Heat dissipation in loudspeakers

Abstract

Designs and methods for heat dissipation in loudspeakers are discussed. A loudspeaker unit can comprise an enclosure defining an internal volume, a duct coupling the internal volume to an exterior of the enclosure, a first audio driver with a first diaphragm coupled to the internal volume, and a second audio driver with a second diaphragm coupled to the internal volume. The second diaphragm is configured to vibrate in the opposite direction to the first audio driver and is spaced apart from it. At least one section of an internal opening of the duct is positioned between the first and second diaphragms.

Description

Cross-reference to related registrations

[0001] This application claims priority over U.S. patent application no. 63 / 504,998, filed on May 30, 2023, which is hereby incorporated by reference in its entirety. Additional incorporations by reference are made throughout the disclosure. Territory of Revelation

[0002] The present disclosure relates to consumer goods and in particular to processes, systems, products, features, services and other elements directed towards media reproduction or any aspect thereof. background

[0003] Options for accessing and listening to digital audio at high volume were limited until SONOS, Inc. began developing a new type of playback system in 2002. Sonos then filed one of its first patent applications in 2003, titled "Method for Synchronizing Audio Playback between Multiple Networked Devices," and began selling its first media playback systems in 2005. The Sonos Wireless Home Sound System allows people to experience music from many sources through one or more networked playback devices. Using a software control application installed on a controller (such as a smartphone, tablet, computer, or voice input device), users can play whatever they want in any room with a networked playback device. Media content (e.g.,Songs, podcasts, and video audio can be streamed to playback devices, allowing each room with a playback device to play different media content. Furthermore, rooms can be grouped for synchronous playback of the same media content, and / or the same media content can be heard simultaneously in all rooms. Brief description of the drawings

[0004] The features, aspects, and advantages of the technology disclosed herein can be better understood by referring to the following description, the attached claims, and the accompanying drawings, as listed below. A person skilled in the art will understand that the features shown in the drawings are for illustrative purposes only and that variations, including different and / or additional features and arrangements thereof, are possible. Fig. Figure 1 is a functional block diagram illustrating certain aspects of an exemplary playback device; Fig. Figure 2 is a 3D view of a section of a loudspeaker according to an example; Fig. Figure 3 is an isometric view of a section of a loudspeaker according to another example; Fig. Figure 4 is a 3D view of an example motor that includes a heat sink; Fig. Figure 5 is a 3D view of another exemplary motor that includes a heat sink; Fig. Figure 6 is a partially cutaway view of part of a loudspeaker, according to an example; and Fig. 7 is an exemplary procedure. Detailed description I. Overview

[0005] Audio drivers comprise one or more motors coupled to a diaphragm, designed to move the diaphragm to produce sound. A typical motor includes a magnet and a voice coil.

[0006] A current driven through the voice coil generates a magnetic field that interacts with the magnetic field generated by the magnet, thereby moving the voice coil relative to the magnet. The voice coil is coupled to the diaphragm, so the movement of the voice coil is at least partially transferred to the diaphragm. When the voice coil is driven by a current corresponding to an audio signal, the resulting movement of the diaphragm produces an audio signal corresponding to that signal.

[0007] The current through the voice coil generates heat through resistance heating. This heating can become significant in certain loudspeaker systems, such as those described in patent applications WO 2018 / 056814 A1 (“LOUDSPEAKER UNIT WITH MULTIPLE DRIVE UNITS”), WO 2019 / 086357 A1 (“LOW PROFILE LOUDSPEAKER DEVICE”), WO 2022 / 029005 A1 (“SPEAKER UNIT”) and WO 2022 / 096560 A1 (“SPEAKER UNIT WITH A SPEAKER FRAME AND TWO OPPOSING SOUND PRODUCING MEMBRANES”), each of which is incorporated by reference for all purposes. The loudspeaker systems described therein use audio drivers that include a distributed plurality of motors to drive the diaphragm, with the plurality of motors distributed away from a center of the diaphragm.For this reason, the voice coils can be thicker and wound more densely than in a conventional audio driver, allowing for a flatter and generally smaller form factor. Since the available surface area (relative to the amount of heat generated) is reduced, heat dissipation becomes important.

[0008] A voice coil's response to an input signal is temperature-dependent, a phenomenon known as power compression. It is therefore beneficial to maintain a voice coil's temperature within a range where it exhibits expected behavior. In the worst-case scenario, an audio driver can fail completely due to an overheated voice coil. This can occur with voice coils made of copper, copper-clad aluminum (CCAW), or aluminum at temperatures above 200°C. Wire insulation can also melt above 150°C, so it may be necessary to specify wire with a higher wire rating or a larger diameter (gauge). Heating can also cause the magnet to become partially demagnetized, thus altering the interaction between the voice coil and the magnet.Controlling the temperature of the voice coils in an audio driver can therefore ensure consistent sound quality from a loudspeaker and increase the driver's lifespan. The embodiments described herein relate to systems and methods for dissipating heat generated by audio drivers.

[0009] The thermally dependent frequency response of voice coils can also lead to a degradation in the performance of an audio driver if the driver incorporates more than one motor. During operation, one motor may become hotter than another, possibly due to the relative positions of the motors within a speaker enclosure. For example, a motor positioned above another motor may become hotter during operation due to warm air rising within the speaker enclosure. Because the motors operate at different temperatures, they will have different frequency responses and thus drive the diaphragm differently. This can affect the sound produced by the diaphragm.It can therefore also be useful to ensure that, if a loudspeaker diaphragm has at least two voice coils or motors, all of the at least two voice coils or motors are arranged to operate at substantially the same temperature.

[0010] Accordingly, in a first example, an audio driver is provided comprising: (i) a diaphragm, (ii) first and second motors configured to drive the diaphragm, and (iii) a thermally conductive component thermally coupling the first and second motors.

[0011] The thermally conductive component allows heat to be distributed between the first and second motors. In other words, the heat between the first and second motors can be shared or averaged. This helps keep the two motors at essentially the same temperature, ensuring that the frequency response of each motor is essentially identical. Averaging the heat between the motors therefore reduces the difference in their frequency responses while simultaneously cooling the hotter motor. The result is improved sound quality and the longevity of the audio driver.

