PATENT DOCUMENT

Publication Number: US-10848846-B2
Application Number: US-201816144528-A
Country: US
Kind Code: B2

Title: Display system having an audio output device

Abstract:
A display system includes a head-mounted display unit and a detachable speaker unit. The head-mounted display unit outputs visual content to a user and provides a visual pass-through of a real environment to the user. The detachable speaker unit is detachably coupleable to the head-mounted display unit for providing aural content to the user. At least one of the visual content or the aural content is changed according to a position of the detachable speaker unit relative to the head-mounted display unit.

Claims:
What is claimed is: 
     
       1. A display system comprising:
 a head-mounted display unit that outputs visual content to a user; and 
 a detachable speaker unit detachably coupleable to the head-mounted display unit for providing aural content to the user; 
 wherein the aural content is changed gradually according to a position of the detachable speaker unit relative to the head-mounted display unit as the position changes. 
 
     
     
       2. The display system according to  claim 1 , wherein the head-mounted display unit includes a built-in speaker, and output of the aural content by one or more of the built-in speaker or the detachable speaker unit is changed gradually according to the position as the position changes;
 wherein audio signal processing of the aural content output by the detachable speaker unit changes as the detachable speaker unit is moved toward a coupling location on the head-mounted display unit, and the audio signal processing includes one or more of changing a volume, equalization, or dynamic range of the aural content output by the detachable speaker unit; and 
 wherein when the detachable speaker unit is in a field of view of the head-mounted display unit, the visual content includes a visual indicator in spatial proximity to the detachable speaker unit, the visual indicator indicating a sound output capability of the detachable speaker unit to the user. 
 
     
     
       3. The display system according to  claim 1 , wherein the head-mounted display unit includes a built-in speaker, and output of the aural content is output from one or more of the detachable speaker unit or the built-in speaker according to the position. 
     
     
       4. The display system according to  claim 3 , wherein the aural content is changed gradually by changing a volume of the built-in speaker according to the position of the detachable speaker unit. 
     
     
       5. The display system according to  claim 4 , wherein the volume of the built-in speaker is positive when the detachable speaker unit is not coupled to the head-mounted display unit, is zero when the detachable speaker unit is coupled to the head-mounted display unit, and is changed gradually as the position of the detachable speaker unit is moved toward the head-mounted display unit, and wherein another volume of the detachable speaker unit is positive when the detachable speaker unit is coupled to the head-mounted display unit. 
     
     
       6. The display system according to  claim 5 , wherein the other volume of the detachable speaker unit is positive when the detachable speaker unit is not coupled to the head-mounted display unit. 
     
     
       7. The display system according to  claim 3 , wherein the aural content is changed gradually by gradually changing audio signal processing of the aural content output by one or more of the detachable speaker unit or the built-in speaker as the position of the detachable speaker unit is changed relative to a coupling location on the head-mounted display unit. 
     
     
       8. The display system according to  claim 7 , wherein the audio signal processing is changed gradually by increasing a volume as the position of the detachable speaker unit is moved toward the coupling location. 
     
     
       9. The display system according to  claim 7 , wherein the audio signal processing is changed gradually by changing low frequency gain as the position of the detachable speaker unit is moved toward the coupling location. 
     
     
       10. The display system according to  claim 7 , wherein the audio signal processing is changed gradually by increasing a dynamic range as the position of the detachable speaker unit is moved toward the coupling location. 
     
     
       11. The display system according to  claim 1 , wherein when the detachable speaker unit is in a field of view of the head-mounted display unit, the visual content includes a visual indicator in spatial proximity to the detachable speaker unit. 
     
     
       12. The display system according to  claim 11 , wherein the visual indicator indicates a sound output capability of the detachable speaker unit to the user. 
     
     
       13. The display system according to  claim 1 , further comprising an audio headset having first and second ones of the detachable speaker units that are detachably coupleable to the head-mounted display unit. 
     
