US3403223A - Microphone combinations of the kind comprising a plurality of directional sound units - Google Patents

Microphone combinations of the kind comprising a plurality of directional sound units Download PDF

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Publication number
US3403223A
US3403223A US456768A US45676865A US3403223A US 3403223 A US3403223 A US 3403223A US 456768 A US456768 A US 456768A US 45676865 A US45676865 A US 45676865A US 3403223 A US3403223 A US 3403223A
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United States
Prior art keywords
microphone
microphones
frequency
output
sound
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Expired - Lifetime
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US456768A
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English (en)
Inventor
Kleis Derk
Hermanus Iding Wilhelmus
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Koninklijke Philips NV
North American Philips Co Inc
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Philips Gloeilampenfabrieken NV
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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
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
    • 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
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
    • 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
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
    • H04R1/406—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones

Definitions

  • ABSTRACT OF THE DISCLOSURE A microphone system in which the output of two groups of microphones are combined with opposite polarity in a frequency range below a predetermined frequency, and are combined with the same polarity in the frequency range above the predetermined frequency.
  • the invention relates to a microphone combination comprising a plurality of sound units arranged at a small distance from each other each of the sound units being connected through filter elements to a common output and formed by one or more microphones.
  • the microphones of the lastmentioned type may be considered to be a combination of an omnidirectional pressure-gradient microphone and a pressure gradient microphone with an eight-shaped directional characteristic.
  • the directional characteristic thus obtained is, in principle, independent of the frequency as long as the dimensions of the microphone are small with respect to the wavelength.
  • a sound receiver with a given directional characteristic by choosing a sound receiving surface which is larger than the wavelength.
  • Examples thereof are a microphone with a parabolic mirror, a microphone with an acoustic lens, a microphone with a transit time tube and a combination of microphones arranged in line with each other (microphone column) or in one plane, said microphones cooperating in phase.
  • the directional characteristic of these sound receivers depends upon the frequency and becomes sharper with an increasing frequency. The directional effect starts at the frequency, at which the wavelength is of the same order as the dimensions of the receiver, that is to say that such microphones, operating on the interference principle, are not very effective for the low tones as directional microphones, unless the dimensions are very large.
  • the dilference microphone also termed higher-order microphone, exhibits a frequency characteristic curve rising by 6 db/octave up to that frequency at which half the wavelength is equal to the distance between the microphones. With higher frequencies the frequency characteristic has a sequence of peaks and valleys.
  • the invention is characterized in that by means of the filter elements the microphone combination operates on the interference principle above a separation frequency 7'' between high and low tones, whereas below said frequency f it operates on the difference principle.
  • the invention has for its object to combine the advantages of the two principles described above, so that with small dimensions of the microphone combination a very satisfactory directional characteristic of linear course from low to high notes can be obtained both for low frequencies and for high frequencies.
  • a microphone combination according to the invention comprises two sound units M and M M being arranged centrally and M symmetrically around M It is characterized in that below the separation frequency f the output signals of M and M are joined with such amplitudes and opposite polarities so that in the direction of the height of the region of M the sensitivity of the microphone combination is zero, while the output signals of M and M have furthermore joined to them the output signal of M in a given ratio and below the frequency f the output signals of M and M are combined independently of frequency.
  • the microphones of each sound unit are connected with equal polarities.
  • the output signals of the sound units M and M are connected by a filter prior to the said addition, the frequency characteristic of said filter being inversely proportional to the square of the frequency lying between a given low frequency f and the separation frequency f
  • the frequency characteristics of M and M combined in the preferential direction are thus equalised to that of M alone.
  • the direction in which the sensitivity of the microphone combination is zero can be varied.
  • FIGS. l-ll illustrate various arrangements of microphone units which may be used in the system of the invention.
  • FIG. 12 is a circuit diagram showing the interconnection of microphone units to a common output circuit according to the invention.
  • FIGS. 1 and 2 therein is illustrated a microphone arrangement in which cardioid microphones are aligned in side-by-side relationship.
  • Each microphone is indicated by a circle.
  • the plus or minus sign in each circle indicates the polarity of the microphone, i.e., the polarity with which it is connected in a circuit.
  • An arrow pointing away from a circle indicates the direction of maximum sensitivity of the microphone. When a circle is shown without an arrow, it is considered that the direction of maximum sensitivity of the corresponding microphone is normal to the plane of the drawing.
  • FIGS. 1 and 2 thus show two views of a microphone arrangement having three cardioid microphones.