[0012] “Thermally conductive”, as used herein, may be understood to refer to a material with a thermal conductivity of more than 0.1 W / mK, which includes most plastics, more than 0.5 W / mK, which excludes most plastics, or more than 10 W / mK, which mainly includes metals.

[0013] In some examples, the thermally conductive component can include a support, such as a converter frame, on which the first and second motors are mounted. The heat generated by each motor can be transferred to the support, primarily by conduction. In this way, the heat can be distributed between the motors so that they operate at essentially the same temperature. Furthermore, this is a modification of an existing component, so no additional component is required.

[0014] More precisely, the first and second motors can each encompass a magnetic post, and the respective voice coil can be positioned to move along that magnetic post. The thermally conductive component can then comprise a thermally conductive frame on which the magnetic posts are mounted. This thermally couples the magnetic posts, thus essentially equalizing their temperatures and also indirectly helping to equalize the temperature of the voice coils.

[0015] Heat generated by the voice coils is transferred to the magnet posts via a combination of conduction, convection, and radiation. Heat from the magnet posts is then transferred to the thermally conductive frame on which they are mounted, primarily by conduction. The thermally conductive frame can be positioned to dissipate heat externally from a loudspeaker enclosure containing the audio driver. This can be achieved by how the thermally conductive frame is positioned relative to the loudspeaker enclosure (e.g., positioned on or forming an external surface that is not covered when the loudspeaker is operating). It can also be achieved by thermally coupling the transducer frame to one or more heat-dissipating elements, such as heat sinks.The coupling between the heat-dissipating elements and the transducer frame can be achieved using an adhesive with good thermal conductivity that does not melt at operating temperatures. Such an adhesive can include thermally conductive particles. The thermal conductivity of the adhesive can be at least 0.1 W / mK, at least 1 W / mK, at least 3 W / mK, or at least 5 W / mK. Suitable adhesives include epoxy resin (one- or two-component), silicone resin, and polyimide resin.

[0016] In some examples, the thermally conductive component may include a suspension that couples the diaphragm to the first and second motors. This also allows for thermal coupling between the motors and the diaphragm, so that heat generated by the motors can be at least partially transferred to the diaphragm (and away from the motors).

[0017] The diaphragm itself can be made of a thermally conductive material, allowing heat generated by the motors to be dissipated through it. At least one surface of the diaphragm can be an external surface, providing an additional pathway for heat dissipation. Heat generated by the voice coils is transferred to the diaphragm via the suspension and can then be dissipated through the diaphragm.

[0018] In some examples, the thermally conductive component may include or be coupled to a heat sink, which is arranged to dissipate heat from the motors. The temperature of the motors can therefore be reduced while simultaneously distributing heat between them so that they generally maintain the same temperature. The heat sink may be part of the thermally conductive component, for example, formed integrally with it, or it may be coupled directly or indirectly, for example, via another component or an air gap. An exemplary configuration is the thermally conductive suspension and membrane described above.

[0019] According to a second example, an audio driver is provided comprising: (i) a diaphragm; (ii) a motor configured to drive the diaphragm, the motor comprising a voice coil; and (iii) a heat sink thermally coupled to the voice coil and covering at least part of the voice coil.

[0020] This allows heat to be dissipated more efficiently from the voice coil to the surrounding air. The heat sink may have fins or protrusions that extend outwards from the voice coil.

[0021] In some examples, the heat sink is attached to the voice coil. This provides more efficient heat dissipation than an air gap, but increases the effective mass of the voice coil. In other examples, the heat sink may be separated from the voice coil by an air gap. This can be easier to retrofit than a heat sink that touches the voice coil, since the effective mass of the voice coil remains unchanged, although this arrangement is less efficient for heat dissipation. Heat dissipation can be improved in this case by reducing the size of the air gap; for example, the air gap at its widest point can be less than 1 mm, less than 0.5 mm, or less than 0.25 mm.

[0022] The motor can be positioned away from the center of the diaphragm, and the heat sink can be arranged to dissipate heat from the voice coil in a direction away from the center of the diaphragm. Audio drivers with motors positioned away from the center of the diaphragm are discussed in WO 2018 / 056814 A1, WO 2019 / 086357 A1, WO 2022 / 029005 A1, and WO 2022 / 096560 A1, which were previously incorporated herein by reference. In this arrangement, the heat sink may be more effective due to its position towards the edge of the audio driver.

[0023] Dissipating heat in a direction away from the center of the driver can reduce heat transfer to other components of the audio driver. For example, at least some of the heatsink fins can be oriented away from the center of the diaphragm. In some examples, the heatsink dissipates heat externally from the driver housing, for instance, by having fins that extend into an outer volume.

[0024] In some examples, the heat sink may partially extend around the circumference of the voice coil. This can allow for a more compact heat sink design. It can also reduce eddy currents within the heat sink. Eddy currents draw energy from the motor, which can affect the motor's frequency response and therefore lead to a reduction in sound quality. The heat sink may extend less than approximately 270°, less than approximately 225°, less than approximately 180°, or less than approximately 135° around the circumference of the voice coil.

[0025] The audio driver with a heatsink, as in the second example, can be combined with the audio driver with a thermally conductive element, as in the first example. Such a combination can exhibit improved heat dissipation while generally helping to balance the temperature of the motors.

[0026] An audio driver, as discussed above for the first and second examples, can form part of a loudspeaker. In a third example, a loudspeaker assembly is provided, comprising: an enclosure defining an internal volume; a duct coupling the internal volume to an external part of the enclosure; a first audio driver with a first diaphragm coupled to the internal volume; and a second audio driver with a second diaphragm coupled to the internal volume. The second audio driver is configured to vibrate in the opposite direction to the first audio driver, with the second diaphragm spaced apart from the first audio driver. At least one section of an internal opening of the duct is positioned between the first diaphragm and the second diaphragm.

