AND METHOD OF PRODUCTION

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FIELD OF THE INVENTION

The present invention concerns a loudspeaker for an acoustic diffuser for high frequencies or high ranges, also called "tweeter", applied advantageously, but not exclusively, to televisions, audio reproduction systems, hi-fi systems, or other electronic apparatuses provided with devices to generate and diffuse sound.

In particular the present invention concerns a loudspeaker provided with at least one vibrating element, or membrane, of a planar shape, configured to reproduce the sound in all the surrounding space.

The present invention also concerns the acoustic diffuser comprising said loudspeaker.

The present invention also concerns the method to make said loudspeaker.

BACKGROUND OF THE INVENTION

Acoustic diffusers for high frequencies, or tweeters, are known, applicable advantageously but not only to televisions, hi-fi systems or other electronic apparatuses for diffusing sound.

Acoustic diffusers in general, which can be associated with corresponding acoustic amplifiers of a known type, are able to transform an electric signal arriving from the acoustic amplifier itself into sound.

In particular, tweeters are able to reproduce signals with a frequency comprised between about 1 KHz and about 20 KHz, and even more.

In particular, acoustic diffusers of the planar type are known, which are provided with loudspeakers comprising at least one vibrating element of a planar shape and with properties of electric conduction, such as for example a thin flat membrane to which conductor components are associated, or a strip of conductor material which, selectively made to vibrate, moves the surrounding air, generating the sound throughout the surrounding space. Precisely because they comprise said vibrating element, these acoustic diffusers are called planar or strip type. Known acoustic diffusers of the planar type are fundamentally divided into two large groups: electrostatic and magneto-planar, the latter being the object of the present invention.

Normally, magneto-planar acoustic diffusers, in particular those for high- frequency signals, provide that the vibrating element, which includes a thin membrane, elongated in shape, flat and thin, or a rectilinear conductor strip made of aluminum, or a polyester resin commonly used to produce films or sheets of plastic, for example made of Kapton or Mylar ®, is stretched and suspended peripherally or between ends of a support element, associated to a plurality of permanent magnets.

In the case of the membrane, a conductor wire is normally provided, or similar electric conduction element, if the membrane itself is not a conductor, through which an electric current flows, generated by the amplifier. The electric conductor, immersed in the magnetic flow and through which the electric current flows, is subjected to an electromagnetic force, which consequently also moves the membrane on which it is attached or applied, thus making it vibrate. The same happens in the case of a strip made of conductor material and suspended between two support elements, called armature, which include the permanent magnets.

The vibration produces a displacement of the air which in turn generates a consequent diffusion of the sound.

One disadvantage of the strip configuration is that the strip, in particular if it is made long and narrow to obtain a correct functioning, is normally constrained at its ends.

This can cause an excessive slackening of the strip in its central zone, with the risk that it can contact the armatures, can be easily damaged and can exit from the ideal zone of the magnetic flow, reproducing the signal inadequately.

To obviate this disadvantage, it can be provided to constrain the strip along the path. However, this solution subjects the strip to a force of displacement precisely at the points of constraint. This can lead to heating of the strip and, in the worst case, it can break.

Moreover, with this technique, the constraint is localized where the magnetic force is greatest, which can be seen as a possible technical contradiction. Another disadvantage is the fragility of the strip which, suspended between the armatures, can easily break, for example due to a gust of air.

Another disadvantage is that the strip, being very thin and substantially free in the air, on the one hand can resonate, while on the other hand it is free, that is, there are no elements that stop it mechanically once the impulse has stopped, and it behaves with a spring-like effect, and is slow to stop.

Another disadvantage is that, given the length of the strip, the contacts to be connected to each of its ends are relatively distant. In some cases, for example when the loudspeaker is disposed in a vertical position, the connection cables to the amplifier suitable to reach each of the ends of the strip are very long, entailing a possible alteration of the signal to be transmitted, especially when the best quality reproduction possible is required.