  • FIG. 2 which may be considered to be a top view of the arrangement, the direction of maximum sensitivity of all microphones is the same (i.e., toward the left) and the microphones are aligned in one place.
  • the microphone in the center, with the positive polarity is considered to be one microphone group or unit M and the two outside microphones with negative polarity are considered to be another group or unit M
  • FIGS. 3 and 4 which also illustrate two views of a microphone arrangement
  • the arrangement of FIG. 1 may be modified to include additional microphones, so that the central group M includes two microphones and the outside group M includes four microphones on each side of the M group, for a total of eight microphones.
  • FIGS. 3 and 4 may be modified, as shown in FIGS. 5 and 6 (which also shows two views of a microphone arrangement) so that the microphones are aligned in the side view, but along a curved line as seen from the top view.
  • a single microphone comprising group M may be surrounded by four microphones of the M group.
  • This arrangement may be modified, as shown in FIG. 8, wherein the central group M comprises eight microphones equally spaced about a central microphone, for a total of 9, while the M group comprises three microphones extending radially outwardly from each of the eight equallyspaced microphones of the M group, for a total of 24 microphones.
  • FIGS. 9-11 show several arrangements of microphones for an omnidirectional system.
  • three nondirectional microphones are shown aligned in two directions, with the microphone in the center comprising the M group and the two outside microphones comprising the M group.
  • five directional microphones are provided in a line, with the central microphone comprising the M group and the four outside microphones, having different directions of maximum sensitivity, comprising the M2 group.
  • FIG. 12 therein is illustrated a circuit for combining the output signals of the microphone groups according to the invention.
  • the output signals of the two groups of microphones M and M are combined so that for frequencies below a separation frequency of, for example, 1500 cycles per second, the signals are combined so that the system operates on the difference principle. For frequencies above the separation frequency, the signals are combined so that the system operates on the interference principle.
  • the outputs of the two groups M and M of microphones are amplified in amplifiers 1 and 2 respectively, and applied to opposite ends of a potentiometer 6 by way of resistors 3 and 4 respectively, and the combined signal appearing at the arm of the potentiometer 6 is applied by way of RC filter 6, 7 to an amplifier 8.
  • the output of the amplifier 8 is connected to a RC filter 9, 10.
  • the signal at the arm of the potentiometer 6, and hence at the output of filter 9, 10 is a difference signal from the microphones of the two groups.
  • the signal from amplifier 2 is also applied by way of an adjustable divider consisting of series variable resistor 12 and shunt resistor 13, to an inverting amplifier 14.
  • the output of the low pass filter 23, 24 is applied by way of resistor 25 to the output terminals 30, 31.
  • the output of the inverter 14 is also applied to input of an amplifier 19 by way of an adjustable potentiometer circuit consisting of series adjustable resistor 15 and shunt resistor 16, and the output of amplifier 1 is also applied to the input of amplifier 19 by way of a series resistor 17 and shunt resistor 18.
  • the output of amplifier 19, is applied by way of high pass filter 20, 21 to the output terminals 30, 31.
  • the signal appearing at the output terminals due to this part of the circuit is thus the sum of the outputs of the microphones M and M in afrequency range above the cut-off frequency of high pass filter 20, 21.
  • a microphone combination of the type comprising a plurality of sound units of one or more microphones arranged at a small distance from each other and connected through filter eleemnts to a common output, comprising first means for combining the outputs of first and second of said sound units with opposite polarity, low-pass filter means for applying the output of said first means to said common output, second means for combining the outputs of said first and second sound units with the same polarity, and high-pass filter means for applying the output of said second means to said common output, whereby the microphone combination operates on the interference principle in excess of a separation frequency between high and low notes, whereas below said frequency f it operates on the difference principle.
  • a microphone combination as claimed in claim 1 characterised in that the sound units are arranged side by side in a uniformly curved line or in a plane.
  • a microphone combination as claimed'in claim 1 characterized in that the microphones of each sound unit are connected with the same polarities.
  • a micro hone system comprising a plurality of closely spaced-apart microphones and means for connecting said microphones by way of first and second channels to a common output circuit, said first channel comprising first filter means for passing signals only less than a predetermined frequency and means for combining the outputs of said microphones with opposite polarity to provide a difference signal output, said second channel comprising second filter means for passing signals only above said predetermined frequency, and means for combining the signal outputs of said microphones with the same polarity to provide an interference signal output.
  • a microphone system comprising a plurality of closely spaced-apart microphones arranged to form first and second microphone groups, an output circuit, first channel means for combining the outputs of said first and second groups with opposite polarity and applying the combined signal output thereof to said output circuit, second channel means for combining the outputs of said first and second groups with the same polarity and for applying the combined signal output thereof to said output circuit, said first channel comprising filter means for passing signals only below a predetermined frequency and said second channel comprising means for passing signals only above said predetermined frequency, whereby said microphone system operates on a difference principle below said predetermined frequency and on an interference principle above said predetermined frequency.