[0027] The port couples the internal volume of the enclosure to the outside, allowing air to escape from inside the enclosure. The movement / vibration of the second diaphragm, in opposition to the first diaphragm, creates a compression and decompression motion, acting like a bellows. For example, the compression motion of the diaphragms pushes air out of the internal volume, and the decompression motion draws air in from the outside. The positioning of the port opening allows for effective air movement from the speaker's internal volume due to the bellows-like action of the diaphragms.

[0028] Additionally, at least one voice coil in the first and / or second audio driver can be arranged so that the airflow generated by the bellows action cools the voice coil. For example, the airflow can serve to remove warm air from the loudspeaker's internal volume or to introduce air at a cooler temperature (such as ambient or room temperature) into the internal volume.

[0029] An outer opening of the channel to the outside of the enclosure can have an axis approximately perpendicular to the first direction, which is the direction in / along which the first audio driver oscillates. This arrangement of the channel allows for efficient air movement via the bellows effect.

[0030] In some examples, an external opening of the channel can occupy at least half the area of ​​one side of the enclosure. Such a relatively large channel allows for more efficient heat dissipation. In some examples, the channel is an opening or hole that is bounded by the enclosure.

[0031] The speaker unit of the third example can use an audio driver with a thermally conductive component (the first example) and / or an audio driver with a heat sink (the second example). Combining at least one of: (i) the thermally conductive component of the first example and (ii) the heat sink of the second example with the channel of the third example can further improve heat dissipation and / or temperature equalization between motors.

[0032] In a fourth example, the following is provided: (i) a housing defining an internal volume and bounding a channel, wherein the channel couples the internal volume to an external surface of the housing, (ii) a first audio driver with a first diaphragm coupled to the internal volume and configured to vibrate in a first direction, and (iii) a second audio driver with a second diaphragm coupled to the internal volume and configured to vibrate in the first direction opposite to the first audio driver, wherein the second diaphragm is spaced from the first audio driver in the first direction, with at least one section of an internal opening of the channel positioned between the first diaphragm and the second diaphragm along the first direction.

[0033] According to a fifth example, a method for cooling a loudspeaker is provided, the method comprising: using a bellows effect of two diaphragms vibrating in opposite directions to drive an airflow into and out of an internal volume of the loudspeaker, the airflow cooling at least one voice coil of the loudspeaker. The two diaphragms may be substantially the same size and arranged one behind the other, perhaps even coaxially.

[0034] The examples described herein can provide effective heat dissipation solutions. They can also, additionally or alternatively, offer a more cost-effective alternative to installing higher thermal conductivity magnets, which are less affected by high temperatures.

[0035] While some of the examples described herein may refer to functions performed by specific actors such as "users," "listeners," and / or other entities, it should be understood that this is for explanatory purposes only. The claims should not be interpreted as requiring action by any such exemplary actor unless explicitly required by the language of the claims themselves.

[0036] In the figures, many of the details, dimensions, angles, and other features shown are merely illustrative of specific embodiments of the disclosed technology. Accordingly, other embodiments may have different details, dimensions, angles, and features without deviating from the spirit or scope of the disclosure. Furthermore, those skilled in the art will appreciate that other embodiments of the various disclosed technologies can be implemented without several of the details described below. II. Exemplary playback device(s)

[0037] Fig. Figure 1 is a functional block diagram illustrating certain aspects of an exemplary playback device 100. The playback device 100 is configured to output audio through one or more drivers 114 into a playback environment in which the playback device is located (such as a room or outdoors). A driver may in some cases be known as an audio driver, loudspeaker driver, and / or transducer. As shown, the playback device 100 comprises various components, each of which is discussed in more detail below, and the various components of the playback device 100 may be effectively coupled to one another via a system bus, a communication network, or some other interconnection mechanism.

[0038] As shown, the playback device 100 comprises at least one processor 102, which may be a clock-controlled computing component configured to process input data according to instructions stored in a memory 104. The memory 104 may be a tangible, non-volatile, computer-readable medium configured to store instructions executable by the one or more processors 102. For example, the memory 104 may be a data storage device that can be loaded with software code 106, which can be executed by the one or more processors 102 to perform certain functions.

[0039] In one example, these functions might include playback device 100 retrieving audio data from an audio source, which could be another playback device or another device, such as a user device or a remote server. In another example, the functions might include playback device 100 sending audio data, data about detected sound (e.g., corresponding to speech input), and / or other information to another device on a network via at least one network interface 120. In yet another example, the functions might include playback device 100 causing one or more other playback devices to play audio synchronously with playback device 100. For example, playback device 100 could be in a group with one or more other playback devices, with devices in the group playing audio synchronously.In yet another example, the functions might include making it easier for the playback device 100 to be grouped (such as paired or otherwise connected) with one or more other playback devices to create a multi-channel audio environment. Numerous other exemplary functions are possible, some of which are discussed below.

[0040] As just mentioned, certain functions may include the playback device 100 synchronizing the playback of audio content with one or more other playback devices. During synchronized playback, a listener may not perceive any time delay between the playback of the audio content by the synchronized playback devices.

[0041] US Patent No. 8,234,395, filed on April 4, 2004, entitled “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is hereby incorporated by reference in its entirety, provides in more detail some examples of audio playback synchronization between playback devices.

[0042] To facilitate audio playback, the playback device 100 includes audio processing components 110, which are generally configured to process audio before the playback device 100 renders the audio. In this respect, the audio processing components 110 may include one or more digital-to-analog converters (“DACs”), one or more audio preprocessing components, one or more audio enhancement components, one or more digital signal processors (“DSPs”), and so on. In some implementations, one or more of the audio processing components 110 may be a subcomponent of the processor 102. During operation, the audio processing components 110 receive analog and / or digital audio and otherwise intentionally process and / or modify the audio to produce audio signals for playback.

[0043] The generated audio signals can then be provided to one or more audio amplifiers 112 for amplification and playback by one or more drivers / converters 114, which are effectively coupled to the one or more amplifiers 112. The one or more audio amplifiers 112 can include components configured to amplify audio signals to a level sufficient to drive one or more of the drivers 114.

