US3919499A - Planar speaker - Google Patents

Planar speaker Download PDF

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Publication number
US3919499A
US3919499A US434214A US43421474A US3919499A US 3919499 A US3919499 A US 3919499A US 434214 A US434214 A US 434214A US 43421474 A US43421474 A US 43421474A US 3919499 A US3919499 A US 3919499A
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United States
Prior art keywords
diaphragm
vibratable
elongate
conductors
backing
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Expired - Lifetime
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US434214A
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English (en)
Inventor
James M Winey
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Magnepan Inc
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Magnepan Inc
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Priority to US434214A priority Critical patent/US3919499A/en
Priority to JP551275A priority patent/JPS5528600B2/ja
Priority to DE2500986A priority patent/DE2500986B2/de
Application granted granted Critical
Publication of US3919499A publication Critical patent/US3919499A/en
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Expired - Lifetime legal-status Critical Current

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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
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/04—Construction, mounting, or centering of coil
    • H04R9/046—Construction
    • H04R9/047—Construction in which the windings of the moving coil lay in the same plane

Definitions

  • ABSTRACT A sound generating transducer or speaker including a ⁇ ihratahle diaphragm on a frame and in spaced and ll Nov. 11. 1975 confronting relation ⁇ ith a polarit defining hacking. preferabl ⁇ magnetic in nature.
  • the diaphragm being di- ⁇ ided into delinite ⁇ ihratahle areas h divider strips hearing against the diaphragm such that each dia phragm area has a fundamental resonant frequency different than other adjacent areas.
  • the ends of the divider strips are spaced from one edge of the diaphragm to define a long strip-like edge portion of the diaphragm which transcends the several ⁇ ihratable areas of the diaphragm.
  • the conductive means are separate bass and mid-range audio frequenc signal conductors and high range audio frequenc signal conductors on the diaphragm and separated in distinct zones.
  • the high range audio frequenc signal conductors located in a ZUIIC extending along the strip-like edge portion and defining a long. narrow tweeter transcending the se ⁇ eral ⁇ ihratahle areas and through the edge areas of the several ⁇ ihratahle areas or woofers which are e ⁇ cited h the signal current in the bass and mid-range audio frequenc) signal conductorsv
  • the mid-range audio irequenet signals ma he separatel) applied along another edge portion or zone of the diaphragm in a separate conductor on the diaphragm.
  • the actual magnitude of vibration or excursion of diaphragm areas producing such high audio frequency sounds is extremely small. amounting to only a few thousandths of an inch. Because of this incremental diaphragm excursion in the tweeter zones, the magnet or source of magnetic field may be located very close to the diaphragm. It has been found that the diaphragm and the conductors thereon in the strip-like tweeter zone should be quite close to the magnet so the magnetic field will have maximum intensity at the diaphragm. The sound output of the tweeter zone will thereby be maximized for any level of signal current in such conductors.
  • edge areas of the diaphragm have a minimum and alomost negligible vibratory movement or excursion. principally because the extreme edge is clamped or physically retained against movement by the frame.
  • edge areas are extremely important and significant to the transducer because they contribute materially to the establishment of a desired low resonant frequency of the diaphragm area of which the edge areas are a part.
  • edge areas are needed for establishment and maintenance ofdesired resonant frequencies, such edge areas may be simultaneously utilized for such strip-like tweeter zones for generating and radiating the higher audio frequency sounds. Whereas such edge areas may vibrate slightly with the diaphragm as a whole, such edge areas may be separately driven or vibrated with higher audio frequency signals to generate sounds of corresponding frequency.
  • Such strip-like tweeter zones may transcent diaphragm areas which are otherwise independent of each other.
  • the edge areas of adjacent large and independent diaphragm areas may be connected together into such a unitary. elongate striplike tweeter zone.
  • the magnet or magnetic system producing the magnetic field at the diaphragm may be advantageously arranged.
  • the magnet may be spaced sufficiently from the woofer zone of the diaphragm area as to avoid interference with the vibration of the diaphragm. Adjacent the tweeter /one. the magnet may be located extremely close to the diaphragm.
  • edge areas of the vibrating diaphragm may carry conductors into which only mid-range audio frequency signals are supplied.
  • the magnet will be spaced somewhat farther from such edge areas than from the high frequency tweeter zones.
  • Audio frequency signals from the amplifier may be separated for application to the energizing conductive means of the diaphragm areas.
  • a simple frequency separating network or crossover circuit may be used.
  • the single output from the amplifier may be connected directly to the conductors of the tweeter section of the transducer diaphragm, and the woofer section conductors in series with a blocking coil maybe connected in shunt with the conductors of the tweeter section.
