US3867586A - Loudspeaker with flat frequency characteristics - Google Patents

Loudspeaker with flat frequency characteristics Download PDF

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Publication number
US3867586A
US3867586A US298907A US29890772A US3867586A US 3867586 A US3867586 A US 3867586A US 298907 A US298907 A US 298907A US 29890772 A US29890772 A US 29890772A US 3867586 A US3867586 A US 3867586A
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United States
Prior art keywords
diaphragm
peripheral edge
annular
loudspeaker
cavity
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
US298907A
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English (en)
Inventor
Kouji Maekawa
Yutaka Tamura
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Pioneer Corp
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Pioneer Electronic Corp
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Publication date
Application filed by Pioneer Electronic Corp filed Critical Pioneer Electronic Corp
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Publication of US3867586A publication Critical patent/US3867586A/en
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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
    • 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 
    • H04R1/30—Combinations of transducers with horns, e.g. with mechanical matching means, i.e. front-loaded horns
    • 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 
    • H04R1/225—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  for telephonic receivers

Definitions

  • FIG. I PRIOR R WV m W M v FREQUENCY FIG.
  • the second attempt has such defects that an unbalance between the up and down motions causes a distortion, because the conditions are different between the upper and lower surface portions of the edge of the diaphragm.
  • the third approach has such defects that it is a difficult task to perforate the corrugated portion of the diaphragm edge with relatively small holes and, in addition, the provision of the small holes reduces the intensity of vibration. Thus, any approach suggested by the prior art is unacceptable.
  • the present invention improves horn or dome type loudspeakers without the occurrence of the above defects and, therefore, it is accordingly a primary object of this invention to provide a loudspeaker with a flat frequency characteristic over the full sound range. This is achieved in the present invention by coupling the cavities occurring above and below the edge of the diaphragm so that the sound pressures on the upper and lower surfaces of the edge are canceled.
  • Another object of the present invention is to provide a loudspeaker which is capable of improving the various characteristics. This is based on the fact that the acoustical load condition remains constant irrespective of the loading of sound absorption material on and around the sound passage.
  • a further object of this invention is to provide a loudspeaker which minimizes the distortion, especially in the lower frequencies. This is achieved by using sound passages whose length is less than a half-wave of the high reproduction threshold frequency. Therefore, approximately equal sound pressures occur at the upper and lower surfaces of the edge and permit the edge to move up and down easily, so that the upward and downward deviation of the edge of the diaphragm will be equal.
  • FIG. 1 is a graph of the frequency characteristic of a conventional horn type loudspeaker.
  • FIG. 2 is a graph of the frequency characteristic of a horn type loudspeaker of the type incorporating the present invention.
  • FIG. 3 is a cross sectional view of one embodiment of a horn type loudspeaker in accordance with the present invention.
  • FIG. 4 is a cross sectional view of a portion of a loudspeaker incorporating the invention and forming an alternative embodiment of the same.
  • a loudspeaker in accordance with the present invention comprises a yoke 1 having a magnet 2 fixed at the center of the same, and a pole 3 fixed to the top surface of the magnet.
  • An annular plate 4 concentrically surrounds the magnet and forms a gap therebetween, the construction as so far described being conventional.
  • a horn 5 (with a throat piece 9) is provided, the bottom of which forms a concavity 51 or ring groove, in this case, in conjunction with the upper surface of the annular plate 4.
  • a pair of gaskets 6 are fixedly positioned within the concavity 51 of horn 5 and plate 4 and support the edge 71 of a diaphragm 7 by sandwiching the edge therebetween.
  • a voice coil 8 is fastened to an annular projection at the bottom of the diaphragm 7, the coil being positioned within the gap between the magnet pole 3 and the annular plate 4 and moving axially of the pole and magnet in conventional fashion. It is noted that the concavity 51 is divided by the edge 71 of the diaphragm into upper and lower cavities respectively.
  • each sound passage is formed such that it is less than the half-wave length of the high reproduction threshold frequency of the speaker.
  • FIG. 4 shows an alternate embodiment of the present invention, in which the concavity 51 is formed entirely within the cover formed by the lower portion of the horn 5 and overlying the annular plate 4, the concavity being axially enlarged in the area of reception of the inner end of the diaphragm edge 71, and in which case, the upper and lower gaskets 6 are attached to the cavity wall only at the outer sidewall of the same.
  • each of the aligned holes 61 and 71a are of a combined length so as to form a sound passage with a length less than the half-wave of the high reproduction threshold frequency of the speaker.
  • Conventional means fix the gasket 6 to the outside sidewall of the concavity 51 and also fix the annular gasket 6 to each side of the diaphragm edge 71, such means taking the form of adhesive of the like.
  • the loudspeaker of the invention is a horn or dome type of loudspeaker with a diaphragm whose edge portion is such as to have a cover overlying its front surface, and having cavities above and below the edge portion which are coupled together through several sound passages with the length of the sound passage being less than the high reproduction threshold frequency, the sound pressures exerted on the upper and lower surfaces at the edge of the diaphragm are canceled. That is, the sound pressure developed by the edge wont affect the sound pressure developed by the center of the diaphragm, therefore, the attenuation on the frequency characteristic does not occur, and a flat characteristic is thus obtained.
  • the construction of the loudspeaker of this invention minimizes the difference of sound pressures between the upper and lower surface, and particularly, at the edge, and permits the edge to vibrate freely and in an axial direction and makes the axial deviation equal so as to prevent distortion.
  • a loudspeaker construction forming'a horn type speaker or the like and including; a casing having an annular plate concentrically surrounding a circular magnet and forming an annular air gap therebetween, a diaphragm having a central portion overlying said magnet, a cylindrical voice coil support extending from the side of the diaphragm facing the magnet and concentrically carried within said annular gap, and an integral peripheral edge portion of the diaphragm overlying said annular plate, a cover overlying the side of said diaphragm not facing the magnet, the improvement comprising: means including at least said cover defining an annular cavity receiving the peripheral edge onlyof said diaphragm, means for fixing said diaphragm to said casing solely at its peripheral edge with said peripheral edge portion dividing said cavity into two portions on either side thereof of equal size comprising a pair of annular gaskets which sandwich the peripheral edge of the diaphragm and a plurality of holes are provided at circumferentially spaced positions within said gas
  • said cover alone includes an annular concavity having an axially enlarged portion remote from said voice coil support forming said cavity and wherein said sandwich is fixed to the outer sidewall of the axially enlarged annual concavity alone.

