LOUDSPEAKER WITH DYNAMICLY CONTROLLED PAIRS OF FEATURE COIL SECTIONS

Abstract

The invention relates to a method for controlling a voice coil of a loudspeaker, comprising the steps of providing a magnetic circuit with an air gap, providing a voice coil suspended in the air gap, and applying an audio signal to the voice coil to move it along an axis of motion. The voice coil comprises a main voice coil section and a pair of auxiliary voice coil sections arranged along the axis of motion, with each auxiliary voice coil section being arranged on both sides of the main voice coil section. Applying an audio signal comprises continuously coupling a main control signal based on the audio signal to the main voice coil and selectively coupling an auxiliary control signal based on the audio signal to the pair of auxiliary voice coil sections.The invention further relates to a voice coil control system and a loudspeaker comprising a voice coil control system.

Description

Field of invention

[0001] The present invention relates to a loudspeaker and in particular a voice coil arranged in such a way as to improve the load capacity and reduce the power consumption of the control electronics. Background of the invention

[0002] Referring to the Fig. 1a-1b will be a loudspeaker 50 Represented according to the state of the art. The loudspeaker 50 is equipped with a voice coil 1 equipped with a multitude of coil windings. The coil windings are driven by a drive power, so that the voice coil 1 the membrane 7 moved back and forth, which creates an acoustic tone signal.

[0003] The coil windings are partially in an air gap. 3 a magnetic circuit 2 with the highest magnetic flux density within the air gap 3arranged. When the coil windings are energized, they interact with the magnetic field of the magnetic circuit. 2 , to generate an electromotive force that drives the voice coil 1 shifts. However, only the windings of the voice coil deliver. 1 , which are essentially within the gap 3 are arranged to exert a substantial force on the voice coil 1 to move back and forth. The windings of the voice coil are located outside the air gap. 3 , which do not contribute with a substantial electromotive force, are also supplied with current at the same time and consequently contribute to the heating of the voice coil, which is a significant limiting factor in loudspeaker design. Summary of the invention

[0004] The inventors have identified the above-mentioned problems and requirements related to the efficiency and heating of the voice coil and have then made the invention described below, which can increase the efficiency and / or reduce the heating of the voice coil.

[0005] One aspect of the invention relates to a method for controlling a voice coil of a loudspeaker, comprising the following steps: Providing a magnetic circuit with an air gap and a voice coil suspended in the air gap; Applying an audio signal to the voice coil suspended in the air gap to generate an electromotive force that moves the voice coil along an axis of motion; characterized by the fact that the voice coil comprises a plurality of voice coil sections, wherein the plurality of voice coil sections comprises a main voice coil section and a pair of auxiliary voice coil sections arranged along the axis of motion, with voice coil sections of the pair of auxiliary voice coil sections arranged on both sides of the main voice coil section; and wherein the step of applying an audio signal comprises the continuous coupling of a main control signal based on the audio signal to the voice coil main section and the selective coupling of an auxiliary control signal based on the audio signal to the pair of voice coil auxiliary sections.

[0006] A voice coil is a coil of wire that, under the influence of a magnetic field, can generate an electromotive force to move the diaphragm of a loudspeaker in order to produce acoustic sounds. The magnetic field can be generated by a magnet, such as a permanent magnet or an electromagnet, present in a magnetic circuit. The magnetic circuit may include an air gap in which the voice coil moves back and forth, thereby producing acoustic sounds by moving the loudspeaker diaphragm back and forth. The back-and-forth movement of the voice coil occurs in response to an applied audio signal, which is to be reproduced by the loudspeaker. The displacement of this back-and-forth movement, i.e.,The reciprocating movements of the loudspeaker's voice coil result in an acoustic reproduction of the applied audio signal, since the reciprocating movements of the voice coil can be transferred to a diaphragm of the loudspeaker, which presses on the air and thereby generates acoustic sound waves.

[0007] According to various embodiments of the invention, the voice coil comprises a plurality of voice coil sections, preferably one or more pairs of voice coil sections.

[0008] A voice coil section is an individual segment of a voice coil. Voice coil sections can be electrically or galvanically isolated from each other, or they can be subsections of a single coil with multiple connections, providing individual electrical or galvanic connections to each voice coil section.

[0009] In one embodiment of the invention, the voice coil comprises a main voice coil section and a pair of auxiliary voice coil sections, wherein one section of the pair of auxiliary voice coil sections is arranged on both sides of the main voice coil section in the direction of the axis of motion. In one embodiment, the voice coil can be divided into a central main voice coil section and two surrounding auxiliary voice coil sections. Each of these auxiliary voice coil sections can have a height defined in one direction along the axis of motion of one-third of the total height of the voice coil defined in one direction along the axis of motion. In various embodiments, the voice coil sections can have the same or different heights, numbers of turns, and winding densities, and can comprise windings made of the same or different materials.The material for the windings of the voice coil sections can be selected from the list, which consists of alloys, aluminum, silver, copper or gold, or any combination thereof.

[0010] To control the voice coil, a main control signal based on the audio signal is coupled to at least one main voice coil section, while an auxiliary control signal, also based on the audio signal, is only selectively coupled to a pair of auxiliary voice coil sections. The selective coupling of an auxiliary control signal to a pair of auxiliary voice coil sections can be achieved by controlling one or more switching units and / or one or more amplifiers to apply an auxiliary control signal to both components of the pair of auxiliary voice coil sections.

[0011] The selective coupling of an auxiliary control signal can be based on a displacement request. The displacement request can be understood as the amount of displacement or a shift from the rest position of the voice coil required for the reproduction of the audio signal.

[0012] For low-amplitude audio signals where small excursions / displacements are required for audio reproduction, the necessary electromotive force may be provided by the main voice coil section, and the voice coil auxiliary sections may not contribute significantly to the electromotive force that moves the voice coil back and forth. Therefore, there may be times when an audio signal is applied to the voice coil where an auxiliary control signal is not coupled to pairs of voice coil auxiliary sections, and typically an idle auxiliary control signal is applied to pairs of voice coil auxiliary sections. This idle auxiliary control signal may be arranged to minimize current and power loss in the windings of the voice coil auxiliary sections when the excursion is small.

[0013] With high-amplitude audio signals, it is possible for pairs of voice coil auxiliary sections to contribute to the generation of an electromagnetic force, and an auxiliary control signal can be selectively coupled to pairs of voice coil auxiliary sections so that these pairs contribute to the generation of an electromotive force. Thus, there may be times when an audio signal is applied to the voice coil while an auxiliary control signal is coupled to pairs of voice coil sections.

[0014] An advantageous method for driving a loudspeaker's voice coil is presented here. The segmented structure of the voice coil and the method of selectively applying a control signal to pairs of voice coil auxiliary sections enable the excursion to reproduce an audio signal in the same way as a prior art loudspeaker with an unsegmented voice coil and a conventional drive method. However, since the selective coupling of an auxiliary control signal to the pair of voice coil auxiliary sections according to the invention avoids the need to provide a control signal to voice coil auxiliary sections for small excursions, both the power consumption and the heating of the voice coil can be significantly reduced. Furthermore, the ability to selectively modify the auxiliary control signal allows for the correction of nonlinearities in the voice coil system.Nonlinearity can be understood as a nonlinear response of the voice coil system, e.g., a nonlinear relationship between the restoring force acting on the voice coil and the displacement of the voice coil, which can lead to undesirable distortions at large displacements of the voice coil.

[0015] According to one embodiment of the invention, the selective coupling of the auxiliary control signal with the pair of voice coil auxiliary sections is carried out on the basis of a representation of the deflection requirement.

[0016] A displacement requirement can be understood as an instruction specifying how much voice coil displacement is required to reproduce the audio signal. The displacement requirement can be expressed in any suitable way that represents the required voice coil displacement. For example, the displacement requirement can be expressed in units of millimeters of displacement from the voice coil's equilibrium position within the air gap when no electromotive force is applied to the voice coil.

[0017] In one embodiment of the invention, the representation of the deflection request is provided on the basis of an audio signal, a control signal, a current and / or voltage signal in a voice coil section, a signal determined from a measurement of the deflection, e.g. by voice coil position sensors, or a combination of any of the above.

[0018] In one embodiment of the invention, the representation of the deflection request is provided based on a signal analysis of the audio signal. The signal analysis can be performed by a signal processor, e.g., a digital signal processor, which receives the audio signal or a representation thereof as an input signal and a mathematical representation of the acoustic system.

[0019] Signal analysis can include the analysis of a signal's mean amplitude, its envelope, or its current amplitude, but it is not limited to these examples. Signal analysis can be performed on a current signal value, past signal values, and / or future signal values. When performing signal analysis on future audio signal values, a time delay can be introduced between the reception of the audio signal and the coupling of the corresponding control signals to sections of the voice coil.

[0020] In embodiments of the invention, the signal analysis comprises performing a prediction of the peak displacement of the voice coil, wherein the coupling of auxiliary coil sections is based on several audio signal cycles. An audio signal cycle can be understood as the time interval between the voice coil passing through its rest position twice, i.e., its natural position when no audio signal is present, from the same direction of movement along the axis of motion.

[0021] A representation of the excursion requirement can also depend on the loudspeaker's frequency response. In the field of loudspeakers, the frequency response typically describes the frequency dependence of the excursion with respect to the frequency of a control signal. Therefore, a representation of the excursion requirement can include both the audio signal and the frequency response of the voice coil and / or diaphragm.

[0022] A displacement estimator can be used to determine the representation of the displacement requirement, e.g., based on a transfer function derived from measurements of system displacement versus frequency. In systems with significant nonlinearity, this can be compensated for by using a level-dependent family of transfer functions for displacement estimation, or by selecting the transfer function that is closest to the displacement transition point of the coupling of the voice coil auxiliary section pair.

[0023] According to various embodiments of the invention, the displacement of the voice coil, when the selective coupling is based on the displacement request, can reproduce an applied audio signal. Since the control signals are only selectively coupled during specific time intervals, as determined by the displacement request, power consumption and overheating can be reduced.

[0024] According to various embodiments of the invention, a displacement of the voice coil is performed to reproduce an audio signal without distortion, while an auxiliary control signal is selectively coupled to auxiliary voice coil sections only if the required displacement cannot be provided by the main voice coil section alone. The selective coupling can be performed based on a representation of the displacement requirement.

[0025] According to one embodiment of the invention, the selective coupling of the auxiliary control signal to the pair of voice coil auxiliary sections is carried out on the basis of a comparison of the representation of the deflection request with a representation of predetermined deflection level thresholds.

[0026] In various embodiments, the representation of the displacement request can be a parameter, the representation of a predetermined displacement level can be a threshold value related to the parameter, and the comparison includes determining whether the parameter has exceeded the threshold value. If the threshold is exceeded, the auxiliary control signal is coupled to the pair of voice coil auxiliary sections.

[0027] In various embodiments of the invention, a prediction of the voice coil peak displacement is compared with a predetermined voice coil peak displacement threshold or a table of threshold values, i.e., a representation of a predetermined displacement level. The prediction and comparison can be performed by a signal processor, e.g., a digital signal processor. If the predicted voice coil peak displacement is greater than the threshold values, an auxiliary control signal is coupled to a pair of voice coil auxiliary sections. This coupling can include the coupling of a transition auxiliary control signal that has a varying signal amplitude. According to these embodiments, changes in the control signal amplitude can occur progressively over several audio signal cycles to reduce the distortion caused by the changes in signal amplitude.The rate of increase of the change in the control signal amplitude can be chosen so that any distortion products are shifted to less audible frequencies or to frequencies at which the acoustic system is insensitive, in order to make them inaudible to the listener.

[0028] In other embodiments of the invention, the representation of the displacement request is based on measurements of the voice coil displacement, and the representation of a predetermined displacement level is a threshold value that is compared with the measured voice coil displacement. An auxiliary control signal is then coupled to auxiliary voice coil sections when the measured displacement exceeds a corresponding threshold level.

[0029] According to one embodiment of the invention, the step of selectively coupling an auxiliary control signal to the pair of voice coil auxiliary sections is carried out by a voice coil control device comprising a signal processor.

[0030] In various embodiments, the selective coupling of an auxiliary control signal to voice coil auxiliary sections is achieved by a voice coil control device. The voice coil control device may include a signal processor, e.g., a digital signal processor. The voice coil control device can perform all tasks related to comparing a representation of the displacement request with a representation of a predetermined displacement level. Furthermore, the voice coil control device can perform all tasks related to delaying an audio signal or providing multiple processed audio signals as the basis for multiple control signals.

[0031] According to embodiments of the invention, the voice coil can comprise any number of pairs of voice coil auxiliary sections, such as two or more pairs of voice coil auxiliary sections arranged along the axis of motion and configured to be selectively coupled pairwise to auxiliary control signals, e.g., based on the voice coil displacement and / or the audio signal, such as based on audio signal analysis. In various embodiments of the invention, the combination of voice coil geometry and the relative amplitude of the control signals supplied to any voice coil sections is adjusted to ensure a linear response of the voice coil to an applied audio signal up to a displacement similar to the height of the voice coil. The linear response can be understood as a linear relationship between the audio signal and the displacement.

[0032] According to one embodiment of the invention, the pair of voice coil auxiliary sections is a first pair of voice coil auxiliary sections and the auxiliary control signal is a first auxiliary control signal; wherein the plurality of voice coil sections further comprises a second pair of voice coil auxiliary sections arranged along the axis of motion, with voice coil sections of the second pair of voice coil auxiliary sections arranged on both sides of the first pair of voice coil auxiliary sections, and wherein the step of applying an audio signal includes the selective coupling of a second auxiliary control signal to the second pair of voice coil auxiliary sections based on the audio signal.

[0033] In various embodiments of the invention, the voice coil consists of a main voice coil section, a first pair of auxiliary voice coil sections arranged around the main voice coil section, and a second pair of auxiliary voice coil sections arranged around the first pair of auxiliary voice coil sections, both pairs being arranged along the axis of motion. The main voice coil section and the first pair of auxiliary voice coil sections are located between the two voice coil sections of the second pair of auxiliary voice coil sections along the axis of motion.

[0034] When an audio signal is applied that requires a displacement the main voice coil section can provide on its own, only the main voice coil section is coupled to a control signal. If an audio signal requires a displacement greater than that the main voice coil section can provide, but not greater than that provided by the first pair of auxiliary voice coil sections and the main voice coil section in combination, the main voice coil section is coupled to a primary control signal, and the first pair of auxiliary voice coil sections is coupled to an auxiliary control signal.If an audio signal requires a displacement greater than that which the first pair of voice coil auxiliary sections in combination with the main voice coil section can provide, the main voice coil is coupled to a control signal, the first pair of voice coil auxiliary sections is coupled to a control signal, and the second pair of voice coil auxiliary sections is coupled to a control signal.

[0035] The selective coupling of auxiliary control signals can be based on at least one representation of the displacement request and at least one representation of a predetermined displacement level. In various embodiments of the invention, in which the voice coil comprises two pairs of voice coil auxiliary sections, i.e., a first pair of voice coil auxiliary sections and a second pair of voice coil auxiliary sections, one representation of the displacement request is compared with two representations of predetermined displacement levels—where a predetermined displacement level is associated with each pair of voice coil auxiliary sections.If the representation of the displacement request meets a predetermined criterion when compared to one of the representations of predetermined displacement levels, a control signal is coupled to the corresponding pair of voice coil auxiliary sections associated with that representation of predetermined displacement level. Furthermore, if the representation of the displacement request meets a predetermined criterion when compared to the other representation of predetermined displacement levels, a control signal is coupled to the other pair of voice coil auxiliary sections associated with that other representation of predetermined displacement level. Thus, when comparing the representation of the displacement request with representations of predetermined displacement levels, it is possible to meet criteria for the simultaneous coupling of multiple auxiliary control signals to pairs of voice coil auxiliary sections.

[0036] A predefined criterion can be understood as a criterion for comparing a representation of the displacement request with a representation of a predefined displacement level, which, if fulfilled, enables the coupling of an auxiliary control signal. For example, the predefined criterion can be fulfilled if a representation of the displacement request is equal to or greater than a representation of the predefined displacement level.

[0037] According to one embodiment of the invention, the representation of a predetermined displacement level is a first representation of a predetermined displacement level, and wherein the selective coupling of the second auxiliary control signal with the second pair of voice coil auxiliary sections is carried out on the basis of a comparison of the representation of the displacement request with a second representation of a predetermined displacement level.