  • the blocking coil will be of such a size as to block the high audio frequency signals from the woofer section conductors.
  • a separate blocking coil may be seriesconnected with the bass signal conductors to also block the mid-range audio frequency signals from the bass signal conductors.
  • the favorable heat dissipation characteristics of the transducer should be noted.
  • the several signal conductors on the diaphragm. in the tweeter. woofer and midrange zones are spread out over a substantial area. Any heating produced by the substantial current carried by the conductors is rapidly dissipated without any adverse effeet. Heating is therefore not a limiting factor in the amount of power that may be supplied to the transducer.
  • the high energy bass and mid-range frequency signals need not be blocked from the high frequency tweeter section conductors because of the adequate heat dissipation.
  • FIG. I is a small scale perspective view illustrating such transducers in use in a room.
  • FIG. 2 is an elevation view of the transducer with the decorative fabric cover removed.
  • FIG. 3 is an enlarged detail section view taken approximately at 3-3 in FIG. 2.
  • FIG. 4 is an enlarged detail section view taken approximately at 44 in FIG. 2.
  • FIG. 5 is a greatly enlarged detail section view taken approximately at 5-5 in FIG. 4.
  • FIG. 6 is a schematic circuit diagram of the transducer for connection to an amplifier.
  • FIG. 7 is a slightly modified schematic circuit diagram of the transducer for connection to the output of an amplifier.
  • FIG. 8 is an enlarged detail section view somewhat similar to a portion of FIG. 3 and showing a modified form of a portion of the magnetic system.
  • FIG. 9 is a detail elevation view illustrating a modified form of the invention.
  • FIG. [0 is an enlarged detail section view taken at I0-l0 of FIG. 9 and having portions thereof broken away facilitating use of a large scale.
  • FIG. II is a schematic circuit diagram including the transducer of FIG. 9 and adapted for connection to the output of an audio amplifier.
  • FIG. I2 is an enlarged detail section view showing a modified form of conductor arrangement on the diaphragm.
  • FIG. I3 is a diagrammatic section view showing a modified form of the invention.
  • FIG. I4 is a view similar to FIG. I3 and showing another modified form of the invention.
  • FIG. 15 is a view similar to FIG. 13 and showing still another modified form of the invention.
  • the transducers hereof are indicated in general by numeral 10 and are generally panel shaped.
  • the transducers are shown in a typical arrangement in FIG. I wherein two such transducers are used as a part of a stcreophonic system to generate sound in accordance with the electric signals provided.
  • These panel shaped transducers may be approximately 5 feet high by 12 to inches wide and approximately an inch in overall thickness. principally due to the thickness of the frame.
  • the transducers are illustrated with plain fabric covers which give a desired decorative effect and provide some degree of protection for the transducer from physical damage.
  • the transducer is shown in FIG. 2 and is set into a frame [1.] extending about the entire periphery of the transducer to produce a rigid structure and resist warpage.
  • the frame II.l may be considered a part of the rigid backing which is indicated in general by numeral 12 which provides the functions of mounting a flexible diaphragm 13 along its edges and defining fields adjacent the diaphragm.
  • the backing 12 includes a rigid spacer 11 extending around the entire periphery of the transducer. and a stiff and generally rigid panel-shaped armature I4 constructed of magnetic material. specifically a ferrous metal or soft iron material and suitably glavanized to resist corrosion.
  • Armature 14 is concavely bowed slightly adjacent each dia- Ill phragm area to accommodate diaphragm excursion.
  • the armature panel is affixed adliesively and. in some cases. mechanically. to the spacer II which may be constructed of wood. pressed fiber. rigid plastic. alurninum. iron or other rigid materials. and the panel may be approximately 18 to 24 gauge galvanized sheet metal. or approximately 0.050 inches thickness.
  • the field-generating backing 12 also includes a plurality of elongate thin flexible strips or magnets 15 formed of any suitable material. but it has been found that a plastic rubber bonded barium ferrite magnetic material known by its trademark PLASTIFORM sold by Minnesota Mining and Manufacturing Company of St. Paul. Minnesota. has proven satisfactory.
  • the magnets may be formed in broad sheets of the same material; in any event. the strips or magnets are magnetized in a direction transversely of the armature plate 14 and of diaphragm I3 so that elongate magnetic zones are defined which extend all along the length of the diaphragm I3.
  • the strips I5 are arranged so that pole faces of adjoining magnetic zones are of opposite polarity as indicated in FIG. 3.
  • the magnetic fields. in elongate zones. are of maximum strength at locations just between adjacent strips I5. and. accordingly. the conductors I6 are secured on the diaphragm I3 at locations approximately between adjacent magnetic strips I5.
