Force counteracting loudspeaker

Abstract

Aspects of the present disclosure relate to a speaker system that uses a single driver that implements both force cancellation and torque cancellation. The speaker system may be mounted within a structure such as a head mounted display. The loudspeaker system comprises a first moving mass block, the first moving mass block comprises a sound production vibrating membrane, and the first moving mass block is connected with a floating basin frame through a main suspension. And the floating basin frame is coupled with a second moving mass block for controlling the voice coil, so that the voice coil is caused to move through the vibrating membrane to generate sound. The auxiliary suspension can couple the suspension basin frame with the fixed frame. The auxiliary suspension can reduce the situation that shaking and pollution generated by the magnetic core / motor assembly permeate into the fixed frame and then permeate into other connecting parts.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 63 / 447,210, entitled “FORCE CANCELING SPEAKER,” filed on February 21, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to speakers / loudspeakers, or devices that produce sound. Background Art

[0004] When a speaker is mounted on a wearable device such as an artificial reality (extra-reality (XR)) device (e.g., a virtual reality (VR) headset, a mixed reality (MR) headset, or augmented reality (AR) glasses), it may cause vibrations to the entire device, resulting in unwanted shake and signal contamination. For example, an XR device may include an inertial measurement unit (IMU) that is used to track the wearer's body and head movements during XR use, and contamination of the IMU signal may lead to inaccurate measurements that are difficult to correct. Audio leakage from wearable devices may also be undesirable because the wearer may want to maintain privacy. However, known speakers, especially those built for better bass performance, often have increased shake and increased leakage, which are not suitable for many wearable device applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a block diagram illustrating an overview of a number of devices on which some embodiments of the present technology may operate.

[0006] Figure 2A is a line diagram illustrating a virtual reality head-mounted view that may be used in some embodiments of the present technology.

[0007] Figure 2B is a line diagram illustrating a mixed reality head-mounted view that may be used in some embodiments of the present technology.

[0008] Figure 2C is a line diagram illustrating a number of controllers that, in some implementations, a user may hold with one or both hands to interact with an artificial reality environment.

[0009] Figure 3is a block diagram illustrating an overview of an environment in which some embodiments of the present technology may operate.

[0010] Figure 4 is a cross-sectional diagram illustrating a force-canceling speaker system for use with some embodiments of the present technology.

[0011] Figure 5 is a cross-sectional diagram illustrating a force-canceling speaker system for use with some embodiments of the present technology.

[0012] Figure 6 is a cross-sectional diagram illustrating a force-canceling speaker system for use with some embodiments of the present technology.

[0013] Figure 7 The effect of a subsuspension on the forces exerted on a loudspeaker system enclosure used with some embodiments of the present technology is graphically illustrated.

[0014] The technology described herein may be better understood by referring to the following detailed description in conjunction with the drawings, wherein like reference numbers indicate identical or functionally similar elements. DETAILED DESCRIPTION

[0015] Aspects of the present disclosure relate to a speaker system that uses a single driver that achieves both force cancellation and moment cancellation. The speaker system can be mounted within a structure such as a head-mounted display. The speaker system includes a first moving mass, a floating basket or "suspension" basket coupled to a second moving mass, and one or more waveguides. The first moving mass can include a diaphragm, a voice coil, and a diaphragm surround. A non-rigid main suspension (i.e., the diaphragm surround) can be attached to the suspension basket. The second moving mass or driver can include steel / magnets / cores / motor.

[0016] A non-rigid secondary suspension (e.g., a decoupled leaf spring or half roll spring) can be coupled between the suspension frame and a fixed frame, which in turn can be coupled to a fixed structure (e.g., a head-mounted display or head-mounted display housing / casing). In one embodiment, the suspension frame is fixed to the second mobile mass so that they move together. In another embodiment, the second mobile mass can be coupled to the suspension frame via a suspension / spring.

[0017] The subsuspension can reduce the amount of wobble and contamination generated by the core / motor assembly from penetrating into the frame and subsequently into other components of the head-mounted display.

[0018] The first mobile mass can be positioned on top of the second mobile mass. The speaker system can be configured to significantly mitigate contamination signals caused by the speaker that would otherwise be transmitted to the structure to which the speaker system is coupled. The secondary and primary suspensions can be positioned at the same radial distance from the center of the speaker system, with the midpoints of the suspension springs aligned with each other. This allows for the cancellation of any radiation generated by the hard components, as there is only one effective radiation source, avoiding peaks and dips in the pressure frequency response due to the interaction between the two radiation sources.

[0019] The speaker system can be configured so that the natural frequency and resonant mass "Q1" of the first mobile mass and primary suspension are substantially the same as the natural frequency and resonant mass "Q2" of the second mobile mass and secondary suspension. In some embodiments, the speaker system can also include air cavities above and below the motor assembly, sized and configured to achieve both force and moment cancellation. This further significantly reduces contaminant signals generated by the speaker that would otherwise be transmitted to the frame and structure.

