JPH01258590A - Motor driven electroacoustic transducer - Google Patents

Abstract

PURPOSE:To eliminate a damage due to the cutting of a lead wire or the disconnection of soldering by moving a field magnet without moving a voice coil and pulling and oscillating the lead wire. CONSTITUTION:In the cylindrical magnetic gap 30 of a magnetic circuit, a cylindrically formed stator voice coil 23 is fixed. The field magnet 22 having internal and external faces magnetized to different poles, the anisotropic characteristic in the radial direction of the cylindrical pole and made of a magnet light in a specific gravity than a conductor forming the stator voice coil 23 is axially movably disposed in the magnetic gap 30 through the stator voice coil 23 and the radial magnetic gap 30. An oscillator 21 is oscillated according to the axial oscillating movement of this field magnet 22.

Description

[Detailed Description of the Invention] [Industrial Application Field of the Invention] The present invention relates to an electrodynamic electroacoustic exchanger for speakers, microphones, earphones, telephones, etc., and its feature is that the voice coil is fixed. The structure is such that the field magnet moves, reducing the weight of the movable body.As a result, the response speed is improved and the efficiency of converting vibration into sound or current is increased, making it easy to produce low-pitched sounds. It can be expected to have a long life since the lead wire does not need to be dragged, and the tS construction can be simplified and mass-produced at low cost. The reason is that it is an efficient electroacoustic exchanger.

[Technical background and problems] Electrodynamic electroacoustic exchanger 1 For example, in a speaker, the voice coil is movably placed in a magnetic field and when a sound current is applied, the voice coil vibrates as the current changes. It is something. In this case, a speaker that reproduces sound waves by moving a vibrating body with a coil is called a dynamic speaker, and a speaker that emits sound waves by directly connecting a coil to a cone-shaped paper or the like is called a dynamic cone speaker. A dynamic horn is a device in which a small vibrating body is moved by a voice coil, and a horn (or trumpet) is attached to the front of the vibrating body to efficiently radiate sound waves.
It's called a speaker. A microphone, for example a dynamic microphone, has a structure similar to a dynamic speaker.

Conversely, when the vibrating body moves in response to sound waves, the voice coil attached to it vibrates within the magnetic field and generates an electric current. Since these electrodynamic electroacoustic exchangers all have similar structures, the speaker will be explained below.

Many conventional dynamic cone speakers 1 are constructed as shown in FIG.

That is, a permanent magnet 4 made of a cylindrical ferrite magnet is placed on a yoke plate 3 equipped with a center ball (center magnetic pole) 2, and an upper yoke plate 5, which is also cylindrical, is fixed with adhesive or the like to create a field. The field section 6 constitutes the fixed side.The field section 6 shown here is called an external magnet type, and uses a yoke, and a columnar permanent magnet and a center magnet are installed in the center of the yoke. It may also be of the so-called internal magnetic type that incorporates a ball.

A cone-shaped frame 7 is coupled to this field section 6.
A peripheral edge of a vibrating body 9 formed of a cone-shaped fiber is bonded to the peripheral edge of the frame 7 with an adhesive or the like, along with a gasket (satellite) 8. A coil bobbin 11 made of paper, thin plastic, or the like and having a cylindrical voice coil 10 wound therein is coupled to the center of the vibrating body 9.

The middle part of the coil bobbin 11 holds the voice coil 10 at the center between the magnetic poles and performs appropriate damping (braking) on vibrations.
The voice coil 10 is supported by a damper 12 for applying pressure, so that the voice coil 10 is correctly positioned within the magnetic gap 13 of the field section 6. Further, a dust cap 14 such as a dustproof cloth is attached to the upper surface of the central portion of the vibrating body 9 to prevent dust in the air from entering the annular magnetic gap 13.

According to such a conventional speaker 1, the voice coil 1
0 drags the lead wire and vibrates, so if used for a long time, the lead wire may break or the solder may come off, leading to damage and shortening the service life. there were.

