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DESCRIPTION JP2017512023 Abstract: The present invention relates to a power supply circuit of an acoustic signal of at least one loudspeaker (HP), which circuit comprises a filter arrangement of resonant peaks occurring at a given frequency of the supply current, the filter arrangement of the peaks being at least Incorporated in the first branch which bypasses the intermediate circuit between the two converters (A, A0), the filter arrangement is purely electrical in the form of impedance (Z), while one of the above mentioned intermediate circuits is Connected to the point, while connected to the grounded device, the impedance (Z) comprises at least one first resistor (R), at least a first capacitor (C) and at least one first resistor (R) arranged in series It is called RLC because it has one first inductor (L), and the first resistor (R), the first capacitor (C), and the first inductor (L) Over data is determined in advance as a function of the resonance peak to be filtered. [Selected figure] Figure 1 Apparatus and method for filtering resonant peaks in a power supply circuit of at least one loudspeaker upstream of the loudspeaker [0001] The present invention relates to an apparatus and method for filtering resonant peaks in a power supply circuit of at least one speaker. [0002] Conventional speakers are known to generally include an electromagnetic actuator consisting of a coil disposed on an assembly movable in the magnetic field generated by the permanent magnet. 11-04-2019 1 [0003] When the coil of the loudspeaker is traversed by the frequency-modulated current, the mechanical displacement induced at the audio frequency is converted into a sound field by means of a membrane acting as a radiation surface, also called an acoustic radiator. [0004] The sound quality of the loudspeaker depends on the frequency response curve, ie the mechanical acceleration response to an electrical load, either current or voltage, which is sought to be constant over the entire bandwidth. Sound quality also depends on the linearity of the device, which is characterized by the presence of harmonic distortion and a minimum of intermodulation. [0005] If the transducer acting as a speaker boosts all frequencies equally, the reproduction of the instrument's timbre, which constitutes a useful overtone, appears to be secured at first glance. [0006] However, reality is more complicated in terms of the need to properly reproduce the momentary attack sounds of typical sounds of high quality musical instrument acoustic signatures. The response of the loudspeaker to the momentary attack sound is an essential requirement of "fidelity", which can be tested by detecting the "smearing" of the membrane when the loudspeaker is requested by a pulse train. The inertial and self-induced forces of the moving assembly contribute to this defect. [0007] 11-04-2019 2 Acoustic, optical and electrical measurements show that there is no ideal loudspeaker, and that each implementation is defective in bandwidth limitations, various resonance peaks and inertia. The connection of several transducers in principle overcomes many drawbacks, but conversely, sometimes these defects build up in the bad direction for high quality music reproduction. [0008] In a loudspeaker, the useful driving force at the starting point of displacement of the moving assembly is the length of the winding traversed by the induced magnetic field denoted B and the current represented by i (t) which is a function of time t Interaction with each element of Locally, the force of the element applied to the displaced load carrier in the induced magnetic field is called Lorentz force, which is applied in a direction perpendicular to the plane defined by the scope and velocity of the carrier. The balance within the component volume of the load carrier subject to that phenomenon leads to the following equation: [0009] Everything happens as if the unwound length of the winding, denoted by l, is exposed to a homogeneous induction field, which is the power factor of the moving parts of the loudspeaker (newton / ampere or tesla meter It allows the definition of the quantity B1 = B · l called). [0010] This force, which is modulated by the intensity, requires a moving assembly, the mechanical behavior of which is represented by three components: inertial force, the product of the mass of the moving part represented by M m and acceleration; damping force, f Expressed in m newtons / meter / s or kilos / sec, and is usually assumed to be proportional to the displacement velocity through a constant; and expressed in restoring forces, k m Newtons / meter, related to mechanical springs, Affected by stiffness. The behavior equation of such an idealized transducer for guided translation on the x-axis is: 11-04-2019 3 [0011] The current-voltage relationship at the terminals of the loudspeaker is governed by the construction of the loudspeaker, which is characterized by the moving assembly moving in the magnetic field. Thus, the electrical behavior is defined by two mechanisms based on the following three contributing elements: electromagnetic interaction in terms of divergence and induced electromotive force by