Other

Commissariat a L'energie Atomique

Siegfried Klein

Rainer Haas

The invention relates to a sound distributor with symmetry of revolution. The distributor comprises two sound reflecting cups, having a convex shape which is an exponential of surface revolution about a fictitious axis. The outer surfaces of these cups are arranged in tail to tail manner. The distributor has at least one sound source positioned facing a small opening of one of the cups. Around an opening in the bottom of the second cup, the distributor also has a trumpet-shaped reflector and a cone-shaped reflector for directing sound along the axis.

Sound distributor with symmetry of revolution

The invention concerns an omnidirectional loudspeaker. This loudspeaker comprises a spherical membrane which includes spires formed of a strip (2) made of a magnetostrictive material, the spires being spiral wound according to a sphere; these spires are kept in place by an elastic support (1) so that, along with the support, they form a spherical membrane. The strip has two opposing faces (11, 12), one of which is directed towards the inside (I) of the sphere, the other being directed towards the outside (E) of the sphere, and two extremities (3, 4) situated in two diametrically opposing zones of the sphere so as to be connected to an electric control device (5) providing a signal corresponding to sound waves to be reproduced, and a device (7) for the continuous polarization of the membrane. According to the invention, one of the faces (11) of the strip (2) is at least partly coated with a thin coating (13) made of a rigid material. Invention may be applied for the diffusion of high quality omnidirectional sound waves.

Spherical membrane omnidirectional loudspeaker using a magnetostrictive

The invention relates to a wide passband omnidirectional loudspeaker which has particular application to high fidelity sound reproduction. The loudspeaker has a rigid, magnetostrictive, spherical diaphragm (3), a medium and high frequency electric control means connected to two terminals (4,5) located at two diametrically opposite points of the diaphragm for creating in the vicinity thereof a homogeneous magnetic field with respect to an electric signal applied to the terminals (4,5) of the control means after filtering (2) for eliminating the low frequencies, and a d.c. polarization means (11,12) for the diaphragm. The loudspeaker also has another low frequency electric control means (14) receiving the electric signal after filtering for eliminating the medium and high frequencies. This low frequency electric control means extends longitudinally along an axis (X'X) of the diaphragm and has two ends (16,17) respectively joined to two opposite zones of the diaphragm (3) traversed by axis (X'X).

Wide passband omnidirectional loudspeaker

In the case of an electroacoustic transducer with a supporting body carrying coil turns and in particular a vibrating hollow body with a curved surface, such as a magnetostrictive ball, in order to obtain an optimum distribution of the modulation energy, it is proposed that the coil is applied to the supporting body (2) as a flat material corrugated strip (3) at right angles to the running direction.

Electroacoustic transducer

Wide pass band elastic wave omnidirectional transducer. It comprises a magnetostrictive material membrane (34, 36) provided with two electrical connections at two diametrically opposite points. The potential difference between these connections is proportional to the elastic wave transmitted or received by said membrane. A continuous polarization means of the magnetostrictive membrane is also provided. It comprises a high magnetic permeability part (40, 42), whose shape substantially corresponds to that of the membrane and which is placed in the vicinity of the latter, and a permanent magnet (38) in contact with said part. Application to the transmission of high frequency elastic waves in water (hydrophone) and to high fidelity sound reproduction in air.

Wide pass band elastic wave omnidirectional transducer

The visual apparatus makes it possible to limit the instantaneous luminous intensity without reducing the field of vision and comprises a plate with an opaque surface having a transparent slot, a support (2) on which said plate is mounted, said support bearing on part of the body of said person, said plate thus being placed in front of an eye of said person and a scanning means (8) connected to said plate for scanning the opaque surface of said plate by said transparent slot. The apparatus is used more particularly as medical spectacles in the case of cataracts, or as sunglasses.

