Loudspeaker system for a motor vehicle, method for forming a loudspeaker system and motor vehicle

Abstract

The present invention relates to a loudspeaker system (1) for a motor vehicle, in particular for an electric motor vehicle, comprising: - a first case (10), - a control unit (50), - at least two loudspeakers (30), each loudspeaker (30) having a voice coil (34) movable in an axis (L), - wherein the at least two loudspeakers (30) are arranged on two opposite side surfaces (11 12) of the first housing (10), - wherein the axes (L) of the at least two loudspeakers (30) are not coaxial, - wherein the loudspeakers (30) can be controlled separately by the control unit (50), - wherein a first operating mode and a second operating mode can be set via the control unit (50), wherein in the first operating mode the loudspeakers (30) are simultaneously supplied with the same current signal and in the second operating mode the loudspeakers (30) are simultaneously supplied with a current signal inverted relative to each other.

Description

[0001] The invention relates to a loudspeaker system for a motor vehicle, in particular for an electric motor vehicle, with the features of claim 1, a method for operating a loudspeaker system with the features of claim 23 and a motor vehicle with the features of claim 274.

[0002] Motor vehicles' loudspeaker systems are known in various configurations from the prior art. For example, in the prior art, loudspeaker systems of this type for motor vehicles are also referred to as AVAS loudspeakers or AVAS loudspeaker systems.

[0003] Initially, the lower noise level was considered a unique selling point of electric cars, but this reduced noise can pose a danger to pedestrians and cyclists. Therefore, all new electric vehicles sold in the EU and the USA must be equipped with Acoustic Vehicle Alerting Systems (AVAS) under certain conditions. AVAS are typically designed as small loudspeaker systems that emit sounds within the required frequency range of 160 to 4000 Hz.

[0004] When using loudspeaker systems in vehicles, especially for sound reinforcement in the vehicle's exterior, these systems must be resistant to moisture, splashes of water, salt, and dust. In particular, sensitive components such as the loudspeaker's voice coil must be protected from such environmental influences. Therefore, the state of the art is loudspeaker systems with a sealed enclosure.

[0005] Patent WO 2020099222 A1 describes a loudspeaker system for a motor vehicle which has a loudspeaker that is arranged inside a closed housing and radiates into an environment.

[0006] A disadvantage of previous loudspeaker systems with closed enclosures is that a representative acoustic appearance cannot be satisfactorily produced, especially in the low frequency range, and loudspeaker systems with an enclosure in which a bass reflex port is used to achieve low frequencies are not suitable for outdoor applications, as dirt, dust and moisture could affect the sensitive components of the loudspeaker.

[0007] In addition to an acoustic vehicle warning system, vehicles require a signaling device such as a horn. These signaling devices are activated at the driver's command and emit a temporary acoustic signal, for example, a warning signal. This signal must have a significantly higher sound level than the acoustic vehicle warning system, although its frequency range can be considerably narrower.

[0008] Previously, acoustic vehicle warning systems and signaling devices such as horns were installed separately in vehicles. Due to the limited installation space within a vehicle, this is often problematic. Furthermore, installation time and costs are higher when two separate systems are required.

[0009] The present invention addresses the problem of proposing a generic loudspeaker system for motor vehicles that effectively eliminates the disadvantages known from the prior art. In particular, the present loudspeaker system should be capable of providing the required characteristics of an acoustic vehicle warning system as well as the required sound pressure level of a signal generator. The proposed loudspeaker system for motor vehicles should also meet high mechanical and acoustic requirements, especially with regard to volume, frequency range, sound pressure level, and distortion. Preferably, the loudspeaker system should also allow for easy adaptation to different vehicles.

[0010] These tasks are accomplished by a loudspeaker system for a motor vehicle, in particular for an electric motor vehicle, with the features of claim 1, a method for operating a loudspeaker system with the features of claim 23, and a motor vehicle with the features of claim 27.

[0011] Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0012] According to the invention, a loudspeaker system for a motor vehicle, preferably an electric vehicle, comprises a first housing. The loudspeaker system has at least two loudspeakers, each of which has at least one voice coil movable on an axis. The at least two loudspeakers are arranged on at least two different, preferably opposite, side faces of the first housing. Furthermore, it can be advantageous if the axes of these loudspeakers are not coaxial.

[0013] Furthermore, the loudspeaker system has a control unit, whereby the loudspeakers can be controlled separately by the control unit, and a first operating mode and a second operating mode can be set via the control unit, whereby in the first operating mode the loudspeakers are simultaneously supplied with the same current signal and in the second operating mode the loudspeakers are simultaneously supplied with a current signal inverted relative to each other.

[0014] The control unit can be permanently installed within the speaker system, or the control system can be designed by an external control system, for example the vehicle control system.

[0015] In connection with this invention, the axis of a loudspeaker is defined as the axis which is oriented in the direction of the stroke movement of the voice coil.

[0016] Furthermore, in connection with this invention, non-coaxial axes mean that the axes run parallel and at a distance from each other, the distance between the axes being non-zero.

[0017] In the context of this invention, antiparallel means that components, in particular loudspeakers, are parallel but oriented in opposite directions.

[0018] Furthermore, in connection with this invention, the inner loudspeaker is defined as the loudspeaker which is arranged on a side surface of the first housing and radiates into the interior of the second housing.

[0019] Furthermore, in connection with this invention, the external loudspeaker is defined as the loudspeaker which is arranged on a side surface of the first housing and radiates into the surroundings.

[0020] Furthermore, in connection with this invention, the current signal is defined as a signal that changes over time and preferably has a sinusoidal or rectangular shape.

[0021] By definition, the coupling volume is the volume of the first housing, in particular the medium located inside the first housing, wherein the first housing is preferably completely sealed.

[0022] In connection with this invention, an acoustic interaction with the interior of the second housing is preferably understood to mean that the corresponding loudspeaker radiates directly into the interior of the second housing.

[0023] By definition, the horizontal view is defined as the view in which the loudspeaker system has a smaller extent in the horizontal direction than in the vertical direction.

[0024] The present invention is based on the idea of ​​providing a loudspeaker system in which one of the at least two loudspeakers forms an external loudspeaker and the other of the at least two loudspeakers forms an internal loudspeaker. The external loudspeaker preferably radiates sound into the surroundings and is preferably capable of producing sounds in the higher frequency range. The internal loudspeaker preferably radiates sound into the second enclosure and is preferably capable of producing sounds in the lower frequency range. By adding a ventilated second enclosure with a bass reflex port and by arranging the loudspeakers on the first enclosure, sound radiation in the low-frequency range is enabled.

[0025] The present invention is further based on the idea of ​​providing a loudspeaker system in which the sensitive loudspeaker components, such as a magnet or a voice coil, are arranged within the - preferably closed - first housing.

[0026] The present invention is further based on the idea that the loudspeaker system is adjustable between a first operating mode and a second operating mode. In one of the two operating modes, the loudspeaker system exhibits the characteristics of an AVAS loudspeaker system. In the other operating mode, the loudspeaker system exhibits the characteristics of a signal transmitter.

[0027] In the first operating mode, the loudspeakers arranged on different side surfaces, especially the voice coils, are supplied with the same current signal in phase, i.e., at the same time.

[0028] If the loudspeakers are arranged antiparallel, this causes the diaphragms of the loudspeakers to move in opposite directions in the first operating mode.

