US2732907A - Sound transducers - Google Patents

Sound transducers Download PDF

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Publication number
US2732907A
US2732907A US2732907DA US2732907A US 2732907 A US2732907 A US 2732907A US 2732907D A US2732907D A US 2732907DA US 2732907 A US2732907 A US 2732907A
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US
United States
Prior art keywords
sound
reflecting surface
diaphragm
axis
ellipsoid
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Expired - Lifetime
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English (en)
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/18—Methods or devices for transmitting, conducting or directing sound
    • G10K11/26—Sound-focusing or directing, e.g. scanning
    • G10K11/28—Sound-focusing or directing, e.g. scanning using reflection, e.g. parabolic reflectors
    • 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
    • H04R1/34—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
    • H04R1/345—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 loudspeakers

Definitions

  • the present invention relates to sound transducers of the kind including a sound generator, in particular a diaphragm loud speaker, in combination with a reflecting surface constituted by a portion of an ellipsoid of revolution, this surface being arranged in such manner that the point forming the virtual acoustic source (substantially the center of the diaphragm or, when this diaphragm is of conical shape, the apex of the cone of this diaphragm) is located at one focus of the ellipsoid whereas the other focus, toward which the reflected sounds converge, is located outside of the reflecting surface and downstream of the outlet aperture thereof.
  • a sound generator in particular a diaphragm loud speaker
  • a reflecting surface constituted by a portion of an ellipsoid of revolution
  • the object of my invention is to provide an improved sound transducer of this kind.
  • the axis of the incident sound beam from the acoustic source is so inclined with respect to the reflecting surface that the angle made by this axis with the axis of the reflected sound beam is greater than 90 and the outlet aperture of the reflecting surface extends to the immediate vicinity of the sound generator.
  • a baflie is provided at the place where the diaphragm is in close vicinity to the outlet aperture or mouth of the reflecting surface. This baffle is then located in a plane substantially perpendicular to the axis of the reflected sound beam.
  • Figs. 1 and 2 are a vertical axial section and a perspective view, respectively, of a sound transducer according to my invention
  • Fig. 1a is a view similar to Fig. 1 and relating to a modification.
  • Figs. 3 and 4 are views of the same kind as Figs. 1 and 2 respectively but relating to another embodiment of my invention.
  • the device shown by Figs. 1 and 2 includes, on the one hand, an acoustic source constituted by a diaphragm 1 of conical shape energized through suitable means not shown, and, on the other hand, a reflecting surface 2.
  • This reflecting surface is in the form of a portion of an ellipsoid of revolution the outlet aperture or mouth of which is located in plane OO (the remainder of the ellipsoid surface being shown by line 2)
  • the foci of the ellipsoid are A and A located along the major axis a.
  • the apex of the conical diaphragm 1 is located at focus A so that the sounds which strike surface 2 and are reflected therefrom are concentrated at point A
  • the plane of the base of conical diaphragm 1 is so inclined with respect to axis AA that the axis AB of this diaphragm intersects reflecting surface 2 and makes an angle at greater than with the axis BA of the sound beam reflected from said surface 2.
  • the outlet aperture or mouth of the reflecting surface located in plane 00 extends into close vicinity to diaphragm 1.
  • O designates the point where the edge of this mouth is closest to the diaphragm.
  • the point B where the axis AB of the loud speaker diaphragm 1 intersects the reflecting surface 2 coincides with the point of intersection with said surface 2 of the minor axis b of the section of the ellipsoid by plane at right angles to the plane 00 and passing through the axis of symmetry of the ellipsoid (i. e. by the plane of Fig. 1).
  • the reflected beam has in this case the shape of a cone the apex of which is at A
  • the apex angle ,8 of this sound cone is the smaller as angle on is greater.
  • a is the greater as the ellipsoid is of a more elongated shape, that is to say as the distance between foci A and A is greater.
  • angle [3 of the reflected sound cone it is always advisable to adapt the angle [3 of the reflected sound cone to the space where the apparatus is to be used. For instance, in a church, where acoustic reverberation is high, angle ;3 is advantageously chosen relatively small. On the contrary, in spaces where acoustic reverberation is smaller, angle 5 is advantageously chosen greater.
  • Fig. 1 gives a sound cone having an angle [3 equal to 60, whereas that of Fig. 2 gives a sound cone having an angle [3 equal to 40.
  • I provide a bathe in the form of a wall 3 located at point 0, the plane of this wall being at least approximately at right angles to axis BA
  • This wall, through which passes reflecting surface 2 may be, for instance, the wall of a radio set to which the transducer system belongs.
  • the sound transducer shown by Figs. 3 and 4 is made according to another embodiment of the invention and includes in combination a reflecting surface made as above described and a resonator of the Helmholtz kind tuned to the natural frequency of oscillation of the movable system of the loud speaker.
  • This resonator is essentially. constituted by a sphere 4 including the space at the rear of diaphragm 1, provided, in close vicinity to said diaphragm, with an outlet aperture 5 fitted with an inwardly extending tubularportion 6.
  • Reflecting sphere 4 is prolonged upwardly by a wall 7 which surrounds the rear of the reflecting surface 2 located above diaphragm 1 and is arranged in the same manner as above described with reference to Figs. 1 and 2. Between reflecting surface 2 and wall 7, there is an upwardly tapering free space.
  • a sound transducer which comprises, in combination, a sound generator, a reflecting surface constituted by a portion of an ellipsoid of revolution, this surface being located and arranged with respect to the sound generator in such manner that the point forming the virtual acoustic source of said generator is located at one focus of the ellipsoid, the second focus of said ellipsoid, toward which the reflected sounds converge, being located on the outside of the reflecting surface and downstream of the mouth thereof, the reflecting surface being shaped and the sound generator being positioned with respect to said reflecting surface so that the axis of sound transmission of said generator intersects said reflecting surface and makes with the axis of the sound beam reflected from said surface an angle greater than 90, and the mouth of the reflecting surface extending to a point in the immediate vicinity of the edge of the sound gencrator.
  • a sound transducer according to claim 1 further including a bafile mounted at the place where the edge of the sound generator is closest to the mouth of the reflecting surface, this baflie being at least approximately perpendicular to the axis of the reflected sound beam.
  • a sound transducer further including a substantially spherical resonator mounted at the rear of the sound generator and a tubular passage extending in the spherical cavity of said resonator, and opening frontwardly.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
US2732907D 1950-01-31 Sound transducers Expired - Lifetime US2732907A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR290349X 1950-01-31