[0038] According to one embodiment of the invention, the pair of voice coil auxiliary sections is arranged along the axis of movement and symmetrically around the voice coil main section, wherein one voice coil auxiliary section of the pair of voice coil auxiliary sections is arranged on both sides of the voice coil main section.

[0039] In various embodiments, at least one pair of auxiliary voice coil sections is arranged around a central main voice coil section. Since a linear response of the voice coil is preferred, it can be advantageous to distribute each pair of auxiliary voice coils symmetrically along the translation axis relative to the central main voice coil section. The plane of symmetry is thus defined by a main voice coil section and is perpendicular to the translation axis. The plane of symmetry therefore intersects the center of the main voice coil section, and voice coil sections of a pair of voice coil sections have the same length and arrangement of coil windings, which are symmetrical about the plane of symmetry.

[0040] According to one embodiment of the invention, the first pair of voice coil auxiliary sections is arranged symmetrically around the voice coil main section, wherein a voice coil auxiliary section of the first pair of voice coil auxiliary sections is arranged on both sides of the voice coil main section, and the second pair of voice coil auxiliary sections is arranged along the axis of movement and is arranged symmetrically around the voice coil main section, wherein a voice coil auxiliary section of the second pair of voice coil auxiliary sections is arranged on both sides of the voice coil main section.

[0041] In various embodiments, at least two pairs of auxiliary voice coil sections are arranged around a central main voice coil section. Since a linear response of the voice coil is preferred, it can be advantageous to distribute each pair of auxiliary voice coils symmetrically along the translation axis relative to the central main voice coil section. The plane of symmetry is thus defined by a main voice coil section and is perpendicular to the translation axis. The plane of symmetry therefore intersects the center of the main voice coil section, and voice coil sections of a pair of voice coil sections have the same length and winding arrangements that are symmetrical with respect to the plane of symmetry.

[0042] In some designs with a main voice coil section and two pairs of auxiliary voice coil sections, a first pair of auxiliary voice coil sections is arranged symmetrically around the main voice coil section, and a second pair of auxiliary voice coil sections is arranged symmetrically around the first pair of auxiliary voice coil sections, both pairs along the axis of motion. Thus, the main voice coil section and the first pair of auxiliary voice coil sections are located between the two components of the second pair of auxiliary voice coil sections along the axis of motion.

[0043] According to one embodiment of the invention, the selective coupling of an auxiliary control signal to the pair of voice coil auxiliary sections comprises the control of at least one amplifier to couple the auxiliary control signal to the pair of voice coil auxiliary sections.

[0044] In some embodiments, an audio signal or a processed audio signal can be supplied to an amplifier connected to a voice coil auxiliary section. If the coupling criteria for the voice coil auxiliary section according to the invention are met, a control device enables the amplifier to be supplied, which amplifies the audio signal to generate an auxiliary control signal that is supplied to the voice coil auxiliary section via a gain channel. If the coupling criteria for the voice coil auxiliary section according to the invention are not met, a control device enables the amplifier to be supplied with less or no power, so that an idle auxiliary control signal is generated and supplied to the voice coil auxiliary section. The idle auxiliary control signal can thus be a reduced-amplitude version of the auxiliary control signal, or it can be no signal at all.In some embodiments, the auxiliary control signal can alternatively be coupled in or out by a trigger, by enabling input to the amplifier, by providing or removing the input to the amplifier, by switching the amplifier output on or off, etc.

[0045] Furthermore, a transition auxiliary control signal for voice coil auxiliary sections can be provided by controlling the gain of the auxiliary control signal. In other words, the gain of the auxiliary control signal can be controlled by modifying the small input signal as needed and amplifying it by a predetermined gain, and / or by receiving an unmodified small input signal and adjusting the gain instead. For Class-D amplifiers, the gain can be adjusted, for example, by adjusting the power supply and / or the pulse generation of the control signals.

[0046] In various embodiments, at least one amplifier is controlled to generate either an auxiliary control signal, an idle auxiliary control signal, or optionally a transition auxiliary control signal, all based on an audio signal. An audio signal or a processed audio signal can be fed to an amplifier connected to a voice coil auxiliary section. When the criteria for coupling an auxiliary control signal to a pair of voice coil auxiliary sections are met, a voice coil control device enables the amplifier to be supplied with power, or it is activated in some other way, which amplifies the audio signal to generate an auxiliary control signal that is fed to the voice coil auxiliary section.If the coupling criteria for the voice coil auxiliary section are not met, the voice coil control device allows the amplifier to receive less or no power, or to be otherwise deactivated or its gain reduced, thus generating an idle auxiliary control signal that is fed to the voice coil auxiliary section. This idle auxiliary control signal can be a version of the auxiliary control signal with a significantly reduced amplitude, or it can be no signal at all.

[0047] Furthermore, a transition auxiliary control signal can be generated by controlling the amplifier's power or otherwise regulating its gain. Preferably, the transition auxiliary control signal can be generated by providing a gain that lies in the range between the gain supplied to the amplifier for generating the auxiliary control signal and the gain supplied to the amplifier for generating the idle auxiliary control signal.

[0048] The individual voice coil sections of a segmented voice coil can have different geometries, e.g., different numbers of turns, winding densities, voice coil section heights, etc. Therefore, it can be advantageous for an auxiliary control signal, selectively coupled to auxiliary voice coil sections, to have a signal gain that differs from the gain of the main control signal coupled to the main voice coil section. In various embodiments, the relative gains can be selected to ensure a linear response of the voice coil to an applied audio signal.

[0049] Different gains in the auxiliary control signal and in the main control signal can also be used in one embodiment to compensate for nonlinearities in the voice coil suspension and in the magnet system at large deflections.

[0050] The amplification of a control signal can be understood as the amplitude of the control signal relative to the input signal or the voltage amplification of the control signal.

[0051] The individual voice coil sections of a segmented voice coil can have similar geometries, e.g., the same number of windings, winding densities, voice coil section heights, etc. Therefore, it can be advantageous for an auxiliary control signal, selectively coupled to auxiliary voice coil sections, to have a signal amplitude corresponding to the amplitude of a main control signal coupled to a main voice coil section when the excursion requirement is high. In various embodiments, the relative amplitudes are chosen to ensure a linear response of the voice coil to an applied audio signal.

[0052] According to one embodiment of the invention, the selective coupling of an auxiliary control signal to the pair of voice coil auxiliary sections comprises the control of at least one switch for coupling the auxiliary control signal to the pair of voice coil auxiliary sections.

[0053] According to embodiments of the invention, switches are used to control the selective coupling of an auxiliary control signal to voice coil auxiliary sections. An auxiliary control signal can therefore always be generated, but is only coupled to voice coil auxiliary sections when a switch controls the coupling of the signal according to the invention. If the auxiliary control signal is not coupled to voice coil auxiliary sections, the voice coil auxiliary sections are coupled to an open-circuit auxiliary control signal or, optionally, to a transition auxiliary control signal. An open-circuit auxiliary control signal can be no signal at all, since a switch can leave the input and / or output to the voice coil auxiliary section open, so that no current and / or voltage is supplied to the voice coil auxiliary section.Alternatively, an idle auxiliary control signal can be a version of the auxiliary control signal with a reduced amplitude and can be coupled to a voice coil auxiliary section by means of a switch, while the auxiliary control signal is uncoupled.

[0054] In various embodiments, the auxiliary control signal can be composed of several signals. For example, in these embodiments, a first control signal can always be applied to a pair of voice coil auxiliary sections. To selectively couple an auxiliary control signal to the pair of voice coil auxiliary sections, a second control signal can be added to the first. That is, the idle auxiliary control signal can be composed of a first control signal, and the auxiliary control signal can be composed of the sum of a first control signal and a second control signal. The selective addition of a second control signal to generate the auxiliary control signal can be controlled by a switch.

[0055] A switch can be understood as an electrical component or device, constructed from discrete components or integrated into an integrated circuit or processor, that can interrupt current or redirect current from one terminal of the switch to another terminal of the switch, such that the redirection of current determines whether a control signal is coupled or not.

[0056] According to one embodiment of the invention, an idle auxiliary control signal is coupled to the pair of voice coil auxiliary sections when the displacement requirement of the transducer is low.

[0057] The coupling of an idle auxiliary control signal, also referred to as the base signal, to pairs of voice coil auxiliary sections, in addition to the selective coupling of the auxiliary control signal, means that the idle or base signal can also be coupled to the voice coil auxiliary sections at times when the auxiliary control signal is selectively uncoupled. The idle auxiliary control signal is preferably a small signal compared to the main control signal, but with a frequency content synchronized with the main control signal, such as a low-amplitude version of the main control signal. In preferred embodiments, the pairs of voice coil auxiliary sections continuously receive at least the idle auxiliary control signal as long as an audio signal is present.In other words, in such embodiments, the selective coupling does not cause the switching on and off of the voice coil auxiliary section, but rather the switching between the supply with an open-circuit signal and the supply with the full auxiliary control signal.

[0058] One advantage of providing the idle auxiliary control signal instead of completely decoupling the voice coil auxiliary section is that the effect of back EMF braking can be avoided or reduced. Back EMF braking is an undesirable disturbance, i.e., a braking, of the voice coil's reciprocating motion due to current induction in a voice coil section, which can potentially lead to energy loss and distortion in the audio signal reproduction. The voice coil sections induce currents in each other due to magnetic coupling. Furthermore, the voice coil sections also generate an EMF due to their relative motion to the magnetic gap. The main voice coil section is continuously driven by the continuously coupled main control signal. A voice coil section that is not actively driven, e.g.,The pair of voice coil auxiliary sections, during times when the auxiliary control signal is uncoupled, will therefore draw a small portion of the energy generated by the nearby active voice coil section (i.e., the main voice coil section) from the magnetic system, especially when the voice coil auxiliary section is located close to the magnetic field of the air gap. This causes the inactive voice coil section to act against the active voice coil section, and the electromotive force caused by the main voice coil in the air gap is slightly reduced, as some of the energy is now used to excite the nearby inactive voice coil sections.To avoid or reduce this undesirable effect, the idle auxiliary control signal serves to apply a bias voltage that compensates for the back EMF generated by the coil movement and any inductive coupling between the active and inactive voice coil sections, thus minimizing power loss in these sections when they are not needed. Since only a relatively small idle auxiliary signal is sufficient for this purpose, e.g., on the order of 5 to 25% of the main control signal, the overall advantages of the invention are retained, such as the reduction of current consumption and voice coil heating by not supplying complete signals to the voice coil auxiliary sections when these can be adequately reproduced by the main voice coil section alone, and such as the possibility of using the voice coil auxiliary sections to compensate for nonlinearities in the voice coil system.

[0059] The idle auxiliary control signal can be based on the audio signal and can therefore be considered a representation of the audio signal. This is very advantageous for using the idle auxiliary control signal to reduce back EMF braking, since the idle auxiliary control signal should cause the voice coil auxiliary section to work with the forces generated by the voice coil main section, rather than against them.

[0060] According to one embodiment of the invention, the idle auxiliary control signal is a first idle auxiliary control signal and the pair of voice coil auxiliary sections is a first pair of voice coil auxiliary sections, and wherein a second idle auxiliary control signal is coupled to a second pair of voice coil auxiliary sections.

[0061] The second idle assist control can also be advantageously based on the audio signal and can therefore be viewed as a representation of the audio signal.

[0062] According to embodiments of the invention, one or more pairs of voice coil auxiliary sections, such as a first and a second pair of voice coil auxiliary sections, can receive idle auxiliary control signals. An idle auxiliary control signal can be a representation of the audio signal with a reduced amplitude and / or a phase shift or an applied delay, i.e., a signal characterized by negative gain, e.g., an attenuated control signal; e.g., a delayed control signal, e.g., an IIR- or FIR-filtered control signal. In some embodiments, an idle auxiliary control signal can be a control signal without amplitude, i.e., a zero signal.This can be particularly relevant for embodiments with two or more pairs of voice coil auxiliary sections, where the second or outer pair of voice coil auxiliary sections is located far from the air gap and therefore does not contribute significantly to the unwanted back EMF damping anyway. With medium-sized audio signals, where the inner voice coil auxiliary sections are fully activated for audio signal reproduction, the outer voice coil auxiliary sections begin to couple with the inner voice coil sections, and a non-zero idle auxiliary control signal can also be applied to the outer or second voice coil auxiliary sections.

[0063] If the voice coil comprises two or more pairs of auxiliary voice coil sections, the different pairs of auxiliary voice coil sections can receive open-loop auxiliary control signals with different gains and / or phases, e.g., different voltage gain, different phase, or different amplitude. As described above, the outer pair of auxiliary voice coil sections does not contribute significantly to back EMF damping for small audio signals and can therefore be used with a smaller or even zero-open-loop auxiliary control signal. In an alternative embodiment of the invention, however, the two open-loop auxiliary control signals can be essentially identical, i.e., have the same gain.

[0064] According to one embodiment of the invention, the amplitude of the idle auxiliary control signal can be adjusted based on the audio signal, for example, based on an analysis of the audio signal's amplitude. Such an analysis can be performed by a voice coil control device that includes a signal processor, for example, a digital signal processor. In embodiments, the low idle auxiliary control signal can be dimensioned as a small signal relative to the voltage, current, or power of the main control signal.

[0065] According to one embodiment of the invention, the gain of the idle auxiliary control signal can be adjusted based on the audio signal, e.g., based on an analysis of the audio signal's amplitude. Such an analysis can be performed by a voice coil control device comprising a signal processor, e.g., a digital signal processor, and determined by processing the audio input signal with digital FIR or IIR filters.

[0066] Analyzing the audio signal with, for example, a voice coil control device that includes a signal processor, such as a digital signal processor, allows for the prediction of future excursion requirements using a look-ahead buffer. This prediction can then influence how the auxiliary coil control signal is applied. For instance, signal analysis of the audio signal might reveal that a specific excursion level is required within a certain time period. To meet this requirement, an auxiliary control signal must be applied to the pair of voice coil auxiliary sections before the excursion is needed. Instead of immediately energizing the auxiliary coils, the auxiliary coil control signal can be applied over the specified time period and gradually ramped up to the desired gain for the given excursion level.By gradually increasing and / or decreasing the gain / phase of the transition auxiliary control signal, as opposed to abruptly switching the desired transition auxiliary control signal on / off, the distortion in the playback of the audio signal due to signal level changes in the auxiliary coils is reduced.

[0067] According to one embodiment of the invention, the gain setting of the aforementioned changes in the auxiliary control signal is limited in the rate of increase.

[0068] The changes to the auxiliary control signal, as described above, can be advantageous because, unlike embodiments with simple on / off switching of the auxiliary control signal (e.g., instantaneous jumping between different levels), they provide a gradual application of the pair of voice coil auxiliary sections as needed. Therefore, it can be advantageous to limit the degree of adjustment of the auxiliary control signal gain. In other words, it can be advantageous to require that the transition between low and high gain, or vice versa, be relatively slow.

[0069] For this purpose, a gain slew rate limit can be implemented. A limit on the order of, for example, a maximum of 10 dB / s can be advantageous to avoid audible artifacts caused by the selective coupling of the auxiliary control signals. This can also be achieved by using a mixer with different exclusion-level auxiliary signals as inputs and a control signal with a limited gain slew rate to gradually change the mixer's input-output ratio from one level to another.

[0070] The slew rate of the voice coil auxiliary section's transition can be precisely controlled, for example by a digital signal processor, to minimize distortion or increase efficiency depending on the target application. For instance, a faster transition leads to higher efficiency at the cost of increased distortion.

[0071] According to one embodiment of the invention, the main section of the voice coil has a height measured in a direction along the axis of movement that is greater than the height of the air gap measured in the direction along the axis of movement.

[0072] The state of the art in the field of loudspeakers includes both so-called over-hung voice coils, whose height is greater than the height of the air gap along the axis of motion, and so-called under-hung voice coils, whose height is less than the height of the air gap along the axis of motion. In this disclosure, the height of the air gap refers to the extent of the air gap along the axis of motion and not to the narrow distance between the magnet or the pole pieces that form the air gap.