[0029] The coupling volume is the volume within the first enclosure filled with a medium, preferably air. In the first operating mode, the coupling volume is compressed and decompressed by the opposing movement of the loudspeaker diaphragms. Both diaphragms move either inwards or outwards. This allows for significantly higher sound pressure levels to be generated in the second operating mode.

[0030] In the second operating mode, each loudspeaker is driven with a current signal inverted from the other. With an antiparallel arrangement of the loudspeakers, their diaphragms move in the same direction, causing the coupling volume within the first enclosure to be shifted back and forth.

[0031] In the first operating mode, the opposing movement of the diaphragms does not displace the coupling volume, but rather compresses and decompresses it alternately. Due to the high air spring stiffness of the coupling volume, this results in a drastic increase in the resonance frequency, the resonance quality, and thus the sound pressure level at resonance.

[0032] Furthermore, in the first operating mode, the laterally offset arrangement of the loudspeakers offers a particular advantage in minimizing the coupling or resonance volume. For example, with 9 cm diaphragms, this can lead to resonance frequencies between 300 and 800 Hz with a suitable enclosure design featuring a coupling volume of 100-200 ml and sound pressure levels up to 110 dB SPL / 2m, as required for signal transmitters, especially horns.

[0033] If the loudspeaker arrangement is parallel and aligned with each other, the coupling volume is compressed and decompressed in the second operating mode. The diaphragms move in opposite directions.

[0034] In a loudspeaker arrangement that is parallel and aligned, the coupling volume within the first enclosure is shifted back and forth in the first operating mode. The diaphragms move in the same direction.

[0035] The first and second operating modes can be switched as often as desired and at any time. This only requires a polarity reversal or phase shift of the current signal at one of the loudspeakers. This change in polarity results in a switch between the states "coupling volume shift" and "coupling volume compression".

[0036] The proposed loudspeaker system preferably has a frequency response in the operating mode in which the coupling volume is compressed and decompressed, in which, preferably, with a sound pressure drop of -3 dB, a low frequency is at approximately 80 Hz and the -10 dB point is at approximately 60 Hz.

[0037] Advantageously, in the operating mode where the coupling volume is moved back and forth, the loudspeaker system exhibits a frequency range of 100 to 4000 Hz. Compared to the previously mentioned operating mode, this mode offers quieter, wider-ranging, and higher-quality reproduction, which can also meet HiFi requirements in terms of frequency response and distortion.

[0038] Preferably, the loudspeaker system, in the operating mode where the coupling volume is compressed and decompressed, achieves a sound pressure level of at least 105 dB SPL / 2m, where SPL / 2m represents a sound pressure level measured at a distance of two meters. The resonant frequencies required to achieve sound pressure levels above 105 dB SPL / 2m are preferably located in the frequency range of 400 to 600 Hz.

[0039] Advantageously, more than two operating modes can be set. For example, three, four, or five operating modes can be set. In these other operating modes, the speaker power signals can be phase-shifted by 90 degrees, 120 degrees, 150 degrees, or 270 degrees.

[0040] The first operating mode, with an antiparallel speaker arrangement, allows the system to be used not only for signal output but also for warning and rescue announcements via voice transmission. In this mode, clear speech intelligibility is achieved even at high volumes, and its narrow frequency response makes it particularly effective in noisy environments, such as aircraft crashes. Prior to this, in the second operating mode, the speaker system can be used to allow passengers to listen to quiet, high-fidelity music.

[0041] Advantageously, the loudspeaker system can also be designed to be portable. By switching from the first to the second operating mode, either entertainment programs or extremely long-range, focused announcements can be played with maximum efficiency and low energy consumption. For example, such a loudspeaker system weighing one kilogram and with an amplifier power of 20 watts can achieve a sound pressure level of 85 dB at a distance of 50 meters.

[0042] In principle, the loudspeaker system can be used in almost any sector beyond the automotive industry. For example, it can be used in all other modes of transportation, in building technology, in industry, or by the military.

[0043] Advantageously, the loudspeaker system has a second enclosure, wherein the second enclosure includes an opening, in particular for bass reflex tuning, and the first and second enclosures are at least partially arranged next to each other, wherein at least one of the at least two loudspeakers, preferably a so-called internal loudspeaker, is in acoustic interaction with the interior of the second enclosure.

[0044] Preferably, a coupling volume is enclosed within the first enclosure, wherein in one of the two operating modes the coupling volume shifts within the first enclosure perpendicular to the axes of the loudspeakers and in one of the two operating modes the coupling volume is compressed and decompressed.

[0045] According to a particularly preferred embodiment of the invention, the second housing has a second opening – also called a sound inlet opening – wherein the second opening is positioned directly on the axis of at least one of the at least two loudspeakers. The second opening is preferably positioned directly in front of the first housing, on the axis of the at least one of the at least two loudspeakers, which is in acoustic interaction with the interior of the second housing and is also referred to as the internal loudspeaker, as before. This allows the sound radiation from the at least one of the at least two loudspeakers to enter the interior of the second housing. The size of the second opening preferably corresponds to the size of the corresponding loudspeaker.

[0046] According to a further advantageous embodiment of the invention, the voice coils of both loudspeakers are arranged completely within the first housing and the loudspeakers are arranged antiparallel to each other.

[0047] According to a particularly preferred embodiment of the invention, in an antiparallel arrangement of the loudspeakers, in the second operating mode the coupling volume within the first housing is shifted perpendicular to the axes of the loudspeakers, and in the first operating mode the coupling volume is compressed and decompressed.

[0048] Loudspeakers can be constructed in a wide variety of ways. Any type of loudspeaker or sound-generating system can be used for the present invention.

[0049] The construction of a conventional loudspeaker serves as an example. A conventional loudspeaker comprises a basket, a voice coil, a pole piece, a spider, a diaphragm, a diaphragm surround, and / or a magnet, to which a front pole plate and a rear pole plate are attached. Preferably, the magnet is a permanent magnet. The two pole plates focus the magnetic field generated by the permanent magnet in the area of ​​the voice coil. Pole plates can also contribute to heat dissipation and distortion reduction.

[0050] The pole plates are preferably made of a ferromagnetic material. The voice coil, the pole core, the magnet, and the pole plates are components of the electromagnetic system.

[0051] The voice coil is wound around a voice coil former that surrounds the pole piece. The magnet and the pole plates each have an opening in their center into which the pole piece, with the coil suspended freely along its respective axis, is inserted. The voice coil is connected to a control unit via wires. The pole piece can also be part of the rear pole plate.

[0052] The front pole plate and / or the basket feature connecting elements. These connecting elements join the basket to the front pole plate. The basket has a circular annular structure and holds all the essential components of the loudspeaker together. In particular, the basket houses the diaphragm, the voice coil, and the spider. Optionally, the basket may also accommodate the magnet. The basket is made of aluminum, steel, or high-strength plastic.

[0053] The basket is configured to allow minimal disruption of air movement and sound waves, and to avoid unwanted resonances.

[0054] The basket can also be integrated into the first housing. The first housing then accommodates the magnet, voice coil, pole plates, and core within its integrated basket. This allows the basket and the first housing to be formed as a single piece, eliminating the need for separate assembly of the basket within the first housing. This reduces costs and manufacturing effort.

[0055] The spider's primary function is to ensure that the voice coil moves only axially during operation, preventing it from colliding with the edges of the magnet or pole piece, which could cause distortion or damage. The spider also returns the diaphragm to its original position after excursion. Particularly at low frequencies, the spider stabilizes the driver system and provides increased mechanical stability.

