Speakerphone and/or microphone arrays and methods and systems of the using the same

• US 9,113,264 B2
• Filed: 11/12/2010
• Issued: 08/18/2015
• Est. Priority Date: 11/12/2009
• Status: Expired due to Fees

• Current Assignee: Frater, Robert H.
• Original Assignee: Frater, Robert H.
• Inventors: Frater, Robert H.
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): HAMID, AMMAR T
• Application Number:
  US12/926,376
• Publication Number:
  US 20110194719A1
• Time in Patent Office: 1,740 Days
• Field of Search: 381/94.1, 381/94.3, 381/66, 381/56, 381/332, 381/92, 381/122, 379/388.01, 379/420.03, 379/420
• US Class Current: 1/1
• CPC Class Codes: G10L 2021/02082 the noise being echo, reverberation of the speech
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: 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
• CPC Class Codes: H04R 1/406 microphones
• CPC Class Codes: H04R 2201/401 2D or 3D arrays of transducers
• CPC Class Codes: H04R 2201/403 Linear arrays of transducers
• CPC Class Codes: H04R 2227/001 Adaptation of signal processing in PA systems in dependence of presence of noise
• CPC Class Codes: H04R 2227/007 Electronic adaptation of audio signals to reverberation of the listening space for PA
• CPC Class Codes: H04R 2410/01 Noise reduction using microphones having different directional characteristics
• CPC Class Codes: H04R 2430/25 Array processing for suppression of unwanted side-lobes in directivity characteristics, e.g. a blocking matrix
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

The present disclosure is directed to devices, methods and systems for microphone arrays wherein enhancing performance of directional microphone arrays is provided. Enhanced performance of speaker phones is also provided. In certain embodiments, the housing of the device is configured to support the at least three microphones and the loudspeaker in a substantially first orientation; and the at least three microphones and the loudspeaker are arranged in a spatial relationship such that appropriate phase and delay characteristics achieve a substantial null response in the at least three microphones and in the loudspeaker in a substantial vertical direction away from the substantially first orientation over a desired audible range of frequencies and the device is able to provide a response to sounds over a range of first oriented elevations.

Claims

1. A device, comprising:

at least three microphone elements;

at least one loudspeaker;

at least one housing, wherein the at least one housing is configured to support the at least three microphone elements in a first orientation and the at least one loudspeaker in a second orientation; and

the at least three microphones are substantially equispaced in a horizontal plane around a circle with a predetermined diameter approximately equal to one-half of the wavelength of a predetermined highest frequency of operation of the device and arranged with appropriate phase and delay characteristics such that when the signals from the array of microphones are appropriately phased, weighted and summed, the resultant signal in a three-dimensional space is substantially zero in the vertical direction and substantially additive in the horizontal plane to achieve a substantial null response in positions having a substantially equal sound path from the at least three microphone elements over a desired audible range of frequencies; and

the device is able to provide a response to sounds over a range of second oriented elevations away from the first orientation containing the at least three microphone elements; and

the uncompensated response of the device falls off at a multiple of 6 dB per octave from high to low frequencies.

2. A device as in claim 1, wherein the at least three microphone elements are substantially equispaced in a circular arrangement with relative phases 0°

, 360°

/n, 2×

360°

/n up to (n−

1)×

360°

/n over the desired frequency range and the at least one loudspeaker is placed substantially below the at least three microphone elements in a position having substantially equal sound paths to each of the at least three microphone elements.

3. A device as in claim 2, wherein the at least three microphone elements are substantially equispaced in a circular arrangement in a substantially horizontal planar configuration.

4. A device as in claim 3, wherein a Hilbert network is used to provide the relative phasing for the microphone elements over the desired bandwidth.

5. A device as in claim 4, wherein there are four microphone elements.

6. A device as in claim 1 where the at least one loudspeaker is arranged such that the loudspeaker is disposed in a zone of insensitivity of the at least three microphone elements and radiates sound away from the at least three microphone elements and towards a surface upon or against which the housing is abutted, such as a desktop or a vertical wall surface and the at least one loudspeaker has a sound radiation axis that is disposed generally perpendicularly to the abutting surface.

7. A device as in claim 1, wherein the at least three microphone elements are arranged to achieve at least one axis of sensitivity defining a zone of microphone sensitivity, and at least one axis of insensitivity defining a zone of insensitivity of the at least three microphone elements over the 300 Hz to 3.3 KHz frequency range.

8. A device as in claim 1, wherein the at least three microphone elements are arranged to achieve at least one axis of sensitivity defining a zone of microphone sensitivity, and at least one axis of insensitivity defining a zone of insensitivity of the at least three microphone elements over the 300 Hz to 3.3 KHz frequency range;

and wherein the at least one loudspeaker is arranged relative to the at least three microphone elements so that the audio from the at least one loudspeaker is also substantially cancelled by the at least three microphone elements in the at least one axis of insensitivity defining a zone of insensitivity of the at least one loudspeaker over the 300 Hz to 3.3 KHz frequency range.