[0020] Embodiments of the disclosed technology may include an artificial reality system, or may be implemented in conjunction with an artificial reality system. Artificial reality or extra reality (XR) is a form of reality that has been adjusted in some way before being presented to a user. Artificial reality or XR may include, for example, virtual reality (VR), augmented reality (AR), mixed reality (MR), hybrid reality, or some combination and / or derivative thereof. Artificial reality content may include fully generated content or generated content combined with collected content (e.g., real-world photos). Artificial reality content may include video, audio, tactile feedback, or some combination thereof, any of which may be presented in a single channel or multiple channels (e.g., stereoscopic video that gives the viewer a three-dimensional effect). In addition, in some embodiments, artificial reality may be associated with applications, products, accessories, services, or some combination thereof, which are used, for example, to create content in artificial reality and / or to be used in artificial reality (e.g., to perform activities in artificial reality). Artificial reality systems that provide artificial reality content can be implemented on a variety of platforms, including a head-mounted display (HMD) connected to a host computer system, a standalone HMD, a mobile device or computing system, a "cave" environment or other projection system, or any other hardware platform capable of providing artificial reality content to one or more viewers.

[0021] As used herein, "virtual reality" or "VR" refers to an immersive experience in which a user's visual input is controlled by a computing system. "Augmented reality" or "AR" refers to systems in which a user views real-world images after they have passed through a computing system. For example, a tablet computer with a camera on its back can capture multiple images of the real world and then display these images on a screen on the side of the tablet opposite the camera. The tablet can process and adjust or "augment" these images as they pass through the system, for example by adding virtual objects. "Mixed reality" or "MR" refers to systems in which the light entering the user's eyes is partially generated by the computing system and partially composed of light reflected from objects in the real world. For example, an MR headset can be shaped like a pair of glasses with a see-through display that allows light from the real world to pass through a waveguide, which simultaneously emits light from a projector in the MR headset, allowing the MR headset to present virtual objects mixed with the real objects visible to the user. As used herein, “artificial reality,” “hyperreality,” or “XR” refers to any of the following: VR, AR, MR, or any combination or hybrid thereof.

[0022] Several embodiments are discussed in more detail below with reference to the accompanying drawings. Figure 1 is a block diagram illustrating an overview of multiple devices on which some embodiments of the disclosed technology may operate. These devices may include hardware components of a computing system 100 that generate audio by driving speakers. In various embodiments, the computing system 100 may include a single computing device 103 or multiple computing devices (e.g., computing device 101, computing device 102, and computing device 103) that communicate over a wired channel or a wireless channel to distribute processing and share input data. In some embodiments, the computing system 100 may include a standalone head-mounted viewer that is capable of providing a computer-created or enhanced experience to a user without the need for external processing or external sensors. In other embodiments, the computing system 100 may include multiple computing devices, such as a head-mounted viewer and a core processing component (e.g., a console, a mobile device, or a server system), wherein some processing operations are performed on the head-mounted viewer and other processing operations are offloaded to the core processing component. The following is combined with Figure 2A and Figure 2BAn example head-mounted view (HMD) is described. In some embodiments, location data and environmental data may be collected solely by sensors incorporated into the HMD device, while in other embodiments, one or more of a plurality of non-HMD computing devices may include sensor components that can track environmental data or location data.

[0023] Computing system 100 may include one or more processors 110 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a holographic processing unit (HPU), etc.). Processor 110 may be a single processing unit or multiple processing units, which are located in one device or distributed across multiple devices (e.g., distributed across two or more computing devices among computing devices 101 to 103).

[0024] The computing system 100 may include one or more input devices 120 that provide input to the processors 110, thereby informing the processors of actions. These actions may be transmitted by a hardware controller that interprets signals received from the input devices and transmits information to the processors 110 using a communication protocol. Each input device 120 may include, for example, a mouse, a keyboard, a touch screen, a touchpad, a wearable input device (e.g., a tactile glove, a bracelet, a ring, an earring, a necklace, a watch, etc.), a camera (or other light-based input device, such as an infrared sensor), a microphone, or other user input device.

[0025] The processor 110 can be coupled to other hardware devices, for example, by using an internal bus or an external bus or a wireless connection, such as a Peripheral Component Interconnect (PCI) bus or a Small Computer System Interface (SCSI) bus. The processor 110 can communicate with a hardware controller of a device (e.g., a display 130). The display 130 can be used to display text and graphics. In some embodiments, the display 130 includes an input device, such as when the input device is a touch screen or is equipped with an eye movement direction monitoring system, the input device is part of the display. In some embodiments, the display is separate from the input device. Examples of display devices are: a liquid crystal display (LCD) display screen, a light emitting diode (LED) display screen, a projection display, a holographic display, or an augmented reality display (e.g., a head-up display device or a head-mounted device), etc.

