US3146308A - Capacitor microphones - Google Patents

Capacitor microphones Download PDF

Info

Publication number
US3146308A
US3146308A US61185A US6118560A US3146308A US 3146308 A US3146308 A US 3146308A US 61185 A US61185 A US 61185A US 6118560 A US6118560 A US 6118560A US 3146308 A US3146308 A US 3146308A
Authority
US
United States
Prior art keywords
microphones
membranes
microphone
pair
electrode plates
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US61185A
Other languages
English (en)
Inventor
Gorike Rudolf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3146308A publication Critical patent/US3146308A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; 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

Definitions

  • the last-mentioned type of microphones also known as gradient microphones, can be used in order to obtain higher-order directional characteristic curves, with a sharper response than those of a lower order.
  • the subject matter of the invention is a capacitor microphone and its application as a gradient microphone of second order whose directional characteristic corresponds to the pressure gradient between two points of the sound field. It is a capacitor microphone with a figureeight-shaped directional characteristic, with two diaphragms lying in parallel planes and made of electrically conductive material or of an insulator with a conductive layer on one side, connected in bucking relationship and placed at a small distance from electrodes with a multiplicity of apertures, respective air chambers being situated each behind one of the electrodes and being interconnected by one or more channels; characterized according to the invention in that the apertures of the electrodes are so numerous and the channel or channels are so dimensioned as to length and cross-section that within the transmission range the mass control of the diaphragms predominates. Thus a frequency response which increases with decreasing frequency occurs in the plane sound field.
  • the frequency response of the microphone according to this invention is not linear (when measured in the plane sound field) but decreases with increasing frequency.
  • FIG. 1 schematically shows an embodiment in section.
  • Two diaphragms 1, 2 made of electrically conductive material, or of an insulator with a conductive layer on one side, are placed at a small distance of the electrodes 3, 4.
  • the electrodes contain numerous apertures in order to provide a sufficiently small frictional resistance.
  • Behind the electrodes 3, 4 are situated the air chambers 5, 6 which are interconnected by a channel 7, situated for instance in a solid body 8.
  • a capacitor microphone of such design has, on account of its predominant mass control in the plane sound field when both diaphragms connected to an electrical source and are in bucking relationship a figure-eight-shaped directional characteristic and a frequency response which increases with decreasing frequency.
  • the amplitude increases linearly with an increase in the distance up to the value
  • the phase of the output voltage of a microphone is shifted by means of a phase-shifting member 11, as illustrated in FIG. 5, so as to obtain for each frequency the transit-time difference for a
  • the same directional characteristic is also realized by placing between the microphones 9 and 10 a third microphone 12 whose diaphraagms are, however, predominantly frictionally damped and also connected in bucking relationship. This arrangement is illustrated in FIG. 7.
  • FIG. 10 A further example for the application of the microphone according to the invention is illustrated in FIG. 10.
  • Two microphones 19, 20, predominantly mass controlled and with a figure-eight-shaped directional characteristic, and one microphone 21, frictionally damped and also provided with a figure-eight-shaped directional characteristic, are used in the lower frequency range up to Further there are present two microphones 22, 23 with a kidney-shaped directional characteristic arranged in bucking electrical relationship. These microphones have each two diaphragms as is known per se, yet only one of these is electrically active at any given time. These microphones operate with regard to their directional characteristic according to the analytical function
  • the microphones 19, 20, 21, 22, 23 are all centered on a common axis.
  • the systems shown in FIGS. 3, 5, 7, 8 and 9 consist all of condenser microphones having a figure-eight-shaped directional characteristic.
  • Microphones of this general class are known in the art as pressure-gradient condenser microphones.
  • the previously known pressuregradient condenser microphones are mainly frictionally damped.
  • Such frictionally damped pressure-gradient condenser microphones are disclosed in, for example, U.S. Patent No. 2,179,361 and are used as microphones 12, 12a, 18 and 21 in the systems shown in FIGS. 7, 8, 9 and 10, where they are labeled with the symbol for a resistor, which is the electrical equivalent of acoustical frictional resistance.
  • a directional microphone for transmitting a predetermined range of audible sound frequencies, comprising a pair of parallel vibratory membranes, a pair of electrode plates each closely spaced from a respective one of said membranes and positioned between them, each of said membranes being provided with at least one conductive surface forming a condenser with the adjacent electrode plate, a support carrying said membranes and said electrode plates and defining two air chambers, each of which adjoins one of said electrode plates on the side opposite the adjacent membrane, said support being provided with at least one channel and said electrode plates being each provided with a multiplicity of perforations for the passage of air between said membranes, the spacing of said perforations being so small that the frictional resistance exerted on the air between each membrane and the electrode plate associated therewith is negligible, the cross-sectional area and length of said channel being selected so that the natural frequency of said membranes as modified by the mass of air in said channel lies near the lower end of said predetermined range of frequencies, means including said condensers for converting the vibrations of said membranes
  • a directional microphone for transmitting a pretermined range of audible sound frequencies comprising an annular housing, a pair of vibratory membranes spanning opposite sides of said housing, a pair of electrode plates in said housing respectively positioned adjacent said membranes, each of said membranes being provided with at least one conductive surface forming a condenser with the adjacent electrode plate and a central disk in said housing dividing the interior thereof into two air chambers adjoining said electrodes, said disk being provided with at least one channel and said electrode plates being each provided with a multiplicity of perforations for the passage of air between said membranes, the spacing of said perforations being so small that the frictional resistance exerted on the air between each membrane and the electrode plate associated therewith is negligible, the crosssectional area and length of said channel being selected so that the natural frequency of said membranes as modified by the mass of air in said channel lies near the lower end of said predetermined range of frequencies.