On the contrary, a possible solution that provides to use a short strip would imply a reduction in impedance and thus the need to use a transformer/adaptor. Document US-A-2007/286447 describes a loudspeaker device provided with a first central magnetic pole, a pair of magnets at the sides of the central magnetic pole and a pair of plates that form respectively a second and a third magnetic pole, vibrating diaphragms disposed in a V and constrained at the ends to the first central magnetic pole and to the plates and a device to drive the diaphragms. One purpose of the present invention is to obtain a loudspeaker, and a corresponding acoustic diffuser, for high-frequency signals that is able to faithfully reproduce the electric signal transmitted by the amplifier and whose parts are resistant to wear.

Another purpose of the present invention is to perfect a method to make a loudspeaker, and a corresponding acoustic diffuser, as described above.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea. In accordance with some forms of embodiment, a loudspeaker is provided for an acoustic diffuser for high-frequency signals.

According to one form of embodiment, the loudspeaker comprises:

- a planar and elongated vibrating element with electric conduction properties and having at least one long internal segment and one or more long external segments opposite to the at least one internal segment;

- at least one pole to which the at least one internal segment of the vibrating element is stably constrained and from which at least one of the external segments protrudes laterally, free to move, that is, not constrained;

- at least one permanent magnet disposed adjacent to the at least one pole, in which the at least one external segment is facing toward the central permanent magnet.

According to another form of embodiment, the loudspeaker comprises:

- a planar and elongated vibrating element with electric conduction properties and having at least one long internal segment and one or more long external segments opposite to the at least one internal segment;

- a central pole to which the at least one internal segment of the vibrating element is stably constrained and from which the external segments protrude laterally, free to move, that is, not constrained;

- at least a pair of permanent magnets disposed externally at the sides of the central pole, in which the external segments are facing toward the permanent magnets; the free external segments, that is, not constrained, therefore face toward the permanent magnets.

According to another form of embodiment, the loudspeaker comprises:

- a planar and elongated vibrating element with electric conduction properties and having at least one long internal segment and long external segments opposite to the at least one internal segment;

- at least a pair of lateral poles to which internal segments of the vibrating element are stably constrained and from which the external segments protrude laterally, free to move;

- a permanent central magnet disposed internally between the lateral poles, in which the external segments are facing toward the central permanent magnet. The loudspeaker according to the present invention is usable to make an acoustic diffuser for high-frequency signals, in general comprised between about 1 KHz and about 20 KHz, possibly even higher, advantageously applicable, but not exclusively, to televisions, audio reproduction systems, hi-fi systems, or other electronic apparatuses provided with means to generate and diffuse sound.

Therefore, since the vibrating element of the loudspeaker is amply constrained along its internal segments and completely unconstrained along its external segments, it is very resistant during its vibration, avoiding, for example, being damaged or broken.

At the same time, the configuration of the loudspeaker according to the invention allows to faithfully reproduce an input signal, in this case an electric current coming from an amplifier, as the vibrating element is free in the zone in which it is subjected to a greater magnetic force.

In some forms of embodiment, the vibrating element is a membrane. In variant forms, the membrane is an elongated "U" shape. In some variants, the membrane is provided at least with an electric conductor wire, or an adhesive tape applied on the surface of the membrane and with electric conduction properties.

In some forms of embodiment, the vibrating element has one pair of internal segments in an intermediate position and pairs of lateral external segments which develop along a two-way path, connected at one side by means of an end connecting segment and defining, on the other side opposite the end segment, separate connection ends paired and configured for connection to an amplifier.

In some forms of embodiment, at least one permanent magnet is disposed at the side of a lateral external segment and at least one other permanent magnet is disposed at the side of an opposite lateral external segment.

In some forms of embodiment, the lateral external segments are facing toward the permanent magnets and free to move.

In some forms of embodiment, the "U" shape of the membrane is defined by two rectilinear segments substantially parallel with respect to each other connected by the end segment.

In some forms of embodiment, the vibrating element, for example a membrane, is constrained to the central pole continuously in correspondence substantially to the whole length of its internal segments. Therefore the vibrating element is attached on a large part of its internal segments, possibly along all its internal segments, thus preventing the onset of spurious resonances.

According to another aspect of the present invention, the central pole is made of iron, or any other ferromagnetic material easily permeated by a magnetic field, so as to close the lines of the magnetic field of the permanent magnets.