[0026] A speaker system and other I / O devices 140 may also be coupled to the processor, and the speaker system and other I / O devices 140 may include one or more speakers with a vibrating membrane. The speaker system may have a motor assembly and a basin, which are connected together to a fixed structure (e.g., the frame / housing of the HMD) via a suspension, thereby reducing vibrations from the motor assembly and the vibrating membrane to the fixed structure. In some embodiments, the one or more speakers may also include air cavities located above and below the motor assembly, the size and configuration of these air cavities being designed to achieve both force cancellation and moment cancellation, thereby further reducing vibrations from the motor assembly to the fixed structure.

[0027] The speaker system and other I / O devices 140 may also include other I / O devices such as a network chip or card, a video chip or card, an audio chip or card, a universal serial bus (USB), FireWire or other external devices, a camera, a printer, a compact disc read-only memory (CD-ROM) drive, a digital video disc (DVD) drive, a disk drive, etc. In some embodiments, the computing system 100 may use input from the I / O devices 140 (e.g., a camera, a depth sensor, an IMU sensor, a global positioning system (GPS) unit, a laser radar (LiDAR) or other time-of-flight sensor, etc.) to identify and map the user's physical environment and track the user's position in the environment. This simultaneous localization and mapping (SLAM) system can generate a map (e.g., a topology, a mesh, etc.) of an area (which may be a room, a building, an outdoor space, etc.) and / or obtain a map previously generated by the computing system 100 or another computing system that has mapped the area. The SLAM system can track users within the area based on factors such as GPS data, match identified objects and structures with mapped objects and structures, monitor acceleration and other position changes, and more.

[0028] The computing system 100 may include a communication device capable of communicating wirelessly or wired with other local computing devices or network nodes. The communication device may communicate with another device or server over a network, for example, using the Transmission Control Protocol / Internet Protocol (TCP / IP). The computing system 100 may utilize the communication device to distribute operations across multiple network devices.

[0029] Processor 110 can access memory 150, which can be included in one of the multiple computing devices in computing system 100, or can be distributed across multiple computing devices in computing system 100, or other external devices. Memory includes one or more hardware devices for volatile or non-volatile storage, and can include both read-only and writeable memory. For example, memory can include one or more of the following: random access memory (RAM), various cache memories, CPU registers, read-only memory (ROM), and writeable non-volatile memory, such as flash memory, hard drives, floppy disks, compact disks (CDs), DVDs, magnetic storage devices, and tape drives. Memory is not a propagating signal that is independent of the underlying hardware; therefore, memory is non-transitory. Memory 150 can include program memory 160, which stores programs and software, such as an operating system 162, audio data generation 164, and other application programs 166. The memory 150 may also include a data memory 170 which may include, for example, mappings of audio data to speaker driver properties, configuration data, settings, user options or preferences, etc., which may be provided to the program memory 160, or any element of the computing system 100.

[0030] Some embodiments may operate with many other computing system environments or configurations. Examples of computing systems, environments, and / or configurations suitable for use with the technology include, but are not limited to, XR headsets, personal computers, server computers, handheld or laptop devices, cellular phones, wearable electronic devices, game consoles, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network personal computers (PCs), minicomputers, mainframe computers, or distributed computing environments that include any of the foregoing.

[0031] Figure 2A2 is a line diagram of a virtual reality head-mounted display (HMD) 200, according to some embodiments. HMD 200 includes a front rigid body 205 and a strap 210. Front rigid body 205 includes one or more electronic display elements of an electronic display 245, an inertial motion unit (IMU) 215, one or more position sensors 220, a plurality of localizers 225, and one or more computing units 230. Position sensors 220, IMU 215, and computing unit 230 may be located internal to HMD 200 and may not be visible to the user. In various embodiments, IMU 215, position sensors 220, and localizers 225 may track the movement and position of HMD 200 in the real world and in an artificial reality environment with three degrees of freedom (3DoF) or six degrees of freedom (6DoF). For example, localizers 225 may emit infrared beams that create light spots on real objects around HMD 200. As another example, the IMU 215 may include: one or more accelerometers; one or more gyroscopes; one or more magnetometers; one or more other non-camera-based position, force, or orientation sensors; or a combination thereof. One or more cameras (not shown) integrated with the HMD 200 may detect light points. The computing unit 230 in the HMD 200 may use the detected light points to infer the position and movement of the HMD 200 and to recognize the shape and position of real objects around the HMD 200.

[0032] One or more electronic displays 245 can be integrated with the front rigid body 205 and can provide image light to the user as directed by the computing unit 230. In various embodiments, the electronic display 245 can be a single electronic display or multiple electronic displays (e.g., one display for each eye of the user). Examples of the electronic display 245 include: a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, an active-matrix organic light-emitting diode (AMOLED) display, a display including one or more quantum dot light-emitting diode (QOLED) sub-pixels, a projector unit (e.g., micro-LED, laser, etc.), some other display, or some combination thereof.