[0044] A driver 114 can, for example, be a subwoofer (e.g., for low frequencies), a midrange driver (e.g., for mid frequencies), or a tweeter (e.g., for high frequencies). In some cases, a driver 114 can be driven by a single corresponding audio amplifier of one or more audio amplifiers 112.

[0045] In addition to generating audio signals for playback by the playback device 100, the audio processing components 110 can be configured to process audio to be sent to one or more other playback devices for playback via the network interface 120. In exemplary scenarios, audio content to be processed and / or played back by the playback device 100 can be received from an external source, such as via an audio line input interface (e.g., an auto-detectable 3.5 mm audio line input connection) of the playback device 100 (not shown) or via the network interface 120, as described below.

[0046] As shown, the at least one network interface 120 can take the form of one or more wireless interfaces 122 and / or one or more wired interfaces 124. A wireless interface can provide network interface functions for the playback device 100 to communicate wirelessly with other devices (e.g., other playback device(s) and / or control / user device(s)) in accordance with a communication protocol (e.g., any wireless standard including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, the 4G mobile communication standard, and so on). A wired interface can provide network interface functions for the playback device 100 to communicate with other devices via a wired connection in accordance with a communication protocol (e.g., IEEE 802.3). While the in Fig. While the network interface 120 shown includes both wired and wireless interfaces, the playback device 100 may in some implementations include only wireless interface(s) or only wired interface(s).

[0047] In general, the network interface 120 facilitates data flow between the playback device 100 and one or more other devices in a data network. For example, the playback device 100 can be configured to receive audio content over the data network from one or more other playback devices, network devices within a LAN, and / or audio content sources over a WAN, such as the Internet. In one example, the audio content and other signals sent and received by the playback device 100 can be transmitted in the form of digital packet data, including an Internet Protocol (IP)-based source address and IP-based destination addresses.In such a case, the network interface 120 can be configured to parse the digital packet data so that the data intended for the playback device 100 is properly received and processed by the playback device 100.

[0048] As in Fig. As shown in Figure 1, the playback device 100 also includes speech processing components 116, which are effectively coupled to one or more microphones 118. The microphones 118 are configured to detect sound (i.e., acoustic waves) in the vicinity of the playback device 100, which is then provided to the speech processing components 116. More precisely, each microphone 118 is configured to detect sound and convert the sound into a digital or analog signal that is representative of the detected sound, which can then cause the speech processing component 116 to perform various functions based on the detected sound. For example, the playback device 100 can receive and then play back specific audio content based on a voice input from a user.In another example, the playback device can reconfigure itself based on voice input from a user. In one implementation, the microphones are arranged as an array of microphones (e.g., an array of six microphones). In some implementations, the playback device includes more than six microphones (e.g., eight microphones or twelve microphones) or fewer than six microphones (e.g., four microphones, two microphones, or a single microphone).

[0049] In operation, the speech processing components 116 are generally configured to capture and process sound received via the microphones 118, to identify potential speech inputs in the captured sound, and to extract data on the detected sound to enable a voice assistant service (VAS) to process speech inputs identified in the data on the detected sound. The speech processing components 116 may include one or more analog-to-digital converters, an acoustic echo cancellation (“AEC”), a spatial processor (e.g., one or more multi-channel Wiener filters, one or more other filters, and / or one or more beamforming components), one or more buffers (e.g., one or more ring buffers), one or more wake-word engines, one or more speech extractors, and / or one or more speech processing components (e.g.,Components configured to recognize the voice of a specific user or a specific set of users assigned to a household include, among other exemplary speech processing components. In some implementations, one or more of the speech processing components 116 may be a subcomponent of the processor 102.

[0050] What's next in Fig. As shown in Figure 1, the playback device 100 also includes power components 126. The power components 126 include at least one interface 128 for an external power source, which may be connected to a power source (not shown) via a power cable or the like, physically connecting the playback device 100 to a wall outlet or other external power source. Other power components may include, for example, transformers, converters, and similar components configured to format electrical energy.

[0051] In some implementations, the power components 126 of the playback device 100 may additionally include an internal power source 130 (e.g., one or more batteries) configured to power the playback device 100 without a physical connection to an external power source. When equipped with the internal power source 130, the playback device 100 can operate independently of an external power source. In some such implementations, the interface 128 for the external power source may be configured to facilitate charging the internal power source 130. A playback device that includes an internal power source may herein be referred to as a "portable playback device".

[0052] The playback device 100 further comprises a user interface 108, which can facilitate user interactions independently of or in conjunction with user interactions facilitated by one or more control / user devices. An exemplary control device may be, for example, a mobile phone, a PC, a tablet computer, etc. An application may be installed on control devices that is configured to control one or more playback devices in a playback system. In various embodiments, the user interface 108 comprises one or more physical buttons and / or supports graphical interfaces provided on touch-sensitive screen(s) and / or surface(s), among other means for a user to provide input directly. The user interface 108 may further include one or more lights (e.g., indicator lights).The playback device 100 includes LEDs and speakers to provide visual and / or audible feedback to the user. The user can control various operations of the playback device 100 via the user interface 108 and / or a control device, such as instructing and controlling the playback of audio content and / or configuring the playback device 100.

[0053] For illustrative purposes, SONOS, Inc. currently offers (or has offered) for sale certain playback devices that can implement certain embodiments disclosed herein, including "PLAY:1", "PLAY:3", "PLAY:5", "PLAYBAR", "CONNECT:AMP", "PLAYBASE", "BEAM", "CONNECT", and "SUB". Any other past, present, and / or future playback device may additionally or alternatively be used to implement the playback devices of the exemplary embodiments disclosed herein. Additionally, it should be understood that a playback device is not limited to the one described in Fig. 1. The example shown is not limited to the Sonos product offerings. For example, a playback device may include or otherwise take the form of a wired or wireless headphone set that can operate as part of a playback system via a network interface or the like. In another example, a playback device may include or interact with a docking station for personal mobile media playback devices. In yet another example, a playback device may be an integral part of another device or component, such as a television, a lamp, or other indoor or outdoor equipment.