Further, as shown in FIG. 7, the lead wire 15 of the voice coil 10 is pulled out from the upper part through the magnetic gap 13, guided to the vibrating body 9 (or the frame 7), and placed at that position. Because it is soldered to ■
In order to pass both terminals of the lead wire 15 of the voice coil 10 into the magnetic gap 13, the voice coil 10 has a limited thickness.
By using this method, the magnetic flux density within the magnetic gap 13 cannot be increased by the thickness of the lead wire 15, resulting in poor efficiency. ■Since both terminals of the lead wire 15 of the voice coil 10 must be passed through the magnetic gap 13, and both terminals of the lead wire 15 must be soldered to the vibrating body 9, etc., it is not suitable for mass production and is expensive. It had become a thing. ■Also, if the vibrating body 9 is made of a thin film plastic these days, when the terminal of the lead wire 15 is soldered to it, holes will be formed due to the heat generated at that time, increasing the defective rate.
The vibrating body 9 could not be formed of a desirable thin film plastic, and mass production could not be carried out at low cost. ■Also, since both terminals of the lead wire 15 of the voice coil 1o are passed through the magnetic gap 13, there is a risk that the lead wire 15 may come into contact with the fixed side when the voice coil 1o vibrates, so it must be manufactured with great precision. The defective rate was also very high.

In addition, in the case of the conventional speaker 1, since the voice coil 10 is vibrated, the specific gravity of the conducting wire that makes up the voice coil 10 (the specific gravity of copper is

7) is heavy, resulting in a large load, slow response speed, and the disadvantage that it is not possible to extract audio signals with higher precision than in 1 over a wide range. In particular, it wasn't good enough to extract dynamic bass. (2) In addition, in order to eliminate the disadvantage (2) above due to the very heavy conductor wire for forming the voice coil 10, the weight of the voice coil 10 should not be too heavy, and the magnetic gap 13 should be widened. In order to prevent the magnetic flux density in the magnetic air gap 13 from decreasing, the conductor wires must be closely wound in one row (also called aligned winding) so that they do not overlap.
Manufacturing the voice coil 10, which is tightly wound in rows, requires very high precision and is difficult, resulting in a high defect rate and high cost. (1) One of the causes of the drawbacks (2) and (2) above is that in conventional speakers 1, etc., the resistance value of the voice coil 10 is, for example, 1 depending on the standard.

This is due to the fact that it is specified as 8Ω, etc. However, manufacturing the voice coil 10 according to the resistance value is extremely troublesome and has the disadvantage of not being suitable for mass production.

In addition, as described above, the voice coil 10 must be formed by tightly winding it in one row, which makes it impossible to wind the conductive wire in multiple turns, which results in the generation of a large driving force to vibrate the voice coil 10. Therefore, in the case of low-pitched sounds, it was not possible to output audio signals with high accuracy. Also,
In particular, when trying to produce bass sounds with high precision, the precision becomes extremely high.

It has not been possible to produce a speaker or the like that can produce accurate bass sounds at low cost.

Note that the large driving force T for vibrating the voice coil 10 is as follows.

T = t・■ t: Number of winding turns of the conductor wire: It is given by the current, but conventionally, for the reasons mentioned above, the number of turns t of the conductor wire cannot be made to a large value, so Not only is it impossible to obtain driving force, but
The value of flow (2) also increases, which has the disadvantage of making the speaker 1 inefficient.

Furthermore, according to the speaker 1, the field section (magnetic circuit) 6
As is clear from Fig. 6, this method requires the use of a large and heavy permanent magnet 4, which results in a heavy object. had the disadvantage of being expensive.

In addition, since the large permanent magnet 4 is used as described above, the permanent magnet 4 must be exposed and attached, so that a considerable amount of the magnetic flux of the permanent magnet 4 leaks, that is, such a large leakage magnetic flux However, there was a risk that it would have a negative impact on various types of audio equipment, which are becoming increasingly densely packaged.

In addition, since the large permanent magnet 4 must be exposed and mounted as described above, a considerable amount of the magnetic flux of the permanent magnet 4 leaks, resulting in an inefficient speaker 1, which requires the use of a large and heavy permanent magnet. Otherwise, a large amount of expensive permanent magnet material capable of generating a strong magnetic force must be used, which increases the disadvantage that the speaker 1 becomes large, heavy, and expensive.

[Section M of the present invention] The object of the present invention is to completely change the concept of the conventional electrodynamic electroacoustic exchanger so that the field magnet is moved without moving the voice coil.