[0056] The diaphragm is directly connected to the voice coil. The voice coil is preferably bonded to the diaphragm with a heat-resistant adhesive. The diaphragm can be made of paper, plastic, or metal. In the present invention, a material is preferably used for the diaphragm that is waterproof and impermeable to dust particles or similar substances. If, for example, moisture penetrates the interior of the second housing, it cannot pass through the diaphragm and reach sensitive components such as the voice coil. For example, the diaphragm could be made of Gore-Tex. ® membrane or Gore-Tex ® It could be a similar membrane. Such a membrane is waterproof and creates a static pressure equalization between the interior of the first housing and the environment. The membrane can also be made of a different material that is waterproof and creates a static pressure equalization with the environment.

[0057] The diaphragm can be conical, dome-shaped, or flat. It can also be dome-shaped, forming a dome or an inverted cone. This allows for a reduction in the speaker's depth and, consequently, the depth of the enclosure.

[0058] The diaphragm surround is typically circular and conforms to the shape of the diaphragm. It is located at the outer edge of the diaphragm, which is not connected to the voice coil. The surround connects the diaphragm to any speaker frame. It must possess high flexibility and elasticity to transmit the movement of the voice coil along its axis without damping. The surround also provides stability and centering.

[0059] As mentioned, the first enclosure contains at least two speakers, which can be of different types. For example, the speakers can be a woofer, midrange driver, and / or tweeter, each covering different frequency ranges. In particular, a flat diaphragm can be used to emit sound only in the low-frequency range.

[0060] The operating principle of a loudspeaker is based on the fundamental idea of ​​converting an electrical signal into mechanical energy and subsequently into sound waves. An electrical signal is transmitted from a control unit via conductors to the voice coil of the loudspeaker. The voice coil is positioned within a fixed magnetic field. An electric current flows through the voice coil. A current-carrying conductor located within a magnetic field is subject to the Lorentz force. Depending on the polarity, the voice coil is deflected axially, either forwards or backwards. Since the voice coil is directly connected to the diaphragm, the diaphragm also undergoes relative movement. This movement of the diaphragm along its axis causes pressure fluctuations in the surrounding air. These pressure fluctuations propagate as sound waves, which are perceived as tones.

[0061] The bass reflex port, or bass reflex channel, is a tube or opening on the second enclosure. It is primarily used to improve overall performance, especially in the lower frequency range.

[0062] The bass reflex port – also called a bass reflex opening – acts as a resonator and its dimensions can be adjusted to match the loudspeaker's resonant frequency. This allows the sound radiated by the port and the driver to combine within a desired frequency range, resulting in a lower frequency response. Loudspeakers with a low Q factor, and therefore higher efficiency, are advantageously used in this configuration. Compared to passive radiator solutions, loudspeaker systems with bass reflex ports are generally more cost-effective.

[0063] The second enclosure, containing the bass reflex port, is not protected against water ingress. It is recommended that the bass reflex port be positioned as low as possible when the enclosure is horizontally oriented. This allows any water that does enter to drain away immediately. As a result, the waterproof diaphragm of the speaker, which projects sound into the interior of the second enclosure, is never subjected to excessive exposure to water, salt, dust, and / or dirt.

[0064] Preferably, the first enclosure and its components, such as the at least two loudspeakers, are always identical in design. The second enclosure can be adapted to the specific application. By changing the internal volume, the geometric dimensions of the bass reflex port, and the arrangement of the first enclosure relative to the second enclosure, adaptation to the respective application is possible. This makes it possible to provide a highly economical and mass-producible basic module, namely the first enclosure with integrated loudspeakers, and to implement customer-specific modifications cost-effectively by using a cost-effective second enclosure, preferably made of plastic.

[0065] Advantageously, a control unit for operating the loudspeaker system is arranged within the first housing. Preferably, a circuit board cavity is formed within the first housing into which the circuit board of the control unit can be inserted. By arranging the control unit within the first housing, the cable lengths from the control unit to the loudspeaker are significantly reduced. This makes the loudspeaker system less susceptible to electromagnetic interference (EMI) and reduces electromagnetic emissions, thus facilitating compliance with the specified normative requirements. Alternatively, the control unit can be arranged outside the first housing. In this case, the control unit can be located directly on the first housing, on another component of the loudspeaker system, or on a component that is not part of the loudspeaker system.The connection of the control unit or control units can then be made via one or more cables, which are led from the control unit through an opening in one of the side surfaces of the first housing into the interior of the first housing.

[0066] In a preferred embodiment of the invention, the control unit comprises a printed circuit board (PCB), which is preferably potted. A PCB cavity can preferably be formed within the first housing, in which the potting process is carried out after the PCB is inserted and a connector is attached. Potting the PCB provides additional protection to the components and conductor tracks located on it. The potting protects against environmental influences that could reduce the service life of the control unit. Furthermore, it increases the mechanical stability of the PCB, which is important because vibrations, particularly during vehicle operation, could damage solder joints and thus impair the functionality of the loudspeaker system. Additional advantages include increased electrical insulation resistance and improved heat dissipation.Epoxy resins, silicones or polyurethanes are used as potting materials.

[0067] A connector can be attached to the control unit. In particular, a single-pole or multi-pole connector can be soldered to the control unit's circuit board. The connector can be routed to the outside through an opening in a side panel of the first housing, enabling communication with a user interface or other control units. The preferred method of potting the circuit board seals the interior of the first housing.

[0068] A particular advantage of a two-pole or multi-pole connector is that each channel can drive a speaker independently, for example, in phase or out of phase, as in the first or second operating mode. The phase switching is accomplished by a control unit located upstream of the amplifier, which is controlled via a CAN interface and alternately provides the phase and signal frequency between the first and second operating modes. This also makes it easy to implement sound effects such as two-tone horns, beat frequencies, tremolo, or phase vibrato by using different current signals on the two channels and speakers.

[0069] According to a particularly preferred embodiment of the invention, the at least one voice coil, the magnet, the front pole plate and / or the rear pole plate are arranged completely within the first housing. This protects all sensitive components from moisture, dirt and / or dust, ensuring that the acoustic reproduction remains satisfactory and durable even in harsh environments.

[0070] In a particularly advantageous embodiment of the invention, a passive radiator is arranged within the first enclosure instead of a loudspeaker. A passive radiator is a loudspeaker diaphragm without its own vibration drive. The passive radiator incorporates a conventional loudspeaker driver. The passive radiator vibrates in response to the movement of the active loudspeaker, thus contributing to more efficient air movement within the enclosure, resulting in enhanced and deeper bass reproduction. The passive radiator can also be implemented by one or more resonant enclosure walls of the second enclosure. For example, such a resonant enclosure wall could be the vehicle's body structure. A key advantage of passive radiators over bass reflex ports is that they do not generate port noise.

[0071] According to a particularly preferred embodiment of the invention, the rear pole plate of the loudspeaker arranged on one side surface is positioned closer to an opposite side surface than the rear pole plate of the loudspeaker arranged on the opposite side surface. This arrangement of the loudspeakers allows for a particularly compact design, especially in the horizontal direction when viewed horizontally. In the simplest case, the opposite side surfaces are arranged parallel to each other, and the at least two loudspeakers are arranged in a mirror-image configuration.