[0054] It is estimated that one or more in Fig. The components shown in Figure 1 are optional and can be omitted from a playback device. In its simplest form, a playback device 100 comprises one or more processors 102, memory 104 that stores instructions, and one or more drivers 114. III. Heat dissipation in loudspeaker systems

[0055] As described above, heat is generated by the voice coils of an audio driver due to resistance heating when current is passed through them. Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. Figure 6 illustrates various audio driver and speaker configurations to provide heat dissipation from voice coils. a. Heat equalization

[0056] In some implementations, a thermally conductive component thermally couples the first and second motors to reduce a temperature gradient between the motors. Fig. Figure 2 shows part of a transducer or loudspeaker, 200, which includes a thermally conductive suspension that thermally couples two motors. In some examples, the loudspeaker 200 is at least partially housed in and / or on a playback device, such as the one shown in Fig. 1 shown playback device 100.

[0057] In the example of Fig. The loudspeaker 200 comprises a frame 202 with a membrane 204 or diaphragm mounted therein. The membrane 204 is elastically attached to the frame 202 and / or flexibly connected to it. The loudspeaker 200 also comprises a first motor 206 and a second motor 208. The first motor 206 comprises a first magnetic component 210, also referred to as a magnet stack or simply magnet, and a first voice coil 212. The second motor 208 comprises a second magnetic component 214 and a second voice coil 216. The first and second magnetic components 210, 214 can be permanent magnets.

[0058] The loudspeaker further comprises a suspension system 218. The suspension system 218 includes first and second suspension elements 220, which couple the first voice coil 212 and the second voice coil 216, respectively, to the frame 202. The suspension elements 220 can be referred to as a spider or loudspeaker damper. The suspension system 218 further comprises a connecting component 222, which connects the first and second suspension elements 220. The connecting component 222 also connects the first and second suspension elements 220 to the diaphragm 204. In operation, a signal is supplied to the first and second voice coils 212 and 216, causing them to move along their respective central axes. The suspension system 218 moves accordingly with the voice coils 212, 216. By transferring the movement of the voice coils 212, 216 to the diaphragm 204, audio can be reproduced through the loudspeaker 200.

[0059] The suspension system 218 in Fig. 2, and in particular the connecting component 222, is thermally conductive. “Thermally conductive,” as used herein, describes the ability of a material to transfer heat from one section of the material to another by conduction. Quantitatively, a thermally conductive material can be one that has a thermal conductivity greater than 0.1 W / mK, which includes most plastics; greater than 0.5 W / mK, which excludes most plastics; or greater than 10 W / mK, which mainly includes metals. Fig. 2 the connecting component 222 is made of metal, such as aluminium, and the suspension elements 220 are made of plastic.

[0060] As from Fig. As can be seen in Figure 2, the suspension elements 220 are located in the immediate vicinity of the first and second voice coils 212, 216. In practice, the suspension elements 220 can be in contact with the voice coils 212, 216. In any case, the suspension elements 220 are thermally coupled to the voice coils 212, 216, so that heat generated by the voice coils 212, 216 during operation is transferred to the suspension elements 220. Primarily by thermal conduction, heat is then transferred from the suspension elements 220 to the connecting component 222.

[0061] Not only is heat transferred away from the voice coils 212 and 216, but the thermally conductive suspension system 218 also allows heat to be transferred from one of the motors to the other. This has the effect of averaging or balancing the heat distribution between the motors 206 and 208, so that during operation the voice coils 212 and 216 have a similar or substantially the same temperature. The frequency response of each of the voice coils will therefore be substantially the same, which means that the effect of the voice coils 212 and 216 on the diaphragm 204 for a given input signal will be substantially the same, and the diaphragm will be driven more evenly.

[0062] The frame 202 further includes recesses 224 that allow the addition of two additional motors. These two additional motors can be similar to the motors 206 and 208 described above and can be coupled to another diaphragm positioned above the diaphragm 204 by another suspension system similar to the suspension system 218 described above. As discussed in more detail below, the arrangement of the motors 206 and 208 allows two diaphragms to be positioned essentially coaxially and to oscillate in opposite directions during operation. These opposing oscillations act in such a way as to compress and decompress the air between the opposing diaphragms. A channel confined within an enclosure containing the audio drivers can allow warm air to be expelled from the enclosure as the diaphragms move toward each other and cooler air to be drawn in as the diaphragms move away from each other.This bellows effect is described in more detail below, but it is understandable that in combination with the thermally conductive suspension system 218, heat can be dissipated from the voice coils and transferred externally out of the housing.

[0063] Fig. Figure 3 illustrates part of a loudspeaker system 300, with one enclosure removed to reveal the internal construction. The loudspeaker 300 comprises four motors, each containing magnetic components 302a-d and voice coils 304a-d.

[0064] The loudspeaker 300 further comprises a frame 306, also referred to as a transducer frame, which is connected to the magnetic components 302a-d and defines an opening 308 in which a diaphragm can be positioned during operation. The majority of the motors comprise two pairs of motors, each configured to drive a respective diaphragm. In this way, the diaphragms of the loudspeaker 300 can operate according to a bellows action to generate sound, as briefly described above.

[0065] The frame 306 provides a support on which the magnetic components 302a-d are mounted. A suspension system 305 can be implemented to couple the voice coils 304a-d to the frame 306 and to the diaphragms. Such a suspension system can be similar to the one described in relation to Fig. The suspension system 218 described in section 2 should be made of a thermally conductive material to distribute generated heat between each pair of voice coils. The diaphragm can also be made of a thermally conductive material, such as a metal or metal alloy, to provide more effective heat dissipation from the interior of the loudspeaker 300 to the environment.