Joule effect related to Ohm's law The voltage drop associated with the resistive component of the solenoid winding assembly, the induced electromotive force associated with the change in flux during the displacement, the self-induced electromotive force governed by the law of Lentz. [0012] Thus, under the assumption of system linearity, the equation of electrical behavior is added to the above equation governing the mechanical behavior of the loudspeaker: [0013] Now taking nonlinearity into account, R e is the pure resistance component of the winding, is temperature sensitive, is measured in ohms, and L e is its self inductance, in function of displacement Yes, measured by Henry. In fact, if the current involved in the left hand side of equation 2 directly follows equation 3, discontinuity or non-linearity associated with the latter will affect the displacement of the membrane and its derivative function. [0014] There are two respective strategies for controlling the loudspeaker: current control or voltage control. In both cases, if the signal processing by the pre-amplification stage results in a control signal that can be consistently measured as a voltage, then in the case of voltage control, it is the dipole that the transducer exhibits when acting as a speaker It depends on the child's impedance naturally. This control is similar to the coupling between an ideal Thevenin generator capable of powering a speaker. Also, the loudspeaker constitutes a load of a nearly zero-impedance power supply tributary, and any electromotive force or electromotive force component generated 11-04-2019 4 directly affects the current flowing through the aggregate circuit. [0015] Conversely, for current control, a current-voltage conversion is provided by a specially designed signal regulator, which is required by the output current of this regulator. This control is similar to an ideal Norton generator capable of powering the converter. The latter represents the load which is then required under infinite impedance, where fluctuations of any electromotive force component EMF generated by the load remain without significantly affecting the behavior of the aggregate circuit. Even better, this voltage is measured and can be used as a correction signal for servo strategies. [0016] In general, voltage control directly requires a loudspeaker given the electrical behavior according to the configuration parameters of the impedance. Much work has been done relatively recently for the design of specifically electrically controlled loudspeakers, given the provision of appropriate regulators. [0017] Among the electrical and mechanical parameters that show the behavior of the loudspeaker, the above three values B1, R e and L e basically determine the reproduction quality of the regulatorconverter aggregate circuit. The interaction is not the same, depending on the choice between the two control modes of current and voltage by the designer. [0018] In current control, the regulator-converter assembly is essentially completely insensitive to the stresses generated. However, for such a choice, it is necessary to detect and correct, if possible, defects inherent in changes in the parameters involved in equation (2), which defects are Show the power of a square or i <2> parasitic term function: 11-04-2019 5 [0019] Equation (2) can be described in the frequency domain: where X is the displacement due to the Laplace transform, I means I times the unit, the ratio f m / M m represents the attenuation, and the relaxation time is It is an inverse function, while k m / M m means the square of the resonant angular frequency. [0020] The transfer function of the displacement applied to the current is shown below by designating f m / M m = 2 / τ, and k m / M m = ω 0 <2>, where ω 0 is the initial angular velocity. Will: [0021] Equations (2) and (3) are considered in the harmonic regime in the frequency domain and can be combined in terms of the cascade transfer function. Denoting the separated complex intensities of their spreads as E 0 and I 0, the index indicates a particular angular frequency called the “phaser” and the following equation is obtained: [0022] The product p. Substituting X, the impedance transfer function is immediately displayed in a complex form including two terms: [0023] Ignoring the reactance component, the impedance of the loudspeaker can be written as: The grouping of parameters leads to the following simple equation: [0024] 11-04-2019 6 It can be seen immediately that the polynomial V 1, which represents the behavior associated with voltage control, is characterized by a much greater attenuation than the polynomial P 1 associated with the current control scheme. The viscous friction coefficient f m of the current control scheme is replaced by the following systematically increased coefficients for the voltage control scheme: [0025] The mechanical resonance coefficients Q m and Q m + e are defined as follows, with respect to the specific times involved (τ m and τ m + e respectively): The specific electrical coefficient Q e is defined by zeroing f m And a simple relationship for coupling the resonant components can be expressed by the following equation: [0026] The impedance of the