[0072] Advantageously, the axis of one loudspeaker, running along an imaginary line, does not intersect another loudspeaker at any point. Thus, the two loudspeakers, arranged on and within the first enclosure, are positioned at least partially side-by-side in the vertical direction. This allows components with smaller vertical dimensions to be cleverly positioned next to each other, increasing the compactness of the first enclosure. Besides the improved compactness, this has the advantage that, unlike a coaxial arrangement, significant deviations in the amplitude frequency response, even total cancellation, are not to be expected when operating with broadband signals up to the high-frequency range. In the simplest case, the axes of the at least two loudspeakers are arranged parallel and spaced apart from each other.The distance between the two axes is preferably between half the mean diameter and the mean diameter of the at least two loudspeakers.

[0073] In a preferred embodiment of the invention, the first housing is made of an electrically and / or thermally conductive material. For example, the first housing can be made of a metal or a metal alloy, preferably zinc or aluminum. The first housing, containing the loudspeakers and the electronics, such as the control unit, is preferably designed to be compact. During operation, heat is generated, which is more difficult to dissipate due to the reduced installation space. By selecting the appropriate material for the first housing, heat can be dissipated from the interior of the first housing.

[0074] Convection cooling can occur on the side surface(s) of the first enclosure that are not directly adjacent to the second enclosure and on which preferably one or at least two loudspeakers are arranged, due to the airflow. The level-dependent airflow caused by the bass reflex port cools the first enclosure on the sides that are adjacent to the second enclosure.

[0075] Furthermore, it is advantageous if the first housing provides EMC shielding. This can be achieved, for example, by manufacturing the first housing from a metal alloy. This significantly reduces the influence and emission of electromagnetic radiation.

[0076] It can also be advantageous if the first housing is a die-cast metal component. On the one hand, this enables simple, cost-effective and mass-producible manufacturing, and on the other hand, such a component can meet requirements for EMC shielding and thermal conductivity.

[0077] In less temperature-sensitive applications, the first housing is preferably made of a plastic or similar material. This reduces manufacturing costs, simplifies production, and lowers the weight. GRP or CFRP materials can also be used, although it should be noted that CFRP materials can also provide EMC shielding.

[0078] The first and second housings can be connected to each other using fasteners – preferably detachable. For example, the fasteners can create a clamping and / or snap-fit ​​connection. This allows the two housings to be easily connected and, preferably, easily separated when needed, e.g., for maintenance, repair, or replacement.

[0079] The first housing can be made of metal, for example, and the second housing of a different material, such as plastic. At the end of the product cycle, the two housings can be separated, allowing for easy recycling of the materials, in this example, metal and plastic. The fact that the first housing and the basket are made from a single piece also simplifies the recycling process.

[0080] According to a further advantageous embodiment of the invention, the second housing has a cavity into which the first housing can be wholly or partially inserted. When the first housing is inserted into the cavity of the second housing, a connection between the two can be established. During this connection, an electrical connection between the first and second housings can be established by means of a suitable electrical contact, e.g., a plug and mating plug, via which the control unit in the first housing can be connected to a vehicle control system.

[0081] In one example, the first and second housings are connected via a snap-fit ​​or clamping connection. The first housing can be pressed – preferably into a cavity – in the side walls of the second housing and then snapped, screwed, or clamped into place. Advantages of such detachable connections include easy assembly with or without simple tools, repeatable disassembly and assembly, and high reliability and durability compared to using a single, integrated housing.

[0082] In a particularly advantageous embodiment of the invention, a seal is arranged between the first housing and the second housing. Preferably, the seal is made of an elastomer. The seal is preferably arranged between the first housing and the second housing around the second opening, i.e., the sound inlet opening.

[0083] Elastomers are polymers that exhibit high elasticity and flexibility, allowing them to return to their original shape after deformation under tension. This enables the separation of the first housing from the second housing to be repeated as often as desired without negatively affecting the sealing properties. There are various types of elastomers, such as nitrile rubber, silicone, ethylene propylene diene monomer (EPDM), and fluoroelastomers.

[0084] Advantageously, the control unit comprises a single-channel or multi-channel control device. Preferably, each channel controls one of the at least two loudspeakers separately. The control device, which is located within the first housing, can be equipped with a power amplifier.

[0085] The two loudspeakers can also be connected in parallel so that when an alternating signal is applied, both diaphragms deflect in the same direction. From a measurement perspective, the two loudspeakers behave like a single loudspeaker with new characteristics.

[0086] By arranging the loudspeakers in opposite directions within the first enclosure and applying the same current signal to both loudspeakers in operating state one, the required enclosure volume is halved due to the doubled spring stiffness of the series-acting diaphragm suspensions, while maintaining the same lower cutoff frequency. This is because the ratio of total spring stiffness to the air spring stiffness of the enclosure is crucial for achieving the same enclosure resonance. This allows for the realization of compact loudspeakers with a particularly low cutoff frequency, which would not be possible with a closed enclosure. Furthermore, with the two loudspeakers arranged in opposite directions, nonlinearities in the spring characteristic of the suspension and the magnetic force factor of the voice coil partially cancel each other out, thus improving the acoustic quality, especially in the high-frequency range.

[0087] In the second operating mode, the coupling volume does not contribute to the change in the resonance frequency when the loudspeakers are arranged antiparallel; this frequency is formed exclusively by the spring stiffness of the diaphragm suspension, namely the surround and diaphragm suspension, and the volume of the first enclosure on which the diaphragm of the inner chassis acts.

[0088] If the loudspeakers are arranged in parallel and aligned, the coupling volume does not contribute to changing the resonance frequency in the first operating mode.

[0089] Advantageously, different types of loudspeakers are used. The combination of identical or different loudspeakers within the first enclosure can also be supported by appropriate external circuitry, such as a crossover network or filtering within a control unit. With a crossover network, the signals from an amplifier, which is controlled by a control unit, are divided into different frequency ranges. The separated frequency ranges are then assigned to the corresponding loudspeakers. Various filter types, such as low-pass, high-pass, and band-pass filters, can be used for this purpose. For example, bass frequencies are produced by a woofer, midrange frequencies by a midrange driver, and high frequencies by a tweeter.

[0090] According to a further advantageous embodiment of the invention, a grill is attached to at least one loudspeaker. Preferably, the grill is arranged on the loudspeaker that does not acoustically interact with the interior of the second housing. However, a grill can also be arranged on each individual loudspeaker in the loudspeaker system. The grill is designed to protect the sensitive components on the outside of the loudspeaker from environmental influences. The grill can be designed to be removable.

[0091] The grille comprises a frame and an acoustically transparent fabric, or a metal or plastic mesh. The grille's mesh can be net-shaped. A net-shaped grille has a first group of bars, the bars of which run parallel to each other. Furthermore, a net-shaped grille has a second group of bars, the bars of which also run parallel to each other. The bars of the first group are preferably arranged at an angle, particularly preferably orthogonally, to the bars of the second group. The grille can also have only one group of bars. The shape of the frame preferably conforms to the shape of the loudspeaker, in particular to the shape of the diaphragm surround.

[0092] In a particularly advantageous embodiment of the invention, the first housing and the basket are formed in one piece. As described above, the basket can support the magnet, the diaphragm, the voice coil, and / or the front and / or rear pole plate and / or the spider of the loudspeaker.

[0093] According to a further advantageous embodiment of the invention, the second housing is preferably made of plastic. Plastic components are generally durable and inexpensive to manufacture. Furthermore, their shape is often adaptable to any desired configuration, so the second housing can be used as an adjustable parameter for the specific application.

[0094] Advantageously, the second housing, and thus its interior, is formed by the vehicle's body structure. The first housing can be attached to the body structure in such a way that the interior – or cavity – of the second housing is created. In this case, a separate second housing is not required, which reduces the installation space. This may allow for an increase in the diaphragm diameter and, consequently, a significant increase in the low-frequency sound level.