[0066] The frame 306 itself can be made of a thermally conductive material. This allows heat generated by the voice coils 304a-d to be transferred to the magnetic components 302a-d and then from the magnetic components 302a-d to the frame 306. Since the frame 306 is in contact with each of the magnetic components 302a-d, it thermally couples each magnetic component 302a-d to one another, which allows heat to be distributed evenly between the magnetic components 302a-d and therefore between the voice coils 304a-d. This can cause the voice coils 304a-d to operate at similar or substantially the same temperatures, resulting in substantially the same frequency responses and therefore improved sound quality.

[0067] The loudspeaker 300 further comprises a thermally conductive component 310, also referred to as a heat-dissipating component. The thermally conductive component 310 is thermally coupled to the frame 306. In the loudspeaker 300, thermal coupling is achieved by physically attaching the thermally conductive component 310 to the frame 306, possibly using a thermally conductive adhesive. In other examples, however, thermal coupling can be achieved by integrally forming the thermally conductive component 310 with the frame 306 or by physically coupling the thermally conductive component 310 directly or indirectly to the frame 306, such as via another component or an air gap.

[0068] The thermally conductive component 310 can form an outer surface of a loudspeaker system in which the loudspeaker 300 is implemented, or it can furthermore be coupled to an outer surface of such a loudspeaker system so that heat generated by the motors can be dissipated externally from the loudspeaker 300. In this example, the heat is not only distributed approximately uniformly between the voice coils 304a-d, but heat is also dissipated externally, which reduces the overall temperature of the voice coils 304a-d. This can allow the voice coils 304a-d to be wound more densely around the magnetic components 302a-d without significantly affecting the frequency response of the voice coils 304a-d, resulting in a loudspeaker with a smaller form factor. b. Heat dissipation via heat sinks

[0069] In some embodiments, a heat sink can be thermally coupled to at least one of the voice coils of an audio driver and at least partially cover the at least one voice coil. This allows for more direct heat dissipation from the voice coils, which are typically the primary source of heat generation in an audio driver.

[0070] Fig. Figure 4 shows a 3D top view of a motor 400 comprising a magnetic component 402 (e.g., a permanent magnet) and a voice coil 404 arranged to move longitudinally along the length of the (cylindrical) magnetic component 402 during operation. A heat sink 406, comprising a plurality of fins, is attached to or in contact with the voice coil 404. Due to its close-fitting design around the voice coil 404, the heat sink 406 can also be referred to as a sleeve.

[0071] This arrangement of the heat sink 406 provides effective heat dissipation from the voice coil 404, as heat transfer is achieved by conduction. As shown, the heat sink 406 extends partially around the circumference of the voice coil 404. This not only allows for a compact design for the heat sink 406, but can also reduce eddy currents within the heat sink 406, which can draw energy from the motor, affect its frequency response, and reduce sound quality.

[0072] The heat sink 406, which partially extends around the circumference of the voice coil 404, further enables directed heat dissipation; in other words, heat is dissipated in a direction corresponding to the positioning of the heat sink 406 on the voice coil 404. When implemented in a loudspeaker, such as the one described above, Fig. 2 and Fig. In the case of the 3 discussed loudspeakers 200, 300, the motor 400 can be arranged so that heat is dissipated in one direction away from the center of a diaphragm, which is typically the center of a loudspeaker system.

[0073] The heat sink 406 can be integrated into a structure that couples the diaphragm and / or fins to the voice coil 404. In this way, the heat sink 406 can be provided as a separate component from the voice coil 404, rather than as an integral part. In other examples, the heat sink 406 can be rigidly attached to the voice coil 404.

[0074] Coupling the heat sink 406 to the voice coil 404 can be difficult because the outer surface of a voice coil 404 may not be sufficiently uniform for consistent attachment between the heat sink 406 and the voice coil 404. To overcome such challenges, the voice coil 404 can use wire profiles that provide a flatter outer surface for the heat sink 406, or a profile of the heat sink 406 can be adapted to the profile of the voice coil 404 to improve the attachment.

[0075] Another challenge for the arrangement of the heat sink 406 is that the attached heat sink 406 adds mass to the voice coil-heat sink system, which alters the effective response of the voice coil 404 to a given input signal. Other parts of the loudspeaker design may need to be modified to compensate for the effect of the increased effective mass of the voice coil 404 so that the loudspeaker exhibits the expected behavior within its operating limits and therefore produces sound as intended. This could be achieved, for example, by reducing the size or diameter of the voice coil wire to decrease the overall weight, or by adjusting the magnetization of the magnetic component, among other modifications known to those skilled in the art.

[0076] In another example, a heat sink can be thermally coupled to a voice coil in such a way that the heat sink is separated from the voice coil by an air gap. Such an example is in Fig. 5 shown, which is a similar 3D top view of an engine 500 as Fig. Figure 4 shows. The motor 500 comprises a magnetic component 502 and a voice coil 504 surrounding it. The motor 500 further comprises a heat sink 506, which is separated from the voice coil 504 by an air gap, so that heat transfer from the voice coil to the heat sink occurs via conduction through the air gap, radiation, and convection, instead of primarily by conduction at a contact point between the voice coil and the heat sink as in the Fig. 4 shown engine 400.

[0077] The arrangement of the heat sink 506, which is in Fig. As shown in Figure 5, this avoids the mounting difficulties and the increased effective mass of the voice coil that are present in the arrangement of the heat sink 406, which is shown in Fig. However, as shown in Figure 4, it may be less efficient for heat dissipation and may require some additional space around the motor within a speaker enclosure due to the slightly larger design of the 506 heat sink compared to the 406 heat sink.

[0078] The efficiency of heat dissipation can be increased by reducing the size of the air gap between the voice coil 504 and the heat sink 506. For example, the air gap can be less than 1 mm, less than 0.5 mm, or less than 0.25 mm wide at its widest point.

[0079] Again, when implemented as part of a loudspeaker, the Motor 500 can be positioned so that the fins are generally directed away from (or at least not towards) a central axis of the diaphragm, so that heat is dissipated away from the center of the audio driver and towards the outside of the loudspeaker.