According to another aspect of the present invention, the vibrating element is constrained to the central pole by means of at least one layer of insulating adhesive material.

This allows to electrically insulate the central pole and thus avoid an electric short circuit. Moreover, the insulating adhesive material contributes to damping the resonances and in the mechanical return, since it acts as a spring that returns the vibrating element to the initial position and as a damper when the impulse has stopped.

According to another aspect of the present invention, the ends connecting to the amplifier are adjacent to each other in correspondence to one of the ends of the loudspeaker.

This allows to avoid additional electric connections for one of the two connecting ends, in particular the more distant one, so as to reproduce the electric signal as faithfully as possible.

According to another aspect of the present invention, at least the permanent magnets and the central pole are interposed between two armatures, which act as support and protection and delimit a region inside which the vibrating element can vibrate.

Some forms of embodiment provide that the permanent magnets are oriented with identical polarities facing toward the central pole, or with opposite polarities, according to need.

Advantageously, with the present invention it is possible to improve the audio performance of the diffuser even at a second moment, with the addition of other permanent magnets, in a modular manner. This possibility, supplied by the specific reciprocal position of the central pole, vibrating element and permanent magnets, is completely innovative with respect to existing loudspeakers that instead do not have any capacity for improving the performance of their components.

The present invention also concerns an acoustic diffuser comprising at least a loudspeaker as described above.

The present invention also concerns a method to produce a loudspeaker as described above. The method provides to:

- make available a vibrating element which is planar and elongated with electric conduction properties;

- stably constrain at least one internal segment of the vibrating element to at least one central pole from which one or more external segments of the vibrating element protrude laterally, free to move;

- dispose at least one permanent magnet adjacent to at least one side of the pole, in which the at least one external segment is facing toward the at least one permanent magnet.

These and other aspects, characteristics and advantages of the present disclosure will be better understood with reference to the following description, drawings and attached claims. The drawings, which are integrated and form part of the present description, show some forms of embodiment of the present invention, and together with the description, are intended to describe the principles of the disclosure.

The various aspects and characteristics described in the present description can be applied individually where possible. These individual aspects, for example aspects and characteristics described in the attached dependent claims, can be the object of divisional applications.

It is understood that any aspect or characteristic that is discovered, during the patenting process, to be already known, shall not be claimed and shall be the object of a disclaimer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of forms of embodiment, given as a non- restrictive example with reference to the attached drawings wherein:

- fig. 1 is a perspective view of forms of embodiment of a loudspeaker according to the present description; - fig. 2 is a perspective view of the loudspeaker in fig. 1 without any elements;

- fig. 3 is a schematization of an acoustic diffuser, comprising the loudspeaker in fig. 1, connected to another element;

- fig. 4 is a cross section of the loudspeaker in fig. 1 ;

- fig. 5a is an enlarged detail of fig. 4;

- figs. 5b - 5d are variants of fig. 5a;

- fig. 6 is the cross section of fig. 4, in which a first effect is shown;

- fig. 7 is the cross section of fig. 4, in which a second effect is shown;

- fig. 8 is the cross section of fig. 4, in which a third effect is shown;

- fig. 9 is the cross section of fig. 4, in which a fourth effect is shown;

- figs. 10 - 16 are cross sections of a loudspeaker in accordance with forms of embodiment described here.

DETAILED DESCRIPTION OF SOME FORMS OF EMBODIMENT

We shall now refer in detail to the various forms of embodiment of the present invention, of which one or more examples are shown in the attached drawing. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one form of embodiment can be adopted on, or in association with, other forms of embodiment to produce another form of embodiment. It is understood that the present invention shall include all such modifications and variants.

Figs. 1 , 2 and 3 are used to describe an acoustic diffuser 12 for high-frequency signals, which includes a loudspeaker 10 according to forms of embodiment in accordance with the present description. The acoustic diffuser 12 can be applied advantageously, but not exclusively, to televisions, hi-fi systems, or other electronic apparatuses provided with means for diffusing sound.

Normally, the acoustic diffuser 12 is also connected to an amplifier 1 1, only schematized in the drawings, with the function of generating an electric signal, in this case an alternate current, to be transmitted to the loudspeaker 10, which has the function of reproducing it as faithfully as possible to obtain the desired diffusion of the sound.