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  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • General Health & Medical Sciences (AREA)
  • Circuit For Audible Band Transducer (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
US456768A 1964-05-20 1965-05-18 Microphone combinations of the kind comprising a plurality of directional sound units Expired - Lifetime US3403223A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6405564A NL6405564A (fr) 1964-05-20 1964-05-20

Publications (1)

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US3403223A true US3403223A (en) 1968-09-24

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US456768A Expired - Lifetime US3403223A (en) 1964-05-20 1965-05-18 Microphone combinations of the kind comprising a plurality of directional sound units

Country Status (12)

Country Link
US (1) US3403223A (fr)
AT (1) AT263871B (fr)
BE (1) BE664110A (fr)
CH (1) CH446442A (fr)
DE (1) DE1274192B (fr)
DK (1) DK118567B (fr)
ES (1) ES313062A1 (fr)
FR (1) FR1444200A (fr)
GB (1) GB1102186A (fr)
NL (1) NL6405564A (fr)
NO (1) NO117082B (fr)
SE (1) SE313599B (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2936082A1 (de) * 1978-09-12 1980-03-20 Polaroid Corp Richtempfangssystem mit vorbestimmtem richtungsansprechen
FR2455415A1 (fr) * 1979-04-26 1980-11-21 Victor Company Of Japan Dispositif microphonique a directivite variable
US4399327A (en) * 1980-01-25 1983-08-16 Victor Company Of Japan, Limited Variable directional microphone system
US4742548A (en) * 1984-12-20 1988-05-03 American Telephone And Telegraph Company Unidirectional second order gradient microphone
US11153472B2 (en) 2005-10-17 2021-10-19 Cutting Edge Vision, LLC Automatic upload of pictures from a camera

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4354059A (en) * 1979-09-11 1982-10-12 Victor Company Of Japan, Ltd. Variable-directivity microphone device
US4521908A (en) * 1982-09-01 1985-06-04 Victor Company Of Japan, Limited Phased-array sound pickup apparatus having no unwanted response pattern
US4696043A (en) * 1984-08-24 1987-09-22 Victor Company Of Japan, Ltd. Microphone apparatus having a variable directivity pattern
US5193117A (en) * 1989-11-27 1993-03-09 Matsushita Electric Industrial Co., Ltd. Microphone apparatus
US5715319A (en) * 1996-05-30 1998-02-03 Picturetel Corporation Method and apparatus for steerable and endfire superdirective microphone arrays with reduced analog-to-digital converter and computational requirements
WO1998046043A2 (fr) * 1997-04-10 1998-10-15 Interkom Electronic Kock & Mreches Gmbh Dispositif capteur acoustique, notamment pour un appareil d'amplification vocale
CN110049405B (zh) * 2018-01-15 2022-02-18 厦门雅迅网络股份有限公司 一种兼容式车载麦克风电路

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2301744A (en) * 1941-05-31 1942-11-10 Rca Corp Electroacoustical signal translating apparatus
US2305599A (en) * 1941-04-08 1942-12-22 S N Shure Conversion of wave motion into electrical energy
US3204031A (en) * 1961-08-29 1965-08-31 Akg Akustische Kino Geraete Moving-coil microphone arrangement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2810786A (en) * 1950-06-12 1957-10-22 Siemens Ag Directional microphone system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2305599A (en) * 1941-04-08 1942-12-22 S N Shure Conversion of wave motion into electrical energy
US2301744A (en) * 1941-05-31 1942-11-10 Rca Corp Electroacoustical signal translating apparatus
US3204031A (en) * 1961-08-29 1965-08-31 Akg Akustische Kino Geraete Moving-coil microphone arrangement

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2936082A1 (de) * 1978-09-12 1980-03-20 Polaroid Corp Richtempfangssystem mit vorbestimmtem richtungsansprechen
FR2436416A1 (fr) * 1978-09-12 1980-04-11 Polaroid Corp Systeme de reception possedant une reponse directionnelle preselectionnee
US4334740A (en) * 1978-09-12 1982-06-15 Polaroid Corporation Receiving system having pre-selected directional response
FR2455415A1 (fr) * 1979-04-26 1980-11-21 Victor Company Of Japan Dispositif microphonique a directivite variable
US4308425A (en) * 1979-04-26 1981-12-29 Victor Company Of Japan, Ltd. Variable-directivity microphone device
US4399327A (en) * 1980-01-25 1983-08-16 Victor Company Of Japan, Limited Variable directional microphone system
US4742548A (en) * 1984-12-20 1988-05-03 American Telephone And Telegraph Company Unidirectional second order gradient microphone
US11153472B2 (en) 2005-10-17 2021-10-19 Cutting Edge Vision, LLC Automatic upload of pictures from a camera
US11818458B2 (en) 2005-10-17 2023-11-14 Cutting Edge Vision, LLC Camera touchpad

Also Published As

Publication number Publication date
GB1102186A (en) 1968-02-07
DK118567B (da) 1970-09-07
CH446442A (de) 1967-11-15
FR1444200A (fr) 1966-07-01
NO117082B (fr) 1969-06-30
AT263871B (de) 1968-08-12
BE664110A (fr) 1965-11-18
DE1274192B (de) 1968-08-01
SE313599B (fr) 1969-08-18
ES313062A1 (es) 1965-10-01
NL6405564A (fr) 1965-11-22

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