[0033] In some embodiments, the HMD 200 can be coupled to a core processing component, such as a personal computer (PC) (not shown), and / or one or more external sensors (not shown). The external sensors can monitor the HMD 200 (e.g., via light emitted from the HMD 200), which the PC can use in conjunction with outputs from the IMU 215 and the position sensor 220 to determine the position and movement of the HMD 200.

[0034] Figure 2B 2 is a line diagram of a mixed reality HMD system 250 that includes a mixed reality HMD 252 and a core processing component 254. The mixed reality HMD 252 and the core processing component 254 can communicate via a wireless connection (e.g., a 60 GHz link) as indicated by link 256. In other embodiments, the mixed reality system 250 includes only a head-mounted view device without an external computing device, or includes other wired or wireless connections between the mixed reality HMD 252 and the core processing component 254. The mixed reality HMD 252 includes a see-through display 258 and a frame 260. The frame 260 can house various electronic components (not shown), such as a light projector (e.g., a LASER, LED, etc.), a camera, an eye tracking sensor, microelectromechanical system (MEMS) components, networking components, etc.

[0035] The projector can be coupled to a perspective display 258, for example, via an optical element, to display media to the user. The optical element can include one or more waveguide assemblies, one or more reflectors, one or more lenses, one or more mirrors, one or more collimators, one or more gratings, etc., for guiding the light from the projector to the user's eyes. The image data from the core processing component 254 can be transmitted to the HMD 252 via a link 256. The controller in the HMD 252 can convert the image data into a plurality of light pulses from the projector, which can be transmitted to the user's eyes as output light via the optical element. The output light can be mixed with the light passing through the display 258, thereby allowing the output light to present following virtual objects: these virtual objects look as if they exist in the real world.

[0036] Similar to the HMD 200, the HMD system 250 may also include motion and position tracking units, cameras, light sources, etc., which allow the HMD system 250 to track itself, for example, with 3DoF or 6DoF, track multiple parts of the user (e.g., hands, feet, head, or other body parts), draw virtual objects to appear stationary when the HMD 252 moves, and make virtual objects react to gestures and other real-world objects.

[0037] Figure 2C The figure shows multiple controllers 270 (including controllers 276A and 276B) that, in some embodiments, a user can hold with one or both hands to interact with the artificial reality environment presented by HMD 200 and / or HMD 250. Controllers 270 can communicate with the HMD directly or through external devices (e.g., core processing component 254). The controllers can have their own IMU units, position sensors, and / or can emit additional light points. The HMD 200 or 250, external sensors, or sensors in the controllers can track these controller light points to determine the position and / or orientation of the controllers (e.g., tracking the controllers with 3DoF or 6DoF). The computing unit 230 or core processing component 254 in HMD 200 can combine the IMU output and the position output and use this tracking to monitor the user's hand position and movement. The controllers can also include various buttons (e.g., buttons 272A to 272F) and / or joysticks (e.g., joysticks 274A and 274B) that the user can actuate to provide input and interact with objects.

[0038] In various embodiments, the HMD 200 or 250 may also include additional subsystems for monitoring user interactions and indications of intent, such as an eye tracking unit, an audio system, various network components, and the like. For example, in some embodiments, one or more cameras included in the HMD 200 or 250, or one or more cameras from a plurality of external cameras, instead of or in addition to a controller, may monitor the position and posture of the user's hands to determine gestures and other hand and body movements. As another example, one or more light sources may illuminate one or both eyes of the user, and the HMD 200 or 250 may use eye-facing cameras to capture reflections of that light to determine eye position (e.g., based on a set of reflected light around the user's corneas) to model the user's eyes and determine gaze direction.

[0039] Figure 33 is a block diagram illustrating an overview of an environment 300 in which some embodiments of the disclosed technology may operate. The environment 300 may include one or more client computing devices 305A through 305D, examples of which may include the computing system 100. In some embodiments, some of the plurality of client computing devices (e.g., client computing device 305B) may be an HMD 200 or an HMD system 250. The client computing device 305 may operate in a network environment using a logical connection to one or more remote computers (e.g., a server computing device) via a network 330.

[0040] In some embodiments, server 310 may be an edge server that receives client requests and coordinates the fulfillment of these requests by other servers (e.g., servers 320A to 320C). Server computing devices 310 and 320 may include computing systems, such as computing system 100. Although each server computing device 310 and 320 is logically shown as a single server, the multiple server computing devices may each be a distributed computing environment that includes multiple computing devices located at the same physical location or at geographically different physical locations.