In particular, some forms of embodiment, which can be combined with all the forms of embodiment described here, concern a loudspeaker 10, also called tweeter, able to reproduce signals at high frequencies, that is, comprised between about 1 KHz and about 20KHz, and possibly even higher.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the loudspeaker 10 in this case comprises a vibrating element 13, planar and with an elongated shape. In particular, according to possible implementations, a single vibrating element 13 can be provided.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 can be a membrane for example, or similar strip-shaped element, 13, for example in the shape of an elongated "U", or a double strip shape, or again a filament shape.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 can be provided with at least a conductor wire 26, or with at least a conductor adhesive strip applied on it, or it can be made itself of an electric conductor material, such as aluminum. By "U" shaped we mean a shape, more or less wide or narrow, or a concave shape, essentially formed by at least two longitudinal segments, substantially rectilinear and parallel to each other, or even slightly curved, connected by an intermediate connection segment on one side and having, on the other side, free ends, so as to define an outward segment and a return segment.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the "U" shape, more or less elongated, or similar conformation of the vibrating element 13, for example like a membrane 13, is defined by two rectilinear segments or strips 21a and 21b, paired and substantially parallel to each other to define a two-way path, and an end connection segment 22 that unites them in proximity to one of the ends of the loudspeaker 10. For example, the end connection segment 22 can have a similar or equal structure to that of the rectilinear segments or strips 21a and 21b, or it can be formed by an electric conductor wire.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13, in the form of a membrane 13 for example, also comprises, at the opposite end with respect to that corresponding to the end segment 22, two separate ends 23a and 23b located on the same side, opposite the end segment 22 and adjacent to each other, configured to connect to corresponding cables, not shown in the drawings, able to be connected with the amplifier 1 1.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, a central pole 20 can be provided, in this example case made of iron, or soft iron, or similar ferromagnetic material (figs. 5a - 9).

In some forms of embodiment, which can be combined with all the forms of embodiment described here, at least one internal segment 14a, 14b of the vibrating element 13, for example a membrane 13, is stably constrained to the central pole 20.

Moreover, external segments 25a, 25b of the vibrating element 13 protrude laterally from the central pole 20 itself, and are free to move, that is, they are not constrained to any other physical object or element.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, at least a pair of permanent magnets 15a, 15b can be provided, disposed externally at the sides of the central pole 20, so that the external segments 25a, 25b are facing toward the permanent magnets 15a, 15b.

The constraint of the vibrating element 13 to the central pole 20 allows to adequately clamp the latter, so that it remains in an ideal zone of the magnetic flow, avoiding going into contact with the armatures or the magnets.

In particular, with the disposition described above, the nearer the vibrating element 13 is to the magnets 15a, 15b, with its own external lateral segments 25a, 25b free, the greater is the magnetic force to which it is subjected and therefore the greater is its freedom to move along the external lateral segments 25a, 25b, for example substantially with an alternate "flipper" type motion. Instead, the further away the vibrating element 13 is from the magnets 15a, 15b, the lower is the magnetic force to which it is subjected and its freedom to move is therefore less. Furthermore, the constraint of the vibrating element 13 described above renders the latter less fragile, since the external stresses only cause the cited "flipper" movement, avoiding damaging it.

We also maintain that the constraint of the vibrating element 13 cited above prevents the onset of spurious resonances since, as it is attached along the internal segments 14a, 14b, in this way it is not free of constraint for excessively long segments. Furthermore, the possible "U" conformation of the vibrating element 13, or similar shape, defining a two-way path, causes the positive and negative poles defined by the separate ends 23a and 23b to be on the same side and near each other, preventing useless and inferior additional electric connections for one of the two poles.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 can have a pair of intermediate internal segments 14a, 14b and a pair of opposite external segments 25a, 25b that develop along a two-way path connected by the end segment 22. In this case, given by way of example, each of the two rectilinear segments 21a and 21b has a corresponding internal segment 14a, 14b and a corresponding pair of external segments 25a, 25b.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, in proximity to each external segment 25a, 25b of the vibrating element 13 at least one permanent magnet 15a, 15b is disposed, for example aligned along a corresponding external segment 25a, 25b. For example, the vibrating element 13 is interposed between two permanent magnets 15a and 15b.