The objective was to provide an electrodynamic electroacoustic exchanger that would have a long life and be highly reliable by eliminating breakage of the lead wires caused by the vibration of the voice coil dragging the lead wires and damage caused by solder coming off. In addition, the lead wire does not need to pass through the magnetic gap 13, and the troublesome process of soldering both terminals of the lead wire to the vibrating body, etc., is omitted, making it suitable for mass production and manufacturing at low cost. This was accomplished with the task of achieving this goal. Another problem of the present invention is that by creating a configuration in which the voice coil does not move, the lead wire does not come into sliding contact with the fixed side. By using a transducer with a specific gravity of 4) and making it stationary, the weight of the transducer can be reduced, the response speed can be increased, and audio signals can be extracted with higher precision over a wider range. The objective of this project was to create a device that could produce particularly dynamic bass sounds at a low cost. In other words, since the field magnet is moved, it is possible to prevent the field magnet from being subjected to a large load, and also to generate a strong magnetic force, and by using a magnetic material that can generate such a strong magnetic force. The object of the present invention was to make the field magnet smaller and lighter in weight so that the field magnet could be constructed at a lower cost. In addition, by creating a configuration that does not require the voice coil to move, it is possible to use flat winding, which eliminates the need for the close winding method of winding conductors in a single row so that they do not overlap, which is extremely difficult to manufacture. The objective of this invention was to make it extremely easy to manufacture nine windings, reduce the defective rate, and enable the voice coil to be mass-produced at low cost and easily. Of course, in the present invention, it goes without saying that the voice coil of a conventional speaker may be used as is.Also, the voice coil is structured to have a sufficient space to accommodate the voice coil wound with a large number of turns. It is possible to generate a large driving force for vibrating the field magnet by using a voice coil in which a conductive wire is wound in a large number of turns without forming a densely wound winding in one row.

This was accomplished with the objective of making it possible to extract audio signals with high accuracy even in the case of low-pitched sounds.

By doing this, the large driving force for vibrating the field magnet T T = t・■ t: Number of winding turns of the conductor ■: Current, the number of winding turns t of the conductor can be made to a large value. By forming it in a manner that allows a large driving force T to be obtained, and by making it possible to reduce the value of the current I, it is possible to obtain an efficient electrodynamic electroacoustic exchanger such as a speaker. The task was to do so.

Yet again. By simplifying the magnetic circuit configuration.

By minimizing the leakage magnetic flux of the field magnet, the structure is configured so that external equipment is not adversely affected by the leakage magnetic flux of the field magnet, and the magnetic circuit can be configured small, resulting in a light weight and small speaker. The objective was to make it possible to construct the system at low cost and easily.

[Means for achieving the object of the present invention] The object of the present invention is to fix a stator voice coil formed in a cylindrical shape in a cylindrical magnetic gap of a magnetic circuit, and to connect the stator voice coil with the radial magnetic gap. It is a radially anisotropic cylindrical single pole whose inner and outer surfaces are magnetized with different polarities so that it can move freely in the axial direction within the magnetic gap, and has a specific gravity higher than that of the conducting wire forming the stator voice coil. This is achieved by providing a field magnet made of a light magnet, and providing a vibrating body directly or at intervals that is interlocked with or in contact with the field magnet as it vibrates in the axial direction.

[Embodiments of the present invention] [First embodiment of the present invention] Fig. 1 shows a dynamic cone speaker 16 of the present invention.
FIG. 2 is an exploded perspective view with a part thereof cut away, and FIG. 2 is a longitudinal sectional view thereof. A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A dynamic cone speaker 16 according to a first embodiment of the present invention is manufactured by molding a magnetic material 1, for example, a magnetic material containing plastic powder.

Center pole (center magnetic pole) 17. Yoke plate 18
and by integrally forming the frame 19.