[0095] The inner loudspeaker is preferably arranged in such a way that its outer diaphragm acts on the air volume in the interior of the second housing or comes into direct contact with it.

[0096] According to a preferred embodiment of the invention, the inner loudspeaker projects sound directly into the interior of the second housing through the second opening, and the outer loudspeaker projects sound into an environment. The environment is a space or volume that is not bounded by either of the side walls of the first or second housing.

[0097] The loudspeaker system can also include more than two loudspeakers. For example, three, four, five, or more loudspeakers can be provided. In particular, more than two loudspeakers can be arranged inside or on the first enclosure. It is not necessary for all loudspeakers to be arranged on or against two opposite side walls. Loudspeakers can also be arranged on the second enclosure. The loudspeakers arranged on the second enclosure can radiate sound into the surrounding environment or into the interior of the second enclosure.

[0098] According to an advantageous embodiment of the invention, at least one maintenance hatch is provided on at least one side surface of the first housing. The maintenance hatch can be opened to perform maintenance or assembly work, such as the installation of the connector, inside the first housing. The maintenance hatch is lockable and forms a positive fit with one or more side surfaces of the first housing. The maintenance hatch can be opened or closed via a hinge mechanism. An advantage of such a maintenance hatch is that it is not necessary to disassemble the loudspeaker system to make changes inside the first housing.

[0099] The maintenance hatch may have an opening into which a waterproof membrane, preferably a Gore-Tex, is inserted. ®A membrane is inserted. This membrane allows for static pressure equalization between the interior of the first housing and the surrounding environment. The opening can also be located at any other point on the first housing containing the pressure equalization membrane.

[0100] Furthermore, it has proven advantageous if the second housing is formed by a body structure of the motor vehicle, which, for example, includes a cavity with the second opening.

[0101] A further aspect of the present invention relates to a method for operating a loudspeaker system, in particular a loudspeaker system for an electric vehicle, comprising a first housing and a loudspeaker arranged on opposite sides of the first housing, wherein each loudspeaker has a voice coil movable on an axis, the axes of these loudspeakers being non-coaxial, comprising the following method steps: operating the loudspeaker system in a first operating mode, wherein in the first operating mode the loudspeakers are simultaneously supplied with the same current signal; and operating the loudspeaker system in a second operating mode, wherein in the second operating mode the loudspeakers are simultaneously supplied with a current signal that is inverted relative to each other.

[0102] Following a further advantageous process step, the loudspeaker system has a second enclosure with an opening for bass reflex tuning, wherein at least one loudspeaker enters into an acoustic interaction with the interior of the second enclosure.

[0103] Furthermore, it has proven advantageous if the current signal is a sinusoidal or rectangular current signal.

[0104] In a further advantageous process step, in one of the two operating modes, a diaphragm of one loudspeaker and a diaphragm of the second loudspeaker are deflected in the same direction, while in one of the two operating modes, the diaphragm of one loudspeaker and the diaphragm of the other loudspeaker are deflected in opposite directions.

[0105] Another aspect of the present invention relates to a motor vehicle, in particular an electric motor vehicle, with a previously described loudspeaker system.

[0106] Two embodiments of the present invention are described in detail below with reference to the accompanying drawing. It shows: Fig. 1 A schematic representation of the loudspeaker system, with a first and second enclosure, two loudspeakers, a grill and a control unit, Fig. 2 a schematic representation of the loudspeaker system, with a first and second enclosure and two loudspeakers, Fig. 3 a schematic representation of the loudspeaker, Fig. 4a a schematic representation of a second embodiment of the loudspeaker system, Fig. 4b a schematic representation of another embodiment of the loudspeaker system, Fig. 5 a schematic representation of a motor vehicle with the loudspeaker system according to a second embodiment, Fig. 6 a schematic representation of a motor vehicle with the loudspeaker system according to a third embodiment, and Fig. 7a Current signals applied to the external loudspeaker and the internal loudspeaker in the second operating mode with antiparallel arrangement of the loudspeakers, and Fig. 7b Current signals applied to the external loudspeaker and the internal loudspeaker in the first operating mode with antiparallel arrangement of the loudspeakers.

[0107] Identical or functionally equivalent parts or features are identified by the same reference numerals in the detailed description of the figures below. Likewise, not all identical or functionally equivalent parts or features in the figures are assigned a reference number.

[0108] The Fig. Figures 1 to 3 show a first embodiment of the invention. Fig. Figure 1 shows a schematic representation of the loudspeaker system 1, in particular the AVAS loudspeaker system.

[0109] The loudspeaker system 1 comprises a first enclosure 10, a second enclosure 20, two loudspeakers 30 and a control unit 50.

[0110] The first housing 10 comprises a first side surface 11, a second side surface 12, an interior 14 and can have a cuboid structure.

[0111] The interior 14 of the first housing 10 is completely sealed against environmental influences. This enables its use in harsh conditions, such as those encountered during daily vehicle operation. The first housing 10 can assume any shape; in particular, it can adapt to the available installation space, which is usually defined by the vehicle body or unobstructed deformation zones.

[0112] The first housing 10 can be made of an electrically and / or thermally conductive material, or of a metal or metal alloy. In particular, the first housing 10 can be made of zinc or aluminum. This significantly improves the EMC properties of the loudspeaker system 1.

[0113] The first housing 10 also contains the control unit 50. A printed circuit board cavity 18 can be formed within the first housing 10. The control unit 50 can be inserted into the printed circuit board cavity 18.

[0114] The control unit 50 comprises a circuit board 51 and an amplifier. The control unit 50 can be connected to a user interface or other control device within the vehicle using a connector 52. The connector 52 can be a multi-pin connector 52 and can be soldered to the circuit board 51. The connector 52 can also be connected to the circuit board 51 via a connector strip attached to the circuit board 51.

[0115] The printed circuit board 51, located in the circuit board cavity 18 of the first housing 10, can be potted. The potting can be carried out before the printed circuit board 51 is inserted into the circuit board cavity 18, or while the printed circuit board 51 is inserted or connected within the circuit board cavity 18. In the latter case, the contact point between the connector 52 and the printed circuit board 51 is also potted. Furthermore, an opening 53, through which the connector 52 is guided into the interior 14 of the first housing 10 or the potting compound, is sealed.

[0116] The circuit board cavity 18 can also be arranged on any other side surface 11 of the first housing 10. The circuit board cavity 18 is arranged below the inner loudspeaker 90.

[0117] Communication between the control unit 50 and the loudspeaker 30 takes place via wired connections. The control unit 50 can be configured as a multi-channel unit, allowing each loudspeaker 30 to be controlled via its own channel. The wires used for communication between the control unit 50 and the loudspeaker are short. This results in excellent EMC performance of the loudspeaker system 1, both in terms of EMC sensitivity and EMC emissions.

[0118] The first housing 10 includes at least two loudspeakers 30.

[0119] Each loudspeaker 30 comprises a basket 40, a spider 32, a voice coil 34, a pole piece 39, a diaphragm 35, a diaphragm surround 38 and a magnet 33, on which a rear pole plate 36 and a front pole plate 37 are arranged.

[0120] The loudspeaker 30 has an axis L, wherein the voice coil 34 is movable in the axis L.