As discussed, the cited separate ends 23a and 23b of the vibrating element 13, being positioned one near the other, advantageously allow to avoid useless additional electric connections for one of the ends 23a, 23b themselves, in particular the most distant one, a situation that could generate disturbed and inadequate sounds, or in any case not faithfully reproducing the electric signal of the amplifier 1 1.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13, for example a membrane 13, of the planar type, can be made for example of an electric conductor material, such as aluminum, or a polyester resin commonly used to produce plastic films or sheets, in Mylar® for example, to which at least a conductor wire is associated, or a conductor adhesive strip or similar electric conductor component. The function of the vibrating element 13 is to vibrate in relation to the electric signal coming from the amplifier 1 1 , generating, during use, the diffusion of the sound, as will be described hereafter in the description. In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13, for example a membrane 13, can be made of any material resistant to deformation and breakage and with the capacity to vibrate as a function of the electric signal of the amplifier 1 1. In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 has smooth surfaces.

In other forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 can have corrugated surfaces, in order to give greater elasticity to its movement. Moreover, in other variants the vibrating element 13 can be holed with incisions or through cuts that facilitate the flection and improve the functioning thereof.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the permanent magnets 15a and 15b are disposed with polarities, N and S, identical toward the central pole 20 (figs. 4, 6-9), which closes the magnetic flow lines M (fig. 6) of the permanent magnets 1 a and 15b. In some forms of embodiment, to reinforce the magnetic flow and close the circuit, two external poles 27a and 27b made of iron are also provided.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the permanent magnets 15a and 15b and the central pole 20 are attached, on their opposite surfaces, to two armatures 17 and 18. The armatures 17 and 18 have a main support function and are made for example of a non-ferromagnetic material, such as aluminum, or they are made of ferromagnetic material, although care must be taken to suitably direct the magnetic flow lines. These armatures 17, 18 can mainly have the function of supporting the permanent magnets 15a and 15b and possibly the central pole 20. In some forms of embodiment, the armatures 17, 18 are disposed so as to cover, in a sandwich, the permanent magnets 15a and 15b, the central pole 20 and the external poles 27a and 27b. The disposition of the two armatures 17 and 18 also delimits a region 28 inside which the vibrating element 13 is able to move.

Fig. 2 is used to describe in more detail the disposition and shape of the vibrating element 13 interposed between the two permanent magnets 15a and 15b. In fig. 2, for ease of comprehension, the loudspeaker 10 is shown without the armature 17 and without the central pole 20. In particular, in some forms of embodiment, the internal segments 14a and 14b of the vibrating element 13 are attached, for example by an adhesive material, to the central pole 20 at about half the thickness, or in another variable position, which allows in any case a suitable constraint of the region 28 delimited by the armatures 17 and 18 (fig. 5a).

As discussed above, in some variants the vibrating element 13 is made of electric conductor material, such as aluminum, through which the electric current generated by the amplifier 11 can pass (fig. 5a).

In other variants, at least one strip is applied on the vibrating element 13, and is made to adhere, for example by adhesive material, or by hot coupling of materials or other techniques, with electric conduction properties; the electric current generated by the amplifier 1 1 can pass through the strip.

In other variants, at least one conductor wire 26 is disposed on the vibrating element 13 and is integrated therewith; the electric current generated by the amplifier 1 1 can pass through the conductor wire 26 (fig. 5b).

In any case, the vibrating element 13, for example a membrane 13, has a conductor through which electric current passes and which is immersed in a magnetic field. Therefore, in a known manner, the conductor is subjected to a magnetic force F 1 (fig. 7) able to make it move as a function of the development of the electric current passing through them. Since the conductor is integrated with the vibrating element 13, or itself constitutes the vibrating element 13, the displacement or vibration of the latter is obtained.

In this case, since it is constrained at its internal segments 14a and 14b, the vibrating element 13 is able to perform a vibration with an amplitude that varies along the width of the vibrating element 13 (fig. 8). In fact, the amplitude of the vibration is at its maximum in correspondence with the external edges 25a and 25b, that is, the non-constrained edges, and is zero in correspondence with the internal segments 14a and 14b, that is, the constrained edges.