[0073] A voice coil section with a height greater than the height of the air gap along the axis of movement can therefore be called an over-hung voice coil section. An over-hung voice coil main section is advantageous because, for audio signals requiring only small levels of voice coil excursion, the main section can always fill the entire air gap height. Furthermore, an over-hung voice coil main section offers the advantage that pairs of voice coil auxiliary sections do not need to be activated by auxiliary control signals, as they would not contribute anything anyway. Thus, for low-amplitude signals, coupling of auxiliary control signals can be avoided, thereby preventing distortion that might result from such a circuit.If the audio signal requires larger deflections than the main voice coil section can provide by its own movement, pairs of auxiliary voice coil sections can be used to provide additional electromotive force for the back-and-forth movement of the voice coil.

[0074] According to one embodiment of the invention, each voice coil section of the pair of voice coil auxiliary sections has a height measured in a direction along the axis of motion that is smaller than the height of the voice coil main section.

[0075] According to one embodiment of the invention, each voice coil section of the second pair of voice coil auxiliary sections has a height measured in a direction along the axis of motion that is smaller than the height of the voice coil main section.

[0076] In some applications of the invention, pairs of voice coil auxiliary sections may only be required to further increase the range of motion of the voice coil, while the main part of the electromotive force is still provided by the main voice coil sections. In such applications, it can be advantageous if the height of the voice coil sections of the auxiliary pairs is smaller than the height of the main voice coil section. If the overall height of the voice coil increases, the mass of the voice coil also increases, and this can affect the frequency response of the voice coil, making it less sensitive to high-frequency signals due to its greater inertia.

[0077] According to embodiments of the invention, the height of each individual voice coil section is smaller than the height of the air gap along the axis of movement.

[0078] According to embodiments of the invention, the height of the individual voice coil sections is each greater than the height of the air gap along the axis of movement.

[0079] According to embodiments of the invention, the combined height of the individual voice coil sections is greater than the height of the air gap along the axis of movement.

[0080] According to embodiments of the invention, the height of the individual voice coil sections is each the same as the air gap along the axis of movement, and in alternative embodiments of the invention, the combined height of the individual voice coil sections is the same as the air gap along the axis of movement.

[0081] According to one embodiment of the invention, the selective coupling of an auxiliary control signal based on the audio signal comprises maintaining the coupling for a duration spanning two or more zero crossings of the audio signal. For example, amplitude changes of the auxiliary coil signal would occur progressively over a number of zero crossings of the main control signal. The speed of the zero crossing or the time interval between zero crossings is important because it indicates the dominant low-frequency component of the audio signal. Therefore, performing gain changes of the auxiliary coil over several cycles of the dominant low-frequency component of the audio signal can minimize the audibility of distortions induced by changes in the auxiliary coil signals.

[0082] A zero crossing of the audio signal is understood to be a point in time in the audio signal at which the amplitude, e.g. voltage, passes through zero.

[0083] Maintaining the coupling of the selectively coupled auxiliary control signal for a period spanning multiple zero crossings or a time interval is advantageous because, compared to an auxiliary control signal coupled for a duration comparable to a typical voice coil oscillation period, less distortion over time may be present in the reproduced audio signal. Even small errors in the switching point during the coupling in and out of control signals once or several times per oscillation result in distortion, since the switching occurs at the same or a similar frequency as the control signal.

[0084] In this sense, the selective coupling of the auxiliary control signal, which involves maintaining the coupling over several zero crossings or time periods, can be considered "slow" or delayed or hysteresis coupling; that is, the coupling is maintained for a duration greater than a characteristic duration of voice coil oscillations, regardless of the intervening decrease in the displacement request. In one embodiment, the slow-acting selective coupling, i.e., the time-delayed selective coupling, is used to deactivate the voice coil auxiliary sections, while the coupling of the auxiliary control signal can occur as soon as possible after the displacement request exceeds the predetermined displacement threshold for the pair of voice coil auxiliary sections.In this sense, maintaining the coupling for a certain period of time can also be considered a peak-hold feature, which serves to prevent changes in the voice coil mixture during frequent peaks in the audio signal, and for this purpose the duration can advantageously be set to a few periods of the lowest desired frequency of the system, e.g. 500 - 500 ms.

[0085] Maintaining the coupling of the auxiliary control signal across multiple zero crossings, together with the adjustable auxiliary control signal feature with gain slew rate limitation described above, is particularly advantageous. Errors in displacement prediction result in only a small increase in low-order distortion products because the slew rate of the coil transitions is slow relative to the control signal bandwidth. Furthermore, this distortion can be avoided by activating the pair of voice coil auxiliary sections earlier or with a smaller displacement, at the cost of overall efficiency.

[0086] According to embodiments of the invention in which the selective coupling of an auxiliary control signal comprises the coupling of a transition auxiliary control signal, the time span may refer to a period of time in which the gain or amplitude of the transition auxiliary control signal is maintained at a constant value of gain or amplitude or phase, such as a constant gain or amplitude value determined on the basis of a signal analysis of the audio signal.

[0087] According to one embodiment of the invention, this duration is a predetermined duration.

[0088] A specified duration can be understood as any duration that exceeds a characteristic oscillation time of the voice coil, e.g., the oscillation period of the voice coil. The oscillation period of the voice coil depends on the frequencies of the control signals applied to the voice coil sections; at the lowest frequencies audible to the human ear, e.g., 20 Hz, the corresponding oscillation period is 50 milliseconds. Therefore, for most audio signals, a specified duration of more than 50 milliseconds would mean that an auxiliary control signal is coupled to a pair of voice coil auxiliary sections for a duration exceeding one oscillation of the voice coil.

[0089] According to one embodiment of the invention, the aforementioned predetermined time period is determined on the basis of a signal analysis of the audio signal.

[0090] An analysis of the audio signal can prescribe that one or more auxiliary control signals be selectively coupled to one or more corresponding pairs of voice coil auxiliary sections for a predetermined duration. The predetermined duration can be set one or more times during the application of the audio signal, e.g., several times, and each successive selective coupling of the auxiliary control signal can last for a different predetermined duration.

[0091] Analyzing the audio signal may make it possible to predict when large voice coil excursions are required if one or more pairs of voice coil auxiliary sections need to be coupled with auxiliary control signals.

[0092] The signal analysis of the audio signal can be performed by a digital signal processor, such as the digital signal processor or the voice coil control device.

[0093] According to one embodiment of the invention, the main control signal and the auxiliary control signal are delayed relative to the audio signal by a time delay.

[0094] The control signals, i.e., the main control signal and auxiliary control signals such as idle and transition auxiliary control signals, can be delayed for a short period, i.e., a time delay also known as look-ahead delay, ranging from a few milliseconds to several hundred milliseconds. The degree of delay can be preferably selected based on the lowest frequency content to be processed, e.g., 20 Hz, or higher for the tweeters of two- or three-way loudspeakers, such that a prediction can be made based on at least one, and preferably several, periods of the lowest intended frequency content. This delay allows certain types of signal analysis to be performed on the audio signal before control signals are applied to voice coil sections. Such analysis can be used to predict future excursion requirements, e.g.,To create representations of the deflection requirement based on a shorter or longer signal content.

[0095] Signal analysis of the audio signal in the context of a time delay can therefore be understood as an analysis that is carried out on parts of the audio signal that have not yet been reproduced using control signals.

[0096] According to one embodiment of the invention, the signal analysis is performed on a time segment of the audio signal.

[0097] A time period can be understood as a short time window in which the audio signal can be analyzed to create a basis for the coupling of control signals, such as a main control signal and auxiliary control signals, such as idle auxiliary control signals and transition auxiliary control signals.

[0098] In some embodiments of the invention, the audio signal is analyzed within a short time interval extending from the present and back. The audio signal applied to the voice coil during this short past interval is then used as the basis for the selective coupling of auxiliary voice coils. For example, an analysis of the applied audio signal might reveal a very high number of high peaks per unit of time. Therefore, the predetermined time interval for the selective coupling of auxiliary control signals can be chosen such that the auxiliary control signals are maintained for a duration exceeding the typical time between such high peaks.At a later point in the audio signal, if a previous peak history in the control signal, as already applied to voice coil sections, shows that the number of high peaks in the audio signal per unit of time is reduced, the specified time duration can be reduced accordingly, so that the power consumption of the voice coil can be reduced.

[0099] According to one embodiment of the invention, the aforementioned time period is identical to the aforementioned time delay.

[0100] When analyzing a time interval, such as a time window, relating to a portion of the audio signal that has not yet been reproduced by the voice coil due to the time delay or look-ahead delay, this time window can have a duration identical to the time delay or look-ahead delay. This is useful because an analysis of an audio signal being reproduced simultaneously cannot extend beyond the duration of the time delay. If the look-ahead delay is 50 milliseconds, then the analysis can only be performed within a time window that is less than or equal to 50 milliseconds.

[0101] According to one embodiment of the invention, the signal analysis of the audio signal includes a peak analysis of the audio signal.

[0102] In various embodiments of the invention, the selective coupling is based on a prediction of the voice coil's peak displacement within the time window. If the prediction of the voice coil peak displacement results in the predicted voice coil displacement exceeding one or more specific threshold values, one or more auxiliary control signals are coupled to auxiliary voice coil sections. Such threshold values ​​can be predefined displacement levels.

[0103] Analyzing the audio signal within the time window can predict a peak in the voice coil excursion requirement that exceeds one or more threshold values. Accordingly, auxiliary control signals can be coupled to pairs of voice coil auxiliary sections. In this sense, suitable auxiliary control signals can be applied to pairs of voice coil auxiliary sections upstream of a section of the audio signal for which the corresponding excursion requirement is requested. In other words, pairs of voice coil auxiliary sections can be coupled to other voice coil auxiliary sections before coupling is deemed necessary to deliver the required excursion dictated by the audio signal. This pre-coupling enables, for example, smooth, selective coupling of transition auxiliary control signals.

[0104] The time window, which represents a time segment of the audio signal, can thus create an environment for predicting the required displacement requirement for that time window, and such a prediction can be based on an analysis of the audio signal within the time window, such as an analysis of a maximum peak of the amplitude of the audio signal within the time window or an analysis of any other parameter relating to the audio signal within the time window.

[0105] As an example, the predetermined duration for the selective coupling of auxiliary control signals can be defined for a given time window and can be established multiple times in successive time windows of the signal analysis. In one embodiment of the invention, the predetermined duration for the selective coupling is identical to the duration of the time window. The analysis of the audio signal can further stipulate that the selective coupling of the auxiliary control signal occurs for a predetermined duration that extends beyond an individual time window, e.g., beyond the collective time of two or more time windows.

[0106] According to one embodiment of the invention, the said signal analysis is repeatedly performed on the said audio signal.

[0107] Signal analysis can be performed repeatedly on successive time intervals of the audio signal as long as an audio signal is present.

[0108] In one embodiment of the invention, the time window is a dynamic time window that follows the temporal progression of the audio signal, although due to a possible time delay it precedes the applied control signal.

[0109] According to one embodiment of the invention, the representation of the deflection requirement is created on the basis of a signal analysis of the audio signal.

[0110] By analyzing the audio signal using signal analysis in combination with a look-ahead delay, it is possible to predict the required excursion to reproduce the audio signal during a future time period, e.g., a period with a duration identical to the time delay. This analysis can be performed by the voice coil control device, which may include a signal processor, such as a digital signal processor.

[0111] In this way, the voice coil control device can be a tiny time ahead of the reproduced audio signal, i.e., the audio signal as it is generated by the reciprocating movement of the voice coil. This time gap allows the voice coil control device to analyze the audio signal and determine how to react to changes in the audio signal before a corresponding control signal needs to be applied to the voice coil.

[0112] The deflection requirement can alternatively or additionally be determined from signal analysis of past audio signal content, i.e., "by experience" rather than "by prediction." Such embodiments avoid the look-ahead delay, which can be undesirable, for example, when used with other audio or video devices, and can instead be based on the assumption that the future signal content is similar to the past signal content.

[0113] According to one embodiment of the invention, the representation of the deflection requirement comprises a property of the audio signal, and the representation of a predetermined deflection level is a threshold value that is related to the property of the audio signal.

[0114] According to various embodiments of the invention, a comparison is made between a property of the audio signal and a predetermined threshold value of that property. The predetermined threshold value can determine when a control signal is to be selectively coupled to voice coil auxiliary sections. The property of the audio signal can be the direct level of the audio signal, an audio signal envelope, a mean value type, e.g., RMS, of the audio signal, its amplitude, a peak maximum of the audio signal, or a predicted loudness. Loudness can be understood as a subjective perception of the sound pressure generated by a loudspeaker system. If the property of the audio signal is greater than its associated threshold value, an auxiliary control signal is coupled to a pair of voice coil auxiliary sections.According to these different embodiments, the auxiliary control signal can be coupled or uncoupled to the pair of voice coil auxiliary sections during several audio signal cycles.

[0115] A comparison of the audio signal's characteristics with a predefined threshold level can be performed based on current audio signal values, past audio signal values, and / or future audio signal values. A prediction of future audio signal values ​​can be generated based on an analysis of the audio signal performed by the voice coil control device.

[0116] According to one embodiment of the invention, this property of the audio signal relates to an amplitude of the audio signal.

[0117] In various embodiments of the invention, the representation of the displacement requirement includes a property of the audio signal, and this property is the amplitude of the audio signal. Typically, the representation of a predetermined displacement level is an amplitude threshold. Therefore, various embodiments of the invention involve comparing the amplitude of the audio signal with an amplitude threshold level to selectively couple a control signal to voice coil auxiliary sections. This amplitude can be the current amplitude of the audio signal, the amplitude of an envelope of the audio signal, a mean value of the audio signal amplitude, a peak maximum of the audio signal amplitude, or a predicted loudness. If the amplitude of the audio signal is greater than the amplitude threshold, an auxiliary control signal is coupled to a pair of voice coil auxiliary sections.In these embodiments, the auxiliary control signal may or may not be coupled to the pair of voice coil auxiliary sections during several audio signal cycles.

[0118] The comparison of the audio signal amplitude with a predefined amplitude threshold can be performed based on a current audio signal value, past audio signal values, and / or future audio signal values. Predicting future audio signal values ​​can be achieved using a voice coil control device with a signal processor, such as a digital signal processor, in combination with an audio signal delay.

[0119] According to embodiments of the invention in which a comparison is made between a representation of the deflection requirement and a representation of a predetermined deflection level, the comparison can be performed at a specific frequency, i.e., at specific time intervals. It may be advantageous to select a frequency that does not lead to distortion. In embodiments with a time window of a specific duration, this duration can serve as a guideline for selecting an interval for performing the comparisons and thus the decisions; for example, a short time window may necessitate the selection of short decision intervals in one embodiment to avoid distortion. Depending on the embodiment of the invention, the comparison frequency can be in the range of 10 Hz to 10 MHz.

[0120] In various embodiments of the invention, the display of a predetermined displacement level can be set to a fixed value or it can be a dynamic value. A fixed value can be selected by a person skilled in the art to minimize distortion of the audio signal or to increase power efficiency, depending on the target application. A dynamic value can be set manually by a user or automatically, e.g., by a digital signal processor. An automatically adjusted dynamic value can depend on the target application or the type of audio signal, e.g., speech, music, etc., but is not limited to these examples. In some embodiments, the display of a predetermined displacement level can also depend on the frequency composition of the audio signal and / or the frequency response of the loudspeaker.

[0121] According to one embodiment of the invention, the coupling of the auxiliary control signal is based on a user-defined input selection.

[0122] A user-defined input selection can be understood as a situation where the user of a loudspeaker containing a voice coil sets a parameter that affects the audio signal reproduction. Such a parameter could be the desired volume or loudness of the reproduced audio signal. This setting can be made, for example, using a volume knob or control. If a user selects a high volume or loudness, it may be necessary to apply auxiliary control signals to one or more pairs of voice coil auxiliary sections to ensure the voice coil excursion required for the user's desired audio signal reproduction.

[0123] According to one embodiment of the invention, the representation of the deflection requirement is based on the measurement of the voice coil deflection using at least one position sensor, and the representation of a predetermined deflection level is a threshold value that is related to the deflection of the voice coil.

[0124] In embodiments of the invention, the representation of the deflection request is based on measuring the position of the voice coil with a sensor. These embodiments include sensors based on magnetic means, optical means, acoustic means and / or inductive means, but the sensors are not limited to these examples according to the invention.