[0121] Each loudspeaker 30 has an inner chamber 31 in which the sensitive components, in particular the voice coil 34, are arranged. The diaphragm 35 is designed to be waterproof and dirt-resistant, so that the diaphragm 35 forms the boundary between the inner chamber 31 and the outer chamber, for example the interior 21 of the second housing 20.

[0122] In the area of ​​the side surfaces 11 of the first housing 10, the diaphragm surround 38 is arranged on the diaphragm 35. The diaphragm surround 38 is connected to the end of the diaphragm that is not connected to the voice coil 34. The diaphragm surround 38 is typically annular in shape. The diaphragm surround 38 is made of a material with high elasticity and flexibility so that it does not distort the vibration behavior of the diaphragm 35.

[0123] The diaphragm 35 is arranged within a basket 40 and has a conical structure. The basket 40 can be made of aluminum or plastic. The spider 32, which centers the diaphragm 35 and the voice coil 34, is located inside the basket.

[0124] The front pole plate 37 is arranged on the underside of the basket 40. The front pole plate 37 is connected to the basket 40 via connecting elements. The basket 40 has a lower circular ring 41 and an upper circular ring 42, the two circular rings 41 and 42 being connected to each other via connecting webs 43. The upper circular ring 42 has a larger outer diameter than the lower circular ring 41.

[0125] A magnet 33 is arranged between the front pole plate 37 and the rear pole plate 36. Both the magnet 33 and the front pole plate 37 are annular in shape. The rear pole plate 36 is also annular or ring-shaped. The magnet 33 is preferably a permanent magnet. The two pole plates 36 and 37 conduct the electric flux of the permanent magnet. The pole plates 36 and 37 are made of a ferromagnetic material, which amplifies and focuses the electric flux.

[0126] The rear pole plate 36 can also form the pole core 39. The pole core 39 and the rear pole plate 36 are thus formed as a single piece, which offers advantages, particularly during assembly and with regard to losses. The pole core 39 can also be connected to the rear pole plate 36. The voice coil 34 is wound around the voice coil former 44, with the voice coil arranged around the pole core 39. The voice coil 34 is arranged radially between the pole core 39 and the magnet 33. An air gap 45 is arranged between the magnet 33 and the voice coil 34. The voice coil 34 is freely mounted, allowing it to move, particularly in the axial direction.

[0127] The diaphragm 35 is mechanically connected to the voice coil 34. When the voice coil 34 moves in an axial direction, the diaphragm 35 moves in the same direction. The diaphragm moves the air molecules, causing sound to propagate in the form of waves.

[0128] Each loudspeaker 30 can also include a grille 70. The grille 70 can be arranged in front of the diaphragm 35 in a direction of radiation, similar to a protective grille and / or mesh. The grille 70 is configured to protect the loudspeaker 30, and in particular the diaphragm 35, from external influences.

[0129] The two loudspeakers 30 are arranged on two opposite side surfaces 11, 12 of the first housing 10, wherein the axes L of the two loudspeakers 30 are not coaxial and preferably do not intersect at any point.

[0130] According to the in Fig. In the exemplary embodiment shown in Figure 1, the two opposite side surfaces 11, 12 are arranged parallel and spaced apart from each other.

[0131] On each of the two opposite side surfaces 11, 12, one of the two loudspeakers 30 is arranged, the arrangement of the two loudspeakers 30 being mirror images of each other. One of the two loudspeakers 30 is the so-called external loudspeaker 91, which will be explained later, and the other loudspeaker 30 is the internal loudspeaker 90, which will also be described later.

[0132] Furthermore, the Fig. As can be seen from Figure 1, the two axes L of the two loudspeakers 30 are arranged parallel and spaced apart from each other, with the distance A between the two axes L being chosen to be as small as possible in order to preferably avoid possible unwanted cancellations in the frequency response. For example, the distance A between the axes L of the loudspeakers 30 is half a mean diameter D. M and approximately two average diameters D M at least two loudspeakers 30. Preferably the distance A is approximately 0.5D.M ≤ A ≤ 2D M , even more preferred 1D M ≤ A ≤ 1.5D M .

[0133] Furthermore, the mean diameters D M The loudspeakers can vary in size. The average diameter D M The diameter of the 90° internal speaker can be between 1.1 and 1.5 times larger than the mean diameter D. M of the external loudspeaker 91 or vice versa. Preferably the middle diameters D M The inner speaker 90 and the outer speaker 91 are of the same size.

[0134] The indoor speaker 90 has a first depth T1. The outdoor speaker 91 has a second depth T. 2 auf The depth T1, T2 is the spatial extent of a loudspeaker 30 along its axis (L). The first and second depths T1 and T2 can be different or the same.

[0135] The first distance D1 is the distance from the rear pole plate 36 of the inner loudspeaker 80 to the second side surface 12 of the first housing 10. The second distance D2 is the distance from the rear pole plate 36 of the outer loudspeaker 91 to the first side surface 11 of the first housing.

[0136] For example, the first distance D1 can be between one-eighth and approximately twice the first depth T1, and / or the second distance D2 can be between one-eighth and approximately twice the second depth T2. Preferably, the first distance D1 is approximately 0.125T2 ≤ D1 ≤ 2T2. More preferably, the second distance D2 is approximately 0.125T1 ≤ D2 ≤ 2T1.

[0137] Particularly preferred is T1 ≤ D2 and / or T2 ≤ D1. Even more preferred is 0.125T2 ≤ D1 ≤ 1T2 and / or 0.125T1 ≤ D2 ≤ 1T1.

[0138] Furthermore, the first distance D1 is preferably between one-eighth and approximately 4 times the first depth T1. Preferably, the first distance D1 is approximately 0.125D1 ≤ T1 ≤ 4D1, and even more preferably 0.125D1 ≤ T1 ≤ 1D1.

[0139] Preferably, the second distance D2 is between one-eighth and approximately four times the second depth T2. Preferably, the first distance D1 is approximately 0.125D2 ≤ T2 ≤ 4D2, and even more preferably 0.125D1 ≤ T1 ≤ 1D1.

[0140] The loudspeakers 30 are arranged such that they are offset from each other when viewed vertically. This means that the two loudspeakers 30 are at least partially positioned next to each other within the first housing 10. The rear pole plate 36 of the inner loudspeaker 90 can be positioned closer to the opposite second side surface 12 than the rear pole plate 36 of the outer loudspeaker 91 is positioned closer to the opposite first side surface 11.

[0141] The circuit board cavity 18 can be arranged on the side surface 11, where the external loudspeaker 91 is also arranged.

[0142] More than one loudspeaker 30 can also be arranged on a side surface 11, 12 of the first housing 10. In particular, two, three, four or more loudspeakers 30 can be arranged on a side surface 11, 12 of the first housing 10.

[0143] Different loudspeakers 30 can be arranged within the first and / or second housing 10, 20. Loudspeakers 30 can be arranged for high-frequency, low-frequency, and mid-frequency generation on the loudspeaker system 1.

[0144] The second enclosure 20 has side surfaces 23, an interior 21, an opening 22 for bass reflex tuning, and a second opening 25. The opening 22 for bass reflex tuning and the second opening 25 are connected to each other by the interior 21 of the second enclosure 20.

[0145] The opening 22 for bass reflex tuning can, viewed from a horizontal perspective, be located near the bottom of the second enclosure 20 when used as intended. The opening 22 for bass reflex tuning can also be referred to as the bass reflex port 22 and can also be configured as a bass reflex channel.