     
       14. The display system according to  claim 13 , wherein the first and second detachable speaker units receive audio signals and power from the head-mounted display unit when coupled thereto. 
     
     
       15. The display system according to  claim 14 , wherein the first and second detachable speaker units are powered and receive audio signals when detached from the head-mounted display unit. 
     
     
       16. The display system according to  claim 13 , wherein the first and second detachable speaker units are detachably coupleable to the head-mounted display unit with magnetic attachments. 
     
     
       17. The display system according to  claim 16 , wherein the magnetic attachments are conductive and transmit one or more of audio signals or power from the head-mounted display unit to the first and second detachable speaker units. 
     
     
       18. The display system according to  claim 1 , wherein as the position of the detachable speaker unit is changed relative to the head-mounted display unit, the aural content is changed gradually by changing audio signal processing of the aural content according to the position. 
     
     
       19. The display system according to  claim 18 , wherein the position is a distance between the detachable speaker unit and the head-mounted display unit, and as the distance decreases, the audio signal processing is changed gradually by one or more of volume, equalization, or dynamic range of the aural content output by the detachable speaker unit. 
     
     
       20. The display system according to  claim 19 , wherein the head-mounted display unit further includes a built-in speaker for outputting the aural content, and wherein the audio signal processing is changed gradually by one or more of volume, equalization, or dynamic range of the aural content output by the built-in-speaker as the distance decreases. 
     
     
       21. The display system according to  claim 1 , wherein the position is a distance between the detachable speaker unit and the head-mounted display unit, and as the distance decreases, the aural content is changed gradually by increasing a volume of the aural content output by the detachable speaker unit. 
     
     
       22. The display system according to  claim 21 , wherein as the distance decreases, the aural content is changed gradually by increasing and subsequently decreasing the volume of the aural content output by the detachable speaker unit. 
     