[0125] Various embodiments of the invention involve comparing a voice coil displacement measurement with a predetermined threshold level of the measured voice coil displacement to selectively couple a drive signal to voice coil auxiliary sections. This comparison can be based on the amplitude of the voice coil displacement measurement. This amplitude can be the current amplitude, the amplitude of an envelope, a mean amplitude, or a peak amplitude. If the amplitude of the voice coil displacement measurement is greater than an amplitude threshold, an auxiliary control signal is coupled to a pair of voice coil auxiliary sections. In these embodiments, the auxiliary control signal can be coupled to the pair of voice coil auxiliary sections or not coupled during several audio signal cycles.

[0126] The comparison of a measurement of the voice coil deflection with a predetermined deflection level can be performed on the basis of a current signal value, past signal values ​​and / or future signal values.

[0127] According to one embodiment of the invention, the representation of the deflection request is based on the current and / or voltage in the voice coil sections, and the representation of a predetermined deflection level is a threshold value that relates to the current and / or voltage in the voice coil sections.

[0128] During the application of a drive signal, each voice coil section experiences an induced current due to the change in magnetic flux through its coils as it passes through the air gap. Therefore, the current in a voice coil section includes an induced current in addition to the applied control signal current. By measuring and analyzing the current and / or voltage in at least one voice coil section, it is thus possible to create a representation of the displacement requirement.

[0129] Various embodiments of the invention involve comparing a measurement of the current and / or voltage in at least one voice coil section with a predetermined threshold level of the measured current and / or voltage to selectively couple a control signal to voice coil auxiliary sections. This comparison can be based on the amplitude of the induced current and / or voltage. This amplitude can be the current amplitude, the amplitude of an envelope, a mean-value type of amplitude, or a peak maximum of the amplitude. If the amplitude of the induced current and / or voltage is greater than an amplitude threshold, an auxiliary control signal is coupled to a pair of voice coil auxiliary sections. In these embodiments, the auxiliary control signal can be coupled to the pair of voice coil auxiliary sections or uncoupled during several audio signal cycles.

[0130] The comparison of the current and / or voltage with a given deflection level can be performed based on a current signal value, past signal values ​​and / or future signal values.

[0131] Various embodiments perform a comparison of a representation of the deflection request and a representation of a predetermined deflection level based on multiple signals, e.g., a comparison based on a combination of the audio signal and the current and / or voltage in at least one voice coil section. Such embodiments can enable more reliable or accurate selective coupling of an auxiliary control signal with voice coil auxiliary sections.

[0132] According to one embodiment of the invention, the pair of voice coil auxiliary sections comprises an upper voice coil section and a lower voice coil section, wherein the upper voice coil section and the lower voice coil section are each arranged on both sides of the main voice coil section along the axis of motion.

[0133] An upper voice coil section can be understood as the first auxiliary section of a pair of auxiliary sections, and a lower voice coil section can be understood as the second auxiliary section of a pair of auxiliary sections. The terminology can also be reversed, so that the upper voice coil section is the second auxiliary section and the lower voice coil section is the first auxiliary section. If the voice coil comprises more pairs of auxiliary sections, such as a second pair, the elements of such a pair can similarly be referred to as a second upper voice coil section and a second lower voice coil section.

[0134] In this sense, the voice coil elements of a pair of voice coil auxiliary sections can be controlled individually, hence the distinction between an upper voice coil section and a lower voice coil section. Controlling individual voice coil sections within pairs of voice coil auxiliary sections is advantageous because rectification of auxiliary control signals can be utilized, and this can further result in the beneficial effects of lower voice coil power consumption and thus also less excessive voice coil heating.

[0135] According to one embodiment of the invention, providing an auxiliary control signal includes providing an upper rectified control signal to the upper voice coil section and providing a lower rectified control signal to the lower voice coil section; wherein the upper rectified control signal is provided by attenuation, such as blocking, of a first current direction of the auxiliary control signal; wherein the lower rectified control signal is provided by attenuation, such as blocking, of a second current direction of the auxiliary control signal; and where the first and second current directions of the auxiliary control signal are opposite current directions.

[0136] A control signal applied to a voice coil can include a current that alternates between a first current direction and a second current direction through the voice coil windings, where the first and second current directions are opposite directions. When current flows through the voice coil windings in a first direction, an electromotive force can be generated on the voice coil in a first direction along the axis of motion, and when current flows through the voice coil windings in a second direction, an electromotive force can be generated on the voice coil in a second direction along the axis of motion, where the first and second directions along the axis of motion are opposite directions.Thus, forces can be exerted on the voice coil in both directions of movement along the axis of movement, which enables the voice coil to move back and forth within the air gap.

[0137] In various embodiments of the invention, the provision of the auxiliary control signal comprises providing an upper rectified control signal to the upper voice coil section and providing a lower rectified control signal to the lower voice coil section. The upper rectified control signal can be generated by attenuating or blocking a first current direction of the auxiliary control signal, while the lower rectified control signal can be generated by attenuating or blocking a second current direction of the auxiliary control signal that is opposite to the first current direction.

[0138] Attenuation of a current can be understood as a reduction of the current and / or voltage of the signal; for example, an upper rectified control signal can be generated by attenuating a first current direction of an auxiliary control signal, and thus the magnitude of the current flow in a first current direction in the upper rectified control signal can be smaller than the magnitude of the current flow in a first current direction in the auxiliary control signal.

[0139] Blocking a current can be understood as a reduction of the current, so that after the current is blocked, no significant current flows.

[0140] In various embodiments, if the current of an auxiliary control signal flows in a first current direction, this current can flow substantially to the lower voice coil section, while its flow to the upper voice coil section is damped or blocked. Similarly, if the current of an auxiliary control signal flows in a second current direction, this current can flow substantially to the upper voice coil section, while the flow to the lower voice coil section is damped or blocked. The upper rectified control signal and the lower rectified control signals are arranged to supply a current flowing in a suitable current direction to generate an electromotive force on the voice coil, thus ensuring correct reproduction of the audio signal.

[0141] Alternatively, in other various embodiments, the current flow can be reversed so that the current flowing in the first direction can flow substantially to the upper part of the voice coil, and its flow to the lower part is damped or blocked. Similarly, if the current of an auxiliary control signal flows in a second direction, this current can flow substantially to the lower part of the voice coil, while its flow to the upper part is damped or blocked. The upper rectified control signal and the lower rectified control signals are arranged to supply a current flowing in a suitable direction to generate an electromotive force on the voice coil, thus ensuring correct reproduction of the audio signal.

[0142] In various embodiments of the invention, the upper rectified control signal is generated by passing the auxiliary control signal through a rectifier unit, e.g., a diode or a MOSFET. A rectifier unit can be understood as a unit, device, circuit, or circuit element that processes current asymmetrically; that is, a rectifier unit can respond in a first way to a current in a first direction and in a second way to a current in a second direction. An example of a rectifier unit is a diode, which, within the current and / or voltage limits of the diode, may be characterized by asymmetric conductivity, i.e., low resistance for one current direction and high resistance for the opposite current direction.To generate the upper rectified signal, a diode can be integrated to block one current direction of the auxiliary control signal while allowing the passage of a second current direction. In this way, the first current direction in the upper voice coil section can be attenuated or blocked by the diode. The above reasoning applies similarly to the generation of the lower rectified control signal, which can be generated in a similar manner by passing the auxiliary control signal through a rectifier unit, such as a diode, to block one current direction while allowing the first current direction to pass. This allows the second current direction in the lower voice coil section to be attenuated or blocked by the diode.

[0143] In another embodiment of the invention, the upper and lower rectified control signals are provided by a voice coil control device, which takes the audio signal as its input signal for processing. The signals can be provided digitally by a digital signal processor of the voice coil control device. The voice coil control device can then supply various control signals, e.g., a main control signal, an upper rectified control signal, and a lower rectified control signal, to the corresponding voice coil sections. In this way, the control signals are generated in the voice coil control device based on an analysis of the audio signal. In this embodiment, the control signals can be supplied to the voice coil sections via one or more amplifiers, such as one or more amplifiers comprising one or more gain channels.

[0144] In various embodiments, if the displacement of the voice coil allows the lower voice coil section to contribute substantially to generating an electromotive force, the control signal received by the lower voice coil section can essentially be the auxiliary control signal. If the displacement occurs in the opposite direction, i.e., the upper voice coil section is closer to the air gap than the lower voice coil section, the lower rectified control signal received by the lower voice coil section can be generated by attenuation or blocking of the auxiliary control signal; that is, the lower rectified control signal cannot supply any substantial current to the lower voice coil section.If the displacement allows the upper voice coil section to contribute substantially to generating an electromotive force, the control signal received by the upper voice coil section can essentially be the auxiliary control signal. If the displacement occurs in the opposite direction, i.e., the lower voice coil section is closer to the air gap than the upper voice coil section, the upper rectified control signal received by the upper voice coil section can be generated by attenuation or blocking of the auxiliary control signal; that is, the upper rectified control signal cannot supply any substantial current to the upper voice coil section.

[0145] According to the invention, the current supplied to the voice coil sections of the segmented voice coil can be reduced by damping or blocking control signals. It is particularly advantageous to block the current to the voice coil sections that do not contribute to generating an electromotive force. In various embodiments, selective coupling of the auxiliary control signal to the pair of voice coil auxiliary sections reduces the power consumption of the invention when the excursion requirement is low. By additionally integrating one or more rectifier units that process the current asymmetrically, e.g., diodes, the invention can be arranged such that the excursion can reproduce the audio signal while further reducing power consumption and overheating, since one of the two voice coil auxiliary sections receives reduced or essentially no current under selective coupling.

[0146] According to one embodiment of the invention, providing the upper rectified control signal includes processing the auxiliary control signal using an upper rectifier unit, and providing the lower rectified control signal includes processing the auxiliary control signal using a lower rectifier unit.

[0147] According to the invention, an upper rectified signal is generated by attenuating or blocking a first current direction of an auxiliary control signal. Similarly, a lower rectified signal is generated by attenuating or blocking a second current direction of an auxiliary control signal. The attenuation and / or blocking of an auxiliary control signal can comprise one or more rectifier units.

[0148] Preferably, a rectifier unit processes an auxiliary control signal by attenuating or blocking a first current or voltage direction and allowing the opposite current or voltage direction to pass. In various embodiments, one rectifier unit processes the auxiliary control signal to generate an upper rectified control signal, and another rectifier unit processes the auxiliary control signal to generate a lower rectified control signal. The processing of the auxiliary control signal to generate an upper rectified control signal can be characterized by an asymmetrical response to the direction of the current or voltage; for example, current or voltage in a first direction is attenuated or blocked, while current in a second direction is allowed to pass to the upper voice coil section without significant attenuation.The processing of the auxiliary control signal to generate a lower rectified signal may be characterized by the opposite asymmetric response compared to the processing of the auxiliary control signal to generate an upper rectified signal, e.g. current or voltage in a second direction is attenuated or blocked, while current in a first direction is allowed to pass to the lower voice coil section without significant attenuation.

[0149] The rectifier unit that processes the auxiliary control signal to provide an upper rectified control signal can also be called the upper rectifier unit, and the rectifier unit that processes the auxiliary control signal to provide a lower rectified control signal can be called the lower rectifier unit.

[0150] In various embodiments, the upper rectifier unit and the lower rectifier unit are constructed from similar or identical components, but are integrated into the invention to enable opposite processing of the auxiliary control signal, e.g. an upper rectifier unit blocks a first current direction and allows current in a second direction to pass through without significant attenuation, while a lower rectifier unit blocks a second current direction and allows current in a first direction to pass through without significant attenuation.

[0151] In some embodiments, the upper rectifier unit and the lower rectifier unit may refer to the same unit, device, circuit, or circuit element, such that this single rectifier unit is capable of providing both an upper rectified control signal and a lower rectified control signal based on an auxiliary control signal. The rectifier unit capable of generating both the upper and lower rectified control signals may be a rectifier circuit.

[0152] A rectifier unit can be connected to both terminals of a voice coil section.

[0153] According to one embodiment of the invention, the upper rectified control signal is provided by rectifying the auxiliary control signal in the first current direction, and the lower rectified control signal is provided by rectifying the auxiliary control signal in the second current direction.

[0154] In various embodiments, the upper rectifier unit comprises a diode. In various embodiments, the lower rectifier unit also comprises a diode. A diode can refer to a device characterized by asymmetric conductivity, i.e., low resistance for one current direction and high resistance for the opposite current direction, within the current and / or voltage limits of the diode. A diode can comprise a piece of semiconductor material. According to the invention, diode types include point-contact diodes, pn-junction diodes, and Schottky diodes, but the invention is not limited to these diode types. The invention can also use components with similar properties to diodes, e.g., thyristors.

[0155] According to one embodiment of the invention, the upper rectifier unit comprises a switch, and the lower rectifier unit comprises a switch.

[0156] A rectifier unit may include a switch. This can also be referred to as active rectification or synchronous rectification. A switch can be understood as an electrical component or device, built from discrete components or integrated within an integrated circuit or processor, that can interrupt current or redirect it from one terminal of the switch to another, such that the redirection of current determines whether a control signal is coupled or not. A switch may be based on a solid-state device such as a transistor, for example, a metal-oxide-semiconductor field-effect transistor or a MOSFET transistor.

[0157] In various embodiments, the upper rectifier unit includes a switch. In various embodiments, the lower rectifier unit also includes a switch. The switch can be controlled based on the auxiliary control signal such that, in a first direction, the current flow of the auxiliary control signal allows the current to be supplied to the lower voice coil section while blocking the current to the upper voice coil section, and in a second direction, the current flow of the auxiliary control signal allows the current to be supplied to the upper voice coil section while blocking the current to the lower voice coil section.

[0158] According to one embodiment of the invention, the upper rectifier unit comprises an amplifier and the lower rectifier unit comprises an amplifier.

[0159] In various embodiments, the upper rectifier unit includes an amplifier. In various embodiments, the lower rectifier unit also includes an amplifier.

[0160] In various embodiments, the upper rectifier unit comprises an amplifier, and the lower rectifier unit also comprises an amplifier. These amplifiers can selectively amplify an auxiliary control signal based on the current direction of the auxiliary control signal. Thus, a first current direction of the auxiliary control signal can cause amplification by the amplifier contained in the lower rectifier unit, so that an amplified signal is delivered to the lower voice coil section, while an amplified signal is not delivered to the upper voice coil section. Similarly, a second current direction of the auxiliary control signal can cause amplification by the amplifier contained in the upper rectifier unit, so that an amplified signal is delivered to the upper voice coil section, while no amplified signal is delivered to the upper voice coil section.

[0161] Selective gain based on the current direction of the auxiliary control signal can include current analysis and amplifier control. Current analysis can include means for determining the current amplitude and / or direction. Amplifier control can include the selective driving and control of amplifiers based on the current analysis.

[0162] One aspect of the invention relates to a voice coil drive system of a loudspeaker, comprising: a magnetic circuit with an air gap; a voice coil suspended in the air gap, the voice coil comprising a plurality of voice coil sections, the plurality of voice coil sections comprising a main voice coil section and a pair of auxiliary voice coil sections arranged along an axis of motion, the voice coil sections of the pair of auxiliary voice coil sections being arranged on both sides of the main voice coil section; and A voice coil control device arranged to apply an audio signal to the air-gap suspended voice coil to generate an electromotive force that moves the voice coil along the axis of motion, wherein the application of an audio signal comprises the continuous coupling of a main control signal based on the audio signal to the voice coil main section and the selective coupling of an auxiliary control signal based on the audio signal to the pair of voice coil auxiliary sections.

[0163] A voice coil drive system is a system designed to generate a driving motion based on an input audio signal, such as an acoustic or digital audio signal. The driving motion, generated by the voice coil suspended in the air gap of the magnetic circuit, can be advantageously used to move a loudspeaker diaphragm back and forth to produce an acoustic sound.

[0164] According to one embodiment of the invention, the voice coil control device is arranged such that, based on a representation of the deflection request, it selectively couples the auxiliary control signal to the pair of voice coil auxiliary sections.

[0165] According to one embodiment of the invention, the pair of voice coil auxiliary sections is a first pair of voice coil auxiliary sections and the auxiliary control signal is a first auxiliary control signal, wherein the voice coil further comprises a second pair of voice coil auxiliary sections and the control device is arranged to selectively couple a second auxiliary control signal with the second pair of voice coil auxiliary sections.