A stator 20 serving as a field section is formed. The center ball 17 is integrally formed with the bottom central portion 18a of the cup-shaped yoke plate 18 and extends upward into a cylindrical shape.
Two cylindrical magnetic gaps 30 are formed between the outer circumference 17a and the inner circumference 18b of the yoke plate 18. A cone-shaped frame 19 is integrally formed at the upper end of the outer periphery 18c of the cup-shaped yoke plate 18. A gas get (not shown) and a peripheral edge of a cone-shaped vibrating body 21 are bonded to the upper edge of the frame 19 by adhesive or the like. The center part of the lower end of this vibrating body 21 has a cone-shaped part 22a at the upper end, and has a thickness of 1 mm or less (this varies depending on the specifications and size of the speaker 16, etc., but in the case of a small speaker 16 etc., the thickness is 0.1 mm or less). A field magnet 22 formed into a cylindrical shape (preferably about 5 mm)
are coupled so that reciprocating vibration can occur in the axial direction within the magnetic gap 30. Field magnet 2
In order to obtain a uniform driving force, the cylindrical field magnet 22 is desirably formed to have a longer axial length than the axial length of the stator voice coil 23, which will be described later. By using a cylindrical magnet made of an anisotropic (radial direction) resin magnet, for example, neodymium, boron, or iron, it is possible to easily form a magnet that fully satisfies the purpose of the present invention. An anisotropic magnet is a magnet with forced spin orientation.
Generally, by applying a strong magnetic field to the magnetic material before it hardens.

Can be manufactured. Here, the optimum magnetic material for forming the field magnet 22 is one that allows the field magnet 22 to be formed to be lighter than the specific gravity of the stator voice coil 23, which will be described later, and has a magnetic flux density that is 1 stronger than that of the stator voice coil 23, and that is easy to process or form. It is desirable to have something that is extremely easy to use, so the field magnet 22 selected and prototyped by the inventor of the present invention is designed to have a strong magnetic force as a magnet and also be extremely thin. Uses a neodymium/boron/iron resin magnet oriented in a radial direction (radial direction) anisotropically with a specific gravity of about 4.

This is formed into a cylindrical shape by a suitable forming means such as a mold. The field magnet 22 has radial anisotropy and has nine magnetization directions regulated, so it is magnetized into a single pole so that the inner and outer circumferences have different polarities. In this example, the inner circumference is made of Ni and the outer circumference is made of S.
It is a single-pole type with magnetization formed on the pole. If the weight of the field magnet 22 becomes heavy, the responsiveness will deteriorate, so it is a typical practice to use a field magnet 22 that is less than three times the weight of the stator voice coil 23, which will be described later. The two types of speakers we actually prototyped had an axial length of 7 mm and an outer diameter of 20 m.
One of them had a radial thickness of 1 mm and a weight of 1 g, and the other had a radial thickness of 0.5 mm and a weight of 0.5 g. As the stator voice coil 23 to be described later, an experiment was conducted using the voice coil 10 shown in FIG. 6, which is used in the conventional speaker 1 and has a weight of 0.5 g and an axial length of 4 mm. went. When the voice coil 10 of 0.5 g is used as the stator voice coil 23, the field magnet 22
, 0.5 g, the weight of the field magnet 22 is twice the weight of the stator voice coil 23, and is equal to the weight of the stator voice coil 23. No matter which of these two types of field magnets 22 was used, it was possible to obtain an accurate and accurate acoustic signal. However, when the field magnet 22 is constructed using the above-mentioned type of magnet material, a stronger magnetic flux can be obtained by using a lighter field magnet 22 with a thickness of 0.5 mm and a weight of 0.5 g. Good results have been obtained.

Therefore, when the conventional voice coil 10 is used as the stator voice coil 23, the field magnet 22 is
If a coil having approximately the same weight as the voice coil 10 is used, a highly efficient speaker 16 that can be expected to be obtained can be obtained. The middle part of the field magnet 22 is supported by a damper (not shown) for holding the field magnet 22 at the center of the magnetic pole and applying appropriate damping (braking) to vibrations, and the field magnet 22 is held at the center of the magnetic pole. It is made to be positioned correctly within the magnetic air gap 30. Further, a dust cap 24 such as a dustproof cloth is attached to the upper surface of the central portion of the vibrating body 21 to prevent dust in the air from entering the magnetic gap 30.

A stator voice coil 23 formed into a cylindrical shape by winding a conducting wire with an appropriate number of turns is fixed to the inner circumferential surface 18b of the yoke plate 18 using adhesive, and the lead wire 25 of the stator voice coil 23 is fixed to the inner peripheral surface 18b of the yoke plate 18. is pulled out from a through hole 26 provided in the lower part of the yoke plate 18 and guided to the outside.

[Second Embodiment of the Invention] FIG. 3 shows a dynamic cone speaker 16 of the present invention.
Fig. 4 is an exploded perspective view of the main parts of ゛. See Figures 3 and 4.

A second embodiment of the present invention will be described below. In addition.