     
       23. The display system according to  claim 1 , wherein the head-mounted display unit is configured to be worn on a head of the user, and wherein the detachable speaker unit is supported by the head-mounted display unit when detachably coupled thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/684,826, filed Jun. 14, 2018, the entire disclosure of which is incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to display systems and, in particular, audio output devices therefor. 
     BACKGROUND 
     Virtual reality systems provide content to a user, which may include visual and aural content. The visual content may be provided by a head-mounted display unit (HMD), while the aural content is often provided by headphones that are physically separate from the head-mounted display unit. 
     SUMMARY 
     Disclosed herein are implementations of display systems. In one aspect, a display system includes a head-mounted display unit and a detachable speaker unit. The head-mounted display unit outputs visual content to a user and provides a visual pass-through of a real environment to the user. The detachable speaker unit is detachably coupleable to the head-mounted display unit for providing aural content to the user. At least one of the visual content or the aural content is changed according to a position of the detachable speaker unit relative to the head-mounted display unit. 
     The head-mount display may include a built-in speaker. Output of the aural content by one or more of the detachable speaker unit or the built-in speaker according to the position. Audio signal processing of the aural content output by the detachable speaker unit may change as the detachable speaker unit is moved toward a coupling location on the head-mounted display unit. The audio signal processing includes one or more of changing a volume, equalization, or dynamic range of the aural content output by the detachable speaker unit. When the detachable speaker unit is in a field of view of the head-mounted display unit, the visual content may include a visual indicator in spatial proximity to the detachable speaker unit. The visual indicator may indicate a sound output capability of the detachable speaker unit to the user. 
     In another aspect, a display system includes a head-mounted display unit and an audio headset. The head-mounted display unit includes first and second built-in speakers. The audio headset includes first and second detachable speaker units that are detachably coupleable to the head-mounted display unit. 
     In another aspect, a method is provided for providing content with a display system having a head-mounted display unit, a movable audio output devices that is movable relative to the head-mounted display unit, a controller, and a sensor. The method includes determining, by the controller with the sensor, a position of the movable audio output device, and providing content with the head-mounted display unit according to the position of the movable audio output device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side view of a display system. 
         FIG. 1B  is a top view of the display system of  FIG. 1A . 
         FIG. 1C  is a schematic view of the display system of  FIG. 1A . 
         FIG. 1D  is a schematic view of a detachable speaker unit of the display system of  FIG. 1A . 
         FIG. 2A  is a partial side view of another display system that is a variation of the display system of  FIG. 1 . 
         FIG. 2B  is a partial rear view of the display system of  FIG. 2A . 
         FIG. 3A  is a partial side view of another display system that is a variation of the display system of  FIG. 1 . 
         FIG. 3B  is a partial rear view of the display system of  FIG. 3A . 
         FIG. 3C  is a partial side view of a head-mounted display unit of the display system of  FIG. 3A . 
         FIG. 3D  is a partial side view of a detachable speaker unit of the display system of  FIG. 3A . 
         FIG. 3E  is a partial side view of the display system of  FIG. 3A  with hidden features illustrated in dashed lines. 
         FIG. 4A  is a first view of an audio headset in a first state. 
         FIG. 4B  is a second view of the audio headset of  FIG. 4A  in a second state. 
         FIG. 4C  is a side view of a display system that is a variation of the display system of  FIG. 1A , which includes the audio headset of  FIG. 4A . 
         FIG. 5  is a flow diagram of a method for outputting sound from the display system of  FIG. 1 . 
         FIG. 6A  is a plot of sound output from the display system of  FIG. 1 . 
         FIG. 6B  is a flow diagram of a method of providing sound output from the display system of  FIG. 1  according to the plot of  FIG. 6A . 
         FIG. 7A  is a plot of sound output from the display system of  FIG. 1 . 
         FIG. 7B  is a flow diagram of a method of providing sound output from the display system of  FIG. 1  according to the plot of  FIG. 7A . 
         FIG. 8A  is a plot of gain vs. distance for equalization of sound output from the display system of  FIG. 1 . 
         FIG. 8B  is a flow diagram of a method of providing sound output from the display system of  FIG. 1  according to the plot of  FIG. 8A . 
         FIG. 9A  is a plot of dynamic range vs. distance for dynamic range compression of sound output from the display system of  FIG. 1 . 
         FIG. 9B  is a flow diagram of a method of providing sound output from the display system of  FIG. 1  according to the plot of  FIG. 9A . 
         FIG. 10A  is a view of the head-mounted display unit having a field of view that includes a real environment and an audio output device. 
         FIG. 10B  is another view of the head-mounted display unit having the field of view of  FIG. 8A  and additionally displaying a visual indicator. 
         FIG. 10C  is another view of the head-mounted display unit having a field of view that does not include the audio output device and additionally displaying another visual indicator. 