  • the backing I2 is acoustically transparent to the sounds produced by the vibrating diaphragm 13, and. accordingly.
  • the plate-like armature 14 has a plurality of apertures I7 therethrough.
  • the apertures 17 are aligned with the spaces 18 between the strips or elon gate magnets 15.
  • top surfaces or pole faces 19 of the strips or magnets lS are spaced substantially from the diaphragm 13 so as to allow the diaphragm to have a significant excursion from its normal position without engaging or impinging the strips 15.
  • the diaphragm 13 is divided into a number of substantially independent vibratable areas 130. I3b. l3c. l3d and 13e. each of which is a different size than the areas adjacent thereto. Accordingly. each of the separate vibratable areas I30 I3e has a fundamental resonant frequency which is significantly different than the fundamental resonant frequencies of the other areas.
  • the diaphragm may be uniformly stretched on the spacer ll so that it has a permanent stretch of approximately one percent or more over its natural size. Ordinarily. the diaphragm 13 will be stretched in a transverse direction. but may also. if the need arises. be stretched in a longitudinal direction. In order to produce the various fundamental resonant frequencies at the various areas. the areas may under certain circumstances all be the same and the mass of the diaphragm in each of the areas may be varied slightly so as to produce a different fundamental resonant frequency.
  • the areas [3e of the diaphragm are defined by divider strips 20 which underlie and are secured as by adhesive to the diaphragm 13.
  • the divider strips 20 overlie and bear upon the magnet strips 15. and may be adhesively secured to the magnet strips.
  • the effect of the divider strips 20 is to immobilize the diaphragm 13 at each of the strips so as to require that the diaphragm. in each of the vibratable areas 130 l3e. will vibrate independently ofvibrations ofthe diaphragm in each of the other areas.
  • one end 200 ofeach of the divider strips is located in spaced relation with the edge of the diaphragm and the adjacent portions of spacer 11.
  • This elongate edge portion of the diaphragm is not anchored by the strips and transcends all of the several vibratable areas 13a l3e.
  • Conducters 16.1 are secured on and extend longitudinally along the full length of the narrow edge portion 13.] of the diaphragm.
  • the conductors 16.1, and also conductors 16, are secured to the diaphragm 13 by an adhesive 21.
  • the backing 12, adjacent the edge portion 13.1 of the diaphragm includes the elongate strip magnets 15.1. which are essentially identical to strips 15, but of somewhat different dimensions, being somewhat narrower, but somewhat deeper or thicker.
  • the spacing between the magnet strips 15.1 and the edge portion 13.1ofthc diaphragm is significantly less than the spacing between the diaphragm and the strips 15. This smaller spacing adjacent the edge portion 13.1 of the diaphragm is permissible because the edge portion of the diaphragm is retained against vibration by the spacer 11 and there is no significant excursion of the diaphragm in the edge portion 13.1.
  • the divider strips 20 may extend entirely across the diaphragm and to the opposite spacers 11; however, the strips would have to be thinner adjacent magnets 15.1 to correspond to the reduced spacing between the magnets 15.1 and the diaphragm 13. Such full width strips 20 produce no bearable change as compared to the operation of the construction illustrated.
  • Vibration of this portion 13.1 of the diaphragm is caused by vibration of the adjacent vibratable areas 13a 13e, caused by the application of an audio frequency signal or current in the conductors 16.
  • the signal applied to conductors 16 will be of bass audio frequency. or midrange audio frequency, and, accordingly, the diaphragm areas 130 136* will be vibrated with a corresponding bass audio frequency.
  • This vibration of the diaphragm induced by the signal in conductors 16 is produced in the edge portion 13.1 as well as in the central portions of the areas 130 13e. However. because the actual movement of the edge portion 13.1 of the diaphragm is minimal, there is no significant sound generated by the vibration ofthe edge portion 13.1 under influence of the bass frequency vibrations.
  • edge portion 13.1 is a portion of each of the adjacent vibratable areas 130 13a ofthe diaphragm, and is free to vibrate therewith, is extremely significant in defining the fundamental resonant frequency for each particular vibratable area 130 Be.
  • the effective diaphragm area for establishing the fundamental resonant frequency for any of the particu lar diaphragm areas 130 13s is somewhat larger be cause the edge portion 13.1 is included, and therefore the fundamental resonant frequencies of the areas are as low as possible.
  • the conductors 16.1 which extend along the narrow edge portion 13.1 of the diaphragm will ordinarily be high audio frequency signals so as to generate the corresponding high audio frequency sounds.
  • This edge area of the transducer including the narrow edge portion 13.1 of the diaphragm is considered a tweeter.