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  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
US298907A 1971-10-19 1972-10-19 Loudspeaker with flat frequency characteristics Expired - Lifetime US3867586A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8209571A JPS5629440B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1971-10-19 1971-10-19

Publications (1)

Publication Number Publication Date
US3867586A true US3867586A (en) 1975-02-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
US298907A Expired - Lifetime US3867586A (en) 1971-10-19 1972-10-19 Loudspeaker with flat frequency characteristics

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US (1) US3867586A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS5629440B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4399334A (en) * 1980-04-17 1983-08-16 Sony Corporation Speaker unit for headphones
US4752963A (en) * 1985-06-12 1988-06-21 Kabushiki Kaisha Kenwood Electroacoustic converter having a recessed step on the center pole
FR2671683A1 (fr) * 1991-01-14 1992-07-17 Pioneer Electronic Corp Haut-parleur a radiateur a dome.
US20050175208A1 (en) * 2004-02-11 2005-08-11 Shaw Clayton C. Audio speaker system employing an annular gasket separating a horn waveguide from a sound reproducing membrane
US20050175207A1 (en) * 2004-02-11 2005-08-11 Alexander Eric J. Audio speaker system employing an axi-symmetrical horn with wide dispersion angle characteristics over an extended frequency range
WO2005077073A3 (en) * 2004-02-11 2006-07-27 Soundtube Entertainment Inc Audio speaker system
US20090288909A1 (en) * 2008-05-21 2009-11-26 Cooper Technologies Company Sintered elements and associated systems
CN102884813A (zh) * 2010-01-15 2013-01-16 Phl音响公司 具有浮置悬架和球顶形体的电动换能器
WO2020185390A1 (en) * 2019-03-08 2020-09-17 Bose Corporation Loudspeaker with waveguide

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56112198A (en) * 1980-02-12 1981-09-04 Sony Corp Electroacoustic transducer