         FIG. 10D  is a flow diagram of a method for providing the visual indicators of  FIGS. 8B and 8C . 
         FIG. 11  is a schematic view of a hardware configuration for a controller of the display system of  FIG. 1A . 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are embodiments of display systems that include a head-mounted display unit and an audio output device, such as an audio headset. The audio output device is detachable from or is otherwise movable relative to the head-mounted display unit in various manners described herein. Aural content provided from the audio output device and/or a built-in audio output device may be output according to the position of the movable audio output device in various manners described herein. Visual content may also be provided according to the position of the movable audio output device in various manners described herein. 
     Referring to  FIGS. 1A-1C , a display system  100  includes a head-mounted display unit  110  and an audio headset  130  that is physically movable relative to the head-mounted display unit  110 , such as being detachable therefrom (as shown) or articulating relative thereto. As discussed in further detail below, the display system  100  may form a mechanical and/or electrical connection between the head-mounted display unit  110  and the audio headset  130 , may provide sound to the user by the head-mounted display unit  110  itself and the audio headset  130 , and/or may provide cues and/or feedback to the user related to use of the audio headset  130  with the head-mounted display unit  110 . The term “audio headset  130 ” refers to an audio output device or a set of audio output devices (e.g., detachable speaker units  132 , as described below) to be held in close proximity to the user&#39;s ear or ears. In the case of multiple audio output devices (e.g., two), the audio output devices of the audio headset  130  may be separate or separable from each other (e.g., need not be affixed to each other, for example, with a headband extending therebetween). The audio headset  130  may also be referred to as a headphone, headphones, an earphone, or earphones. 
     The display systems disclosed herein may be configured to provide computer-generated reality (e.g., virtual reality or mixed reality), as described below. The term “virtual,” as used generally refers to content or an experience that is “computer-generated.” For example, the content described herein may be referred to as virtual or computer-generated content, such as visual content (e.g., also referred to as virtual or computer-generated visual content or graphics) and aural content (e.g., also referred to as virtual or computer-generated aural content or audio). 
     The head-mounted display unit  110  generally includes a support  112  and a display screen  114 . The support is configured to be worn on a user&#39;s head H to thereby support the display screen  114  in a suitable position relative to eyes of the user. As shown, the support is configured as a strap that surrounds the head H of the user. The display screen  114 , such as the screen of a smartphone or a dedicated screen, provides the visual content to the user. In the case of the display screen  114  being a smartphone or other video output device that is removable, the head-mounted display unit  110  may be considered coupleable to the display screen  114 . 
     The display system  100  may be configured to provide a mixed reality experience by providing a visual pass-through by which the user may view the real environment. As shown, the head-mounted display unit  110  utilizes a video pass-through in which case one or more cameras  116  of the head-mounted display unit  110  capture images of the real environment, which are displayed by the display screen  114  to the user. Such a display system  100  may also function to provide a virtual reality experience in which case images of the real environment are not displayed by the display screen  114  and the real environment is otherwise partially or wholly blocked from the view of the user. As an alternative to video pass-through, the head-mounted display unit  110  may utilize an optical pass-through in which case the user views the real environment directly. For example, the head-mounted display unit  110  may include a reflector that both permits light from the real environment to pass therethrough to eyes of the user and reflects light from the display screen  114  to eyes of the user to provide the visual content. 
     The head-mounted display unit  110  may additionally include speakers  118 , which transmit or output aural content to ears of the user. The speakers  118  are, for example, coupled to the support  112  in proximity to ears E of the user and direct sound thereto. The speakers  118  are fixedly coupled to the head-mounted display unit  110  (e.g., to the support  112  or a housing of the display screen  114 ), so as to not be easily removable therefrom. This stands in contrast to the speaker units  132  of the audio headset  130 , which are detachably coupleable to the head-mounted display unit  110 , so as to be easily removable therefrom. As such, the speakers  118  may be referred to as fixed audio output devices, fixed speakers, built-in speakers, or HMD speakers, while the speaker units  132  may be referred to as detachable speakers or detachable speaker units. The audio headset  130  and the detachable speaker units  132  may also be referred to as audio output devices or movable audio output devices. 
     The HMD speakers  118  additionally permit sound from the real environment to reach the ears of the user. For example, the HMD speakers  118  may be positioned above and/or in front of the ears of the user, thereby not obstructing sound from the real environment from reaching the ears of the user. Thus, the head-mounted display unit  110  may provide the mixed reality experience aurally to the user by allowing the user to hear the real environment, while simultaneously transmitting the aural content to the user. As such, the HMD speakers  118  may also be referred to as extra-aural speakers. 