  • the pole faces of the magnetic strips 15.1 are located in close proximity to the diaphragm.
  • the approximate spacing between the diaphragm and the pole faces of the magnetic strips 15.1 may be 0.020 inches.
  • the impedance of the conductors 16 may cumulatively amount to approximately cumualtive 12 ohms; and, similarly, the conductors 16.1 have cumulative impedance of 12 ohms.
  • a blocking coil 21 is connected in series with the conductors 16 to block the high audio frequency signals from the conductors 16, thus preventing any significant generation ofhigh audio frequency sounds thereby, which sounds would be highly directional.
  • the coil 21 may have an impedance of 398 microhenrys.
  • the conductors 16 are arranged in side by side runs on the diaphragm and are regularly spaced from each other at a spacing of about four conductors per inch.
  • the tweeter conductors 16.1 are spaced equally from each other, and approximately eight conductors per inch.
  • the effective width of the long strip-like tweeter may be approximately V2 to 1 inch. and the width of the diaphragm area to which conductors 16 are applied may be approximately seven inches.
  • the rigid divider strips 20 are approximately 7 inches long.
  • each of the diaphragm areas 13a 13a includes the adjacent edge portion 13.1 as a part of it for defining its fundamental resonant frequency. and driven by bass frequency signals applied in conductors 16.1. the edge portion 13.] also acts separately as a tweeter for independently and separately generating the high range audio frequency sounds.
  • conductors 16 may be 22 gauge cop per wire in runs approximately 0.310 in. apart. and conductors 16.1 may be 32 gauge aluminum wire spaced 0.210 in. apart. The mass of the conductors 16.1 will be considerably less than the mass of conductors 16.
  • Magnet strips 15 may be 0.085 in. thick by 0.260 in. wide and minimally spaced 0.040 in. from the half mil diaphragm; and the magnet strips 15.1 may be 0.105 in. thick by 0.150 in. wide and spaced 0.020 in. from the diaphragm.
  • the high frequency signal carrying 32 gauge aluminum wire in the aforesaid example. is in runs 0.210 inches apart. therefore requiring 4.76 lineal inches of aluminum wire per square inch of diaphragm area which weighs 2.34 X l()' pounds per square inch ofdiaphragm area.
  • the mass or weight of the aluminum wire per square inch of diaphragm area will therefore be seen to he significantly less than the mass or weight of the 22 gauge copper wire per square inch of diaphragm area. by a ratio of approximately I to 22.3.
  • the aluminum wire weighs only 4.5 percent of the weight of the copper wire. or otherwise stated.
  • the mass of the aluminum conductor 16.1 is 95.4 percent less per unit of area of the diaphragm than the mass of the copper conductor 16.
  • Low range or bass audio frequency sounds will therefore emanate from each of the several vibratable areas 13a l3e in both forward and rearward directions and at all the various angles from side to side.
  • the high range audio frequency sounds are generated at the tweeter strip or edge portion 13.1. and. because of the narrow configuration. these high range audio frequency sounds will emanate horizontally outwardly in substantially all directions. both forward and rear.
  • the conductors 16 and 16. may carry a significant current. there is little concern for heating because the conductors are spread out widely on the diaphragm with the effect of dispersing large amounts of heat without damage to any of the components.
  • the several conductors 16 and 16.1 are typically designed with an impedance of 6 ohms each.
  • the blocking coil 21 is connected in series with the bass audio frequency signalreceiving conductor 16, and a condenser 22 of approximately microfarads is connected in series with the tweeter conductor 16.1.
  • This arrangement is a conventional L-C crossover circuit.
  • the impedance is the same at any frequency. It can handle larger amplifiers and does not shift maximum power to the low frequency end. A more accurate sound is thereby produced.
  • the form of the transducer 10.1 illustrated in FIG. 8 is substantially identical to that illustrated in FIGS. 1 5 with the exception that the magnetic strips 15.1 beneath the narrow edge portion or tweeter section 13.1 of the transducer are of thin construction and are supported upon an acoustically transparent spacer plate 25 which is a portion of the magnetic armature.
  • the spacer plate 25 is also constructed of a ferrous metal and preferably a soft iron so as to form a low reluctance path for the magnetic field, together with the magnet strips 15.1 and the armature plate 14.
  • the transducer 10.2 illustrated in FIGS. 9 -11 is substantially the same as that illustrated in FIGS. 1 S.
  • the diaphragm 13 is similarly divided into a number of separate vibratable areas. each with a different fundamental resonant frequency, the separate vibratable areas illustrated in FIG. 9 being designated 13d and 13a.