Publications (1)

Publication Number Publication Date
US2732907A true US2732907A (en) 1956-01-31

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ID=8887650

Family Applications (1)

Application Number Title Priority Date Filing Date
US2732907D Expired - Lifetime US2732907A (en) 1950-01-31 Sound transducers

Country Status (6)

Country Link
US (1) US2732907A (fr)
CH (1) CH290349A (fr)
DE (1) DE940357C (fr)
FR (2) FR1012676A (fr)
GB (2) GB690889A (fr)
NL (1) NL84969C (fr)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068955A (en) * 1959-11-27 1962-12-18 Albert A W J Van Hedel Device for the radiation of sound waves
US4357490A (en) * 1980-07-18 1982-11-02 Dickey Baron C High fidelity loudspeaker system for aurally simulating wide frequency range point source of sound
US4421200A (en) * 1981-12-16 1983-12-20 Ferralli Michael W Elliptically shaped transducer enclosure
WO1990009084A1 (fr) * 1989-01-31 1990-08-09 Riley Michael D Lentille acoustique focalisee sur l'oreille
USD397118S (en) 1997-04-15 1998-08-18 Keating Stephen D Combined external directional sound dome reflector and deflector for motor vehicle speaker enclosure
US6068080A (en) * 1998-04-13 2000-05-30 Lacarrubba; Emanuel Apparatus for the redistribution of acoustic energy
US20040065500A1 (en) * 2002-10-04 2004-04-08 Lacarrubba Emanuel Acoustic reproduction device with improved directional characteristics
EP0868828A4 (fr) * 1995-12-20 2006-03-22 Emanuel Lacarrubba Reflecteur acoustique
US20080123884A1 (en) * 2006-08-22 2008-05-29 David Donenfeld Passive hearing aid device
US20100290659A1 (en) * 2009-05-12 2010-11-18 Sony Corporation Loudspeaker assembly and electronic equipment
US20140198941A1 (en) * 2011-07-15 2014-07-17 Kpo Innovation Ab Acoustical signal generator using two transducers and a reflector with a non-flat contour
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device
US10149058B2 (en) 2013-03-15 2018-12-04 Richard O'Polka Portable sound system
USD958119S1 (en) * 2021-08-17 2022-07-19 Shenzhen Xunweijia Technology Development Co., Ltd. Microphone stand
US20230007389A1 (en) * 2019-12-04 2023-01-05 Sony Group Corporation Speaker system and sound output method

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1126928B (de) * 1959-11-20 1962-04-05 August Wilhelm Johan Va Albert Einrichtung zur Abstrahlung von Schallwellen
US3234501A (en) * 1962-05-07 1966-02-08 Gen Signal Corp Protective casing for ultrasonic transducers
US4564841A (en) * 1981-01-15 1986-01-14 Neidell Norman S Navigational systems using phase encoded angular coordinates