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
US61185A 1959-10-09 1960-10-07 Capacitor microphones Expired - Lifetime US3146308A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT732959A AT211394B (de) 1959-10-09 1959-10-09 Kondensatormikrophon

Publications (1)

Publication Number Publication Date
US3146308A true US3146308A (en) 1964-08-25

Family

ID=3594916

Family Applications (1)

Application Number Title Priority Date Filing Date
US61185A Expired - Lifetime US3146308A (en) 1959-10-09 1960-10-07 Capacitor microphones

Country Status (3)

Country Link
US (1) US3146308A (de)
AT (1) AT211394B (de)
GB (1) GB921818A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4307825A1 (de) * 1993-03-12 1994-09-15 Sennheiser Electronic Wandler für Kondensatormikrofone mit variabler Richtcharakteristik
US20100135514A1 (en) * 2008-11-24 2010-06-03 Sennheiser Electronic Gmbh & Co. Kg Microphone
US20100303274A1 (en) * 2009-05-18 2010-12-02 William Ryan Microphone Having Reduced Vibration Sensitivity
US20160100246A1 (en) * 2014-10-07 2016-04-07 Kabushiki Kaisha Audio-Technica Unidirectional condenser microphone unit

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005043664B4 (de) * 2005-09-14 2011-06-22 Sennheiser electronic GmbH & Co. KG, 30900 Kondensatormikrofon

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT93214B (de) * 1921-04-11 1923-06-25 Joseph Massolle Kapazitives Telephon.
US1753137A (en) * 1926-08-12 1930-04-01 Seibt Georg Electrostatic loud-speaker
US2293258A (en) * 1939-11-24 1942-08-18 Bell Telephone Labor Inc Acoustic device
US2301744A (en) * 1941-05-31 1942-11-10 Rca Corp Electroacoustical signal translating apparatus
DE856615C (de) * 1948-10-02 1952-11-24 Julius Dipl-Ing Lorenz System zur Umwandlung von Schwingungen
US2678967A (en) * 1949-02-22 1954-05-18 Nordwestdeutscher Rundfunk Capacity microphone with variable directional characteristic
DE960904C (de) * 1949-11-06 1957-05-02 Siemens Ag Einrichtung fuer Schallempfaenger mit zwei durch ein Mikrofon gebildeten Druckkammern und daran angeschlossenen Rohren
FR1182557A (fr) * 1956-09-10 1959-06-26 H J Leak & Company Ltd Haut-parleur électrostatique
AT209396B (de) * 1959-03-04 1960-06-10 Akg Akustische Kino Geraete Kondensatormikrophon