16. The device of claim 4 wherein the response of the at least three microphone elements is substantially null in the vertical direction thereby reducing the effect of reflections from a ceiling and reducing echo sounds received by the device.

9. A device, comprising:

at least six microphone elements; and

at least one housing, wherein the at least one housing is configured to support the at least six microphone elements in a first orientation; and

the at least six microphones are substantially equispaced in a horizontal plane around a circle with a predetermined diameter approximately equal to one wavelength of a predetermined highest frequency of operation of the device and arranged with appropriate phase and delay characteristics such that when the signals from the at least six microphones are appropriately phased, weighted and summed, the resultant signal in a three-dimensional space is substantially zero in the vertical direction and substantially additive in the horizontal plane direction to achieve a substantial null response in positions having a substantially equal sound path from the at least six microphone elements over a desired audible range of frequencies; and

the device is able to provide a response to sounds over a range of second oriented elevations away from the first orientation containing the at least six microphone elements; and

the uncompensated response of the device falls off at a multiple of 6 dB per octave from high to low frequencies.

10. A device as in claim 9, wherein the at least six microphone elements are substantially equispaced in a circular arrangement with relative phases 0°

, 720°

/n, 2×

720°

/n up to (n−

1)×

720°

/n over the operating frequency range.

12. A device as in claim 9 where the device is incorporated in a speakerphone.

13. A device combining two devices identical to the device of claim 9, a first device of the two devices operating over part of the desired audible range of frequencies, and a second device of the two devices operating over the rest of the desired audible range of frequencies.

11. A device comprising:

at least three microphone elements;

at least one housing, wherein the at least one housing is configured to support the at least three microphone elements in a first orientation, and the at least three microphone elements are substantially equispaced in a first circular arrangement and the first circular arrangement has a first diameter and each microphone element has a relative phase 0°

; and

a second at least three microphone elements which are substantially equispaced in a second circular arrangement with a second diameter and each microphone element has a relative phase 180°

;

wherein the first diameter is greater than the second diameter

wherein the at least three microphones and the second at least three microphones are configured such that when the signals from the at least three microphones and the second at least three microphones are appropriately phased, weighted and summed, the resultant signal in a three-dimensional space is substantially zero in the vertical direction and substantially additive in the horizontal plane to achieve a substantial null response in positions having a substantially equal sound path from the at least three microphones and the second at least three microphones.

20. A device as in claim 11, wherein the at least three microphone elements in the first circular arrangement are in a substantially horizontal planar configuration.

21. A device as in claim 11, wherein the second at least three microphone elements in the second circular arrangement are in a substantially horizontal planar configuration.

22. A device as in claim 11, wherein the at least three microphone elements in the first circular arrangement are in a substantially horizontal planar configuration, and the second at least three microphone elements are in a substantially horizontal planar configuration.

14. A device, comprising:

at least three microphone elements;

at least one loudspeaker; and

at least one housing, wherein the at least one housing is configured to support the at least three microphone elements in a first orientation and the at least one loudspeaker in a second orientation;

wherein the at least three microphones are of substantially equal gain and substantially equal phase arranged on a substantially horizontal plane in a circle of diameter 2d, where d is approximately equal to half of the wavelength at a predetermined highest frequency of operation of the device; and

wherein at least one further microphone element is positioned at the centre of the circle with gain of approximately n times that of the n microphone elements and a phase shift of 180 degrees relative to the n microphone elements such that when the signals from the at least three microphones and the at least one further microphone are appropriately phased, weighted and summed, the resultant signal in a three-dimensional space is substantially zero in the vertical direction and substantially additive in the horizontal plane to achieve a substantial null response in positions having a substantially equal sound path from the at least three microphones and the at least one further microphone.

15. The device of claim 14 wherein the uncompensated response of the device falls off at a multiple of 6 dB per octave from high to low frequencies.

17. The device of claim 14 wherein the device comprises n microphone elements and a set of n/2 microphone elements are configured in a plane and with substantially the same sensitivity and having their signals added to create a resultant signal, and the resultant signal being subtracted from a combined signal from another set of n/2 microphone elements in the same plane.

18. The device of claim 14 wherein the device comprises n microphone elements of substantially equal gain and substantially equal phase arranged on a substantially horizontal plane in a circle of diameter 2d, where d is approximately equal to half of the wavelength at a predetermined highest frequency of operation of the device;

and wherein at least one further microphone element is positioned at the centre of the circle with gain of approximately n times that of the n microphone elements and a phase shift of 180 degrees relative to the n microphone elements.

19. The device of claim 18 wherein the at least one further microphone element comprises n microphone elements positioned in a circle substantially smaller than the circle of diameter 2d to achieve an improved signal-to-noise ratio relative to the at least one further microphone element with n times gain.