  • additional separate vibratahlc areas with different fundamental resonant frequencies will be utilized as illustrated in connection with FIG. 2.
  • the bass audio frequency signal-carrying conductors 16 traverse the central portion of each of the separate vibratable areas of the diaphragm; and in a manner similar to that described in connection with FIGS. 1 5.
  • the high audio frequency signal-carrying conductor 16.] extends the full length of the narrow edge portion of tweeter strip 13.1 to generate and emanate high audio frequency range sounds.
  • an additional edge portion 13.2 of the diaphragm remains free of the divider strips 20. both ends of which are in spaced relation with the adjacent frames and the edges of the diaphragm. However. as in the form of FIGS. 1 5. strips 20 may extend entirely across the diaphragm to opposite sides of the frame. making provision for varying magnet to diaphragm spacings.
  • the elongate and narrow diaphragm area 13.2 carries additional conductors 16.2 for receiving midrange audio frequency signals and producing vibration of the diaphragm area 13.2 in accordance with these frequencies.
  • the blocking coil 21 which blocks the midrange and high audio frequency signals from the conductor 16.1.
  • additional blocking coil 21.1 is connected in series with the midrange frequency signal-carrying conductor 16.2 so as to block all of the high range audio frequency signals.
  • the impedance to high audio frequency signals remains high at about 12 ohms.
  • the impedance of the transducer to signals in the approximate range of 2 KHz may be approximately 6 ohms. while the impedance to signals of approximately 12 Hz may be approximately 4 ohms.
  • this provides an advantageous balancing effect for producing a well balanced sound.
  • conventional L-C crossovers for three way systems may also be used.
  • the magnet strips 15.2 adjacent the edge portion 13.2 of the diaphragm are somewhat higher than the strips 15 beneath conductors 16 and somewhat lower than the magnet strips 15.1 beneath the edge portion 13.1 of the diaphragm. This spacing between magnet strips 15.2 and the diaphragm allows some additional excursion of the diaphragm in producing the midrange frequency signals as is required for such signals.
  • FIGS. 13. 14 and 15 show various modes of producing the variance in the spacing between the diaphragm and the face of the magnet in the backing.
  • the armature 14.1 as well as the magnets or strips thereon, are arcuately curved so that the edge portions of the backing including the magnet are closer to the diaphragm than the middle portion.
  • the same armature 14 is utilized as in FIGS. 1 5, but the upper faces of the magnets or strips 15' on the armature are comulatively concavely curved to vary the spacing across the width of the transducer.
  • the form of the transducer illustrated in FIG. 15 employs acoustically transparent spacers beneath the magnets at the edge portions of the transducer. both beneath the tweeter section, but also beneath the midrange audio frequency section of the transducer.
  • a sound generating transducer comprising:
  • an audio sound-producing flexible diaphragm secured to the backing in confronting relation therewith and defining a vibratable area, the edges of the vibratable area being stationary against vibration with respect to the backing, the vibratable area of the diaphragm having a central portion with low frequency signal carrying conductive means thereon for vibrating the entire vibratable area generating low frequency sounds,
  • said vibratable area also having an elongate and narrow strip portion with high frequency signal carrying conductive means affixed thereon and substantially throughout said strip portion for vibrating the narrow strip portion of the diaphragm and generating high frequency sounds, and the mass of the high frequency signal carrying conductor means per square inch of diaphragm area on said strip portion being substantially less than the mass of the low frequency signal carrying conductive means per sqare inch of area of the diaphragm, and
  • said backing having means defining polarity characteristics to alternately attract and repel the diaphragm and cause diaphragm vibrations for sound production upon application of audio frequency electric signals to the conductive means.
  • a sound generating transducer comprising:
  • an audio sound-producing flexible diaphragm having its edges secured to the backing, the diaphragm being disposed in confronting and spaced relation with the backing and having a pair of adjacent vibratable areas, each of said vibratable areas having a central portion with conductive means thereon to receive bass audio frequency signals for vibrating the diaphragm area as a woofer,
  • divider means between said adjacent vibratable areas and engaging and retaining the diaphragm against vibrating at the edge of the vibratable areas
  • the diaphragm having an elongate and narrow edge portion extending into both vibratable areas, said elongate and narrow edge portion of the diaphragm having conductive means thereon to receive high audio frequency signals for vibrating the narrow edge portion of the diaphragm as a tweeter, the tweeter forming a portion of and transcending adjacent woofers, and
  • said backing having means defining polarity characteristics to alternatively attract and repel the diaphragm and cause diaphragm vibrations for sound production upon application of audio frequency electric signals to the conductive means.