[0166] A voice coil drive system as described herein can exhibit all the advantages and benefits described above in relation to the method for driving a voice coil. Thus, a loudspeaker according to the present invention can offer the advantageous effect of low power consumption and a reduction in excessive heating within the loudspeaker due to the efficiency of the segmented voice coil.

[0167] One aspect of the invention relates to a loudspeaker comprising a diaphragm, an interface configured to receive an audio signal and a voice coil drive system, as described in one of the paragraphs above. List of characters

[0168] In the following, various embodiments of the invention are described with reference to the drawings, wherein Fig. Figures 1a-1b illustrate a conventional voice coil drive system known according to the state of the art, Fig. 2 A voice coil control system with a voice coil, comprising a voice coil main section and a pair of voice coil auxiliary sections, illustrated according to an embodiment of the invention, Fig. Figures 3a-3d illustrate the reciprocating translation of a voice coil comprising three voice coil sections according to embodiments of the invention. Fig. 4 shows a loudspeaker that receives an audio signal according to an embodiment of the invention, Fig. Figures 5a-5c illustrate various alternative embodiments of the invention, in particular an embodiment comprising five voice coil sections, an embodiment comprising a displacement sensor system, and an embodiment in which the individual voice coil sections are dependent on each other. Fig. Figures 6a-6c illustrate different configurations for providing a main control signal and auxiliary control signals for voice coil sections according to embodiments of the invention. Fig. Figures 7a-7b illustrate different configurations of a control device suitable for coupling a control signal to a plurality of voice coil sections based on an input audio signal, according to various embodiments of the invention. Fig. 8 illustrates the ability of the voice coil sections to generate an electromotive force according to various embodiments of the invention; Fig. 9a-9b Flowcharts of methods for coupling control signals to pairs of voice coil auxiliary sections according to embodiments of the invention, Fig. 10a-10d Current directions in individual voice coil sections during operation of an exemplary preferred embodiment of the invention, Fig. 11 illustrates an exemplary determination of the selective coupling time based on zero crossings of an audio signal according to embodiments of the invention, Fig. Figures 12a-c illustrate different methods for determining a deflection requirement based on an audio signal according to embodiments of the invention. Fig. Figure 13 shows an exemplary method for determining an auxiliary control signal amplification according to embodiments of the invention, and Fig. Figures 14a-14e illustrate different configurations for generating rectified control signals for an upper and a lower voice coil section based on an auxiliary control signal according to embodiments of the invention. Detailed description

[0169] Fig. Figure 1a shows a sectional view of a state-of-the-art loudspeaker. Fig. Figure 1b shows a section view along line 1b-1b in Fig. 1a. The loudspeaker contains two concentrically aligned magnetic elements. 2 , which form a magnetic circuit. These magnetic elements 2 are arranged in such a way that within the magnetic circuit 2 a circular air gap 3 is formed.

[0170] A voice coil 1, which comprises a multitude of coil windings, is furthermore located in the air gap 3 suspended. The windings of the voice coil 1 are arranged in such a way that when an electric current flows through the coil 1 An electromotive force is directed to the voice coil. 1 within the air gap 3 shifts, so that a membrane or diaphragm 7 It is activated. An alternating current causes the membrane to move back and forth. 7 , which generates an acoustic tone signal.

[0171] With reference to Fig. 2 is a voice coil control system 51 illustrated according to one embodiment of the invention. The voice coil control system 51 includes a magnetic circuit 2 , which consists of two concentrically aligned magnetic elements 2 is formed. The magnetic elements can be permanent magnets or metal poles. The magnetic circuit2 is arranged in such a way that within the magnetic circuit 2 a circular air gap 3 is formed by the two magnetic elements 2 is completed. The circular air gap 3 is a volume of air that takes the form of a volume located between two axially aligned cylinders of different widths.

[0172] As is known to those skilled in the art, several alternative voice-coil-based loudspeaker configurations are known in the technical field of loudspeakers and acoustic transducers. These configurations feature different magnetic circuit and air gap configurations, including various permanent magnet configurations, pole pieces, front and rear plates, enclosures, and various air gap configurations, including circular, as described above, linear, polygonal, irregular, single, or multiple air gaps, etc. The present invention, as defined in the claims, is therefore not limited to the magnetic circuit and air gap configurations shown in the drawings, but can readily be applied by those skilled in the art to other voice-coil-based transducers.

[0173] A voice coil 1 is in the air gap 3 suspended. The voice coil 1 includes a variety of voice coil sections 21and 22a-b , wherein a voice coil main section 21 centrally located and equipped with a pair of voice coil auxiliary sections 22a-b is surrounded, each of which is arranged on both sides of the main voice coil section, with all voice coil sections axially along an axis of motion 4 the voice coil 1 are aligned. Each voice coil section comprises a multitude of metal windings arranged around the inner magnetic element. 2 and an axis of movement 4 , as in Fig. 2 shown, winding. The voice coil sections are mechanically coupled, but not necessarily electrically coupled, to wind the voice coil. 1 to form. The mechanical coupling can include a support, such as a tube, grid or wire structure made of cardboard, plastic or metal, e.g. a film.

[0174] The voice coil sections 21-22bare configured so that when an electric current passes through a voice coil section 21-22b is guided, which is at least partially within the air gap 3 of the magnetic circuit 2 An electromotive force is located in the respective voice coil section. 21-22b along the axis of movement 4 shifts. Since all voice coil sections 21-22b mechanically coupled elements of the same voice coil 1 are, an electromotive force is generated by one of the voice coil sections. 21-22b is generated, the entire voice coil 1 along the axis of movement 4 shift. The displacement of the voice coil 1 along the axis of movement 4 This causes the voice coil to 1 a membrane 7 a loudspeaker 50 pushes and pulls. Through the movement of the membrane 7 An acoustic tone signal is generated.

[0175] The coupling of the voice coil 1 and the membrane 7 This can be achieved through the aforementioned mechanical coupling of the voice coil section, e.g., by a plastic foil tube, or by including further support elements, as known to those skilled in the art, e.g., a spider and a diaphragm surround. The rest position of the voice coil 1 It can be controlled by support elements known to those skilled in the art, e.g., a spider and / or a diaphragm surround and a frame. In a preferred embodiment, the entire voice coil height is centered in the air gap in the rest state, so that, with three voice coil sections as shown in the examples, the middle voice coil section is aligned with the magnetic circuit and the air gap.

[0176] Since the magnetic field is essentially contained within the air gap 3 in the magnetic circuit 2 As it is arranged, only the voice coil sections can 21-22b, which are at least partially located within the air gap, generate a substantial electromotive force when an electric current is applied. Generally, the more of a particular voice coil section is contained within the air gap, the greater the force generated when an electric current is applied. With regard to the in Fig. At point 2 shown, only the voice coil section is visible. 21 wholly or partially within the air gap 3 arranged, while the voice coil sections 22a and 22b completely outside the air gap 3 are arranged. Since the magnetic field density within the air gap 3 is highest and outside the air gap 3 rapidly decreasing, only the voice coil section 21 generate a substantial electromotive force to drive the voice coil 1 to shift while the voice coil sections 22a and22b sufficiently far from the air gap 3 are removed, so that the efficiency in the conversion of electrical control force into electromotive force is in comparison to the efficiency in the conversion of electrical control force into electromotive force for the voice coil section. 21 considerably smaller and practically insignificant.

[0177] Windings of the voice coil sections 21-22b , which are separated from the air gap 3 Positions located far away primarily contribute to excessive voice coil heating only when electrical drive power is applied, and contribute only slightly to voice coil displacement. 1 along the axis of movement 4 Therefore, based on these considerations, it is advantageous to avoid applying current to any sections of the voice coil. 21-22b e.g. 22a-22b , which are not at least partially located in the air gap, to be avoided.

[0178] In general, a loudspeaker system aims to reproduce an audio signal. 30 by the deflection of a voice coil 1 to reproduce, whereby the deflection determines the position of the voice coil 1 relative to their resting position. An audio signal 30 This can include a representation of different sound intensities, which may require different excursions for playback. For example, an audio signal can... 30 require a range of deflections that can be provided by utilizing the electromotive force that is only available from the main section of the voice coil 21 for the audio signal to be reproduced 30 can be generated. For a different audio signal 30 A range of deflections may be required that can only be achieved using the main section of the voice coil. 21 together with the pair of voice coil auxiliary sections 22a-22b can be provided so that the audio signal30 can be reproduced.

[0179] Referring to Fig. 2 are all voice coil sections 21-22b electrically with a voice coil control device 53 connected. The voice coil control device 53 is arranged to receive a main control signal 41 to the main section of the voice coil 21 to deliver and also to determine whether an auxiliary control signal is needed at a given time 42a-42b to the pair of voice coil auxiliary sections 22a-22b It must be coupled in order to play back the audio signal. The control signals 41-42b are the actual electrical signals that the respective voice coil sections 21-22b through to generate an electromotive force to displace the voice coil 1 along the axis of movement 4 to generate the control signals. 41-42b are the voice coil sections 21-22bProvided via channels, e.g., cables or wires, preferably electrical connections. As in Fig. Figure 2 shows the voice coil control device. 53 a common auxiliary control signal for the pair of voice coil auxiliary sections, which is fed into a single connection 42a-42b The signal is split to each of the voice coil auxiliary sections of the pair. The main control signal 41 can, as in Fig. Figure 2 shows a separate output of the voice coil control device. 53 be, or be taken from the same output as the auxiliary control signal. The voice coil auxiliary sections are used in this process. 22a-22b controlled as a pair, possibly differently than the control of the main voice coil section. 21 .

[0180] In the exemplary embodiment of the invention, as shown in Fig. As shown in Figure 2, the control signals are coupled. 41-42bthrough a voice coil control device 53 The voice coil control device 53 It accepts an audio signal as input. 30 on, which via an interface 52 supplied, which is used to receive the audio signal 30 is designed. The control signals 41-42b are from the audio signal 30 derived, either directly or through processing, as described in more detail below. A main control signal 41 is continuously applied to the main section of the voice coil 21 coupled as long as an audio signal 30 is received, and the voice coil control device 53 selectively couples an auxiliary control signal 42a-42b to the pair of voice coil auxiliary sections 22a-22b The selective coupling of the auxiliary control signal 42a-b to the pair of voice coil auxiliary sections 22a-b based on a comparison of a representation of the displacement requirement, i.e., the required displacement of the voice coil 1 to play back the audio signal 30 at any given time, with a representation of a predetermined displacement level, i.e., a level of displacement of the voice coil 1 , in which the coupling of the auxiliary control signal 42a-b for generating an electromotive force to move the voice coil back and forth 1 is considered necessary. In practice, this comparison can be an analysis of the audio signal. 30 be, which are controlled by the voice coil control device 53 is performed to determine if a peak amplitude of the audio signal 30 greater than a certain threshold for the activation of the pair of voice coil auxiliary sections 22a-b is. If for the playback of the audio signal 30a deflection range is required that is solely determined by the main section of the voice coil. 21 The voice coil control device can be generated. 53 no auxiliary control signal 42a-42b to the voice coil auxiliary sections 22a-22b deliver. Instead, the voice coil control device can 53 According to other embodiments of the invention, an idle control signal is sent to the voice coil auxiliary sections. 22a-22b supply. The idle control signal is a control signal characterized by a low signal strength, e.g., a low current, or a control signal without significant current, e.g., no current.

[0181] Since the selective coupling of the auxiliary control signal 42a-42b to the voice coil auxiliary sections 22a-22b Since this is done on pairs of voice coil sections, the requirements for the voice coil control device are 53, which performs the selective coupling, is significantly reduced compared to a system with segmented voice coils, where a control device may have to perform selective coupling of control signals to individual voice coil sections.

[0182] The voice coil sections 21-22b the voice coil 1 can be configured in various ways, depending on the relative positioning and dimensioning of the voice coil sections 21-22b In the illustrated embodiments, the voice coil comprises 1 three voice coil sections 21-22bHowever, the present invention, as defined in the claims, can be configured with various other numbers and geometries of voice coil sections. Using the examples of voice coil section configurations, control devices, and positioning described below, the person skilled in the art will be able to increase the number of voice coil sections to, for example, five sections (i.e., one main voice coil section and two pairs of auxiliary voice coil sections), or even more, taking into account a balance between the achieved resolution of power efficiency and the additional complexity of manufacturing and control.

[0183] Referring to the Fig. 3a-d is the dynamic behavior of a voice coil 1 , comprising three voice coil sections, as illustrated in embodiments of the invention.

[0184] Fig. 3a shows a voice coil 1 , comprising a voice coil main section 21 and a pair of voice coil auxiliary sections 22a-22b , at a point during the application of an audio signal 30 . Due to the applied audio signal 30 has the electromotive force, which is generated by a main control signal 41 is generated by the voice coil 1 along the axis of movement 4 slightly in an upward direction 5 shifted. To obtain this deflection, it is not necessary to use an auxiliary control signal. 42a-42b with the pair of voice coil auxiliary sections 22a-22b to couple, and such an auxiliary control signal 42a-42b Therefore, it is preferably not used with the voice coil auxiliary sections. 22a-22b coupled to the voice coil.

[0185] Fig. 3b shows the same voice coil 1 as in Fig. 3a at a later point in their back-and-forth movement. Due to the attached signal 30 has the main control signal 41 generated electromotive force the voice coil 1 along the axis of movement 4 slightly in a downward direction 6 The direction of the electromotive force depends on the current direction in the windings of the voice coil sections, and the current direction in the windings of the voice coil main section. 21 has separated from Fig. 3a to Fig. 3b changed to modify the voice coil 1 in opposite directions of movement 5-6 to postpone. In order to postpone the in Fig. To obtain the deflection shown in 3b, it is still not necessary to use an auxiliary control signal. 42a-42b with the voice coil auxiliary sections 22a-22b to couple, and such an auxiliary control signal 42a-42b Therefore, it is preferably not used with the voice coil auxiliary sections. 22a-22b the voice coil 1 coupled.

[0186] Fig. 3c represents the same direction of movement 5 the voice coil 1 as in Fig. 3a, but the voice coil 1 will now be more along the axis of movement 4 shifted. This is an example of a large voice coil deflection. 1 , since the main section of the voice coil 21 now completely outside the air gap 3 of the magnetic circuit 2 is arranged and only one element 22b of the pair of voice coil auxiliary sections 22a-b partially within the air gap 3 is arranged. To achieve this deflection of the voice coil 1 To obtain this, it may therefore be necessary to use an auxiliary control signal. 42a-b to the pair of voice coil auxiliary sections 22ab to couple.

[0187] Fig. 3D illustrates the same direction of movement6 the voice coil 1 as in Fig. 3b, but the voice coil 1 will now be more along the axis of movement 4 shifted. This is an example of a large voice coil deflection. 1 , since the main section of the voice coil 21 now completely outside the air gap 3 of the magnetic circuit 2 is arranged and only one element 22a of the pair of voice coil auxiliary sections 22a-b partially within the air gap 3 is arranged. To achieve this deflection of the voice coil 1 To obtain this, it may therefore be necessary to use an auxiliary control signal. 42a-b to couple to the pair of voice coil auxiliary sections n.

[0188] Fig. 4 represents a loudspeaker 50 that which is an audio signal 30 receives. The speaker can receive the audio signal. 30 via an interface 52(not shown) received. The loudspeaker comprises one or more of the voice coil drive systems described here. 51 When receiving an audio signal 30 The speaker outputs the audio signal 30 again, and by moving one or more loudspeaker diaphragms back and forth 7 (not shown), which in turn generates pressure waves, i.e., sound waves, thus producing an acoustic signal. The membrane 7 each voice coil control system 51 of the loudspeaker 50 is powered by a voice coil 1 moved back and forth, which is controlled according to the embodiments of the invention described herein.

[0189] Referring to the Fig. Figures 5a-c show alternative voice coil geometries according to embodiments of the invention.

[0190] Fig. 5a shows a voice coil 1, which comprises five voice coil sections; one main voice coil section 21 , a first pair of voice coil auxiliary sections 23a-b and a second pair of voice coil auxiliary sections. The five voice coil sections are mechanically coupled, but not necessarily electrically coupled, to control the voice coil. 1 to form. The mechanical coupling can include a support, such as a tube, grid or wire structure made of cardboard, plastic or metal, e.g. a film.