In this way, electric energy is transformed into mechanical vibration energy, which causes a displacement of air that in turn determines the diffusion of the sound throughout the surrounding space.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the invention provides to use, in order to attach the vibrating element 13 to the central pole 20, a layer 24 of insulating adhesive material (fig. 5), for example Kapton, so as to insulate the vibrating element 13 electrically and prevent a short circuit. This is advantageous, in particular, in the case of a vibrating element 13 made of electric conductor material, as shown for example in fig. 5a.

Kapton is a film able to remain stable in a wide range of temperatures and is also used in flexible printed circuits and in devices used to guarantee heat protection.

The presence of the insulating adhesive material also allows to damp the resonances and the mechanical return, since it functions as a spring that returns the vibrating element 13 to the initial position.

On the contrary, fig. 5b is used to describe forms of embodiment in which the vibrating element 13 is provided with said at least one conductor wire 26 or, equivalently, with an adhesive tape with electric conduction properties. In this case, the layer 24 may not be provided.

Fig. 5c is used to describe other variants of fig. 5a, in which the vibrating element 13 is made of conductor material and is aligned and flush with the central pole 20. In particular, in this variant the vibrating element 13 has the segments 14a, 14b which are aligned outside the central pole 20, clamped between two layers 24 of insulating adhesive material disposed in a sandwich in the central pole 20 and distanced to allow to insert and clamp the internal segments 14a, 14b of the vibrating element 13, but without the vibrating element 13 extending inside the central pole 20, in any case allowing the external segments 25a, 25b to vibrate. Fig. 5d is used to show variants of fig. 5c in which a filling material 24a is provided between the layers 24, to compensate a possible flexion or deformation thereof.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the vibrating element 13 is amply constrained only at its internal segments 14a and 14b; in this way it can move in a controlled and orderly manner and remain in the ideal zone of the magnetic flow. Advantageously, the risk of possible contacts with the armatures 17 and 18 and/or with the permanent magnets 15a and 15b is thus limited, as well as possible damage to the vibrating element 13. Another important aspect is that, the greater the magnetic force F l to which the vibrating element 13 is subjected, that is, as it draws nearer to the permanent magnets 15a and 15b, the greater is the freedom of movement of the vibrating element 13, since the latter is constrained only to the internal segments 14a and 14b.

Vice versa, the greater the distance from the permanent magnets 15a and 15b, the smaller is the magnetic force F to which the vibrating element 13 is subjected.

According to the invention therefore, the configuration of the loudspeaker 10 is coherent in the ratios of force, displacement and geometry.

Furthermore, the loudspeaker 10 is sufficiently robust, or in any case more robust than known loudspeakers. In fact, the constraint to the internal segments 14a and 14b, which can even be substantially along the whole length of the vibrating element 13, can cause only the vibration of the latter in the above mode, without damaging or even tearing off part of the vibrating element 13.

In some forms of embodiment, which can be combined with all the forms of embodiment described here, the two armatures 17 and 18, which are substantially identical, have a planar development and each have a plurality of rectangular through holes 19 (fig. 1), aligned or not aligned with each other which, during use, are disposed coincident with the region 28 and hence with the vibrating element 13, so that the air moved by the latter passes through the rectangular holes 19 (fig. 9). In fig. 9, the arrows F2 indicate the flow of air moved by the vibrating element 13.

In some forms of embodiment, therefore, the vibrating element 13 can be attached substantially along all its internal segments 14a and 14b, thus preventing the onset of spurious resonances.

Due to the configuration of its parts, and in particular to the type of constraint of the vibrating element 13, the loudspeaker 10 in its entirety is able to faithfully reproduce high-frequency signals transmitted by the amplifier 1 1 , advantageously also having a high resistance to wear.

The loudspeaker 10 also has an adequate angular dispersion. In fact, by putting the listening point in an angled position with respect to the loudspeaker 10, the sound characteristics are stable and the sound emitted is clear, or in any case better than that emitted by known loudspeakers. Figs. 10-16 are used to describe other forms of embodiment, which can be combined with all the forms of embodiment described here, of loudspeaker 10 according to the present description.

