Claims
- 1. A method of determining whether a plurality of microphones have sufficiently matched frequency response characteristics to be used in a multi-order directional microphone array, the method including:
determining the Δp of each of the microphones; determining the resonant frequency of each of the microphones; and determining whether the differences between the Δp's of each of the microphones and the resonant frequencies of each of the microphones falls within an acceptable tolerance.
- 2. For a microphone array having at least three microphones, wherein one of the microphones is disposed between the other of the microphones, a method of determining the arrangement of the microphones in the array, the method including:
measuring the response of each of the microphones at a frequency above the resonant frequency of each of the microphones; and selecting the microphone having the middle response as the microphone in the array between the other two of the microphones.
- 3. A directional microphone system comprising:
first, second and third omni-directional microphones, each of the microphones for converting an audible signal to a corresponding electrical signal; means for converting the corresponding electrical signal of each of the microphones into a single, multi-order directional signal; means for converting the corresponding electrical signal of two of the microphones into a single, first-order directional signal; and means for summing the multi-order directional signal and the first order directional signal.
- 4. The system of claim 3 consisting of three microphones.
- 5. The system of claim 3 including means for adjusting the relative gain of the first, second and third microphones.
- 6. The system of claim 5 wherein the magnitude adjusting means adjusts the relative gain of the first, second and third microphones such that their magnitudes are substantially equal.
- 7. The system of claim 3 including a high pass filter for filtering the multi-order directional signal.
- 8. The system of claim 3 including a low pass filter for filtering the first-order directional signal.
- 9. The system of claim 3 including:
a high pass filter for filtering the multi-order directional signal; and a low pass filter for filtering the first-order directional signal.
- 10. The system of claim 3 wherein the first-order directional signal forms a hyper-cardioid pattern.
- 11. The system of claim 3 wherein the first-order directional signal forms a cardioid pattern.
- 12. The system of claim 3, wherein:
each of the first, second and third microphones have a Δp and a resonant frequency; and the differences between the Δp's of each of the microphones and the resonant frequencies of each of the microphones fall within an acceptable tolerance.
- 13. The system of claim 3 wherein:
each of the microphones has a resonant frequency and a response magnitude at a common frequency above each of the resonant frequencies; the microphones are disposed in an array; and one of the microphones is disposed between the other two of the microphones in the array, the middle microphone having a response magnitude at the common frequency between the response magnitude of the other two microphones.
- 14. A directional microphone system comprising:
first, second and third omni-directional microphones, each of the microphones for converting an audible signal to a corresponding electrical signal; means for adjusting the relative gain of the first, second and third microphones such that the magnitudes are substantially equal; means for converting the corresponding electrical signal of each of the microphones into a single multi-order directional signal; means for converting the corresponding electrical signal of two of the microphones into a single, first-order directional signal; a high pass filter for filtering the multi-order directional signal; a low pass filter for filtering the first-order directional signal; and means for summing the filtered multi-order directional signal and the filtered first order directional signal.
- 15. The system of claim 14, wherein:
each of the first, second and third microphones have Δp and a resonant frequency; and the differences between the Δp's of each of the microphones and the resonant frequencies of each of the microphones falls within an acceptable tolerance.
- 16. The system of claim 14 wherein:
each of the microphones has a resonant frequency and a response magnitude at a common frequency above each of the resonant frequencies; the microphones are disposed in an array; and one of the microphones is disposed between the other two of the microphones in the array, the middle microphone having a response magnitude at the common frequency between the response magnitude of the other two microphones.
- 17. A directional microphone system comprising:
means for creating a single multi-order directional signal; means for creating a single, first-order directional signal; and means for summing the multi-order directional signal and the first order directional signal.
- 18. The system of claim 17 consisting of three omni-directional microphones.
- 19. The system of claim 18 including means for adjusting the relative gain of the first, second and third microphones.
- 20. The system of claim 19 wherein the magnitude adjusting means adjusts the relative gain of the first, second and third microphones such that their magnitudes are substantially equal.
- 21. The system of claim 17 including a high pass filter for filtering the multi-order directional signal.
- 22. The system of claim 17 including a low pass filter for filtering the first-order directional signal.
- 23. The system of claim 17 including:
a high pass filter for filtering the multi-order directional signal; and a low pass filter for filtering the first-order directional signal.
- 24. A method of determining whether a plurality of microphones have sufficiently matched frequency response characteristics to be used in a multi-order directional microphone array, the method including:
determining the Δp of each of the microphones; determining the resonant frequency of each of the microphones; and determining whether the differences between the Δp's of each of the microphones and the resonant frequencies of each of the microphones falls within an acceptable tolerance.
- 25. For a microphone array having at least three microphones, wherein one of the microphones is disposed between the other of the microphones, a method of determining the arrangement of the microphones in the array, the method including:
measuring the response of each of the microphones at a frequency above the resonant frequency of each of the microphones; and selecting the microphone having the middle response as the microphone in the array between the other two of the microphones.
- 26. A directional microphone system comprising:
means for providing a first order signal representing a first order pattern; means for low pass filtering the first order signal; means for providing a second order signal representing a second order pattern; means for high pass filtering the second order signal; and means for summing the low pass filtered first order signal and the high pass filtered second order signal.
- 27. A method of providing a directional microphone signal comprising:
providing a first order signal representing a first order pattern; low pass filtering the first order signal; providing a second order signal representing a second order pattern; high pass filtering the second order signal; and summing the low pass filtered first order signal and the high pass filtered second order signal.
- 28. A directional microphone system comprising:
means for providing a first order signal representing a first order pattern; means for low pass filtering the first order signal; means for providing a multi-order signal representing a multi- order pattern; means for high pass filtering the multi-order signal; and means for summing the low pass filtered first order signal and the high pass filtered multi-order signal.
- 29. A method of providing a directional microphone signal comprising:
providing a first order signal representing a first order pattern; low pass filtering the first order signal; providing a multi-order signal representing a multi-order pattern; high pass filtering the multi-order signal; and summing the low pass filtered first order signal and the high pass filtered multi-order signal.
- 30. A method of determining whether a plurality of microphones have sufficiently matched frequency response characteristics to be used in a multi-order directional microphone array, the method including:
determining the Q of each of the microphones; determining the resonant frequency of each of the microphones; and determining whether the differences between the Q's of each of the microphones and the resonant frequencies of each of the microphones falls within an acceptable tolerance.
- 31. For a microphone array having at least three microphones, wherein one of the microphones is disposed between the other of the microphones, a method of determining the arrangement of the microphones in the array, the method including:
measuring the response of each of the microphones in a frequency band from below the resonant peak to the highest operational frequency of the array; and ordering the microphones in the array such that the magnitude of the directivity error term is minimized.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from, and expressly incorporates by reference, U.S. Provisional Patent Application No. 60/236,768, filed Sep. 29, 2000 and U.S Provisional Patent Application No. 60/322,211, filed Sep. 11, 2001.
Provisional Applications (2)
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Number |
Date |
Country |
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60236768 |
Sep 2000 |
US |
|
60322211 |
Sep 2001 |
US |