[0191] The main section of the voice coil 21 is from a main control signal 41 powered, while the first pair of voice coil auxiliary sections 23a-b is driven by a first auxiliary control signal and the second pair of voice coil auxiliary sections 24a-b is driven by a second auxiliary control signal. The voice coil is shown in the figure. 1 centered with the air gap 3of the magnetic circuit 2 aligned, with the main section of the voice coil 21 partially within the air gap 3 is arranged. The inclusion of further voice coil sections in comparison to the voice coil 1 the Fig. 3a-3d can have the further advantage that larger deflections of the voice coil are possible. 1 This can be achieved because the individual voice coil sections have a similar height and winding density (i.e., windings per length of the voice coil section, measured in one direction along the axis of motion). 4 ).

[0192] All discussions relating to a voice coil with three voice coil sections, i.e., a main voice coil section 21 and a pair of voice coil auxiliary sections 22a-b , refer to, apply equally to a voice coil with further pairs of voice coil sections, such as two or more pairs of voice coil auxiliary sections.

[0193] In further embodiments of the invention, the voice coil 1 even contain further pairs of voice coil auxiliary sections, which are supplied by further corresponding auxiliary control signals.

[0194] Fig. 5b shows a voice coil 1 , comprising three voice coil sections; one main voice coil section 21 and a pair of voice coil auxiliary sections 22a-b The voice coil sections contain a sensor system comprising one or more displacement measuring units. 15 In this example, there are three displacement units. 15 represented in the form of displacement measuring coils, which are arranged in such a way that they determine the position of the voice coil in relation to the air gap 3determine. These deflection measuring coils 15 These are small coils / windings that are arranged on the voice coil, and when the voice coil is in the air gap 3 moved back and forth, due to a time-dependent change in the magnetic field, such as that produced by the measuring coils 15 It was discovered that a measuring current is induced in the coils. By measuring the induced currents in each of the displacement measuring coils 15 Is it therefore possible to determine the displacement / deflection of the voice coil? 1 to determine the displacement, and suitable control signals can be coupled based on this determined displacement. In other embodiments of the invention, any other number of displacement measuring units can be used. 15 can be used, and these can determine the position of the voice coil using other means, such as optical means, e.g., by measurements with a laser.

[0195] Fig. 5c shows a voice coil1 , which includes a voice coil main section 21 and a pair of voice coil auxiliary sections 22a-b includes. Each of the voice coil sections has a height that is less than the height of the air gap. 3 Such voice coils can be referred to as under-dwelling voice coil sections, while the voice coil sections that are in the Fig. Figures 3a-3d show that can be referred to as overhung voice coil sections, since the height of the voice coil sections is the height of the air gap. 3 of the magnetic circuit 2 exceeds.

[0196] Fig. Figures 6a-c illustrate examples of ways to provide control signals for the voice coil main section and the pair of voice coil auxiliary sections.

[0197] The Fig. 6a-c each show a voice coil 1 , which includes a voice coil main section 21and a pair of voice coil auxiliary sections 22a-22b This includes the current input and output channels of the various voice coil sections. In each subfigure of the Fig. 6a-6c the auxiliary control signal is provided by various exemplary approaches.

[0198] Referring to Fig. 6a will be a main control signal 41 to the main section of the voice coil 21 supplied, and the current of the signal can power the voice coil 1 via a canal 43 Exit. Selective coupling of an auxiliary control signal 42a-42b to the voice coil auxiliary sections 22a-22b can be powered by two amplifiers 12 They are controlled. Control signals 32 , which are connected to the two amplifiers 22a-22b are connected, can control whether the input signals of the amplifiers 12Whether the input signals are amplified to perform the coupling, or not amplified to prevent coupling. The current of the auxiliary control signal. 42a , which is attached to the voice coil auxiliary section 22a is delivered through an output channel 44a exit, and the current of the auxiliary control signal 42b , which is attached to the voice coil auxiliary section 22b is delivered through an output channel 44b resign.

[0199] Referring to Fig. 6b will be a main control signal 41 to the main section of the voice coil 21 supplied, and the current of the signal can power the voice coil 1 via a canal 43 Exit. Selective coupling of an auxiliary control signal 42a-42b to the voice coil auxiliary sections 22a-22b can be from an amplifier 12 be controlled. One connected to the amplifier. 12 connected control signal32 It can control whether the amplifier's input signal is amplified to perform the coupling, or whether the input signal is not amplified to prevent the coupling. The current of the auxiliary control signal 42a , which is the voice coil auxiliary section 22a is delivered through an output channel 44a exit, in order to reappear as an input auxiliary signal 42b for the voice coil auxiliary section 22b to be used, and then finally the voice coil 1 through the output channel 44b leave.

[0200] Referring to Fig. 6c will be a main control signal 41 to the main section of the voice coil 21 supplied, and the current of this signal can power the voice coil section 21 via a canal 43 exit. A switching unit 10 , which are controlled by a control signal 32If the current is controlled, it can either be used for coupling as an auxiliary control signal. 42a-42b to the voice coil auxiliary sections 22a-22b pass on or allow this current to power the voice coil 1 to leave. The control signal 32 and the switching unit 10 This allows for the selective coupling of an auxiliary control signal to a pair of voice coil auxiliary sections. In some embodiments, a modification of the output current is possible. 43 may be required to be used as an auxiliary control signal, and such a modification can be achieved by implementing an optional amplification or attenuation element. 11 be carried out. After this optional element, the auxiliary control signal is transmitted. 42b a voice coil auxiliary section 22b supplied. Then the signal current leaves the voice coil auxiliary section. 22b through the output channel 44b, and this current is used as an auxiliary control signal 42a for the other voice coil auxiliary section 22a used. Finally, the signal current leaves the voice coil section. 22a through the output channel 44a and exits the voice coil through the channel 45 .

[0201] According to the invention, methods for providing a main control signal and an auxiliary control signal are not limited to the exemplary embodiments described above.

[0202] Referring to Fig. Figures 7a-b show configurations of a control device which, according to some embodiments of the invention, are suitable for coupling control signals to voice coil sections.

[0203] In preferred embodiments, a main control signal is used. 41 continuously to a voice coil main section 21 coupled and an auxiliary control signal 42a-b is selectively applied to a pair of voice coil auxiliary sections. 22a-b coupled. This can be achieved by a voice coil control device. 53 This may involve one or more switching units, amplifiers, power supply units and / or a signal processor, e.g. a digital signal processor.

[0204] Fig. 7a shows an exemplary embodiment of the invention, in which the voice coil 1 through a voice coil control device 53 It is controlled by a digital signal processor. 14 provides a control signal 32 to a power supply unit 13 The digital signal processor 14 generated control signal 32 can, for example, be on the audio signal 30 based on the digital signal processor 30 It can also modify the audio signal 30 to perform a processed audio signal 31to generate. Such modifications include a delay of the audio signal, which may be preferred in some embodiments of the invention. The power supply unit 13 can continuously operate an amplifier capable of generating a main control signal 41 based on a processed audio signal 31 to generate. In addition, the power supply unit can 13 two additional amplifiers based on the control signal 32 operate and thus the selective coupling of auxiliary control signals n to voice coil auxiliary sections 22a-b undertake.

[0205] Fig. Figure 7b shows another exemplary embodiment of the invention, in which the voice coil 1 through a voice coil control device 53 It is controlled. Here, a digital signal processor generates a control signal. 32 and a processed audio signal 31, both based on the audio signal 30 A power supply unit 13 powers an amplifier 12 , which processes the audio signal 31 amplified to generate a control signal that is sent to a switching unit 10 is sent. The switching unit 10 is processed by the digital signal processor 14 via the control signal 32 controlled and is capable of continuously generating a main control signal 41 to the main section of the voice coil 21 to deliver while selectively providing an auxiliary control signal 42a-42b to the voice coil auxiliary sections 22a-22b couples.

[0206] Configurations of the voice coil control device are not limited to the two examples described above. A person skilled in the art can arrange many different configurations of signal processors, amplifiers, switching units, power supply units, and / or other electrical components to accomplish the task of selectively coupling an auxiliary control signal to voice coil auxiliary sections while continuously coupling a main control signal to a voice coil main section.

[0207] Fig. Figure 8 shows the ability of the different voice coil sections of the voice coil to generate an electromotive force.

[0208] The magnitude of an electromotive force exerted on a voice coil by passing a current through it in a magnetic field can depend on the total length of the current-carrying wire within the magnetic field and the strength of the magnetic field. The product of the wire length within the magnetic field and the magnetic field strength can therefore describe the ability of a voice coil or a section of a voice coil to generate an electromotive force and can be denoted as BL. This parameter can vary with the displacement of the voice coil, as, for example, current-carrying wire can leave or enter a region of the magnetic field.

[0209] Referring to the table P11 in Fig. Figure 8 shows the BL contribution of individual voice coil sections for an exemplary embodiment of the invention with three voice coil sections for a range of deflections. The curveL1 shows the BL contribution of a voice coil main section, which is greatest when the displacement 0 The ability to generate an electromotive force gradually decreases as the displacement from zero is increased or decreased, i.e., as the main section of the voice coil is moved out of the air gap. The curves L2a and L2b The curve describes the BL contribution of each pair of voice coil auxiliary sections. When the displacement is reduced below 0, the curve shows... L2a , that the ability of a voice coil auxiliary section to generate an electromotive force is increased, and when the displacement is increased above 0, the curve shows L2b , that the capability of the other voice coil auxiliary section is increased. Table P11This illustrates how voice coil auxiliary sections can support a voice coil main section depending on the displacement requirement.

[0210] Referring to the table P12 in Fig. Figure 8 shows an effective BL for a similar exemplary embodiment. The effective BL can be understood as the sum of BL contributions from a voice coil main section and from voice coil auxiliary sections, where the BL contribution of the voice coil auxiliary sections has been multiplied by a gain factor. The curves L3-L7 These correspond to amplification factors from 0% to 100%. A gain of 0%, represented by the curve... L3 As shown, only the main section of the voice coil can contribute to generating an electromotive force. With increasing amplification, the width and height of the effective BL curves along the displacement axis also increase.

[0211] In various embodiments of the invention, an effective BL curve is ideal that is approximately constant over a wide range of deflections. In the exemplary embodiment shown, this is achieved with a gain of 90%, as the curve L6 Figure 1 shows an effective BL curve that is flat in a deflection range of -0.6 to 0.6. In other various embodiments, it may be preferred that a BL curve is not flat; for example, the effective BL can increase when the deflection is sufficiently increased or decreased. This is achieved by a 100% gain, as shown by the curve. L7This shows where the effective BL is greater at displacements of -0.7 and 0.7 than at a displacement of 0. This can enable corrections of nonlinearities in the voice coil system, e.g., a nonlinear relationship between the restoring force acting on the voice coil and the displacement of the voice coil, which can lead to distortion at large voice coil displacements.

[0212] The exemplary embodiment described above in Fig. Figure 8 illustrates how voice coil auxiliary sections can support a voice coil main section and how different gains can be advantageous depending on the target application. Other embodiments of the invention may have different effective BL curves, depending on the number of voice coil sections, winding density, magnetic field geometry, auxiliary control signal gain, etc.

[0213] The Fig. Figures 9a-b illustrate flowcharts of methods for coupling control signals to a pair of voice coil auxiliary sections according to embodiments of the invention.

[0214] The flowchart of Fig. 9a shows the steps S1-S4 a method for performing the selective coupling of an auxiliary control signal 42 to a pair of voice coil auxiliary sections 22a-b The procedural steps S1-S4 are all controlled by a voice coil control device 53 carried out in one step S1 A representation of the deflection requirement is created, and in one step S2 A representation of a predetermined displacement level is provided. In one step S3A comparison is made between the displacement requirement and the predetermined displacement level. If predetermined conditions are not met, e.g., the displacement requirement does not exceed a predetermined displacement level, the procedure starts from step [number] of the process. S1 However, if the comparison shows that the predetermined condition is met, the procedure proceeds to step 1. S4 the process continues, in which an auxiliary control signal is applied to a pair of voice coil auxiliary sections. The procedure then continues with step S1 repeated.

[0215] The flowchart of Fig. 9b shows the steps S5-S15 a method for performing the selective coupling of control signals with a pair of voice coil auxiliary sections 22a-b The procedural steps S5-S15 are all controlled by a voice coil control device 53 carried out in one step S5A prediction (pep) of the deflection requirement is performed using signal analysis. In the steps S6 and S7 A first peak displacement threshold (petl) and a second peak displacement threshold (pet2) are provided. In one step S8 The prediction (pep) of the deflection request is compared with the provided first (pet1) and second (pet2) peak deflection threshold.

[0216] If in one step S9 It is determined that pep is smaller than pet1, this is done in step S12 It only generates an idle control signal. However, if the comparison is done in one step... S10 This shows that pep lies between the two values ​​pet1 and pet2, and is done in step S13 Furthermore, a transition auxiliary control signal is generated. It is assumed that an idle auxiliary control signal is also generated. The comparison in one step yields... S11That pep is larger than pet2 is stated in step S14 A complete auxiliary control signal is generated. A complete auxiliary control signal can be understood as the sum of an idle auxiliary control signal and a transition auxiliary control signal at its maximum. The generated control signals are processed in one step. S15 coupled with the pair of voice coil auxiliary sections, and then the procedure is carried out with step S5 repeated completely once more.

[0217] Referring to the Fig. Figures 10a-d show different current directions in individual voice coil sections at selected times during operation for a preferred embodiment of the invention.

[0218] A typical control signal for driving a voice coil comprises a current flow that alternates between two opposite current directions. According to the invention, the main control signal and the auxiliary control signal comprise current flowing in the same azimuthal direction around the axis of movement. 4 the voice coil 1 flows. The azimuthal direction can be understood as the angular direction around an axis, e.g., the axis of motion. An azimuthal direction can therefore be a direction 60 clockwise around the axis of movement 4 or a direction 61 counterclockwise around the axis of movement 4 The current direction should therefore preferably be synchronized between the voice coils, i.e., at any given time, no current should flow in one direction in any one voice coil section. 60 clockwise, while in another, the current flows in one direction 61is present counterclockwise. According to the invention, it is preferred at certain times that in the voice coil auxiliary sections 22a-22b Essentially no current flows while in the main section of the voice coil 21 Electricity is flowing.

[0219] According to the invention, a main control signal is continuously applied to a voice coil main section. 21 coupled, while an auxiliary control signal is selectively applied to voice coil auxiliary sections. 22a-22b is coupled. In various embodiments, therefore, with non-selective coupling of an auxiliary control signal, the current is mainly in the main section of the voice coil. 21 flow. In some cases, it flows clockwise. 60 around the axis of movement 4 , as in Fig. 10a is shown, and in other cases counterclockwise. 61 around the axis of movement 4 , as in Fig. Figure 10b shows that the current preferably flows in the auxiliary sections of the voice coil. 22a-22b no current counterclockwise 61 , when in the main section of the voice coil 21 Current flows clockwise 60 flows, and likewise no current flows clockwise. 60 in the voice coil auxiliary sections 22a-22b , when in the main section of the voice coil 21 Current counterclockwise 61 flows.

[0220] If an auxiliary control signal is coupled instead, the current flow direction in each voice coil section is the same at any given time, i.e., the current either flows in the main voice coil section or in the other direction. 21 and in the voice coil auxiliary sections 22a-22b clockwise 60 as in Fig. 10c shown or counterclockwise 61 as in Fig. 10d shown.

[0221] In other embodiments of the invention, an idle auxiliary control signal and / or a transition auxiliary control signal is used with the voice coil auxiliary sections. 22a-22b coupled when a complete auxiliary control signal is not required, and in these embodiments the current flow in the voice coil auxiliary sections is in the same current flow direction as the current flow in the main coil section. In these different embodiments, the current flow direction in each voice coil section is the same at any given time, i.e., either the current flow in the voice coil main section is 21 and in the voice coil auxiliary sections 22a-22b clockwise 60 , as in Fig. 10c shown, or counterclockwise 61 , as in Fig. 10d shown.

[0222] The Fig. Figures 10a-10d show exemplary illustrations, and the current flow according to the invention is not limited to these examples. In various other embodiments, a voice coil 1 The voice coil is segmented into five sections, wherein the current flow in any one of the sections can, at any given time, proceed in the same azimuthal direction around an axis of motion. In various other embodiments, an upper and a lower rectified control signal are supplied to an upper and a lower voice coil section, respectively, arranged on either side of the main voice coil section, wherein a substantial current can only flow in the main voice coil section and either in the upper or the lower voice coil section.