transducer combines a purely electrical component with a second component called the kinetic impedance. Thus, the speaker impedance Z HP is written as Z HP = Z e + Z m, where: [0027] The kinetic impedance appears to be influenced by a characteristic quadratic polynomial exhibiting band-pass behavior. Also, if it is customary to define the nominal impedance according to a predetermined value, use 4W and 8W for the power converter, 16W and 32W for the mini and micro systems worn on the headphones, and The contribution can never be neglected if the converter has to be energized. Similarly, as the frequency increases, the inductive reactance component j. L. w gradually attenuates the regeneration of the signal. [0028] 11-04-2019 7 The behavior of the voltage application mode converter shows the coupling of equations (8) and (9b) combined in terms of the composite transfer function. Here, considering the relative displacement function X (p), the previous expression of equation (6) is resumed. [0029] Also, equation (11), which describes the impedance of the transducer, results in the following equation: ## EQU11 ## Thereby the transfer function of the velocity and acceleration of the diaphragm is expressed in two equations in terms of derivative quantities: [0030] If we consider a function related to displacement, we can generally express [0031] Looking at the scheme near resonance, in the case of current control, the need for correction by filtering appears immediately as an important result of the description herein. Voltage control, as often referred to as a conclusive argument justifying the choice of voltage control, has a much larger natural damping effect than current control and has great advantages in this respect. [0032] Document FR-A-2 422 309 (patent document 1), in its introductory part, for current-controlled loudspeakers, the membrane of the loudspeaker can be the location of deformation or standing waves at high frequencies, which means that current control It is stated that it is particularly disadvantageous for Conversely, this document recognizes that voltage control can only be used in a limited frequency range. [0033] 11-04-2019 8 In order to improve current control, this document proposes combining current control and servo acceleration for frequencies covering all mechanical resonances of the loudspeaker. However, this solution has never been satisfactory because the servo acceleration could not compensate for all mechanical resonances specific to each speaker. [0034] In its introductory part GB-A-2 473 921 (patent document 2) that the sound quality of the electrodynamic speaker can be significantly improved by providing current control instead of voltage control often used for the speaker It is disclosed. Current control is obtained when the source impedance seen by the driver is high compared to the driver's self-impedance. [0035] This document also shows that, in current control, the typical peak frequency of the rising process of a cone loudspeaker can not be compensated by simply adding an RC network in parallel with the conductor, after which the high impedance of the power supply I realize that I will be lost. [0036] Thus, this document provides dual coil control of the speaker for use in combination with one impedance, which deactivates one of the voice coils at high frequencies and produces the required response correction, while Maintain relatively high source impedance. [0037] However, the addition of dual coils requires the complete reconstruction of the current control coil, which is not usually double. This is too expensive for current control and presents design specific settings. [0038] 11-04-2019 9 Although the above prior art documents have recognized the advantages of current control in speakers, a solution has been developed to date that effectively rectifies the two major drawbacks inherent in current control: Not: First, the presence of a resonant peak that can not be corrected, while the voltage control results in a natural correction to the resonant peak due to the effect of the kinetic impedance matched to the resonant frequency of the transducer. Second, according to acoustical studies, as the frequency goes up, the increasing directivity effect of the loudspeaker makes it possible to measure the sound pressure level in the axial direction perpendicular to the diaphragm, this phenomenon being called the "horn effect" be called. Again, when using voltage control, the inductive component of the transducer compensates for this effect locally before reducing the level of sound at high frequencies. [0039] ＦＲ−Ａ−２４２２３０９ ＧＢ−Ａ−２４７３９２１ [0040] The object of the present invention is to maintain the current control of the loudspeaker for any category of loudspeaker by electrical means and without making any particular adaptation to the current control of the loudspeaker, which remains unchanged from the prior art. Correcting the presence of at least a resonance peak. [0041] To this end the invention is a power supply circuit of an acoustic signal of at least one loudspeaker, which circuit is a filter arrangement of resonant peaks occurring at a given frequency of the power supply current of said at least one loudspeaker; And at least two