the combined front microphone signal to form a filtered combined front microphone signal,
filtering the combined rear microphone signal to form a filtered combined rear microphone signal, and
combining the filtered combined front microphone signal and the filtered combined rear microphone signal to form a directional microphone signal;
the second signal comprising the directional microphone signal.

### Claim 14 (depends on 9)

The method of claim 9, further comprising operating the first and second sets of filters simultaneously.

### Claim 15 (depends on 9)

The method of claim 9, wherein the first signal is more sensitive to sounds originating in a first direction than to sounds originating in other directions, and the method further comprises:
applying a third set of filters to combine at least the first set of microphone signals to generate a first anti-noise signal that will cancel sounds at the first earphone when output by the first speaker; and
applying a fourth set of filters to combine at least the second set of microphone signals to generate a second anti-noise signal that will cancel sounds at the second earphone when output by the second speaker.