Portions common to those in the first embodiment are denoted by the same reference numerals, and explanations thereof are omitted, and corresponding portions are denoted by dashes.

A dynamic cone speaker 16' representing a second embodiment of the present invention includes a center ball 17' having a cup-shaped longitudinal section, a yoke plate 18°, and a frame 19' that are integrally formed by pressing a magnetic material such as an iron plate. By doing so, a stator 20' serving as a field section is formed. In order to reduce weight and cost, the center ball 17' is integrally formed into a cup shape by pressing means so that the inside is hollow at the center of the bottom surface of the cup-shaped yoke plate 18'. It is extending. Center ball 17'
A nine cylindrical magnetic gap 30 is formed between the outer circumference of the yoke plate 18' and the inner circumferential surface of the yoke plate 18'. A cone-shaped frame 19 is attached to the upper end of the outer periphery of the cup-shaped yoke 18'.
° is integrally formed. A through hole 27 is formed in the frame 19'' by means of a press.

Further, a flange 29 having a through hole 28 is formed at the upper end peripheral edge of the frame 19° to connect the peripheral edge of the cone-shaped vibrating body 21' with a screw or the like together with a gasket (not shown). In addition, in the vibrating body 21' in this embodiment,
In order to increase the vibration efficiency, a bellows portion 31 is formed in the middle. The configuration of the other parts of this speaker 16' is the same as that shown in the first embodiment, so a description thereof will be omitted. Note that the reference numeral 26' indicates a through hole.

[Third Embodiment of the Present Invention] Referring to FIG. 5, in this third embodiment, a vibrating body 21'' made of thin film plastic and a field magnet 22 are formed by two-color molding of plastic and a plastic magnet. FIG. 5 shows an example in which the vibrating body 21'
teeth.

Needless to say, it is made of thin film plastic.
The ends of the vibrating body 21° and the field magnet 22, which are made of thin film plastic, can be joined together not only by the method described above, but also by any suitable means such as adhesive or ultrasonic welding. The formed vibrating body 21'' can be easily formed by using an appropriate method and material.
Now, by selecting a speaker having a large number of fine holes, or by changing the material and thickness, it is possible to form a speaker 16 with a variety of tones with various characteristics.

[Operation of the invention] In the present invention, the principle of operation is the same, so to explain with reference to the first embodiment, in the speaker 1,
When an alternating current with a magnitude based on the acoustic signal is passed through the voice coil 23, a force that reciprocates along the axial direction of the magnetic air gap 30 is generated according to Fleming's left-hand rule, so the field magnet 22 is connected to the magnetic air gap. 30 and reciprocatingly vibrates along its axial direction. For this reason, the field magnet 2
A vibrating body 21 fixed to 2 vibrates to generate an acoustic signal sound having an appropriate wavelength and size.

[Effects of the Invention] Since the present invention has the above configuration, the field magnet moves without moving the voice coil.
It is possible to obtain a highly reliable and long-life electrodynamic electroacoustic exchanger that is free from breakage of the lead wires due to vibration caused by dragging the lead wires and damage due to solder coming off. Furthermore, since the troublesome step of soldering both terminals of the lead wire to the vibrating body or the like can be omitted, mass production is excellent and manufacturing is possible at low cost. Furthermore, since the lead wire terminals do not need to be soldered to the vibrating body, the vibrating body can be easily mass-produced at low cost using a desirable thin film plastic. The field magnet is made of radially anisotropic material, such as neodymium, boron, or iron-based resin magnet material, which has a specific gravity lighter than that of the conductive wire and can strengthen the magnetic force, and is preferably less than three times the weight of the stator voice coil. Because the field magnet is made thinner to maintain the same level of thickness, the field magnet can generate strong magnetic force and requires less magnet material, which reduces the weight of the vibrator and increases response speed. This has been difficult in the past, as it has become faster and allows audio signals to be extracted over a wider range with greater precision.