  • the diaphragm also having an elongate edge portion located along the edge of the diaphragm opposite the tweeter and also extending across the adjoining end of the divider means and into both vibratable areas and carrying conductive means to receive midrange audio frequency signals for vibrating the diaphragm.
  • the woofer and tweeter conductive means including current-carrying conductors cooperating with the magnetic means ofthc backing in vibrating the diaphram.
  • a sound generating transducer comprising:
  • a stiff and acoustically transparent backing having a broad and substantially flat shape and including a magnetic means producing magnetic fields adjacent the backing
  • said vibratable area also having an elongate and narrow edge portion with current-carrying conductors thereon to receive high audio frequency signals for vibrating the narrow edge portion of the diaphragm
  • the magnetic means of said backing having pole faces confronting the diaphragm and lying parallel to the diaphragm adjacent said elongate narrow edge portion and the pole faces also being spaced significantly closer to the diaphragm adjacent said elongate narrow edge portion than at said central portion.
  • the sound generating transducer according to claim 11, and said magnetic means including a platelike armature of magnetic material, and field generating means on the armature adjacent the central and along the narrow edge portions of the vibratable area.
  • a sound generating transducer comprising:
  • the hacking ineluding magnetic means defining elongate zones to form magnetic pole faces. adjacent pole faces being of opposite polarity to define a plurality of elongate magnetic fields adjoining the magnetic means.
  • an audio sound-producing flexible diaphragm having edges secured to the backing in confronting and spaced relation therewith and defining a vibratable area. the edges of the vibratable area being stationary against vibration with respect to the backing. the vibratable area of the diaphragm having a central portion with current-carrying conductors thereon and extending along the elongate zones of the magnetic means to receive low audio frequency signals and causing vibration of the entire vibratable area and generating low frequency sounds.
  • said vibratable area also having an elongate and narrow edge portion with current-carrying conductors thereon and extending along the elongate zones of the magnetic means to receive high audio frequency signals for vibrating the narrow edge portion of the diaphragm, and
  • the conductors in the elongate and narrow edge portion having a spacing from each other significantly less than the spacing between adjacent conductors at the central portion of the vibratable area. and the elongatc zones and magnetic pole faces of the magnetic means being spaced from adjacent zones and faces in accordance with the spacing between adjacent conductors on the diaphragm.
  • the sound generating transducer according to claim l6, and the pole faces of the magnetic means being uniformly spaced from the diaphragm adjacent the elongate narrow edge portion of the vibratable area. and also being positioned significantly closer to the diaphragm and conductors thereon adjacent the elongate narrow edge portion of said area than adja cent the conductors on the central portion of the vi hratable area.
  • the sound generating transducer according tr claim 16 and the field generating means having a generally concavely shaped surface confronting and facing the diaphragm and being spaced significantly closer tr the elongate and narrow edge portion of the vibratable area than from the central portion of the vibratablc area of the diaphragm;
  • a sound generating transducer comprising:
  • the backing including magnetic means defining a plurality of elongate and parallel magnetic zones forming magnetic pole faces. adjacent pole faces being ofopposite polarity to define a plurality of elongate magnetic fields adjoining such faces an audio sound producing flexible diaphragm having edges secured to the backing and defining a vibratable area in confronting and spaced relation with said pole faces. the diaphragm being permanently stretched in excess of its natural size, but within the elastic limits of the diaphragm.
  • the vibratable area ofthe diaphragm having adjoining portions with current carrying conductors thereon and extending along the elongate zones ofthe magnetic means.
  • one of said portions of the vibratable area being broad with low frequency carrying conductors thereon and extending along the elongate zones of the magnetic means to receive low audio frequency signals and causing vibration of the entire vibratable area and generating sounds of comparable low frequencies,
  • another of said portions of the vibratable area being in the form of an elongate and narrow strip with high frequency conductors thereon and extending along the elongate zones of the magnetic means to receive high audio frequency signals for vibrating the elongate and narrow strip at such high audio frequencies.