[0041] Client computing device 305, as well as server computing devices 310 and 320, can each act as a server or client for one or more other server / client devices. Server 310 can be connected to database 315. Servers 320A to 320C can each be connected to a corresponding database 325A to 325C. As discussed above, each server 310 or 320 can correspond to a group of servers, and each of these servers can share a database or have its own database. Although databases 315 and 325 are logically shown as a single unit, databases 315 and 325 can each: be a distributed computing environment including multiple computing devices; can be located within their corresponding servers; or can be located at the same physical location or at geographically different physical locations.

[0042] Network 330 may be a local area network (LAN), a wide area network (WAN), a mesh network, a hybrid network, or other wired or wireless network. Network 330 may be the Internet or some other public or private network. Client computing device 305 may be connected to network 330 via a network interface, such as via wired or wireless communication. Although the connections between server 310 and multiple servers 320 are shown as separate connections, these connections may be any type of local area network, wide area network, wired network, or wireless network, including network 330 or a separate public or private network.

[0043] As mentioned above, a speaker produces sound through the vibration of a diaphragm. For known speakers, the movement of the diaphragm causes the spring suspension to shift, which in turn causes force to be transferred to the basin frame through the spring, thereby generating undesirable structural vibration caused by the speaker module. When the speaker is mounted on a wearable device (e.g., an XR device) or a wrist-worn device (e.g., a smartwatch), it may generate vibrations in the wearable device. These vibrations are detected by the inertial measurement unit (IMU) of the wearable device. These vibrations interfere with sensitive components (e.g., MEMS mirrors), cause undesirable noise interference, etc. For example, when the IMU detects these vibrations, they may be "contamination signals" that can reduce the accuracy of motion tracking. Because the response of the gyroscope to audio band vibrations is nonlinear, time-varying, and non-quantized, these contamination signals may be difficult to eliminate through purely algorithmic processing. One known mitigation method is to use a speaker system with a dual driver module, which includes two drivers moving in opposite directions to cancel out the forces (i.e., vibrations) caused by the speaker. However, this approach requires two independent moving voice coils and diaphragms that must be matched. Disadvantages of this known approach include increased cost for having two drivers, reduced packaging efficiency due to having to accommodate two drivers, and increased weight.

[0044] In contrast to known approaches, the embodiments disclosed herein utilize a single actuator and a non-rigid suspension / spring that decouples the basin from the fixed structure, thereby suspending the basin to mitigate the transmitted forces.

[0045] Figure 4 is a cross-sectional view illustrating a force-canceling speaker system 400 for use with some embodiments of the present technology. In some embodiments, the speaker 400 is circular with a central axis (not shown). The system 400 includes a diaphragm / cone 401 (i.e., the portion of the first moving mass that includes the voice coil) coupled to the top of a suspension basket 402 via a main suspension / surround 420, which in turn may be coupled to a fixed frame 405, which may be vented, via an optional suspension 426. The fixed frame 405 is part of or coupled to an enclosure / housing 406 of a device / structure containing the speaker system (e.g., HMD 200).

[0046] In some embodiments, the diaphragm 401 is a thin, semi-rigid membrane configured to generate sound pressure waves when vibrating. The diaphragm 401 includes a front surface and a rear surface. In some embodiments, the surround 420 is a spring in the shape of a half-coil and is formed of rubber. The surround 420 suspends the diaphragm 401 and is configured to flex and allow the diaphragm 401 to move.

[0047] System 400 also includes a voice coil 404. In some embodiments, voice coil 404 comprises a metal wire tightly wound around a cylindrical structure and is configured to generate a magnetic field when an electric current (i.e., an audio drive signal) is applied. The base of voice coil 404 is coupled to the rear surface of diaphragm 401. In some embodiments, voice coil 404 is coupled to the end of diaphragm 401 at a relatively close distance from surround 420.

[0048] The voice coil 404 is located within the magnetic air gap 470 of the motor assembly 410. During speaker operation, current is applied to the voice coil, which generates a magnetic field. The magnetic field generated by the voice coil interacts with the magnetic field generated by the steel motor assembly, generating a magnetic force that causes the voice coil to move up and down with equal and opposite forces (thus producing the desired sound from the diaphragm 401) and moves the motor assembly 410 in the opposite direction, thereby producing undesirable vibrations. The up and down movement of the voice coil causes the diaphragm to vibrate, with positive and negative sound pressure waves generated on the front surface of the diaphragm. These sound pressure waves propagate through the air from the front of the speaker system.

[0049] The system 400 also includes a steel part / magnet / motor assembly 410 (i.e., a second moving mass, also referred to as a "driver," "hard component," or "motor yoke"). The motor assembly 410 is directly coupled to the suspension basin 402. The suspension basin 402 is coupled to the frame 405 via a secondary suspension / spring 422 (e.g., a leaf spring or a bending spring) that decouples the suspension basin 402 from the frame. In another embodiment, the motor assembly 410 can be coupled to the suspension basin 402 using another suspension (not shown). In another embodiment, the motor assembly 410 can be further coupled to the fixed frame 405 using an optional suspension 424 (e.g., another leaf spring or a bending spring).