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1619981A (en) * 1923-03-14 1927-03-08 Sargeant P Knut Sound magnifier
US1786279A (en) * 1927-03-31 1930-12-23 Rca Corp Reflector
FR41374E (fr) * 1931-08-17 1933-01-07 Perfectionnements aux amplificateurs de sons
US2005300A (en) * 1933-12-15 1935-06-18 Arthur M Pfalzer Baffle for loud speakers
US2239170A (en) * 1939-04-26 1941-04-22 Crosley Corp Radio apparatus
US2643727A (en) * 1950-01-31 1953-06-30 Elipson S A Sound transmitting device with an ellipsoidal reflector

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1619981A (en) * 1923-03-14 1927-03-08 Sargeant P Knut Sound magnifier
US1786279A (en) * 1927-03-31 1930-12-23 Rca Corp Reflector
FR41374E (fr) * 1931-08-17 1933-01-07 Perfectionnements aux amplificateurs de sons
US2005300A (en) * 1933-12-15 1935-06-18 Arthur M Pfalzer Baffle for loud speakers
US2239170A (en) * 1939-04-26 1941-04-22 Crosley Corp Radio apparatus
US2643727A (en) * 1950-01-31 1953-06-30 Elipson S A Sound transmitting device with an ellipsoidal reflector

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3068955A (en) * 1959-11-27 1962-12-18 Albert A W J Van Hedel Device for the radiation of sound waves
US4357490A (en) * 1980-07-18 1982-11-02 Dickey Baron C High fidelity loudspeaker system for aurally simulating wide frequency range point source of sound
US4421200A (en) * 1981-12-16 1983-12-20 Ferralli Michael W Elliptically shaped transducer enclosure
WO1990009084A1 (fr) * 1989-01-31 1990-08-09 Riley Michael D Lentille acoustique focalisee sur l'oreille
US4997056A (en) * 1989-01-31 1991-03-05 Riley Michael D Ear-focused acoustic reflector
EP0868828A4 (fr) * 1995-12-20 2006-03-22 Emanuel Lacarrubba Reflecteur acoustique
USD397118S (en) 1997-04-15 1998-08-18 Keating Stephen D Combined external directional sound dome reflector and deflector for motor vehicle speaker enclosure
US6068080A (en) * 1998-04-13 2000-05-30 Lacarrubba; Emanuel Apparatus for the redistribution of acoustic energy
US20040065500A1 (en) * 2002-10-04 2004-04-08 Lacarrubba Emanuel Acoustic reproduction device with improved directional characteristics
US6820718B2 (en) * 2002-10-04 2004-11-23 Lacarrubba Emanuel Acoustic reproduction device with improved directional characteristics
US20080123884A1 (en) * 2006-08-22 2008-05-29 David Donenfeld Passive hearing aid device
US20100290659A1 (en) * 2009-05-12 2010-11-18 Sony Corporation Loudspeaker assembly and electronic equipment
US20140198941A1 (en) * 2011-07-15 2014-07-17 Kpo Innovation Ab Acoustical signal generator using two transducers and a reflector with a non-flat contour
US9467772B2 (en) * 2011-07-15 2016-10-11 Kpo Innovation Ab Acoustical signal generator using two transducers and a reflector with a non-flat contour
US10462561B2 (en) 2011-07-15 2019-10-29 Kpo Innovation Ab Audio generator including a reflector with a non-flat contour
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
US9560442B2 (en) 2013-03-15 2017-01-31 Richard O'Polka Portable sound system
US10149058B2 (en) 2013-03-15 2018-12-04 Richard O'Polka Portable sound system
US10771897B2 (en) 2013-03-15 2020-09-08 Richard O'Polka Portable sound system
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device
US20230007389A1 (en) * 2019-12-04 2023-01-05 Sony Group Corporation Speaker system and sound output method
US11877121B2 (en) * 2019-12-04 2024-01-16 Sony Group Corporation Speaker system and sound output method
USD958119S1 (en) * 2021-08-17 2022-07-19 Shenzhen Xunweijia Technology Development Co., Ltd. Microphone stand

Also Published As

Publication number Publication date
GB690889A (en) 1953-04-29
DE940357C (de) 1956-03-15
FR1012676A (fr) 1952-07-16
GB719969A (en) 1954-12-08
NL84969C (fr)
CH290349A (fr) 1953-04-30
FR61796E (fr) 1955-05-17

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