In particular, fig. 10 is used to describe forms of embodiment in which the loudspeaker 10 in substance is divided into half with respect to the forms of embodiment described using figs. 1-9. This loudspeaker 10 comprises the two armatures 17, 18, in particular made for example of diamagnetic material, a magnet 15a disposed adjacent to a central pole 20, an external pole 27a and the vibrating element 13 connected to the central pole 20 by the layer 24. The vibrating element 13 is provided with an internal segment 14a constrained to the central pole 20 and a single external segment 25a, free to move. These forms of embodiment can be useful if a particularly narrow version of the loudspeaker 10 is needed; however, since the vibrating element 13 itself does not create the return, an external conductor is provided to connect the central pole 20 that represents the other end of the vibrating element 13.

Fig. 1 1 is used to described forms of embodiment similar to those described using fig. 10, in which the magnet 15a is optimized in shape toward the vibrating element 13, which reproduces the geometry of the movement of the vibrating element 13, guaranteeing the same flow as the range of movement varies. In particular, it can be seen how one face 15c of the magnet 15a facing toward the vibrating element 13 has a concave shape that reproduces a segment of bend mating with the profile of the path spanned by the end of the vibrating element 13.

Fig. 12 is used to describe forms of embodiment similar to those described using figs. 10 and 1 1, in which the magnet 15a has one face 15d of the magnet 15a facing toward the vibrating element 13 shaped as a point, or in any case as a cusp or converging toward the center. This shape of the face 15d can be configured to concentrate the magnetic flow in the zone of the vibrating element 13, when the flow is to be greatly increased, and hence the efficiency of the loudspeaker, on condition that the range of movement remains limited, and hence with rather high working frequencies, so that it does not exit from the magnetic flow. These forms of embodiment described using figs. 1 1 and 12 can also be applied to forms of embodiment described using figs. 1-9, that is, with the whole loudspeaker 10 not halved, in which the vibrating element 13 is for example U- shaped, with return.

Figs. 13 and 14 are used to describe forms of embodiment, which can be combined with all the forms of embodiment described here, in which a loudspeaker 10 is provided that also comprises one or more components 30 configured to generate a desired acoustic load, of the trumpet type in the case of the drawing, which serves to modify the efficiency, the angular dispersion and the frequency response (obtaining the so-called "acoustic lens" effect). The form of the acoustic load generated by the one or more components 30 can vary as a function of the needs that are to be met. In particular, these forms of embodiment can also be applied to forms of embodiment of the loudspeaker 10 described using figs. 1-9. Finally, the structure of the one or more components 30 for the acoustic loading can become a structural part of the loudspeaker 10, becoming a support structure or matrix, which can protect the magnets 15a, 15b and which can have particular styles able to give acoustic load to the loudspeaker 10. Moreover, the structure of the one or more components 30 for the acoustic loading can be modular, it can house magnets of different shapes, with or without iron, etc.. (see for example fig. 14).

Fig. 15 is used to describe forms of embodiment, which can be combined with all the forms of embodiment described here, similar to those described using fig. 13 and in which an iron bar is used, with a shape such as to perform a structural function and also a function of closing the lines of magnetic flow. In this case too, it can be used in a double version, with a U-shaped filament and split structure, as in the forms of embodiment of the loudspeaker 10 described using figs. 1-9.

Fig. 16 is used to describe forms of embodiment, which can be combined with all the forms of embodiment described here, in which the loudspeaker 10 has an inverted structure compared with what was described using figs. 1-9 for example. In particular, a central magnet 1 15 is provided, and two lateral poles 120, with the vibrating element 13 constrained with its segments 14a to the lateral poles 120 and which has free, unconstrained segments 25a, facing toward the central magnet 1 15.

The forms of embodiment described using figs. 15 and 16 can provide the magnet 15a, 15b, 1 15 shaped for example as in the forms of embodiment described using fig. 1 1, or in the forms of embodiment described using fig. 12, or again the magnet 15a, 15b, 1 15 with a flat face as described using figs. 1-10, 13, 14.

It is clear that modifications and/or additions of parts may be made to the loudspeaker 10 as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of loudspeaker, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.