[0050] In some embodiments where there is only one suspension (e.g., only suspension 422) between the suspension basket 402 and the frame 405, the suspension can be placed in the height direction on a horizontal plane that intersects the center of mass of the hard component. In some embodiments where there are more than one suspension (e.g., suspension 422 and suspension 424), the two suspensions can be placed as far apart as possible in the height direction to maximize the rocking natural frequency of the hard component by minimizing the moment of inertia.

[0051] In some embodiments, a hanger such as hanger 422 can be attached to a mounting flange that suspends stand 402 and frame 405. If there is no mounting flange, the hanger can be attached to any other portion of the stand and / or frame, including directly to a vertical surface.

[0052] In some embodiments, the motor assembly 410 includes a magnet, a pole piece (not shown), an air gap 470, and a top member (not shown). The magnet is configured to generate a magnetic field and is mounted on the pole piece, with the air gap 470 being generated between the magnet and the pole piece. The pole piece is configured to guide the magnetic field generated by the magnet in the air gap 470.

[0053] The system 400 may also include vents 475 , 476 that allow air generated by the moving diaphragm 401 and the moving motor assembly 410 to escape.

[0054] In some embodiments, the main suspension 420 and the secondary suspension 422 are located at approximately the same radial distance from the central axis of the speaker system (as shown by the dotted line 450), with the midpoints of the suspension springs substantially aligned with each other. When the speaker system 400 is in use, the magnetic field force generated by the interaction between the current and the magnetic field produces two forces. The first force pushes the diaphragm 401 upward, while the second force pushes the motor assembly 410 downward. Because the mass of the motor assembly 410 is larger relative to the diaphragm 401, the acceleration experienced by the motor assembly 410 is much smaller than that of the diaphragm 401. In some embodiments, the motor assembly 410 is approximately 30 times heavier than the diaphragm 401, and therefore the acceleration experienced by the motor assembly 410 is approximately 30 times smaller than that of the diaphragm 401.

[0055] When the suspension basket 402 radiates with the second moving mass 410, the bottom surface of the suspension basket 402 has a volume velocity (indicated by arrow 478) that would normally radiate sound. The opposing surfaces produce equal and opposite volume velocities (indicated by arrow 480). The radiating surface can be any non-perpendicular surface. This causes the volume velocities to cancel each other out, thereby eliminating all or most of the radiation produced by the suspension basket 402. The suspension 420 and the suspension 422 have approximately the same radial distance from the central axis, which causes the relative radiating surface sizes of the basket 402 to be approximately equal. In some embodiments, for example using a motor decoupling spring (e.g., as shown below) Figure 6 The motor decoupling spring 626 in the motor assembly 410 forms an acoustic mass in the motor assembly 410 so that the acoustic load impedance of the two moving mass blocks can be matched.

[0056] In some embodiments, to account for radiated sound from additional surfaces (e.g., the horizontal inner diameter portion of surround 424), the midpoints of the multiple additional surfaces should be aligned unless a "short circuit sound path" exists. Thus, for example, suspension 424 could have its midpoint aligned similarly to suspension 422. However, if there is a short / easy path for air to flow from the front to the rear of the radiating surface, the benefits of aligning the suspension centers are reduced. For example, Figure 4As shown, the misalignment of the midpoint between the suspension 422 and the suspension 424 results in a net volume displacement that can escape through the vent 475, but the sound generated by this small amount of air can easily pass through the vent 475 to the underside of the suspension 424 to be canceled. Aligning the midpoints may be necessary if there are long baffles (e.g., housing / casing 406) to prevent a "short circuit" path.

[0057] As discussed, in some embodiments, additional secondary suspensions / springs can be added to couple the bottom portion of the suspension basket 402 to the fixed frame 405 (e.g., suspension 424) and / or to couple the top portion of the suspension basket 402 to the fixed frame 405 (e.g., suspension 426). This dual-plane suspension embodiment increases the robustness of the speaker system to drops and swaying. In some embodiments, the springs 424, 426 do not form a seal between the basket and the frame, but are segmented so that air can flow between the springs.

[0058] Figure 5 is a cross-sectional view illustrating a force-canceling speaker system 500 for use with some embodiments of the present technology. The speaker system 500 is an example force-canceling speaker system having a U-shaped yoke architecture. Figure 4 Similar to the loudspeaker system 400 of FIG. 5 , the primary suspension 520 couples the outer edge of the diaphragm 501 to the top of the suspension basket 502, while the secondary suspension 522 couples a portion of the suspension basket 502 to a flange on the fixed frame 505. The secondary suspension 522 and the primary suspension 520 are located at approximately the same radial distance from the center of the loudspeaker system, with the midpoints of the suspension springs aligned with each other as shown by the dashed line 550.