[0080] While heat sinks 406 and 506 are shown to extend approximately 180 degrees around the circumference of the voice coil, it is understandable that such a heat sink could extend to a greater or lesser extent around the circumference of the voice coil. For example, the heat sink may extend less than approximately 270 degrees, less than approximately 225 degrees, less than approximately 180 degrees, or less than approximately 135 degrees around the circumference of the voice coil. In some examples, the heat sink may completely surround the voice coil.

[0081] Heat sinks coupled to the voice coils, as described above, can be implemented in any of the audio drivers discussed herein. For example, such heat sinks can be implemented in an audio driver that includes a thermally conductive component arranged to distribute heat evenly between two or more motors, as described above. The combined action of the heat sinks and the thermally conductive component can provide more effective heat dissipation from the voice coils while maintaining the voice coils at essentially the same temperature. c. Loudspeaker enclosure with channels

[0082] Further possibilities for heat dissipation arise when an audio driver comprising opposing diaphragms is implemented in a loudspeaker.

[0083] As previously mentioned, loudspeakers with two diaphragms moving in opposite directions are described in WO 2018 / 056814 A1, WO 2019 / 086357 A1, WO 2022 / 029005 A1, and WO 2022 / 096560 A1, which were previously incorporated herein by reference. The movement / vibration of a second diaphragm opposite a first diaphragm results in a compression and decompression motion that compresses air within a volume enclosed between the opposing diaphragms as they move towards each other, and decompresses air in that enclosed volume as the opposing diaphragms move away from each other. This can be used to provide a bellows effect, which can aid cooling.

[0084] In some embodiments, the enclosure defines a channel, opening, hole, passage, or vent that couples the enclosure's internal volume to an exterior (such as the environment surrounding the loudspeaker). At least one section of an internal opening of the channel may be positioned between the first and second diaphragms. The internal opening of the channel may have an axis that is generally perpendicular to a direction of vibration of the diaphragms. In this way, the diaphragms and the channel act similarly to a bellows, with the compression movement of the diaphragms forcing (hot) air out of the internal volume and the decompression movement of the diaphragms drawing in (cold) air from the outside.

[0085] This can provide an effective way to remove heat from the speaker's internal volume, generated by the action of the voice coils producing audio. The orientation of the port opening allows for effective air movement from the speaker's internal volume due to the bellows-like action of the diaphragm.

[0086] Adding the channel to the enclosure will affect the acoustic properties of the loudspeaker, and other parts and / or dimensions of the loudspeaker may need to be adjusted to compensate for this.

[0087] Fig. Figure 6 shows a perspective cutaway view of part of another exemplary loudspeaker 600. The loudspeaker 600 comprises a housing 602, which defines an internal volume. The loudspeaker further comprises a first motor 606 and a second motor 608, which are configured to drive respective diaphragms, causing them to vibrate in a first direction 610. The housing 602 delimits three channels 604 along an outer surface of the housing 602 that is perpendicular to the direction of vibration of the diaphragms. The geometry of the motors and diaphragms allows the channels to occupy most of the area of ​​the housing 602 that delimits the channels 604. Such large channels 604 enable more efficient heat dissipation from the internal volume of the housing 602. The in Fig. The 6 channels shown (604) are relatively short, and it is understandable that longer channels are also possible.

[0088] The outer opening of the channels 604 can form an opening in the loudspeaker unit in which the loudspeaker 600 is implemented, so that one side of the loudspeaker unit is essentially open. In another example, the outer opening of the channels 604 can be positioned against an outer surface of the loudspeaker unit, but still allow thermal coupling of the internal volume with the exterior of the loudspeaker unit.

[0089] The channels 604 can also be arranged with respect to the motors 606, 608 such that the airflow generated by the bellows action of the diaphragms cools the motors 606, 608. For example, the airflow can remove warm air from the internal volume of the loudspeaker 600 and lower the temperature of the motors 606, 608 by increasing the convection rate in the air surrounding the voice coil when cool air is drawn into the housing 602, similar to heat loss through wind chill.

[0090] In some examples, a loudspeaker may include at least one channel or passage arranged to direct air over the motors. As the diaphragms compress and decompress the air inside the loudspeaker, air is forced through the channel(s) and over the motors, providing a cooling effect.

[0091] The loudspeaker 600 further comprises a first thermally conductive component 612, here made of aluminum, which couples the first motor 606 with another motor that is positioned adjacent to the first motor 606, but in Fig. 6 is not visible. The loudspeaker 600 further comprises a second thermally conductive component 614, also made of aluminum, which couples the second motor 608 to another motor positioned adjacent to the second motor 608, also not visible in Fig. 6.

[0092] The first and second thermally conductive components 612, 614 are arranged to equalize heat between motors, so that they operate at essentially the same temperature, as described above. The thermally conductive components 612, 614 can also act as heat sinks to dissipate additional heat.

[0093] Fig. Figure 7 shows an exemplary method 700 for cooling a loudspeaker, such as the one in Fig.The loudspeaker 600 shown in Figure 6 is provided in Block 702, which provides a loudspeaker with opposing loudspeaker diaphragms. For example, the loudspeaker may include two diaphragms configured to vibrate in opposite directions to produce sound, as described above. The two diaphragms may be substantially the same size and / or back-to-back and / or coaxial. Other configurations are possible; for example, the opposing diaphragms may be offset and / or not of the same size.

[0094] Block 704 provides a channel with an opening between the opposing loudspeaker diaphragms. For example, a loudspeaker enclosure may contain one or more channels that couple the enclosure's internal volume to an external volume. In other examples, the channel may be part of a support structure for the loudspeaker diaphragms, such as a discrete component attached directly or indirectly to the support structure. The channel may also be an integral part of the support structure, formed, for example, by molding or additive manufacturing the support structure.

