EP0413086B1 - Elektroakustischer Wandler - Google Patents

Elektroakustischer Wandler Download PDF

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Publication number
EP0413086B1
EP0413086B1 EP90107295A EP90107295A EP0413086B1 EP 0413086 B1 EP0413086 B1 EP 0413086B1 EP 90107295 A EP90107295 A EP 90107295A EP 90107295 A EP90107295 A EP 90107295A EP 0413086 B1 EP0413086 B1 EP 0413086B1
Authority
EP
European Patent Office
Prior art keywords
plate
microphone
boundary area
membrane
sound
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
EP90107295A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0413086A1 (de
Inventor
Bernard Dipl.-Ing. Müller
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.)
Georg Neumann GmbH
Original Assignee
Georg Neumann GmbH
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 Georg Neumann GmbH filed Critical Georg Neumann GmbH
Publication of EP0413086A1 publication Critical patent/EP0413086A1/de
Application granted granted Critical
Publication of EP0413086B1 publication Critical patent/EP0413086B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
    • H04R1/342—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means for microphones
    • 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
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/222—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  for microphones

Definitions

  • the invention relates to an interface microphone according to the preamble of claim 1.
  • Such an interface microphone is known from DE-A-3 334 945.
  • the reverberant plates used in known interface microphones are either circular, square or rectangular.
  • the transducer element is usually attached centrally.
  • the edge of the panel usually has a phase of approximately 45 °, while in the case of thin panels, the edge is usually only broken.
  • the plate is irregularly rounded or flattened towards the edge.
  • the transducer element is attached outside the center of the plate at a peripheral point. It has been shown that the frequency responses of the interface microphones with circular, square or rectangular plates have strong peaks and dips in the case of vertical sound.
  • these microphones show strong irregularities in the polar diagram in the front half space, so that the result is strong and direction-dependent discoloration of the sound.
  • These inadequacies can be explained by the fact that, in the case of an interface microphone, the wave front just incident produces a secondary sound field. This secondary sound field is created by sound diffraction at the edge of the plate. A so-called “creeping wave” arises, which spreads from the edge of the plate over its surface. The phase position of the creeping wave in relation to the incident wave depends on the phase jump at the plate edge. This phase jump is different depending on the nature of the edges and the impedance of the surfaces of the microphone body and the interface.
  • the creeping wave thus generates a more or less complicated interference pattern.
  • the superposition of the incident wave with the creeping wave at the installation location of the transducer is decisive. Negative effects on the frequency response and the directional characteristic can only be avoided if creeping waves are either completely avoided or if they have an overall frequency-independent phase position and a frequency-independent level at the installation location of the converter.
  • the creeping wave can only be avoided if the mounting plate were infinitely thin or infinitely extended.
  • a thickness of 1 to 2 mm which would be sufficient in practice to avoid creeping waves, is technically not feasible, since no electrostatic converter is available for installation in such a thin mounting plate.
  • the object of the invention is to achieve a frequency-independent, hemispherical directional characteristic with a high sound fidelity in the case of an interface microphone of the type mentioned at the outset, even with vertical sound incidence.
  • the interface microphone according to the invention is optimized with regard to the geometric shape of its mounting plate and the mounting position of its electroacoustic transducer in the mounting plate so that creeping waves have an overall frequency-independent phase position and a frequency-independent level at the mounting location of the transducer. For every angle of incidence, it is thus ensured that the superposition of the incident wave with the secondary sound field at the transducer location, which is caused by diffraction at the microphone plate there is no linear influence on the frequency response.
  • the path lengths from each edge point of the plate to the membrane center are evenly distributed in a length range, the upper limit of which is determined by the sound wavelength of the upper limit frequency of the electroacoustic transducer, and the lower limit of which is determined by half the sound wavelength of the crossover frequency, at which A sound pressure build-up begins to form in front of the microphone area.
  • the plate is designed as an oblique-angled triangle.
  • the embodiment of an interface microphone according to the invention shown in plan view in FIG. 1 and in section in FIG. 2 has a triangular carrier plate P with the side edges or triangular legs a, b and c.
  • the capsule of a transducer W is recessed so that the diaphragm M of the transducer W is flush with the surface of the plate P facing the incident sound.
  • the exact location of the transducer W is in the example shown on the line of gravity s1 between its base point F and the center of gravity S.
  • the transducer W is connected through the plate with a microphone cable K, which installs at the base of the line of gravity s2 or the shortest leg b is and ends at its other end in a cable connector St.
  • the section according to FIG. 2 shows the flush installation of the membrane M and the mounting of the transducer W in a recess in the mounting plate P.
  • An electrostatic, pressure-calibrated transducer can preferably be provided as the transducer W, i.e. a transducer that delivers a constant voltage in the listening area at constant sound pressure.
  • the frequency response of the interface microphone according to FIGS. 1 and 2 were measured at different sound incidence angles of 0 °, 30 °, 60 ° and 90 °, based on the plane of the mounting plate P.
  • the results are in the figures 3a to 3d shown using the solid curve # 1.
  • the corresponding frequency responses of known interface microphones with a rectangular carrier plate (dashed curve # 2) and a circular carrier plate (curve # 3) are shown in FIGS. 3a to 3d drawn.
  • the flat frequency response achieved with the boundary microphone according to the invention at all sound incidence angles ideally means a frequency-independent, hemispherical directional characteristic. Direct sound and diffuse sound do not result in different sound colorations, as occurs, for example, with a microphone in the free sound field due to the diffraction and shadowing effects on the microphone body.
  • the surface-flush installation of the transducer in the plate avoids sound colorations, such as occur with conventional microphones due to delayed reflections at the space boundary surfaces and the associated comb filter effects.