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1930915A (en) * 1932-07-13 1933-10-17 Bell Telephone Labor Inc Acoustic device
US2832844A (en) * 1957-04-29 1958-04-29 Univ Loudspeakers Inc Speaker driver
US2858377A (en) * 1953-04-29 1958-10-28 Arthur Blumenfeld Driver unit for loudspeakers
US2907837A (en) * 1956-09-18 1959-10-06 Brami Joseph Sound reproducing system
US2942071A (en) * 1954-10-01 1960-06-21 Rca Corp Horn-type transducer
US2974204A (en) * 1954-07-06 1961-03-07 Kane Corp Du Transducer
US3718779A (en) * 1967-06-22 1973-02-27 Electronic Res Ass Inc Loudspeaker diaphragm having marginal air release passages and center high frequency propagator

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5016085Y2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1971-08-26 1975-05-20

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1930915A (en) * 1932-07-13 1933-10-17 Bell Telephone Labor Inc Acoustic device
US2858377A (en) * 1953-04-29 1958-10-28 Arthur Blumenfeld Driver unit for loudspeakers
US2974204A (en) * 1954-07-06 1961-03-07 Kane Corp Du Transducer
US2942071A (en) * 1954-10-01 1960-06-21 Rca Corp Horn-type transducer
US2907837A (en) * 1956-09-18 1959-10-06 Brami Joseph Sound reproducing system
US2832844A (en) * 1957-04-29 1958-04-29 Univ Loudspeakers Inc Speaker driver
US3718779A (en) * 1967-06-22 1973-02-27 Electronic Res Ass Inc Loudspeaker diaphragm having marginal air release passages and center high frequency propagator

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4399334A (en) * 1980-04-17 1983-08-16 Sony Corporation Speaker unit for headphones
US4752963A (en) * 1985-06-12 1988-06-21 Kabushiki Kaisha Kenwood Electroacoustic converter having a recessed step on the center pole
FR2671683A1 (fr) * 1991-01-14 1992-07-17 Pioneer Electronic Corp Haut-parleur a radiateur a dome.
US5157731A (en) * 1991-01-14 1992-10-20 Pioneer Electronic Corporation Dome radiator speaker
US20050175208A1 (en) * 2004-02-11 2005-08-11 Shaw Clayton C. Audio speaker system employing an annular gasket separating a horn waveguide from a sound reproducing membrane
US20050175207A1 (en) * 2004-02-11 2005-08-11 Alexander Eric J. Audio speaker system employing an axi-symmetrical horn with wide dispersion angle characteristics over an extended frequency range
WO2005077073A3 (en) * 2004-02-11 2006-07-27 Soundtube Entertainment Inc Audio speaker system
US7203329B2 (en) * 2004-02-11 2007-04-10 Soundtube Entertainment, Inc. Audio speaker system employing an axi-symmetrical horn with wide dispersion angle characteristics over an extended frequency range
US20090288909A1 (en) * 2008-05-21 2009-11-26 Cooper Technologies Company Sintered elements and associated systems
US7938223B2 (en) * 2008-05-21 2011-05-10 Cooper Technologies Company Sintered elements and associated systems
CN102884813A (zh) * 2010-01-15 2013-01-16 Phl音响公司 具有浮置悬架和球顶形体的电动换能器
US20130114846A1 (en) * 2010-01-15 2013-05-09 Phl Audio Electrodynamic transducer having a dome and a buoyant hanging part
US8989429B2 (en) * 2010-01-15 2015-03-24 Phl Audio Electrodynamic transducer having a dome and a buoyant hanging part
CN102884813B (zh) * 2010-01-15 2015-08-12 Phl音响公司 具有浮置悬架和球顶形体的电动换能器
WO2020185390A1 (en) * 2019-03-08 2020-09-17 Bose Corporation Loudspeaker with waveguide
US10791394B1 (en) 2019-03-08 2020-09-29 Bose Corporation Loudspeaker with waveguide

Also Published As

Publication number Publication date
DE2250697B2 (de) 1976-03-11
JPS4847824A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-07-06
JPS5629440B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1981-07-08
DE2250697A1 (de) 1973-05-03

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