[0059] When the suspension basket 502 radiates during loudspeaker operation, the bottom surface of the suspension basket 502 may radiate sound (indicated by arrow 578). The flange opposite this surface generates equal and opposite volume velocities (indicated by arrow 580). This causes the volume velocities to cancel each other, thereby eliminating any radiation generated by the suspension basket 502.

[0060] In other embodiments, an additional secondary suspension 570 may be added to the bottom of the speaker system to couple the motor assembly 510 to the fixed frame 505. This creates two planes of suspension, which provide rotational stiffness to the speaker system.

[0061] Figure 6is a cross-sectional view illustrating a force-canceling speaker system 600 for use with some embodiments of the present technology. Speaker system 600 is similar to speaker system 400 in that it includes a diaphragm 601 coupled to a suspended / floating basket 602 via a primary suspension / surround 620. The suspended basket 602 is coupled to a fixed frame 605 via a secondary suspension 624 (i.e., a basket decoupling spring). Additionally, a motor assembly 610 is coupled to a bottom portion of the suspended basket 602 via a motor decoupling spring 626. The midpoint of the surround 620 is substantially aligned with the basket decoupling spring 624, thereby reducing radiation from the motor assembly and basket.

[0062] like Figures 4 to 6 As shown, in some embodiments, the secondary suspension (i.e., decoupling spring) 624 can be a single-plane suspension or a dual-plane suspension, and can be various types of suspensions (e.g., a leaf spring or a semi-coil spring). The secondary suspension 624 can be adjusted to a frequency that is approximately the same as the fundamental resonant frequency of the speaker system. The material of the secondary suspension 624 can match the material of the main suspension 620 to provide them with similar damping characteristics. The secondary suspension 624 can be stiffer than the main suspension 620 to support heavier motor components.

[0063] In some embodiments, the secondary suspension 624 can be a spring that is linear during normal operation of the speaker system and becomes nonlinear and stiffens when the spring's displacement exceeds the normal operating displacement. This nonlinearity is designed into the spring, which can be a leaf spring or a curved spring (e.g., a half-coil spring), by allowing the spring to deform by bending during normal operation (i.e., low / operating displacements) and deform by stretching / tension at large displacements. This can be achieved by using a short span leaf spring, or, if the spring is curved, by setting the length of the curved spring freely so that the spring becomes taut at large displacements.

[0064] Some embodiments of the speaker system form a dipole configuration, in which sound is radiated to a localized area from both the front and rear. When the voice coil 603 moves the diaphragm 601 in an up-and-down motion, the diaphragm 601 generates sound pressure waves that radiate from the front of the speaker through a first waveguide. A second waveguide is formed in part by the rear surface of the diaphragm and the top surface of the motor assembly. The waveguide is configured to discharge airflow through a front port and a rear port.

[0065] In some embodiments, the rear port (the motor side of the diaphragm 601) opens toward the wearer's ear, while the front port opens away from the ear—thus forming a dipole (i.e., both ports radiate outward). Due to the air venting in this design, the volume velocity from the front of the second moving mass is equal and opposite to the volume velocity from the rear of the second moving mass. This allows for the cancellation of at least some of the radiation generated by the suspended hard components, so there is now only one effective radiation source, avoiding peaks and dips in the pressure frequency response due to interaction between the two radiation sources.

[0066] Figure 7 The effect of a secondary suspension on the forces exerted on the housing of a speaker system (e.g., speaker systems 400 and 500) used with some embodiments of the present technology is graphically illustrated. Curve 702 represents the magnitude of the forces generated by the motor assembly and transmitted to the speaker system housing. As shown, at lower frequencies, substantially all of the forces are transmitted (i.e., the secondary suspension provides substantially no isolation). However, at higher resonant frequencies, as indicated after peak 704 of curve 702, the forces transmitted to the motor assembly are dramatically reduced due to the presence of the secondary suspension.

[0067] In some embodiments, the force cancellation performance of a speaker system can be improved by modifying the properties of speaker system components to account for manufacturing defects. In some embodiments, an additional mass can be added to the magnet assembly (e.g., to the yoke / hard member) to adjust the tuning frequency of the second moving mass to approximately the tuning frequency of the first moving mass. In other embodiments, the effective length of the secondary suspension (e.g., a leaf spring) can be adjusted to change the compliance of the suspension of the second moving mass.

[0068] References in this specification to "embodiments" (e.g., "some embodiments," "various embodiments," "one embodiment," "an embodiment," etc.) mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearances of these expressions in different places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily separate embodiments or alternative embodiments that are mutually exclusive of other embodiments. In addition, various features are described that may be exhibited by some embodiments but not by others. Similarly, various requirements are described that may be requirements of some embodiments but not others.