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)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
  • Measuring Fluid Pressure (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
EP90107295A 1989-08-16 1990-04-18 Elektroakustischer Wandler Expired - Lifetime EP0413086B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3926884 1989-08-16
DE3926884A DE3926884A1 (de) 1989-08-16 1989-08-16 Elektroakustischer wandler

Publications (2)

Publication Number Publication Date
EP0413086A1 EP0413086A1 (de) 1991-02-20
EP0413086B1 true EP0413086B1 (de) 1994-06-01

Family

ID=6387125

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90107295A Expired - Lifetime EP0413086B1 (de) 1989-08-16 1990-04-18 Elektroakustischer Wandler

Country Status (5)

Country Link
US (1) US5168525A (enrdf_load_stackoverflow)
EP (1) EP0413086B1 (enrdf_load_stackoverflow)
JP (1) JPH0388599A (enrdf_load_stackoverflow)
AT (1) ATE106650T1 (enrdf_load_stackoverflow)
DE (2) DE3926884A1 (enrdf_load_stackoverflow)

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD352039S (en) 1992-05-19 1994-11-01 Sun Microsystems, Inc. Microphone for computer
US5574794A (en) * 1995-01-19 1996-11-12 Earmark, Inc. Microphone assembly for adhesive attachment to a vibratory surface
US6421444B1 (en) * 1995-09-28 2002-07-16 Nortel Networks Limited Embedded higher order microphone
US5684756A (en) * 1996-01-22 1997-11-04 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Noise reducing screen devices for in-flow pressure sensors
DE19703311A1 (de) * 1997-01-30 1998-08-06 Sennheiser Electronic Grenzflächenmikrofon
US7349546B2 (en) * 2003-09-04 2008-03-25 Kyocera Wireless Corp. System and method for identifying a headset type in an electrical device
US7106875B2 (en) * 2003-09-09 2006-09-12 King James T Dual boundary pressure zone three dimensional microphone and hearing aid
US7970151B2 (en) * 2004-10-15 2011-06-28 Lifesize Communications, Inc. Hybrid beamforming
US7903137B2 (en) * 2004-10-15 2011-03-08 Lifesize Communications, Inc. Videoconferencing echo cancellers
US7826624B2 (en) * 2004-10-15 2010-11-02 Lifesize Communications, Inc. Speakerphone self calibration and beam forming
US8116500B2 (en) * 2004-10-15 2012-02-14 Lifesize Communications, Inc. Microphone orientation and size in a speakerphone
US7720236B2 (en) * 2004-10-15 2010-05-18 Lifesize Communications, Inc. Updating modeling information based on offline calibration experiments
US20060132595A1 (en) * 2004-10-15 2006-06-22 Kenoyer Michael L Speakerphone supporting video and audio features
US7720232B2 (en) * 2004-10-15 2010-05-18 Lifesize Communications, Inc. Speakerphone
US7760887B2 (en) * 2004-10-15 2010-07-20 Lifesize Communications, Inc. Updating modeling information based on online data gathering
US7991167B2 (en) * 2005-04-29 2011-08-02 Lifesize Communications, Inc. Forming beams with nulls directed at noise sources
US7970150B2 (en) * 2005-04-29 2011-06-28 Lifesize Communications, Inc. Tracking talkers using virtual broadside scan and directed beams
US7593539B2 (en) * 2005-04-29 2009-09-22 Lifesize Communications, Inc. Microphone and speaker arrangement in speakerphone
DE202009015757U1 (de) * 2009-11-17 2010-09-23 Maier, Andreas Mikrofon-Halterung
JP5708629B2 (ja) * 2012-02-21 2015-04-30 ヤマハ株式会社 マイクロホン装置
US10419850B2 (en) 2017-01-18 2019-09-17 Trident Acoustics Dynamic boundary pressure zone microphone
FI20175954A1 (fi) * 2017-10-27 2019-04-28 Teknologian Tutkimuskeskus Vtt Oy Kotelo melumittaria varten ja melumittari

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2394221A1 (fr) * 1977-06-10 1979-01-05 Thomson Csf Dispositif transducteur electro-acoustique reversible a caracteristique de directivite constante dans une large bande de frequences
JPS5859697A (ja) * 1981-10-05 1983-04-08 Matsushita Electric Ind Co Ltd 平板スピ−カ
JPS5957596A (ja) * 1982-09-27 1984-04-03 Sony Corp マイクロホン装置
SE443483B (sv) * 1983-01-14 1986-02-24 Gustav Georg Arne Bolin Mottagardon for ljudvagor bestaende av en resonansskiva och en for dennas av ljudvagorna framkallade svengningar reagerande piezoelektrisk mikrofon av kristalltyp
DE3331657A1 (de) * 1983-09-02 1985-03-21 Canton Elektronik GmbH & Co, 6395 Weilrod Lautsprecher
JPS60244190A (ja) * 1984-05-17 1985-12-04 Matsushita Electric Ind Co Ltd 角形平面スピ−カ
JPS6124399A (ja) * 1984-07-12 1986-02-03 Onkyo Corp Ｎ角形平板型振動板
US4742548A (en) * 1984-12-20 1988-05-03 American Telephone And Telegraph Company Unidirectional second order gradient microphone

Also Published As

Publication number Publication date
EP0413086A1 (de) 1991-02-20
JPH0388599A (ja) 1991-04-12
DE3926884C2 (enrdf_load_stackoverflow) 1991-11-28
DE59005896D1 (de) 1994-07-07
US5168525A (en) 1992-12-01
DE3926884A1 (de) 1991-02-21
ATE106650T1 (de) 1994-06-15

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