In particular, it has the effect of being able to construct a highly efficient device that can extract dynamic bass sounds at low cost. In addition, by increasing the length of the field magnet in the axial direction of the stator voice coil to obtain sufficient magnetic flux, more driving force can be obtained reliably, and as a result, audio signals can be extracted with higher accuracy. , which has been difficult in the past. In particular, it has the effect of being able to construct a highly efficient device that can extract dynamic bass sounds at low cost. In addition, field magnets are small and extremely lightweight, so
The magnetic circuit can be configured very easily, the magnetic path of the field magnet can be sufficiently closed, and the leakage magnetic flux caused by the field magnet does not have an adverse effect on external devices of the speaker. In addition, field magnets can configure the magnetic circuit so that only a small amount of leakage magnetic flux is generated.
Compared to ferrite magnets, neodymium, boron, and
Even if iron-based resin magnets are used, the field magnets are very thin and light in weight, so the amount of magnetic material that makes up the field magnets is small, which makes field magnets cheaper. There is an effect that can be formed.

It also simplifies the magnetic circuit including the field magnet.

Since it can be made small and lightweight, it has the effect that an electrodynamic electroacoustic exchanger such as a speaker can be made small and lightweight. Furthermore, there is enough space and
Since the voice coil does not need to be moved, it is possible to manufacture single windings, which eliminates the need to use the close winding method of winding conductors in a single row so that they do not overlap, which is extremely difficult to manufacture. This has the effect of greatly simplifying the process, reducing the defective rate, and making it possible to mass-produce the voice coil at low cost and easily.

Yet again. The field magnet is made of a magnetic material that can generate strong magnetic force even if it is thin (especially recent technology has made this possible), and a voice coil wound with many turns can be used, making it possible to generate a strong magnetic force using a large number of conducting wires. By using a turn-wound voice coil to generate a large driving force to vibrate the field magnet, it is possible to extract highly accurate audio signals even at low frequencies. There is.

That is, the large driving force for vibrating the field magnet T T = t - I t: Number of winding turns of the conducting wire I: Current, since the number of turns t of the conducting wire can be made to a large value,
Since a large driving force T can be obtained and the value of the current I can also be made small, there is an effect that an efficient electrodynamic electroacoustic exchanger such as a speaker can be obtained. Although the embodiments of the present invention have mainly been described with respect to speakers, the present invention is naturally applicable to electrodynamic electroacoustic exchangers such as microphones that share the same structural principle.

[Brief explanation of the drawing]

FIG. 1 shows a dynamic cone according to a first embodiment of the present invention.
FIG. 2 is a vertical sectional view of the speaker, FIG. 3 is an exploded perspective view of the main parts of a dynamic cone speaker according to a second embodiment of the present invention, and FIG. 4 is a vertical sectional view of the same, FIG. 5 is a partial explanatory diagram for explaining the third embodiment of the present invention, and FIG. 6 is a diagram of a conventional dynamic cone.
A vertical cross-sectional view of the speaker, and FIG. 7 is an explanatory view of the same portion. [Explanation of symbols] 1...Dynamic cone speaker. 2...Center ball (center magnetic pole). 3...Center ball, 4...Permanent magnet. 5... Upper yoke plate, 6... Field section. 7...Frame. 8... Gasket (arrow paper), 9... Vibrating body. 10...Voice coil. 11... Coil bobbin, 12... Damper. 13...Magnetic gap. 14...Dust cap. 15... Lead wire. 16.16', 16°'...Dynamic cone speaker. 17.17' ...Center ball. 17a...outer circumference. 18.18'...Yoke plate. 18a... Bottom part 518b... Inner peripheral surface. 18c...outer circumference. 19.19''... Frame. 20.20'... Stator. 21.21''... Vibrating body. 22... Field magnet. 22a... cone-shaped part. 23...Stator voice coil. 24...Dust cap. 25... Lead wire. 26.27.28...Through hole. 29...flange, 30...magnetic gap.

Claims (3)

[Claims] (1) A cylindrical stator voice coil is fixedly provided in a cylindrical magnetic gap of a magnetic circuit, and is movable in the axial direction within the magnetic gap via a radial magnetic gap with the stator voice coil. A field magnet is provided, which is a cylindrical unipolar radially anisotropic magnet whose inner and outer surfaces are magnetized with different polarities so that , an electrodynamic electroacoustic exchanger comprising a vibrating body that is interlocked with or in contact with the field magnet by vibration movement in the axial direction, either directly or at intervals. (2) The field magnet has a weight that is three times or less that of the stator voice coil.
The electrodynamic electroacoustic exchanger described in . (3) The electrodynamic electroacoustic exchanger according to claim (2), wherein the field magnet has a weight that is approximately the same or less than that of the stator voice coil.