  • the spacing between said high frequency current carrying conductors in said strip being significantly less than the spacing between the low frequency carrying conductors on the diaphragm, the width of said elongate magnetic zones adjacent said high frequency current carrying conductors being substantially less than the width of the elongate magnetic zones adjacent said low frequency carrying conductors and the spacing between adjacent elongate mangetic zones conforming to the corresponding spacing between the adjacent low frequency and high frequency current carrying conductors on the diaphragm, respectively,

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
US434214A 1974-01-11 1974-01-11 Planar speaker Expired - Lifetime US3919499A (en)

Priority Applications (3)

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US434214A US3919499A (en) 1974-01-11 1974-01-11 Planar speaker
JP551275A JPS5528600B2 (en)van) 1974-01-11 1975-01-10
DE2500986A DE2500986B2 (de) 1974-01-11 1975-01-11 Elektrodynamischer Wandler, insbesondere Lautsprecher

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US434214A US3919499A (en) 1974-01-11 1974-01-11 Planar speaker

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US4210786A (en) * 1979-01-24 1980-07-01 Magnepan, Incorporated Magnetic field structure for planar speaker
FR2446044A2 (fr) * 1978-04-04 1980-08-01 Daniere Joannes Systeme pour la reproduction de signaux acoustiques de frequences tres basses jusqu'aux plus elevees
EP0048434A1 (en) * 1980-09-19 1982-03-31 Electro-Magnetic Corporation Electro acoustic planar transducer
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US8767979B2 (en) 2010-06-14 2014-07-01 Parametric Sound Corporation Parametric transducer system and related methods
US8903104B2 (en) 2013-04-16 2014-12-02 Turtle Beach Corporation Video gaming system with ultrasonic speakers
US8934650B1 (en) 2012-07-03 2015-01-13 Turtle Beach Corporation Low profile parametric transducers and related methods
US8942408B1 (en) 2011-07-22 2015-01-27 James Joseph Croft, III Magnetically one-side driven planar transducer with improved electro-magnetic circuit
US8958580B2 (en) 2012-04-18 2015-02-17 Turtle Beach Corporation Parametric transducers and related methods
US8988911B2 (en) 2013-06-13 2015-03-24 Turtle Beach Corporation Self-bias emitter circuit
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US9197965B2 (en) 2013-03-15 2015-11-24 James J. Croft, III Planar-magnetic transducer with improved electro-magnetic circuit
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US6188772B1 (en) 1998-01-07 2001-02-13 American Technology Corporation Electrostatic speaker with foam stator
US6304662B1 (en) 1998-01-07 2001-10-16 American Technology Corporation Sonic emitter with foam stator
US20020076069A1 (en) * 1998-01-07 2002-06-20 American Technology Corporation Sonic emitter with foam stator
US6175636B1 (en) 1998-06-26 2001-01-16 American Technology Corporation Electrostatic speaker with moveable diaphragm edges
US20050100181A1 (en) * 1998-09-24 2005-05-12 Particle Measuring Systems, Inc. Parametric transducer having an emitter film
US8199931B1 (en) 1999-10-29 2012-06-12 American Technology Corporation Parametric loudspeaker with improved phase characteristics
US7251342B2 (en) 2000-03-03 2007-07-31 American Technology Corporation Single end planar magnetic speaker
WO2001067812A1 (en) * 2000-03-03 2001-09-13 American Technology Corporation Single end planar magnetic speaker
US20030228029A1 (en) * 2000-03-03 2003-12-11 David Graebener Single end planar magnetic speaker
WO2001084883A3 (en) * 2000-05-03 2003-02-13 Wisdom Audio Corp Planar speaker wiring layout
US20040022410A1 (en) * 2000-05-03 2004-02-05 Bohlender Jack T Planar speaker wiring layout
US7099488B2 (en) 2000-05-03 2006-08-29 Wisdom Audio Corp Planar speaker wiring layout
US20070127767A1 (en) * 2001-01-22 2007-06-07 American Technology Corporation Single-ended planar-magnetic speaker
US7142688B2 (en) 2001-01-22 2006-11-28 American Technology Corporation Single-ended planar-magnetic speaker
US20020191808A1 (en) * 2001-01-22 2002-12-19 American Technology Corporation Single-ended planar-magnetic speaker
US20060050923A1 (en) * 2001-01-26 2006-03-09 American Technology Corporation Planar-magnetic speakers with secondary magnetic structure
US6934402B2 (en) 2001-01-26 2005-08-23 American Technology Corporation Planar-magnetic speakers with secondary magnetic structure
US20020118856A1 (en) * 2001-01-26 2002-08-29 American Technology Corporation Planar-magnetic speakers with secondary magnetic structure