[0223] Fig. 11 shows a representation P21 an audio signal 30 , which provides a time-domain representation of the amplitude of the audio signal 30is, i.e., the representation shows the amplitude of the audio signal. 30 as a function of time. As shown, the audio signal changes. 30 on both sides of a zero point in the amplitude. As shown in the figure, the audio signal includes 30 multiple peaks, e.g. a significant audio signal peak 67 , as well as several zero crossings 68 The zero crossings 68 are points in time along the audio signal 30 , in which the amplitude is zero. The audio signal peak 67 can create a point in the audio signal 30 represent, the reproduction of which not only involves the use of the main section of the voice coil 21 the voice coil 1 , but also the use of a pair of voice coil auxiliary sections 22a-b the voice coil 1 requires. In other words, the peak 67This requires selective coupling of a pair of voice coil auxiliary sections. The selective coupling of the pair of voice coil auxiliary sections 22a-b will last for a longer period of time after the peak 67 Retain such extended coupling of an auxiliary control signal after the presence of an audio signal peak. 67 This can also be referred to as peak hold or peak lock. The coupling of the auxiliary control signal occurs during a peak-lock time window. 66b maintained, which deviates from the peak 67 from and extends for a certain period of time afterwards. In this example, the peak-lock time window 66b a time period that includes twenty zero crossings 68 including the audio signal. In other embodiments of the invention, the time window can be 66b but any number of zero crossings 68These include, for example, multiples of ten zero crossings, hundreds of zero crossings, or even thousands of zero crossings.

[0224] The Fig. Figures 12a-c illustrate different methods for determining a deflection requirement. 70 based on an audio signal 30 .

[0225] Fig. 12a shows a representation P31 an audio signal 30 , which provides a time-domain representation of the amplitude of the audio signal 30 is, i.e., the representation shows the amplitude of the audio signal. 30 as a function of time. As shown, the audio signal changes. 30 on both sides of a zero point in the amplitude.

[0226] The audio signal 30 is used in a voice coil control device 53 (in Fig. 12 (not shown) received, which performs a signal analysis of the audio signal. 30This analysis includes an analysis of the peaks or spikes in the audio signal. Based on this analysis, the voice coil control device determines 53 a displacement requirement, i.e., the voice coil control device determines, based on the audio signal, how much the voice coil should move. 1 (in Fig. 12 (not shown) move from their rest / equilibrium position at different times in the audio signal 30 must move in order to transmit the audio signal 30 to reproduce accurately.

[0227] The Fig. 12b shows a representation P32 , which represents the deflection requirement 70 is, which is controlled by the voice coil control device 53 based on the audio signal 30 is determined. The representation of the deflection requirement. 70 , as shown in the tablet of Fig. The figure shown in 12b is clearly not identical to the deflections as they appear directly in the audio signal.30 This can be seen, and is also illustrated in the figure for better understanding. The deflection requirement does not perfectly follow the amplitude changes of the audio signal. 30 This is because it is preferable to maintain auxiliary control signals over a longer period, e.g., a period spanning several zero crossings. This is advantageous because, compared to an auxiliary control signal coupled for a duration comparable to a typical oscillation period of the voice coil, less time-dependent distortion may be present in the reproduced audio signal. Even small errors in the switching point when coupling an auxiliary control signal in and out once or several times during each oscillation lead to significant distortion, since the switching occurs at the same frequency as the control signal.

[0228] The in Fig. 12b shown deflection requirement 70is controlled by a voice coil control device 53 Determined based on a signal analysis. This signal analysis identifies high amplitude peaks / spikes in the audio signal. 30 and applies a peak-lock time window 66a after such a peak, a period also known as peak hold. The peak-lock time window 66a is a time period for which the deflection requirement 70 is fixed to a level determined by the amplitude of the peak. As can be seen in the figure, the displacement requirement follows 70 approximately an envelope of the audio signal until an audio signal peak 67 is present in the audio signal. From this point on, the deflection request 70 for passing through the peak-lock time window 66a The level was maintained at a constant level for a specified period of time.

[0229] Alternatively to the one in Fig. In the embodiment shown in 12b, the deflection requirement can be70 can also be determined with a look-ahead time delay, as in the embodiment of Fig. 12c shown.

[0230] Fig. 12c shows a representation P33 , which represents the deflection requirement 70 is, which is controlled by the voice coil control device 53 based on the audio signal 30 is determined / predicted. In this embodiment of the invention, the control signals, i.e., the main control signal, are 41 and the auxiliary control signal 42a-b , coupled to the respective voice coil sections with a time delay relative to the reception of the audio signal. In practice, this means that the voice coil control device 53 Before applying the control signals, perform a signal analysis on a portion of the audio signal. 30with a duration up to the duration of the time delay. The duration of this part of the signal is referred to in this example as the look-ahead time window. 66b This is referred to as the look-ahead time window. It is clear that this window is defined as... 66b It is not a static time window, but rather a time window that follows the evolution of the audio signal at a speed corresponding to the speed of the reproduced audio signal. In other words, the time window is a window that always adjusts the audio signal as it is reproduced by one unit determined by the look-ahead time window. 66b is ahead of schedule.

[0231] The in Fig. 12c shown look-ahead time window 66b each contain one or more high amplitude peaks 67 or spikes of the audio signal 30 , and the voice coil control device 53It can identify the largest peak within the time window. The highest peak is therefore used to determine the maximum required displacement within the time window. 66b used. In this embodiment, the displacement requirement is set to a constant level up to this highest peak, and in this sense the voice coil can 1 be prepared to reproduce this peak, as the displacement requirement 70 The current is already set to the required value before the peak even occurs. This results in current flowing in the voice coil auxiliary sections before the current is absolutely necessary, leading to an unnecessarily high number of input and output couplings of control signals within the look-ahead time window. 66b This can be avoided. According to other embodiments of the invention, the deflection requirement is gradually increased until the highest deflection requirement is reached within the look-ahead time window.66b The required excursion is increased, and this requirement is met by providing a transitional auxiliary control signal to the voice coil auxiliary sections. A transitional auxiliary control signal allows for a gradual increase in the current in the voice coil auxiliary sections to reproduce such a gradual increase or decrease in the excursion requirement.

[0232] Fig. Figure 13 illustrates a method for determining the gain of an auxiliary control signal according to embodiments of the invention.

[0233] In Fig. 13 is a representation P41 an audio signal 30 shown, which is a time-domain representation of the amplitude of the audio signal. 30 is, i.e., the representation shows the amplitude of the audio signal. 30 as a function of time. The audio signal 30 serves as an input signal for a voice coil control device 53, and using signal analysis of the audio signal 53 The voice coil control device supplies control signals to the voice coil sections of the voice coil. 1 Using signal analysis based on a look-ahead time window 66b , as in relation to Fig. As described in section 12c, a representation of the deflection requirement by the voice coil control device is given. 53 determined. The determination of the deflection requirement 70 This therefore occurs with a head start in relation to the audio signal due to a time delay between the reception of the audio signal. 30 and the playback of the audio signal. The deflection requirement 70 , which are controlled by the voice coil control device 53 based on the audio signal 30 The determination is shown in Figure P42. Fig. Figure 13 shows that the displacement requirement follows a smoothed version of the audio signal's envelope. 30 , as depicted P41 This can be seen with deflection requirements that arise before a high peak in the audio signal. 30 somehow maintained for a short period of time.

[0234] In the presentation P42 There are also two representations of the specified deflection levels. 65a-65b The specified deflection levels are preselected deflection values ​​that trigger couplings of auxiliary control signals, and the voice coil control device compares these values. 53 based on the audio signal 30 determined deflection requirement 70 with the specified deflection levels 65a-65b and, based on this comparison, performs couplings of control signals. These couplings are shown in more detail in Figure P43, which shares a common time axis with Figures P41 and P42.

[0235] When considering the presentation P42 First, there is a time period of the audio signal in which the curve of the deflection requirement 70 the lower specified deflection level 65a does not exceed this time period, which is also known as the idle auxiliary control signal period. 62 As designated, only an idle auxiliary control signal is sent to the pair of voice coil auxiliary sections. 22a-b The idle auxiliary control signal is a control signal with a reduced signal strength. In this example, the idle auxiliary control signal has an amplitude that is 10% of the amplitude, or a gain of 0.1, of the corresponding main control signal. 41is, which is always continuously connected to the main section of the voice coil 21 is coupled as long as an audio signal 30 is supplied. In other embodiments of the invention, the gain or amplitude of the idle auxiliary control signal is a different value, e.g. a value between 10% and 100% or a value between 0% and 10%, where 0% is identical to a zero signal.

[0236] The purpose of the idle auxiliary control signal is to supply a small control current to the pair of voice coil auxiliary sections. 22a-b to maintain, even though this current is not needed to generate the electromotive force that powers the voice coil 1 This prevents back EMF braking of the voice coil. 1 .

[0237] In later time periods of the audio signal 30 The curve of the deflection requirement lies 70in a range between the lower specified deflection level 65a and the upper specified deflection level 65b During these time periods, a transitional auxiliary control signal is applied, which is also known as the transitional control signal period. 63 The transition auxiliary control signal is an auxiliary control signal whose gain is adjustable and which can be gradually adjusted from zero gain (i.e., no signal) to a high signal gain comparable to the gain of the main control signal. During the transition control signal period... 63 The idle auxiliary control signal is either retained as a control signal independent of the transition auxiliary control signal or is embedded in the transition auxiliary control signal as a constant basis of the transition auxiliary control signal.

[0238] In other time periods of the audio signal 30 exceeds the deflection requirement 70the upper specified deflection level 65b (see illustration) P42 in Fig. 13) These periods, also known as auxiliary control signal periods 64 These are time periods in which the transition auxiliary control signal is most complete. In other words, the time period 64 refers to the period in which the auxiliary control signal is most complete. In other embodiments of the invention, the upper predetermined displacement level is a level that triggers the coupling of further auxiliary control signals with further respective voice coil auxiliary sections for voice coils. 1 represents, which include additional pairs of voice coil auxiliary sections.

[0239] The lower representation P44 in Fig. Figure 13 shows the gain of the entire auxiliary control signal with respect to the main control signal; that is, zero gain represents no auxiliary control signal at all, and a gain of 1 represents a complete auxiliary control signal with a signal strength essentially identical to the main control signal. The gain curve inherits the same common time axis as the representations. P41-P43 The total auxiliary control signal is, for example, the sum of the no-load auxiliary control signal and the transition auxiliary control signal, e.g., the resulting control signal as it would be measured by measuring the control signal in a voice coil auxiliary section. As shown in the diagram. P44 As can be seen, the gain of the auxiliary control signal never drops below a value lower than the gain or amplitude of the idle auxiliary control signal. This means that regardless of how the audio signal behaves, 30developed so that a basic signal is always applied to pairs of voice coil auxiliary sections, thus avoiding back EMF braking.

[0240] Therefore, in the time span from 0 to the auxiliary control signal transition time t1 , i.e., the first idle auxiliary control signal period 62 , only an idle auxiliary control signal to the pair of voice coil auxiliary sections 22a-b coupled, in addition to the main control signal 41 , which is continuously applied to the main section of the voice coil 21 is coupled. In the period from time t1 until the second auxiliary control signal transition time t2 , i.e., the first transition auxiliary control signal period 63 A transition auxiliary control signal is coupled to the pair of voice coil auxiliary sections. As can be seen, the transition auxiliary control signal changes gradually within this time period before deviating from the time in the following time period. t2currently t3 is decoupled or turned down to zero. As can be seen, in the time span between the time t10 and t11 , i.e., an auxiliary control signal period 64 , the amplification of the auxiliary control signal most completely.

[0241] With reference to the Fig. 14a-e are different configurations for generating an upper rectified control signal. 46a for an upper voice coil section 25a and a lower rectified control signal 46b for a lower voice coil section 25b illustrated according to embodiments of the invention.

[0242] In various embodiments of the invention, one or more rectifier units can be used. 17 the current directions of an auxiliary control signal 42 dampen or preferably block to obtain an upper rectified control signal 46a for an upper voice coil section25a and a lower rectified control signal 46b for a lower voice coil section 25b to generate. Consequently, if current from an auxiliary control signal flows in one direction, this current can flow substantially to the lower voice coil section, while its flow to the upper voice coil section is damped or blocked. Similarly, if current from an auxiliary control signal flows in the opposite direction, this current can flow substantially to the upper voice coil section, while its flow to the lower voice coil section is damped or blocked. The upper rectified control signal and the lower rectified control signals are arranged to supply a current flowing in a suitable direction to generate an electromotive force on the voice coil so that the audio signal is reproduced correctly.

[0243] Fig. Figure 14a shows a typical embodiment comprising rectifier units. An auxiliary control signal 42a is connected to a rectifier unit 16 supplied to provide an upper rectified signal 46a to generate that which is connected to an upper voice coil section 25a is supplied, and an auxiliary control signal 42b is connected to a rectifier unit 16 supplied to provide a lower rectified signal 46b to generate that which is connected to a lower voice coil section 25b The auxiliary control signal can be selectively coupled. Simultaneously, a main control signal is supplied. 41 continuously to a voice coil main section 21 coupled.

[0244] In some embodiments, one or more rectifier units comprise at least one switching unit. An exemplary embodiment is shown in Fig. 14b shown. A main control signal 41is the main section of the voice coil 21 supplied while an auxiliary control signal 42 to a switching unit 10 is connected, which is connected to a control signal 32 is controlled. The switching unit 10 Either the auxiliary control signal can 42 to an upper voice coil section 25a or a lower voice coil section 25b forward. That to the switching unit 10 supplied control signal 32 can preferably ensure that one current direction of the auxiliary control signal 42 to the upper voice coil section 25a can be reached and the opposite current direction of the auxiliary control signal. 42 to the lower voice coil section 25b can be reached.

[0245] In other embodiments, one or more rectifier units comprise at least one diode. An exemplary embodiment is shown in Fig. Shown in 14c. A main control signal 41 is the main section of the voice coil 21 supplied while an auxiliary control signal 42 on two diodes 17 is connected. The two diodes are connected with opposite terminals, so that one of the diodes 17 primarily a current direction of the auxiliary control signal 42 allows through and the other diode 17 Primarily allows the opposite current direction of the auxiliary control signal to pass. If a diode 17 If it allows current to pass in one direction, it essentially blocks the opposite direction. Therefore, an upper rectified signal can 46a after a diode 17 generated and connected to an upper voice coil section 25a be forwarded, and a lower rectified signal 46b can be searched for after another diode 17 generated and connected to a lower voice coil section 25b will be forwarded.

[0246] In some embodiments, one or more rectifier units comprise at least one MOSFET, i.e., a metal-oxide-semiconductor field-effect transistor. Based on a control signal, a MOSFET can 18 so that it functions as a switch. An exemplary embodiment in which at least one MOSFET according to the invention is used is shown in Fig. 14d shown. A main control signal 41 is connected to the main section of the voice coil 21 delivered while an auxiliary control signal 42a-42b on two MOSFETs 18 is supplied, with each MOSFET additionally equipped with a control signal 32 is connected. Based on the control signal 32 can a MOSFET 18 Allowing current to flow. A MOSFET is preferred. 18 allow one current direction of the auxiliary control signal to pass through in order to generate an upper rectified control signal 46ato generate that corresponds to the upper voice coil section 25a is supplied, while the other MOSFET 18 allows the opposite current direction of the auxiliary control signal to pass through in order to produce a lower rectified control signal 46b to generate that corresponds to the lower voice coil section 25b is supplied.

[0247] In some other embodiments, one or more rectifier units comprise at least one amplifier. An exemplary embodiment is described in Fig. 14e shown, in which two amplifiers 12 through control signals 32 They must be actively controlled to generate the upper rectified control signal. 46a and the lower rectified control signal 46b to generate a control signal. 32 can determine the amplitude of the current that an amplifier can generate at its output. Therefore, an amplifier can 12so that it only delivers a substantial output current when the current of the auxiliary control signal is 42 exhibits a current direction to generate an upper rectified control signal 46a to generate, while another amplifier 12 so that it can be controlled so that it only delivers a substantial output current when the current of the auxiliary control signal 42 has an opposite current direction to produce a lower rectified control signal 46b to generate the upper and lower rectified control signals. 46a-46b can then be used to access the upper and lower sections of the voice coil. 25a-25b be supplied.