Visual apparatus

Omnidirectional, wide pass band, elastic wave transducer comprising a rigid magnetostrictive diaphragm, each surface element of the diaphragm constituting a unidirectional elastic wave transducer in its normal direction, and an electric control means provided with two electric terminals for producing in the vicinity of the diaphragm a homogeneous magnetic field in keeping with an electric signal applied to the terminals of the control means or for supplying an electric signal in keeping with the variation of the magnetic field in the diaphragm as a function of an elastic wave received. The diaphragm is preferably a closed surface of revolution. Application in submarine transmission (hydrophone) and in high fidelity sound reproduction (loudspeaker, microphone) with a very wide pass band.

Omnidirectional transducer of elastic waves with a wide pass band and

A loudspeaker primarily for the high frequency audio region includes a driving device coupled to a diaphragm of convex outer configuration and extending over more than 180.degree. spherical angle. The driving device changes the distance between the two coupling areas of the diaphragm under the action of an electrical signal applied thereto. Elastic deformations appear on the diaphragm which give rise to an emission of soundwaves.

Loudspeaker

Transducer for the transformation of electrical modulations into vibratory modulations, comprising a needle-shaped discharge electrode, which is embedded, except in the region of its tip, in an electrode holder of substantially cylindrical form, made of an electrically insulating, and heat-resistant material, and a counter-electrode spaced from the discharge electrode and surrounding the latter. The counter-electrode has substantially the form of a sphere embodied in a perforated, electrically conductive material permeable to sound waves, and has a passage in which electrode holder is fitted. The discharge electrode extends radially into the interior of the spherical counter-electrode up to a point situated in proximity to the center of the sphere. The transducer thus embodied is omnidirectional.

Transducer for the transformation of electrical modulations into

A high-frequency loudspeaker has a movable diaphragm which is moved to and fro by an actuating unit. The actuating unit, under the impulses of a signal to be converted into sound waves, changes in dimension in at least two opposed directions. The diaphragm is made up of two rigid hemispherical shell diaphragms which are connected together through a resilient ring to constitute a pulsating, closed sphere. An actuating unit is disposed inside the sphere and is firmly connected to the two diaphragms, so that the forces emanating therefrom are imparted to the two diaphragms and in directions at right angles to the plane connecting between the two diaphragms. A device is provided for equalizing the atmospheric pressure within and outside the closed, spherical body. Instead of connecting the diaphragms through a ring it is also possible to have the diaphragms merge without contact through a labyrinthic seal.

High-frequency loud speaker

An electrodynamic loudspeaker radiates sound in all directions and with a high output for a low and medium sound frequencies. It comprises two hemispherical movable diaphragms which are arranged on either side of a disc-shaped carrier part. The diaphragms are connected with the carrier part by flanges and constitute a pulsating sphere. In this sphere and connected in each case with one of the diaphragms are actuating units with permanent magnets and in each case, an oscillatory coil. Each oscillatory coil is connected to its respective diaphragm through stiff transition parts, preferably in the form of spherical shells. Openings are provided for an atmospheric pressure equalization between the interior and exterior of the breathing sphere.

Electrodynamic loudspeaker for low and medium sound frequencies

A corona effect sound emitter including a discharge electrode producing corona discharge and surrounded by a spherical counter electrode is partially inserted in a housing which encloses a high frequency generator, modulation transformer and a power supply transformer of which the power supply transformer supplies the discharge electrode with electric current. A thin plate of a magnetic metal transversally extends in the housing so that secondary windings of the transformers are positioned above the plate and are separated from the primary windings of the transformers disposed below the plate.

Corona-effect sound emitter

Sound emitter comprising a circuit generating an electrical signal at high frequency and high voltage, which is modulated by a low frequency signal which is to be transformed into sound waves, and which is applied to a corona-effect transducer at the input of an exponential horn. Transducer appears in the form of a cylindrical cartridge which is mounted slidably in a passage in the housing of the emitter, and one end of which is engaged in an accommodation provided at the input of the horn, while its other end projects beyond the outer end of passage; the discharge electrode has a cylindrical contact part which is exposed in an intermediate zone of the transducer, between the accommodation and the inner end of the passage; a metal contact member is electrically connected to the output of the generating circuit and is in sliding contact with the contact part of electrode; a metal plug is fixed detachably at the outer end of said passage and holds the transducer in place axially.

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Paris, France

Siegfried Klein