noninverter converters arranged in series upstream of the at least one speaker, each of the two converters having a positive power terminal, a negative power terminal, and an output And the topmost converter of the two converters has a positive supply terminal connected to the input power supply of the circuit, while the output of the topmost converter is connected via the intermediate circuit to the positive of the second converter. At least one speaker resonance in a power supply circuit of an acoustic signal of at least one speaker, connected to the power supply terminal, the output of the second converter being connected to the at least one speaker The filter device is integrated in the first branch which bypasses the intermediate circuit between the two converters, the filter device being purely electrical in the form of an impedance, while being connected to one point of the intermediate circuit And, on the other hand, to a grounded device, 11-04-2019 10 whose impedance has at least one first resistor, at least one first capacitor, and at least one first inductor, arranged in series. And wherein the parameters of the first resistor, the first capacitor, and the first inductor are preset as a function of the filtered resonant peak of the at least one speaker. And a power supply circuit of an acoustic signal of at least one speaker. [0042] The technical effect is to be able to use current control, which has the advantages mentioned above, while hiding the main drawback of current control which, unlike in the case of voltage control, produces a resonance peak which is not compensated by this current control. [0043] Virtual inductors are particularly beneficial because they can be easily changed by changing their interaction and / or behavior without replacing the elements that make up them. Thus, such a virtual impedance is easy to operate in the operating conditions of the at least one speaker, including but not limited to monitoring changes in resonant peak frequency, for example due to temperature changes of the at least one speaker or overheating of the speakers. Provide the great advantage of being [0044] Advantageously, the value of the first virtual inductor is equal to the product of the values of the first auxiliary resistor, the second auxiliary resistor and the auxiliary capacitor. The first resistor and the second auxiliary resistor are preferably distinguished from one another from the total resistance by the following equation: R 3 = R 03 -RA preferably the second capacitor is between the two converters Located in a second branch bypassing the intermediate circuit, the second capacitor with a second resistor, the parameters of the second capacitor and the second resistor being pre-reduced to reduce high frequency signals It is set. [0045] 11-04-2019 11 Preferably, the intermediate circuit between the two non-inverter converters is arranged between the output of the most upstream non-inverter converter and the first branch of the intermediate circuit incorporating the filter arrangement, a third resistor Have. Advantageously, for a resonant peak of 197 Hz, the value of the at least one first resistor is equal to zero, the values of the at least first capacitor and the at least one first inductor are respectively 0.29 μF and 2. Equal to 28H, the values of the first and second auxiliary resistors are equal to 1,200 ohms and 400 ohms, respectively, and the value of the third resistance is 3,000 ohms. [0046] Advantageously, each non-inverter converter has its own feedback loop, the output of which is connected to the negative power supply terminal of the respective non-inverter converter, and which respective feedback loop is the most upstream conversion Have a fourth resistance, bypassing the intermediate circuit between the two non-inverter converters, and for the most downstream converter, downstream of at least one speaker It is mounted bypassing the equipment grounding circuit. [0047] The invention also relates to a method of controlling the supply of power to the acoustic signal of at least one loudspeaker, the power supply incorporating a filter arrangement of resonant peaks, wherein the method comprises correction of resonant peaks by the filter arrangement. A step is performed, the correction step being performed upstream of the at least one speaker. [0048] Advantageously, the overall resonant components of the loudspeaker and filter arrangement are set relative to the Butterworth filter. Advantageously, if the at least one loudspeaker comprises a diaphragm, the reduction of the level of sound at high frequencies in the direction of the axis perpendicular to the diaphragm of the at least one loudspeaker is performed simultaneously with the filtering of the resonant peak. [0049] 11-04-2019 12 Advantageously, the temperature change of the at least one loudspeaker is taken into account by the filter device by a change corresponding to the parameter of the impedance of the filter device. [0050] Current control, unlike voltage control, does not adjust the overheating of the at least one speaker. This can be a drawback in addition to the two drawbacks mentioned above, namely the formation of uncompensated resonance peaks and the increase in the