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT93214B (de) * 1921-04-11 1923-06-25 Joseph Massolle Kapazitives Telephon.
US1753137A (en) * 1926-08-12 1930-04-01 Seibt Georg Electrostatic loud-speaker
US2293258A (en) * 1939-11-24 1942-08-18 Bell Telephone Labor Inc Acoustic device
US2301744A (en) * 1941-05-31 1942-11-10 Rca Corp Electroacoustical signal translating apparatus
DE856615C (de) * 1948-10-02 1952-11-24 Julius Dipl-Ing Lorenz System zur Umwandlung von Schwingungen
US2678967A (en) * 1949-02-22 1954-05-18 Nordwestdeutscher Rundfunk Capacity microphone with variable directional characteristic
DE960904C (de) * 1949-11-06 1957-05-02 Siemens Ag Einrichtung fuer Schallempfaenger mit zwei durch ein Mikrofon gebildeten Druckkammern und daran angeschlossenen Rohren
FR1182557A (fr) * 1956-09-10 1959-06-26 H J Leak & Company Ltd Haut-parleur électrostatique
AT209396B (de) * 1959-03-04 1960-06-10 Akg Akustische Kino Geraete Kondensatormikrophon

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4307825A1 (de) * 1993-03-12 1994-09-15 Sennheiser Electronic Wandler für Kondensatormikrofone mit variabler Richtcharakteristik
US20100135514A1 (en) * 2008-11-24 2010-06-03 Sennheiser Electronic Gmbh & Co. Kg Microphone
US8213661B2 (en) 2008-11-24 2012-07-03 Sennheiser Electronic Gmbh & Co. Kg Microphone
US20100303274A1 (en) * 2009-05-18 2010-12-02 William Ryan Microphone Having Reduced Vibration Sensitivity
US20120039499A1 (en) * 2009-05-18 2012-02-16 William Ryan Microphone Having Reduced Vibration Sensitivity
US20160100246A1 (en) * 2014-10-07 2016-04-07 Kabushiki Kaisha Audio-Technica Unidirectional condenser microphone unit
US9462372B2 (en) * 2014-10-07 2016-10-04 Kabushiki Kaisha Audio-Technica Unidirectional condenser microphone unit

Also Published As

Publication number Publication date
AT211394B (de) 1960-10-10
GB921818A (en) 1963-03-27

Similar Documents

Publication Publication Date Title
US3118022A (en) Electroacoustic transducer
CN204425650U (zh) 压电陶瓷双频耳机结构
US4456796A (en) Unidirectional electret microphone
US3439128A (en) Miniature ceramic microphone
US3715500A (en) Unidirectional microphones
US3548116A (en) Acoustic transducer including piezoelectric wafer solely supported by a diaphragm
US3007012A (en) Directional electrostatic microphone
US3573400A (en) Directional microphone
GB1487847A (en) Microphone units
US7577269B2 (en) Acoustic transducer
CN109923875A (zh) 平面磁体扬声器
US3778561A (en) Electret microphone
US2387845A (en) Electroacoustic transducer
US3663768A (en) Electret transducer
US3403223A (en) Microphone combinations of the kind comprising a plurality of directional sound units
US3859477A (en) Electrostatic transducer
US3146308A (en) Capacitor microphones
JPH07143595A (ja) 可変指向性コンデンサマイクロホン
US3588381A (en) Transducer having spaced apart oppositely flexing piezoelectric members
US3497731A (en) Bender type transducers
US3562429A (en) Sound transmitter with feedback and polarization circuitry
US2699473A (en) Pressure gradient responsive microphone
US2553539A (en) Directional microphone with a compliant link interconnected between the two diaphragms
EP2911413B1 (de) Lautsprecher mit piezoelektrischen Elementen
CN218473391U (zh) 一种带新型音头极板的电容音头