SU843312A1 - Electroacoustic transducer - Google Patents

Description

(54) ELECTROACOUSTIC CONVERTER

I

The invention relates to instrumentation, in particular to the field of electroacoustics and can be used in the design of electrodynamic loudspeakers.

Known electroacoustic transducer containing a magnetic circuit and voice coil. The principle of operation of this device is to move the sound coil relative to the magnetic circuit when signals are received on the winding of coil 1.

The disadvantage of this converter is the unevenness of the frequency response.

Closest to what is described is an electroacoustic transducer containing a magnetic core and a voice coil. The skeleton of the voice coil is made in the form of a split ring of paramagnetic material. When the sub-signal on the sound wheel; it interacts with the magnetic field of the magnetic system, moves together with the skeleton. At high frequencies, the input impedance increases the increase in impedance of the sound coil, which is inductive in nature.

As a result, the amplitude of the current through the coil winding decreases with increasing signal frequency, which reduces the magnitude of the interaction between the coil and the magnetic system and leads to uneven frequency response of the converter 2.

The purpose of the invention is to reduce the nonlinearity of the frequency response.

This goal is achieved by the fact that an electroacoustic transducer containing a magnetic core and a spinner roll is equipped with two leveling rolls, all the rolls are placed coaxially on the magnetic core, the sonic roll is mounted between the leveling rolls and can be moved oppositely to the sound rolls.

The goal is also achieved by the fact that the inductances of all the coils are equal, and the magnetic circuit is made of ferrite.

FIG. I depicts the described electroacoustic transducer; in fig. 2 is a circuit for connecting it to a two-wire line.

Claims (2)

The electroacoustic transducer contains a voice coil 1 located on the magnetic circuit 2. On the one and the other side of the voice coil 1, leveling coils 3-4 are placed on the magnetic conductor 2, each of which is included with the sound coil 1. The first lead of the coil 3 is connected to terminal 5 The second terminal of the roller 3 is connected to one terminal of the voice coil 1 and terminal 6, and the other terminal of the audio roller 1 is connected to terminal 7 and the first terminal of the roller 4, the second terminal of which is connected to terminal 8. The two-wire line converter contains diodes 9, 10, 11, and 12, and terminals 5 and 6 of the electro-acoustic converter are connected to the anodes of diodes 9 and 10, respectively, whose cathodes are connected to the input terminals 13-M and to the anodes of diodes 11 and 12, respectively, and the cathodes diodes 11 and 12 are connected respectively to terminals 7 and 8 of the electroacoustic converter. Electro-acoustic transducer works as follows. Since the coils 1, 3, 4 are on the main magnetic circuit 2, each leveling coil 3 or 4 is inductively coupled to the sound coil 1, and the coils of each leveling coils 3 and 4 are connected in opposition to the winding of the sound coils 1. When voltage is applied terminals 5 and 7 through the winding of the additional coil 3 and the winding of the sonic coil 1 flow counter currents. The currents in the windings of the coils 3 and 1 create magnetic fields, which are directed in such a way that they cause pushing away of the coils 3 and 1. As the additional coil 3 is fixed, then the sonic coil 1, which is movable on the magnetic core 2, begins to move (push) in the axial direction. When voltage is applied to terminals 6 and 8, the counter currents flow through the winding of the leveling roll 4 and the sound roll 1, these currents create magnetic fields that cause a mechanical displacement of the sound pushing away 1 from the leveling roll 4. In the axial direction of the magnetic circuit 2, due to the counter-engagement of the cutters 3 or 4 and the sound coil 1, the inductive nature of the input impedance appears slightly. For the most complete reduction of the inductance of the input impedance at terminals 5 and 7, as well as at terminals 6 and 8, the inductances of all three coils 1, 3 and 4 are chosen equal. To increase the interaction and inductive coupling between the rollers, material has been selected as the material of the magnetic core 2. with high magnetic permeability - ferrite. In order to provide an oscillatory movement of the sound coil 1, the control voltage must be divided into two components. This is achieved by using an electroacoustic converter connection device to the two-wire line shown in FIG. 1. The control voltage goes to the input terminals 13 and 14. If the potential on terminal 13 is higher than that on terminal 14. then the current flows through diode 12, the windings of coils 4 and 1, diode 10, if the potential on terminal 13 is lower, than at terminal 14, current flows through diode 11, windings of coils 1 and 3 and diode 9. Thus, depending on the polarity of the control voltage at terminals 13 and 14, sonic coil 1 oscillates in one direction or another. When using the proposed transducer as a moving system of an electrodynamic loudspeaker, the voice coil 1 must be associated with a diaphragm. The use of the proposed electroacoustic converter, for example, as a mobile speaker system, makes it possible to ensure the constancy of the input impedance in the working frequency range. This results in a uniform power emission in the frequency range, i.e., improves one of the main characteristics of the loudspeaker. Claims 1. Electro-acoustic transducer comprising a magnetic core and a voice coil, characterized in that. in order to reduce the non-linearity of the frequency response, it is equipped with two leveling rolls, all the rolls are placed coaxially on the magnetic conductor, while the sonic roll is mounted between the leveling rolls with the possibility of movement, and each leveling roll is connected opposite to the sound one. 2. Converter according to claim 1, characterized in that the inductances of all the coils are equal. 3. A converter according to claim 1, characterized in that the magnetic core is made of ferrite. Sources of information taken into account in the examination 1. The author's certificate of the USSR 329681, cl. H 04 R 9/06, 03.08.70. 2. Authors certificate of the USSR 478457, cl. H 04 R 9/04, 06.25.73 (Protocol about 13 & ABOUT QB 07 FIG.