level of high frequency sound in the axial direction orthogonal to the diaphragm of at least one loudspeaker. Also, the frequency of the resonance peak may change in response to the temperature change of at least one speaker. Therefore, preferably at least one loudspeaker temperature change should be taken into account, in particular when correcting the resonance peak. [0051] All these can be compensated by changing the impedance of the filter arrangement, in particular the parameters of the inductor, which may be a virtual inductor. In this case, taking into account the temperature of the loudspeaker that can be measured or estimated is automatically performed by changing the various elements making up the virtual inductor, for example but not limited to the auxiliary transducers. [0052] Other advantages and features of the present invention will become apparent on reading the detailed description of a non-limiting embodiment and the accompanying drawings which follow: FIG. 1 shows a resonance peak according to the first embodiment of the invention And a 11-04-2019 13 schematic diagram of an acoustic signal power supply circuit of at least one speaker comprising the filter arrangement of Fig. 5 shows an embodiment of the filter arrangement of the acoustic signal power supply circuit shown in Fig. 1, the inductor of the filter arrangement being in the form of a virtual inductor, which virtual inductor is enlarged in this figure compared to Fig. 1 . FIG. 3 shows an impedance with a virtual inductor for the embodiment shown in FIG. 2; A curve of each acceleration reference unit at the time of current control of a speaker with and without a filter device of a resonance peak, and at the time of voltage control is shown, and filtering is performed with a filter device by a 1st embodiment of the present invention here Be done. Fig. 2 shows a curve of the angle as a function of frequency, the filtering being carried out using the filter arrangement according to the first embodiment of the invention shown in Fig. 1; [0053] According to the invention, the ideal current control solution is filtering that filters the two effects, namely the resonance peak and the directivity effect of the loudspeaker, without changing the current control index known as CDI. It is to find a way. According to the invention, it is possible to filter only resonant peaks while maintaining the current control index in an optimal way. [0054] Applying a filter to the current control of the loudspeaker excludes any filter structure placed parallel to the loudspeaker due to the property of finite impedance, even at low values, from the point of view of the Thevenin power supply become. This can have a negative impact on the index CDI and thereby ruin the useful part of the spectrum. [0055] The present invention provides a passive solution to the correction upstream of the at least one loudspeaker, since the correction of the resonance peak relates to the inherent behavior of the converter. Thus, the invention relates to a method of current control of an acoustic signal power supply circuit of at least one loudspeaker HP, the power supply comprising a filter arrangement of resonant peaks, the method being carried out by the step of correcting resonant peaks by means of a filter arrangement , And the correction step is performed upstream of at least one speaker HP. 11-04-2019 14 [0056] The correction performed upstream of the loudspeaker, also called a priori correction, also called "feed-forward correction", is to ensure that the control index of the current or the CDI is invariant with respect to the control of the loudspeaker. [0057] Advantageously, if at least one loudspeaker has a diaphragm, filtering of the resonance peak is carried out simultaneously with the reduction of the level of the highest frequency sound in the axial direction perpendicular to the loudspeaker's diaphragm. In embodiments of the acoustic signal power supply circuit, this reduction is provided by a connected resistor and capacitor system that bypasses the main circuit, which will be described in detail later. [0058] Advantageously, the resonant components of the entire loudspeaker and filter arrangement take on the value of the Butterworth filter, which will be detailed later. [0059] In accordance with the invention and referring in more detail to FIGS. 1-3, the acoustic signal power supply circuit of at least one loudspeaker HP according to the invention comprises a filter arrangement of resonant peaks. The circuit comprises at least two non-inverter converters (A, A 0) arranged in series upstream of at least one speaker (HP), each of the two converters (A, A 0) being It has a positive power terminal, a negative power terminal, and an output. [0060] 11-04-2019 15 The uppermost converter (A) of the two converters (A, A 0) has a positive supply terminal connected to the input power supply of the circuit, while the output of the uppermost converter (A) is intermediate Connect via a circuit to the positive power supply terminal of the second converter (A 0). The output of the second converter (A 0) is connected to the at least one speaker (HP), and a resonant peak occurs at a given frequency of the supply current of the at least