[0146] The first enclosure 10 and the second enclosure 20 can be arranged at least partially adjacent to each other. The first enclosure 10 is positioned relative to the second enclosure 20 such that one of the loudspeakers 30 is located in front of or within the second opening 25, thus acoustically interacting with the interior 21 of the second enclosure 20. This loudspeaker 30 is the inner loudspeaker 90 and is located on the first side surface 11 of the first enclosure 10, radiating into the interior 21 of the second enclosure 20.

[0147] On the second side surface 12, facing away from the second housing 20, the other of the two loudspeakers 30, the so-called external loudspeaker 91, is arranged, which radiates into the surroundings.

[0148] The external loudspeaker 91 is preferably used for generating medium to high frequency tones, while the internal loudspeaker 90 is preferably used for generating low frequency tones, preferably tones with a frequency range up to 80 Hz, more preferably up to 60 Hz at a level drop of -10dB.

[0149] The first housing 10 and the second housing 20 can be connected to each other via detachable fasteners, for example a snap-fit ​​connection. The first housing 10 can have a locking lug and the second housing 20 a locking groove.

[0150] When the two housings 10 and 20 are connected, the locking lug of the first housing 10 engages in the locking groove of the second housing 20, preventing the components from unintentionally separating. The first housing 10 can also be screwed and / or clamped to the second housing 20 to create a permanent mechanical connection between the two components. The first housing 10 and the second housing 20 can also be glued together. The first housing 10 can also be inserted or placed inside the second housing 20. Furthermore, the first housing 10 and the second housing 20 cannot touch each other.

[0151] A seal 80 can be arranged between the first housing 10 and the second housing. The seal 80 is preferably arranged around the second opening 25 and seals the interior 21 of the second housing 20 against environmental influences such as dust, stone chips and moisture.

[0152] The seal 80 is preferably designed as an elastomer seal. Elastomer seals have the advantage of high elasticity and flexibility, which allows gaps to be filled in a form-fitting manner and enables repeated installation and removal of the first housing without problems.

[0153] The second housing 20 can also, as shown in Fig. Figure 1 shows a cavity 26 into which the first housing 10 can be at least partially inserted and which can correspond to the shape of the first housing 10. The second opening 25 is arranged in the cavity 26.

[0154] The first housing 10 is made of a metal, a metal alloy, or a thermally and electrically conductive material. The first housing 10 can also be made of plastic.

[0155] Additional loudspeakers 30 can also be arranged on the second housing 20. The loudspeakers 30 can be arranged on each side surface 23 of the second housing 20. The loudspeakers 30 can radiate sound either into the interior 21 of the second housing 20 or into the surrounding environment. More than one loudspeaker can also be arranged on each side surface 23 of the second housing.

[0156] The second housing 20 is made of plastic. The second housing can also be made of metal, a metal alloy, or similar material.

[0157] For simplified maintenance, the maintenance hatch can be located on the underside 4 of the motor vehicle 2, allowing the first housing, together with the two loudspeakers 30 and the control unit 50, to be removed for maintenance, replacement or repair purposes.

[0158] Fig. Figure 4a shows another embodiment of the loudspeaker system 1.

[0159] The loudspeaker system 1 comprises a first housing 10, two loudspeakers 30 and a control unit 50.

[0160] The loudspeakers 30 are arranged antiparallel and on two opposite side surfaces 11, 12. The loudspeakers are not arranged coaxially.

[0161] The loudspeakers 30, in particular the critical components of the loudspeaker system 1, such as the voice coil 34, are arranged within the first housing 10.

[0162] The control unit 50 is located inside the first housing 10.

[0163] In the second operating mode, the coupling volume is moved back and forth within the first housing.

[0164] In the first operating mode, the coupling volume is compressed and decompressed, with the compression and decompression processes alternating periodically.

[0165] Fig. Figure 4b shows another embodiment of the loudspeaker system 1.

[0166] The loudspeaker system 1 comprises a first housing 10, two loudspeakers 30 and a control unit 50.

[0167] The 30 loudspeakers are arranged in parallel and aligned with each other.

[0168] The control unit 50 is located inside the first housing 10.

[0169] In the second operating mode, the coupling volume is compressed and decompressed, with the compression and decompression processes alternating periodically.

[0170] In the first operating mode, the coupling volume is moved back and forth within the first housing.

[0171] Fig. Figure 5 shows a motor vehicle 2, wherein the previously used loudspeaker system 1 is arranged on the underside 4 of the motor vehicle 3 according to a second embodiment.

[0172] In contrast to the embodiment described so far, the second housing 20 is not formed by a separate component, but is formed by the body structure 3 of the motor vehicle 2, which has a recess 5 forming the interior 21.

[0173] The second housing 20 has, as previously described, a first opening 22 and a second opening 25, wherein the first housing 10 can be detachably attached to the second housing 20, i.e. in this embodiment to the body structure, to form the loudspeaker system 1, such that one of the two loudspeakers 30, i.e. the inner loudspeaker 90, is positioned in front of or in the second opening 25 and can radiate into the interior 21 of the second housing 20.

[0174] Fig. Figure 6 shows a schematic representation of a motor vehicle with the loudspeaker system according to the first embodiment.

[0175] In Fig. 7a and Fig. 7b the loudspeakers 30 are arranged antiparallel on two opposite side surfaces 11, 12.

[0176] Fig. Figure 7a shows the current signals 90A, 91A at the terminals of the voice coil 34 of the external loudspeaker 91 and the internal loudspeaker 90 in the first operating mode. The current signals 90A, 91A are sinusoidal signals. The current signals 90A, 91A are in phase, so that each of the voice coils 34 is energized with the same current signal 90A, 91A at the same time. Since the external loudspeaker 91 and the internal loudspeaker 90 are arranged on different side surfaces 11, 12 of the first housing 10, the diaphragms 35 move in opposite directions along the axis (L) when the voice coils 34 are energized in the same direction. This opposing movement of the diaphragms 35 of the external loudspeaker 91 and the internal loudspeaker 90 achieves a relatively wide frequency range, which meets the requirements for signal transmitters, especially horns.

[0177] Fig. Figure 7b shows the current signals 90A, 91A at the terminals of the voice coil 34 of the outer loudspeaker 91 and the inner loudspeaker 90 in the second operating mode. The current signals 90A, 91A are sinusoidal signals. The current signals 90A, 91A are out of phase, i.e., inverted relative to each other. The voice coils 34 are simultaneously energized with the current signal 90A, 91A, which is mirrored along the time axis. Since the outer loudspeaker 91 and the inner loudspeaker 90 are arranged on different side surfaces 11, 12 of the first housing 10, the diaphragms 35 move in the same direction along the axis (L) when the voice coils 34 are energized in opposite phase. The synchronous deflection of the diaphragms 35 of the outer loudspeaker 91 and the inner loudspeaker 90 alternately compresses and decompresses the medium in the first housing 10, thereby achieving a high sound pressure level of up to 110 dB SPL / 2m, which meets the standardized requirements for the AVAS loudspeaker system.

[0178] The 30 loudspeakers can also be arranged in parallel and aligned, as for example in Fig. 4b shown. Then, in the second operating mode, the coupling volume would be compressed and decompressed, and in the first operating mode, the coupling volume would be moved back and forth within the first housing 10.

[0179] In both the first and second operating modes, the current signal 90A, 91A can have a waveform other than a sinusoidal one. For example, the current signal 90A, 91A can have a rectangular, triangular, or trapezoidal waveform. In principle, the current signals 90A, 91A can assume any type of time-varying signal.