[0095] In Block 706, Method 700 includes the use of a bellows effect of the loudspeaker diaphragms for cooling. The bellows effect can be generated by the two diaphragms vibrating in opposite directions to drive an airflow into and out of an internal volume of the loudspeaker via the duct(s). This can serve to expel warmer air from the internal volume, providing a cooling effect. In some examples, the duct can be configured to direct the airflow over the voice coils, providing additional cooling of these components. IV. Conclusion

[0096] The present disclosure discussed various examples by which the thermal performance of a loudspeaker can be improved. The person skilled in the art understands that, while the examples discussed above may consider a single type of improvement in thermal performance, these can be combined in other examples.

[0097] For example, combining a channel within a loudspeaker enclosure with a thermally conductive component positioned to equalize heat between two or more motors, and / or heat sinks coupled to the voice coils, can provide particularly effective heat dissipation. For instance, heat from the voice coils can be dissipated via heat sinks into the air within the enclosure's internal volume and more efficiently evacuated by a bellows-like movement of the opposing diaphragm. Similarly, the thermally conductive component can serve to dissipate some heat from the motors while also maintaining them at essentially the same temperature. Some of this heat can be dissipated externally through a thermally conductive diaphragm and / or a thermally conductive substrate on which the motors are mounted.

[0098] Patent applications WO 2018 / 056814 A1, WO 2019 / 086357 A1, WO 2022 / 029005 A1 and WO 2022 / 096560 A1 describe examples of loudspeaker units with which the heat-dissipating means described herein can be used. Other types of loudspeakers can also be used with the techniques described herein.

[0099] The above description discloses, among other things, various exemplary systems, processes, devices, and manufactured articles, which include, but are not limited to, firmware and / or software running on hardware. It is understood that such examples are merely illustrative and should not be considered limiting. For instance, it is conceivable that any or all firmware, hardware, and / or software aspects or components could be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and / or firmware. Accordingly, the examples provided are not the only way(s) to implement such systems, processes, devices, and / or manufactured articles.

[0100] Additionally, references herein to "embodiment" mean that a particular feature, structure, or property described in connection with the embodiment may be included in at least one exemplary embodiment of an invention. The appearance of this term in various places within the description does not necessarily all refer to the same embodiment, nor do separate or alternative embodiments exclude one another from other embodiments. As such, the embodiments described herein, as understood explicitly and implicitly by a person skilled in the art, may be combined with other embodiments.

[0101] The description is largely presented in the form of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing equipment coupled to networks. These process descriptions and representations are typically used by those skilled in the field to most effectively communicate the content of their work to other skilled workers. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understandable to those skilled in the art that certain embodiments of the present disclosure may be practiced without certain specific details. In other cases, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.Accordingly, the scope of the present disclosure is defined by the attached claims and not by the preceding description of embodiments.

[0102] If any of the attached claims is read as covering a pure software and / or firmware implementation, at least one of the elements in at least one example is hereby expressly defined as comprising a tangible, non-volatile medium such as a memory device, DVD, CD, Blu-ray, etc., which stores the software and / or firmware. 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] US 63 / 504,998

[0001] WO 2018 / 056814 A1 [0007, 0022, 0083, 0098] WO 2019 / 086357 A1 [0007, 0022, 0083, 0098] WO 2022 / 029005 A1 [0007, 0022, 0083, 0098] WO 2022 / 096560 A1 [0007, 0022, 0083, 0098] US 8,234,395

[0041] Cited non-patent literature

[0000] SONOS, Inc. began developing a new type of playback system in 2002. Sonos then filed one of its first patent applications in 2003, entitled "Method for Synchronizing Audio Playback between Multiple Networked Devices," and began in 2005

[0003]

Claims

[1] Audio drivers, including: a membrane; first and second motors designed to drive the diaphragm; and a thermally conductive component that thermally couples the first and second motors. [2] Audio driver according to claim 1, wherein the thermally conductive component comprises or is coupled to a heat sink arranged to dissipate heat from the motors. [3] Audio driver according to claim 1 or claim 2, wherein: The thermally conductive component includes a carrier on which the first and second motors are mounted. [4] Audio driver according to any one of the preceding claims, wherein: The thermally conductive component includes a suspension that couples the diaphragm to the first and second motors. [5] Audio driver according to claim 4, wherein the membrane comprises a thermally conductive material. [6] Audio drivers, comprehensive: a membrane; a motor configured to drive the diaphragm, the motor comprising a voice coil; and a heat sink that is thermally coupled to the voice coil and at least partially covers the voice coil. [7] Audio driver according to claim 6, wherein the heat sink is attached to the voice coil. [8] Audio driver according to claim 6, wherein the heat sink is separated from the voice coil by an air gap. [9] Audio driver according to any one of claims 6 to 8, wherein the motor is positioned away from the center of the diaphragm and the heat sink is arranged to dissipate heat from the voice coil in a direction away from the center of the diaphragm. [10] Audio driver according to one of claims 6 to 9, wherein the heat sink extends partially around a circumference of the voice coil. [11] Audio driver according to claim 10, wherein the heat sink extends less than about 270 degrees around the circumference of the voice coil. [12] Loudspeaker comprising an audio driver according to any of the preceding claims. [13] Loudspeaker unit comprising: a housing that defines an internal volume; a channel that couples the internal volume to an outside of the housing; a first audio driver with a first diaphragm coupled to the internal volume; and a second audio driver with a second diaphragm coupled to the internal volume and configured to vibrate in the opposite direction to the first audio driver, wherein the second diaphragm is spaced apart from the first audio driver, with at least one section of an internal opening of the channel positioned between the first diaphragm and the second diaphragm. [14] Loudspeaker unit according to claim 13, wherein an outer opening of the channel to the outside of the housing has an axis which is approximately perpendicular to a first direction, wherein the first direction is a direction along which the first audio driver oscillates. [15] Loudspeaker unit according to claim 13 or claim 14, wherein an outer opening of the channel occupies at least half the area of ​​one side of the housing. [16] Loudspeaker unit according to any one of claims 13 to 15, wherein the channel is an opening bounded by the housing. [17] Method for cooling a loudspeaker, the method comprising using a bellows effect of two diaphragms vibrating in opposite directions to drive an airflow into and out of an internal volume of the loudspeaker, the airflow cooling at least one voice coil of the loudspeaker.

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