[0248] According to the invention, methods for generating an upper rectified control signal are 46a and a lower rectified control signal 46b not limited to the exemplary embodiments described above.

Claims

[1] Method for driving a voice coil (1) of a loudspeaker (50), comprising the steps: Providing a magnetic circuit (2) with an air gap (3) and a voice coil (1) suspended in the air gap (3); Applying an audio signal (30) to the voice coil (1) suspended in the air gap (3) to generate an electromotive force which Voice coil (1) moves along a movement axis (4); characterized by , that the voice coil (1) comprises a plurality of voice coil sections, wherein the plurality of voice coil sections comprises a voice coil main section (21) and a pair of voice coil auxiliary sections (22a; 22b) arranged along the movement axis (4), wherein the voice coil sections of the pair of voice coil auxiliary sections (22a; 22b) are each arranged on both sides of the voice coil main section (21); and wherein the step of applying an audio signal (30) comprises continuously coupling a main control signal (41) based on the audio signal (30) to the main voice coil section (21) and selectively coupling an auxiliary control signal (42a; 42b) based on the audio signal (30) to the pair of auxiliary voice coil sections (22a; 22b). [2] A method for driving a voice coil (1) according to claim 1, wherein the selective coupling of the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) is performed on the basis of a representation of the deflection request (70). [3] A method for driving a voice coil (1) according to claim 2, wherein the selective coupling of the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) is performed on the basis of a comparison of the representation of the deflection request (70) with a representation of a predetermined deflection level (65a; 65b). [4] A method of driving a voice coil (1) according to any one of the preceding claims, wherein the step of selectively coupling an auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) is performed by a voice coil control device (53) comprising a signal processor. [5] A method for driving a voice coil (1) according to claim 4, wherein the signal processor of the voice coil control device (53) is a digital signal processor. [6] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the pair of voice coil auxiliary sections (22a; 22b) is a first pair of voice coil auxiliary sections (23a; 23b) and the auxiliary control signal is a first auxiliary control signal; wherein the plurality of voice coil sections further comprises a second pair of voice coil auxiliary sections (24a; 24b) arranged along the movement axis (4), wherein voice coil sections of the second pair of voice coil auxiliary sections (24a; 24b) are respectively arranged on both sides of the first pair of voice coil auxiliary sections (23a; 23b); and wherein the step of applying an audio signal (30) comprises selectively coupling a second auxiliary control signal to the second pair of voice coil auxiliary sections (23a; 23b) based on the audio signal (30). [7] A method for driving a voice coil (1) according to claim 6, wherein the representation of a predetermined excursion level is a first representation of a predetermined excursion level (65a), and wherein the selective coupling of the second auxiliary control signal to the second pair of voice coil auxiliary sections (24a; 24b) is performed based on a comparison of the representation of the excursion request (70) with a second representation of the predetermined excursion level (65b). [8] A method for driving a voice coil (1) according to claim 7, wherein the second representation of a predetermined excursion level (65b) is greater than the first representation of a predetermined excursion level (65a). [9] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the pair of voice coil auxiliary sections (22a; 22b) are arranged along the movement axis (4) and are arranged symmetrically around the voice coil main section (21), one voice coil auxiliary section of the pair of voice coil auxiliary sections (22a; 22b) being arranged on each side of the voice coil main section (21). [10] A method for driving a voice coil (1) according to any one of claims 6-9, wherein the first pair of voice coil auxiliary sections (23a; 23b) is arranged along the movement axis (4) and is arranged symmetrically around the voice coil main section (21), wherein one voice coil auxiliary section of the first pair of voice coil auxiliary sections (23a; 23b) is arranged on each side of the voice coil main section (21), and the second pair of voice coil auxiliary sections (24a; 24b) is arranged along the movement axis (4) and is arranged symmetrically around the voice coil main section (21), wherein one voice coil auxiliary section of the second pair of voice coil auxiliary sections (24a; 24b) is arranged on each side of the voice coil main section (21). [11] A method for driving a voice coil (1) according to any one of the preceding claims, wherein selectively coupling an auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) comprises controlling at least one amplifier (12) to couple the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b). [12] A method for driving a voice coil (1) according to claim 11, wherein controlling at least one amplifier (12) comprises generating the auxiliary control signal (42a; 42b) or an idle auxiliary control signal and / or a transient auxiliary control signal based on comparing the representation of the excursion request (70) with a representation of a predetermined excursion level (65a; 65b). [13] A method for driving a voice coil (1) according to any one of the preceding claims, wherein continuously coupling a main control signal (41) to the voice coil main section (21) comprises coupling the main control signal (41) using an amplifier (41). [14] Method for controlling a voice coil (1) according to one of the preceding claims, wherein the auxiliary control signal (42a; 42b) characterized by is that it has a gain that differs from a gain of the main control signal (41). [15] Method for controlling a voice coil (1) according to one of claims 1-13, wherein the auxiliary control signal (42a; 42b) characterized by is that it has a gain which is the same as a gain of the main control signal (41). [16] A method for driving a voice coil (1) according to any one of the preceding claims, wherein selectively coupling an auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) comprises controlling at least one switch (10) for coupling the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b). [17] A method of driving a voice coil (1) according to any one of the preceding claims, wherein an idle auxiliary control signal is coupled to the pair of voice coil auxiliary sections (22a; 22b). [18] A method for driving a voice coil (1) according to claim 17, wherein the idle auxiliary control signal is based on the audio signal (30). [19] A method for driving a voice coil (1) according to claim 17 or 18, wherein the idle auxiliary control signal is a first idle auxiliary control signal and the pair of voice coil auxiliary sections (22a; 22b) is a first pair of voice coil auxiliary sections (23a; 23b), and wherein a second idle auxiliary control signal is coupled to a second pair of voice coil auxiliary sections (24a; 24b). [20] A method for driving a voice coil (1) according to claim 19, wherein the first idle auxiliary control signal and the second idle auxiliary control signal are different control signals. [21] A method for driving a voice coil (1) according to any one of claims 17-20, wherein the amplitude of the idle auxiliary control signal is in the interval from 1% to 99% of the main control signal (41), such as from 2% to 50% of the main control signal (41), such as from 5% to 15% of the main control signal (41), eg 10% of the main control signal (41). [22] Method for controlling a voice coil (1) according to one of claims 17-20, wherein the main control signal (41) characterized by is that it has a gain, and wherein the idle auxiliary control signal characterized by is that it has a gain in the interval from 1% to 99% of the gain of the main control signal (41), such as from 2% to 50% of the gain of the main control signal (41), such as from 5% to 15% of the gain of the main control signal (41), eg 10% of the gain of the main control signal (41). [23] A method for driving a voice coil (1) according to claims 17-22, wherein selectively coupling the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) comprises selectively coupling a transition auxiliary control signal based on the audio signal (30). [24] A method of driving a voice coil (1) according to claim 23, wherein selectively coupling a transition auxiliary control signal comprises controlling a gain of the transition auxiliary control signal. [25] A method for driving a voice coil (1) according to claim 24, wherein the gain of the transition auxiliary control signal is adjusted based on an analysis of the audio signal (30). [26] A method for driving a voice coil (1) according to claim 24 or 25, wherein the gain of the transition auxiliary control signal is adjusted based on the representation of the deflection request (70). [27] A method for driving a voice coil (1) according to any one of claims 24-26, wherein the gain setting of the transition auxiliary control signal is limited in slew rate. [28] A method of driving a voice coil (1) according to any one of claims 23-27, wherein selectively coupling the transition auxiliary control signal comprises controlling one or more amplifiers (12). [29] A method of driving a voice coil (1) according to any one of claims 23-28, wherein selectively coupling the transition auxiliary control signal comprises controlling one or more switches. [30] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the main control signal (41) and the auxiliary control signal (42a; 42b) comprise current flowing in the same azimuthal direction (60; 61) around the axis of movement (4) of the voice coil (1). [31] Method for driving a voice coil (1) according to one of the preceding claims, wherein the magnetic circuit (2) is provided by a magnet. [32] A method for driving a voice coil (1) according to claim 31, wherein the magnet is a permanent magnet. [33] A method for driving a voice coil (1) according to claim 31, wherein the magnet is an electromagnet. [34] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the voice coil main section (21) has a height measured in a direction along the movement axis (4) that is greater than a height of the air gap (3) measured in the direction along the movement axis (4). [35] A method for driving a voice coil (1) according to any one of the preceding claims, wherein each voice coil portion of the pair of voice coil auxiliary portions (22a; 22b) has a height measured in a direction along the movement axis (4) which is smaller than the height of the voice coil main portion (21). [36] A method for driving a voice coil (1) according to any one of the preceding claims, wherein each voice coil section of the second pair of voice coil auxiliary sections (24a; 24b) has a height measured in a direction along the movement axis (4) which is smaller than the height of the voice coil main section (23). [37] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the selective coupling of an auxiliary control signal (42a; 42b) based on the audio signal (30) comprises maintaining the coupling for a time period (66a; 66b) comprising at least two zero crossings (68) of the audio signal (30), such as at least ten zero crossings (68) of the audio signal (30), such as at least one hundred zero crossings (68) of the audio signal (30), such as at least one thousand zero crossings (68) of the audio signal (30). [38] A method for driving a voice coil (1) according to claim 37, wherein the time period (66a; 66b) is a predetermined time period. [39] A method for driving a voice coil (1) according to claim 37 or 38, wherein the predetermined time period is in the range of 50 milliseconds to 10 seconds. [40] Method for driving a voice coil (1) according to one of claims 37-39, wherein the predetermined time period is determined on the basis of a signal analysis of the audio signal (30). [41] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the main control signal (41) and the auxiliary control signal (42a; 42b) are delayed by a time delay with respect to the audio signal (30). [42] Method for driving a voice coil (1) according to one of the preceding claims, wherein the signal analysis is carried out in a time segment of the audio signal (30). [43] A method for driving a voice coil (1) according to claim 42, wherein the time period is identical to the time delay. [44] Method for driving a voice coil (1) according to one of claims 40-43, wherein the signal analysis of the audio signal (30) comprises a peak analysis of the audio signal (30). [45] Method for driving a voice coil (1) according to one of claims 40-44, wherein the signal analysis is repeatedly performed on the audio signal (30). [46] Method for controlling a voice coil (1) according to one of the preceding claims, wherein the representation of the deflection request (70) is created on the basis of a signal analysis of the audio signal (30). [47] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the representation of the excursion request (70) comprises a property of the audio signal (30) and the representation of a predetermined excursion level (65a; 65b) is a threshold value related to the property of the audio signal (30). [48] A method for driving a voice coil (1) according to claim 47, wherein the property of the audio signal relates to an amplitude of the audio signal. [49] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the coupling of the auxiliary control signal (42a; 42b) is based on a user-defined input selection. [50] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the representation of the deflection request (70) is based on the measurement of the voice coil deflection using at least one position sensor (15) and the representation of a predetermined deflection level (65a; 65b) is a threshold value related to the deflection of the voice coil (1). [51] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the representation of the deflection request (70) is based on current and / or voltage in the voice coil sections (21; 22a; 22b) and the representation of a predetermined deflection level (65a; 65b) is a threshold value related to current and / or voltage in the voice coil sections (21; 22a; 22b). [52] A method for driving a voice coil (1) according to any one of the preceding claims, wherein the pair of voice coil auxiliary sections (22a; 22b) comprises an upper voice coil section (25a) and a lower voice coil section (25b), the upper voice coil section (25) and the lower voice coil section (25b) being arranged on both sides of the voice coil main section (21) along the movement axis (4), respectively. [53] A method for driving a voice coil (1) according to claim 52, wherein providing an auxiliary control signal (42a; 42b) comprises providing an upper rectified control signal (46a) to the upper voice coil section (25a) and providing a lower rectified control signal (46b) to the lower voice coil section (25b); wherein the upper rectified control signal (46a) is provided by attenuating, such as blocking, a first current direction of the auxiliary control signal (42; 42a; 42b); wherein the lower rectified control signal (46b) is provided by attenuation, such as blocking, of a second current direction of the auxiliary control signal (42; 42a; 42b); and wherein the first and second current directions of the auxiliary control signal (42; 42a; 42b) are opposite current directions. [54] A method for driving a voice coil (1) according to claim 53, wherein providing the upper rectified control signal (46a) comprises processing the auxiliary control signal (42; 42a; 42b) using an upper rectifier unit (16) and providing the lower rectified control signal (46b) comprises processing the auxiliary control signal (42; 42a; 42b) using a lower rectifier unit (16). [55] A method for driving a voice coil (1) according to claim 53 or 54, wherein the upper rectified control signal (46a) is provided by rectifying the auxiliary control signal (42; 42a; 42b) in the first current direction and wherein the lower rectified control signal (46b) is provided by rectifying the auxiliary control signal (42; 42a; 42b) in the second current direction. [56] A method for driving a voice coil (1) according to claim 55, wherein the rectification comprises passive rectification. [57] A method for driving a voice coil (1) according to claim 55 or 56, wherein the rectification of the auxiliary control signal (42; 42a; 42b) is a half-wave rectification. [58] A method for driving a voice coil (1) according to any one of claims 54-57, wherein the upper rectifier unit (16) comprises a rectifier circuit, and / or wherein the lower rectifier unit (16) comprises a rectifier circuit. [59] A method for driving a voice coil (1) according to any one of claims 54-58, wherein the upper rectifier unit (16) comprises a diode and wherein the lower rectifier unit (16) comprises a diode. [60] A method for driving a voice coil (1) according to any one of claims 54-59, wherein the upper rectifier unit (16) comprises a switch and wherein the lower rectifier unit (16) comprises a switch. [61] Method for driving a voice coil (1) according to one of claims 54-60, wherein the upper rectifier unit (16) comprises an amplifier (12; 11) and wherein the lower rectifier unit (16) comprises an amplifier (12; 11). [62] Voice coil drive system (51) of a loudspeaker (50), comprising: a magnetic circuit (2) with an air gap (3); a voice coil (1) suspended in the air gap (3), the voice coil (1) comprising a plurality of voice coil sections, the plurality of voice coil sections comprising a voice coil main section (21) and a pair of voice coil auxiliary sections (22a; 22b) arranged along a movement axis (4), the voice coil sections of the pair of voice coil auxiliary sections (22a; 22b) being arranged on both sides of the voice coil main section (21), respectively; and a voice coil control device (53) arranged to apply an audio signal (30) to the voice coil (1) suspended in the air gap (3) to generate an electromotive force that moves the voice coil (1) along the movement axis (4), wherein the application of an audio signal (30) comprises continuously coupling a main control signal (41) based on the audio signal (30) to the main voice coil section (21) and selectively coupling an auxiliary control signal (42a; 42b) based on the audio signal (30) to the pair of auxiliary voice coil sections (22a; 22b). [63] A voice coil drive system (51) according to claim 62, wherein the voice coil control device (53) is arranged to selectively couple the auxiliary control signal (42a; 42b) to the pair of voice coil auxiliary sections (22a; 22b) based on a representation of the deflection request (70). [64] A voice coil drive system (51) according to claim 62 or 63, wherein the pair of voice coil auxiliary sections (22a; 22b) is a first pair of voice coil auxiliary sections (23a; 23b) and the auxiliary control signal (42a; 42b) is a first auxiliary control signal, and wherein the voice coil (1) further comprises a second pair of voice coil auxiliary sections (24a; 24b) and the voice coil control device (53) is arranged to selectively couple a second auxiliary control signal to the second pair of voice coil auxiliary sections (24a; 24b). [65] A voice coil drive system (51) according to any one of claims 62-64, wherein the voice coil control device (53) comprises a signal processor. [66] Voice coil drive system (51) according to any one of claims 62-65, wherein the voice coil drive system (51) comprises one or more amplifiers (12). [67] Voice coil drive system (51) according to any one of claims 62-66, wherein the voice coil drive system (51) comprises a switching unit (10). [68] Voice coil drive system (51) according to any one of claims 62-67, wherein the voice coil control device (53) is arranged to carry out the method according to any one of claims 1-61. [69] Loudspeaker, comprising: a membrane (7); an interface (52) configured to receive an audio signal (30); and a voice coil drive system (51) according to any one of claims 62-68.

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