[0069] As used herein, being above a threshold value means that the value of the compared item is higher than the other values specified, the compared item is located in a certain specified number of items with a maximum value, or the compared item has a value within a specified highest percentage value. As used herein, being below a threshold value means that the value of the compared item is lower than the other values specified, the compared item is located in a certain specified number of items with a minimum value, or the compared item has a value within a specified lowest percentage value. As used herein, being within a threshold value means that the value of the compared item is between two other values specified, the compared item is located in a certain specified number of items in the middle, or the compared item has a value within a middle specified percentage range. When not otherwise defined, relative terms such as high or unimportant can be understood to mean assigning a value and determining how the value is compared with the established threshold value. For example, the phrase "selecting a fast connection" can be understood to mean selecting a connection with a value corresponding to its connection speed that is assigned and is higher than a threshold value.

[0070] As used herein, the word "or" refers to any possible permutation of a group of items. For example, the expression "A, B, or C" refers to at least one of A, B, C, or any combination thereof, such as any of the following: A; B; C; A and B; A and C; B and C; A, B, and C; or a plurality of any items, such as A and A; B, B, and C; A, A, B, C, and C; etc.

[0071] Although the subject matter has been described using language specific to structural features and / or methodological acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Specific embodiments and implementations have been described herein for illustrative purposes, but various modifications may be made without departing from the scope of these embodiments and implementations. The specific features and acts described above are disclosed as example forms of implementing the appended claims. Therefore, the embodiments and implementations are not limited except in the appended claims.

[0072] Any patents, patent applications, and other references mentioned above are intended to be incorporated herein by reference. Various aspects may be modified, if necessary, to provide alternative embodiments using the systems, functions, and concepts of the various references described above. If statements or themes in documents incorporated by reference conflict with statements or themes in the present application, the present application shall prevail.

Claims

1. A speaker system comprising: basin rack; Voice coil; a first mobile mass, the first mobile mass including a diaphragm and coupled to the voice coil, the first mobile mass being coupled to the basket via a non-rigid primary suspension having a first center; as well as a second mobile mass, the second mobile mass comprising a motor assembly, the second mobile mass being directly coupled to the basin frame; wherein the basin frame is coupled to the fixed frame via a non-rigid secondary suspension having a second center; and Wherein, a first radius from the central axis of the speaker system to the center of the non-rigid primary suspension is substantially the same as a second radius from the central axis to the center of the non-rigid secondary suspension.

2. The speaker system according to claim 1, wherein The primary suspension includes a surround coupled to the diaphragm.

3. The speaker system according to claim 1, wherein The secondary suspension includes a decoupling spring.

4. The speaker system according to claim 3, wherein The decoupling spring includes a leaf spring.

5. The speaker system according to claim 3, wherein The decoupling spring includes a half-coil spring.

6. The speaker system of claim 1, further comprising a third suspension coupling a bottom portion of the basket with the fixing frame.

7. The speaker system of claim 1, further comprising a fourth suspension coupling a top portion of the basket with the fixing frame.

8. The speaker system of claim 1, further comprising a motor decoupling spring coupling the motor assembly to a bottom portion of the basket.

9. The speaker system according to claim 1, wherein In response to an audio drive signal applied to the voice coil, the diaphragm is configured to move in a first direction, and the motor assembly is configured to move in a second direction opposite the first direction.

10. The speaker system according to claim 1, wherein The basin frame includes opposing radiating surfaces of substantially equal size.

11. A method of operating a wearable device, the wearable device comprising a fixed frame and a speaker system, the method comprising: applying an audio drive signal to the speaker system, The speaker system includes: a basket; a voice coil; a first mobile mass, the first mobile mass including a diaphragm and coupled to the voice coil, the first mobile mass being coupled to the basket via a non-rigid main suspension having a first center; and a second mobile mass, the second mobile mass including a motor assembly, the second mobile mass being directly coupled to the basket. wherein the basin frame is coupled to the fixed frame via a non-rigid secondary suspension having a second center; and Wherein, a first radius from the central axis of the speaker system to the center of the non-rigid primary suspension is substantially the same as a second radius from the central axis to the center of the non-rigid secondary suspension.

12. The method according to claim 11, wherein The primary suspension includes a surround coupled to the diaphragm.

13. The method according to claim 11, wherein The secondary suspension includes a decoupling spring.

14. The method according to claim 13, wherein: The decoupling spring includes a leaf spring.

15. The method according to claim 13, wherein: The decoupling spring includes a half-coil spring.

16. The method according to claim 11, wherein The speaker system further includes a third suspension coupling a bottom portion of the basket with the fixing frame.

17. The method according to claim 11, wherein The speaker system further includes a fourth suspension coupling a top portion of the basket with the fixing frame.

18. The method according to claim 11, wherein The speaker system also includes a motor decoupling spring coupling the motor assembly to a bottom portion of the basket.

19. The method according to claim 11, wherein In response to an audio drive signal applied to the voice coil, the diaphragm is configured to move in a first direction, and the motor assembly is configured to move in a second direction opposite the first direction.

20. The method according to claim 11, wherein The basin frame includes opposing radiating surfaces of substantially equal size.

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