US20090097693A1 (en) * 2001-01-26 2009-04-16 Croft Iii James J Planar-magnetic speakers with secondary magnetic structure
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US7203332B2 (en) 2002-05-02 2007-04-10 Harman International Industries, Incorporated Magnet arrangement for loudspeaker
US7236608B2 (en) 2002-05-02 2007-06-26 Harman International Industries, Incorporated Conductors for electro-dynamic loudspeakers
US7149321B2 (en) 2002-05-02 2006-12-12 Harman International Industries, Incorporated Electro-dynamic loudspeaker mounting system
US7155026B2 (en) 2002-05-02 2006-12-26 Harman International Industries, Incorporated Mounting bracket system
US7035425B2 (en) 2002-05-02 2006-04-25 Harman International Industries, Incorporated Frequency response enhancements for electro-dynamic loudspeakers
US20040042632A1 (en) * 2002-05-02 2004-03-04 Hutt Steven W. Directivity control of electro-dynamic loudspeakers
US20040022407A1 (en) * 2002-05-02 2004-02-05 Steere John F. Film tensioning system
US7146017B2 (en) 2002-05-02 2006-12-05 Harman International Industries, Incorporated Electrical connectors for electro-dynamic loudspeakers
US20040008862A1 (en) * 2002-05-02 2004-01-15 Garner David B. Conductors for electro-dynamic loudspeakers
US7278200B2 (en) 2002-05-02 2007-10-09 Harman International Industries, Incorporated Method of tensioning a diaphragm for an electro-dynamic loudspeaker
US7627134B2 (en) 2002-05-02 2009-12-01 Harman International Industries, Incorporated Magnet retention system in planar loudspeakers
US7316290B2 (en) 2003-01-30 2008-01-08 Harman International Industries, Incorporated Acoustic lens system
US20040182642A1 (en) * 2003-01-30 2004-09-23 Hutt Steven W. Acoustic lens system
US7564981B2 (en) 2003-10-23 2009-07-21 American Technology Corporation Method of adjusting linear parameters of a parametric ultrasonic signal to reduce non-linearities in decoupled audio output waves and system including same
WO2006089382A1 (en) * 2005-02-23 2006-08-31 Gradiente Eletrônica S.A. Electro-acoustic transducer
US7607512B2 (en) 2005-08-23 2009-10-27 Ronald Paul Harwood Speaker assembly for a structural pole and a method for mounting same
US20070045040A1 (en) * 2005-08-23 2007-03-01 Harwood Ronald P Speaker assembly for a structural pole and a method for mounting same
US20080069394A1 (en) * 2006-09-14 2008-03-20 Bohlender Graebener Corporation Planar Speaker Driver
US20080069395A1 (en) * 2006-09-14 2008-03-20 Bohlender Graebener Corporation Planar Speaker Driver
US8031901B2 (en) * 2006-09-14 2011-10-04 Bohlender Graebener Corporation Planar speaker driver
US8116512B2 (en) 2006-09-14 2012-02-14 Bohlender Graebener Corporation Planar speaker driver
US8275137B1 (en) 2007-03-22 2012-09-25 Parametric Sound Corporation Audio distortion correction for a parametric reproduction system
DE102007016582B3 (de) * 2007-04-07 2008-06-19 Technische Universität Dresden Magnetostatischer Lautsprecher, insbesondere Tieftonlautsprecher
US8903116B2 (en) 2010-06-14 2014-12-02 Turtle Beach Corporation Parametric transducers and related methods
US8767979B2 (en) 2010-06-14 2014-07-01 Parametric Sound Corporation Parametric transducer system and related methods
US9002032B2 (en) 2010-06-14 2015-04-07 Turtle Beach Corporation Parametric signal processing systems and methods
US8942408B1 (en) 2011-07-22 2015-01-27 James Joseph Croft, III Magnetically one-side driven planar transducer with improved electro-magnetic circuit
US9036831B2 (en) 2012-01-10 2015-05-19 Turtle Beach Corporation Amplification system, carrier tracking systems and related methods for use in parametric sound systems
US8958580B2 (en) 2012-04-18 2015-02-17 Turtle Beach Corporation Parametric transducers and related methods
US8934650B1 (en) 2012-07-03 2015-01-13 Turtle Beach Corporation Low profile parametric transducers and related methods
US9197965B2 (en) 2013-03-15 2015-11-24 James J. Croft, III Planar-magnetic transducer with improved electro-magnetic circuit
US8903104B2 (en) 2013-04-16 2014-12-02 Turtle Beach Corporation Video gaming system with ultrasonic speakers
US8988911B2 (en) 2013-06-13 2015-03-24 Turtle Beach Corporation Self-bias emitter circuit
US9332344B2 (en) 2013-06-13 2016-05-03 Turtle Beach Corporation Self-bias emitter circuit
US11805365B2 (en) 2021-03-24 2023-10-31 Audeze, Llc Electroacoustic diaphragm, transducer, audio device, and methods having subcircuits

Also Published As

Publication number Publication date
JPS50107919A (en)van) 1975-08-25
JPS5528600B2 (en)van) 1980-07-29
DE2500986A1 (de) 1975-07-24
DE2500986B2 (de) 1979-02-01
DE2500986C3 (en)van) 1979-09-20

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