one speaker (HP). [0061] The most essential feature of the circuit is that the filter system of the resonance peak of at least one loudspeaker (HP) is incorporated in the first branch which bypasses the intermediate circuit between the two transducers (A, A 0) It is. The filter arrangement is purely electrical in the form of impedance (Z 3), while connected to one point of the intermediate circuit and connected to the ground equipment on the other hand. This impedance (Z 3) is at least one first resistor (R 3), at least one first capacitor (C 3), and at least one first inductor (L 3) arranged in series. When it has, it is called RLC. The parameters of the first resistor (R 3), the first capacitor (C 3), and the first inductor (L 3) are pre-determined based on the filtered resonant peaks of the at least one loudspeaker (HP). Set to [0062] Preferably, the first inductor (L 3) is a virtual inductor, ie the first inductor (L 3) consists of a system of active circuits which for example function as an inductor. Such proposed corrections are initially preset and the filtering solution upstream of the at least one loudspeaker (HP), also called "feed-forward correction", is built on elements of medium power The current can remain less than 50 mA and replace the inductance with a system of active circuits. [0063] In embodiments using a virtual inductor, the fundamental advantage of the filtering upstream arrangement of the voltage-to-current converter is the low intensity value associated with the filtering, whereby many standard components of low noise op amps Can be used to configure a virtual inductor. An effective filter device that is low noise and has no copper windings can be built this way. 11-04-2019 16 [0064] Ultimately, this embodiment with a virtual inductor enables self-tuning during operation of the filter device to compensate for any variations associated with possible environmental changes of the loudspeaker (HP). This can lead to the automatic correction of the resonance frequency displacement due to the heating of the speaker HP. The process is thus part of the coupling of the thermal feedback loop with the electrical control upstream of the filter device. [0065] Advantageously, the active circuit system is constituted by two auxiliary non-inverter converters (A1 / 2, A2 / 2) arranged in series. Each of the two auxiliary converters has a positive supply terminal and a negative supply terminal and an output terminal. The most upstream (A 1/2) of the two auxiliary converters (A 1/2, A 2/2) has its positive supply terminal connected to the output of the first capacitor (C 3), while the most upstream The output of the auxiliary converter (A 1/2) is connected to the positive supply terminal of the second auxiliary converter (A 2/2) by means of a first auxiliary intermediate circuit. [0066] The first auxiliary intermediate circuit has an auxiliary capacitor (CA) and is connected to an auxiliary equipment grounding circuit with a first auxiliary resistor (RB) in the circuit. The output of the second auxiliary converter (A 2/2) is connected to the first auxiliary converter (A 1/2) by a second auxiliary intermediate circuit with a second auxiliary resistor (R A), and The auxiliary converter (A 1/2, A 2/2) has the output of the feedback loop connected to its negative supply terminal. [0067] Advantageously, for components of the impedance (Z 3), they fulfill a compromise between minimum noise and current maintained at low values, eg a current strength of 5 mA in the impedance (Z 3) Less than. The value of the first virtual inductor (L 3) is preferably equal to the 11-04-2019 17 product of the values of the first auxiliary resistor (R B) and the second auxiliary resistor (R A) and the auxiliary capacitor (C A). [0068] In one preferred embodiment, a second capacitor (C h) may be arranged on a second branch bypassing the intermediate circuit between the at least two transducers (A, A 0) described above. The second capacitor (C h) is accompanied by a second resistor (R h) and the parameters of the second resistor (R h) and the second capacitor (C h) have an intrinsic effective time R p. It is preset to reduce the high frequency signal by C h. The values of the second resistor (R h) and the second capacitor (C h) may be R h: about 1 Ω and C h: about 4.7 nF, respectively. But this value is just an example. [0069] Current control is known to not cause high frequency attenuation, unlike voltage control where the inductive component of the speaker naturally reduces the signal level. It is therefore appropriate to expect to force reduction in high frequency, in particular in terms of the increased directivity of the loudspeaker leading to an increase in the level of sound measured in the axial direction perpendicular to the diaphragm, in current control . [0070] Advantageously, the intermediate circuit between the two non-inverter converters (A, A 0) is between the output of the upstream non-inverter converter and the first bypass branch of the intermediate circuit with the filter arrangement. It has a third resistance (R p). [0071] Advantageously, each non-inverter converter (A, A 0) has its own feedback loop, which connects its output to the negative power supply terminal