[0180] The loudspeaker system 1 can assume more than two operating modes. For example, the loudspeaker system 1 can have three or more operating modes in which the current signals 90A, 91A can vary with respect to frequency, phase shift and amplitude.

[0181] For example, the current signals 90A and 91A, which are present at the terminals of the outdoor speaker 91 and the indoor speaker 90, can be out of phase with each other. The phase shift can be 90 degrees, 120 degrees, 210 degrees, 270 degrees, or any other value.

[0182] The current signals 90A and 91A can also differ in frequency. Furthermore, the current signals 90A and 91A can have different amplitudes. Reference symbol list 1 speaker system 2 motor vehicles 3 Body structure 4 Underside 10 first case 11 First side surface 12 Second side surface 14 Interior 18 printed circuit board cavities 14 Interior 20 second case 21 Interior 22 Opening 23 side surface 25 second opening 26 Cavity 30 speakers 31 Interior 32 Centering spider 33 Magnet 34 Voice coil 35 Membran 36 rear pole plate 37 front pole plate 38 Membrane surround 39 pole core 40 basket 41 lower circular ring 42 upper ring 43 connecting bridges 44 voice coil formers 45 air gap 50 control unit 51 circuit board 52 plugs 53 Opening 70 Grill 80 Seal 90 indoor speakers 90A 91 Outdoor speaker 91A L Axle A distance D1 First Distance D2 Second Distance D M Average diameter T1 First Depth T2 Second Depth QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2020099222 A1

[0005]

Claims

[1] Loudspeaker system (1) for a motor vehicle, in particular for an electric motor vehicle, comprising: - a first case (10), - a control unit (50), - at least two loudspeakers (30), each loudspeaker (30) having a voice coil (34) movable in an axis (L), - wherein the at least two loudspeakers (30) are arranged on two opposite side surfaces (11 12) of the first housing (10), - wherein the axes (L) of the at least two loudspeakers (30) are not coaxial, - wherein the loudspeakers (30) can be controlled separately by the control unit (50), - wherein the control unit (50) can be set to a first operating mode and a second operating mode, wherein in a first operating mode the loudspeakers (30) are simultaneously supplied with the same current signal and in a second operating mode the loudspeakers (30) are simultaneously supplied with a current signal inverted relative to each other. [2] Loudspeaker system (1) according to claim 1, characterized by , that the loudspeaker system (1) has a second enclosure (20), wherein the second enclosure (20) includes an opening (22), and the first and second enclosures are at least partially arranged next to each other, wherein at least one of the at least two loudspeakers (30) is in acoustic interaction with the interior (21) of the second enclosure (20). [3] Loudspeaker system (1) according to any one of the preceding claims, characterized by, that within the first enclosure (10) a coupling volume is enclosed, wherein in one of the two operating modes within the first enclosure (10) the coupling volume shifts perpendicular to the axes (L) of the loudspeakers (30) and in one of the two operating modes the coupling volume within is compressed and decompressed. [4] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the second housing (20) has a second opening (25), wherein the second opening (25) is positioned directly on the axis (L) of at least one of the at least two loudspeakers (30). [5] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the control unit (50) has a printed circuit board (51) which is preferably potted. [6] Loudspeaker system (1) according to any one of the preceding claims, characterized by, that the voice coils (34) of both loudspeakers (30) are arranged completely within the first housing (10) and the loudspeakers (30) are arranged antiparallel to each other. [7] Loudspeaker system (1) according to claim 6, characterized by , that in an antiparallel arrangement of the loudspeakers (30) in the second operating mode the coupling volume within the first housing (10) is shifted perpendicular to the axes (L) of the loudspeakers (30) and in the first operating mode the coupling volume is compressed and decompressed. [8] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that a voice coil (34), a magnet (33) and / or a front and / or a rear pole plate (36, 37) of at least one of the at least two loudspeakers (30) are arranged completely within the first housing (10). [9] Loudspeaker system (1) according to any one of the preceding claims, characterized by, that the second housing (20) is made of plastic. [10] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that at least one of the at least two loudspeakers (30) is arranged at least partially on or inside the interior (21) of the second housing (20). [11] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the rear pole plate (36) of the loudspeaker (30), which is arranged on a side surface (11), is arranged closer to an opposite side surface (11) than the rear pole plate (36) of the loudspeaker (30), which is arranged on the opposite side surface (11). [12] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the axis (L) of a loudspeaker (30) running along an imaginary line does not intersect any other loudspeaker (30) at any point. [13] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the first housing (10) is made of an electrically and / or thermally conductive material and / or a metal or metal alloy, preferably zinc or aluminium. [14] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the first housing (10) and the second housing (20) are connected to each other via a preferably detachable connection, preferably a snap-fit ​​or clamp connection. [15] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that a seal (80), preferably an elastomer seal, is arranged between the first housing (10) and the second housing (20). [16] Loudspeaker system (1) according to any one of the preceding claims, characterized by, that the control unit (50) is a multi-channel control unit (50), wherein in the multi-channel control unit (50) each channel separately controls one of the at least two loudspeakers (30). [17] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that a grill (70) is attached to at least one of the at least two loudspeakers (30), preferably the grill (70) is arranged on the loudspeaker (30) which does not acoustically interact with the interior (21) of the second housing (20). [18] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the first housing (10) forms a basket (40) which carries a magnet (33), a diaphragm (35), a voice coil (34), the front pole plate (36) and / or the rear pole plates (37) as well as the spider (32) of the loudspeaker (30). [19] Loudspeaker system (1) according to any one of the preceding claims, characterized by, that the second housing (20) and its interior (21) are formed by a body structure of the motor vehicle. [20] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that one of the at least two loudspeakers (30) is an indoor loudspeaker (90) that radiates directly into the interior (21) of the second enclosure (20) and that the other of the at least two loudspeakers (30) is an outdoor loudspeaker (91) that radiates into an environment. [21] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that a maintenance hatch is formed on at least one side surface (11) of the first housing (10). [22] Loudspeaker system (1) according to any one of the preceding claims, characterized by , that the second housing (20) is formed by a recess (5) in the body structure (3). [23] Method for operating a loudspeaker system (1), in particular a loudspeaker system (1) for an electric motor vehicle, comprising a first housing (10) and a loudspeaker (30) arranged on opposite side surfaces (11, 12) of the first housing (10), wherein each loudspeaker (30) has a voice coil (34) movable in an axis (L), wherein the axes (L) of these loudspeakers (30) are not coaxial, comprising the following method steps: - Operating the loudspeaker system (1) in a first operating mode, wherein in the first operating mode the loudspeakers (30) are simultaneously supplied with the same current signal, - Operating the loudspeaker system in a second operating mode, in which the loudspeakers are simultaneously supplied with a current signal that is inverted relative to each other. [24] Method according to claim 19, characterized by, that the loudspeaker system (1) has a second housing (20) with an opening (22) and that at least one loudspeaker (30) enters into an acoustic interaction with the interior (21) of the second housing (20). [25] Method according to claim 21, characterized by that the current signal is a sinusoidal or rectangular current signal. [26] Method according to claim 19 or 22, characterized by , that in one of the two operating modes a diaphragm of one loudspeaker and a diaphragm of the second loudspeaker are deflected in the same direction, and in one of the two operating modes the diaphragm of one loudspeaker and the diaphragm of the other loudspeaker are deflected in opposite directions. [27] Motor vehicle (2), in particular electric motor vehicle, with a loudspeaker system (1) according to one of the preceding claims.

Images