of each converter, each feedback loop , For the upstream converter A, bypass the intermediate circuit between the two non-inverter converters (A, A 0), and for the downstream converter (A 0), the speaker (HP) Are mounted to bypass the equipment grounding circuit having the fourth resistor (R B1), which is disposed downstream of [0072] 11-04-2019 18 V 1 and V 3 are the voltages shown in FIG. 1 and V 3 is the voltage between the bypass point of the first branch of the resonant peak filter device and the ground circuit, which bypasses the intermediate circuit, and V 1 Is the voltage between the output of the first upstream converter A and the ground circuit, and according to prior art calculations, the transfer function of the filter constituted by the series arrangement of R p and R 3 L 3 C 3 series networks It is possible to obtain V 3 / V 1 as follows: [0073] Thus, the filtering performed, possibly combined with the high frequency reduction by the filter R h, C h, maintains only the function of the voltage-current regulator assigned to the power amplifier and supplies the power to at least one speaker to enable. The specificity of this configuration is in the virtual configuration of the inductor (L 3) using two active elements. In fact, taking into account the impedance of the assemblies R A, R B, C A, A, A 0, the following two relations can be combined: [0074] Component identification results in the following impedance behavior: [0075] The combination behaves like an inductor or choke with the value L 3 = R A RR B CC A placed in series with the resistor (R A). It is possible to make the formula R 3 = R 03 -R A giving R 3 by R A. The setting of the selected parameter eliminates the need to mount this part, and the value of the R A series, as described in equations (9) and (10), ensures the desired attenuation, 1 / Qm. It has almost the necessary value. In fact, if: 11-04-2019 19 [0076] Advantageously, the overall resonant component can be defined by taking the value of the Butterworth filter which corresponds to the optimum value, Q HP + Z 3 = 1 / √2. [0077] Starting from the above equation, the selection of the following parameter values is carried out: [0078] FIG. 4 shows a curve of acceleration reference units of the loudspeaker with and without resonant peak filtering, with current control of the loudspeaker and voltage control, the filtering being according to the embodiment of the invention shown in FIGS. 1-3 Is executed by [0079] The unfiltered current control curve is shown by the rectangular points, the filtered current control curve is shown by the circle points, and the voltage control curve is shown by the diamond shaped points. [0080] The curve in the middle of the circle points is the curve that is current controlled and filtered by the filter arrangement according to the first embodiment and shows no resonance peak, unlike the upper curve showing current control without filtering. In addition, the middle curve has a frequency range in which the acceleration reference unit has a substantially constant frequency, which is wider than the curve below the diamond shaped point, which is a curve of voltage control. [0081] It has a resonant peak and is filtered if it is not considered disadvantageous to add two active circuits with two auxiliary transducers to obtain an inductor with a value close to L 3 = 6H The acceleration reference unit has satisfactory behavior. 11-04-2019 20 [0082] FIG. 5 shows an angle curve with respect to frequency, the filtering being performed by the filter device according to the embodiment of the invention shown in FIGS. The phase of the loudspeaker (HP) is shown by a curve of rectangular points, and the phase V 3 / V 1 is shown by a curve of round points. The curve in FIG. 5 shows that the phase displacement angle remains in the range of completely acceptable values in the frequency range of interest. [0083] In a preferred embodiment of the invention, an intermediate value of the order of the microfarads assigned to the capacitance enables the implementation of polypropylene MKP capacitors, which are well adapted to transients. [0084] Non-limiting examples with the following characteristics for loudspeakers are now given: Bl = 2.675 Tm, M m = 3.67 g, f m = 0.539 N / m, k m = 5650 N / m, resonant frequency = 197 Hz, R e = 3.65 Ω, L = 0.12 mH. In such a loudspeaker, the following values are selectable for the various circuit elements according to the invention: R 3 = 0Ω, C 3 = 0.29 μF, R p = 3 kΩ, and L 3 = R A = 400Ω , R B = 1200 Ω, C A = 4.7 μF, or L 3 is equal to 2.28H. [0085] In the above description at least one non-inverter converter is used in the circuit to simplify the calculation. 11-04-2019 21 This is not a limitation, and the invention is also applicable to circuits having multiple noninverter converters and one or more inverter converters. [0086] The market for sound reproduction, in particular high performance reproduction, relates to the filter device according to the invention. Bose (R), Bang & Olufsen (R), Harman Kardon (R), B & W (R) and other major brands will definitely show interest in the commercial distribution of such filter devices. 11-04-2019 22

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