     As discussed in further detail below, the HMD speakers  118  are additionally configured to allow the audio headset  130  to provide the aural content to the user in conjunction with or exclusive of the HMD speakers  118 . In some embodiments, the HMD speakers  118  may be omitted in which case the aural content is provided by the audio headset  130 . 
     The head-mounted display unit may also include various sensors that detect conditions pertaining to the user, the head-mounted display unit  110 , and/or the audio headset  130 . For example, in addition to the camera  116 , the head-mounted display unit  110  may include motion sensors  120 , such one or more of accelerometers, gyroscopes, magnetometers, inertial measurement units (IMU), cameras, or the like, which measure conditions pertaining to the position and/or orientation of the head H of the user and/or the head-mounted display unit  110 . The camera  116  and/or motion sensors  120  may also be configured to determine the position, orientation, and/or motion of the audio headset  130  relative thereto, for example, using visual recognition of the audio headset  130 , being configured to detect, locate, and/or track markers of the detachable speaker unit  132 , and/or being configured to detect, locate, and/or track beacon signals emitted from the detachable speaker unit  132 . The head-mounted display unit  110  may also include eye sensors  122 , such as cameras, which are used to measure conditions of the user&#39;s eye (e.g., focal distance, pupil size, etc.). 
     The audio headset  130  includes the detachable speaker units  132 , which provide aural content to the user by transmitting sound to the ears E of the user. The detachable speaker units  132 , for example, include a right detachable speaker unit  132   r  and a left detachable speaker unit  132   l , which are to be physically associated with a right ear E and a left ear E, respectively, of the user for providing the aural content thereto. 
     Each of the detachable speaker units  132  generally includes a housing  134 , as well as one or more speakers  136  and electronics  138  of various types. The housing  134  contains the one or more speakers  136  and the electronics  138 , and is configured to connect to the support  112  of the head-mounted display unit  110  to be supported thereby, receive audio signals therefrom, and/or receive electric power therefrom. The speaker  136  outputs the sound (i.e., of the aural content) to the user. The electronics  138  are cooperatively configured with the speaker  136  to provide the sound output, and may provide other functionality. 
     As illustrated, the audio headset  130  may have an over-ear configuration in which case the housing  134  is configured to surround an entirety of the ear of the user. Alternatively, the audio headset  130  may have an on-ear configuration in which case the housing  134  is configured to rest on the ear of the user, or have an in-ear configuration in which a portion of the housing  134  is positioned in the ear E (e.g., partially in the ear canal) of the user. 
     As shown schematically in  FIG. 1D , the electronics  138  of the speaker unit  132  may include an amplifier  138   a , power electronics  138   b , signal electronics  138   c , sensing electronics  138   d , and/or ambient sound electronics  138   e . The amplifier  138   a  is configured to drive the speaker  136  for outputting the sound. The power electronics  138   b  are configured to power the various other electronics of the detachable speaker unit  132 , such as the amplifier  138   a , the signal electronics  138   c , and/or the sensing electronics  138   d . The power electronics  138   b  may, for example, provide for wired power and/or locally stored power, such as with a battery. The signal electronics  138   c  are configured to receive and/or send signals to and/or from the head-mounted display unit  110  or another component, such as a controller  150  discussed below. The signal electronics  138   c  may, for example, include communications interfaces to send and/or receive signals, such as via wireless, conductive, or optical connections. Such signals may, for example, include audio signals received for outputting the aural content from the detachable speaker unit  132  and/or sensing signals for providing sensing information of the detachable speaker unit  132  (e.g., position). The signal electronics  138   c  may also provide outputs to assist determining the position and/or orientation of the detachable speaker unit  132  relative to the head-mounted display unit  130 , for example, by providing a passive or active marker (e.g., visible or invisible light source) or a beacon (e.g., emitting another type of detectable and locatable output signal). The sensing electronics  138   d  are configured to sense various parameters of the detachable speaker unit  132 , such as a position, orientation, and/or motion (e.g., changes in position and orientation) of the detachable speaker unit  132  in real space or relative to another part of the display system  100 , such as the head-mounted display unit  110 , the support  112  thereof, or coupling locations or features thereon. The sensing electronics  138   d  may include one or more appropriate sensors for detecting such position, orientation, and/or motion, such as accelerometer(s), gyroscope(s), inertial measurement unit (IMU), proximity sensor(s), and/or cameras (e.g., for video recognition). 
     The ambient sound electronics  138   e  function to detect ambient sounds (e.g., from the real environment using a microphone  138   e ′), process the detected ambient sounds (e.g., with a signal processor  138   e ″), and cause the speaker  136  to output a processed sound according thereto (e.g., using the amplifier  138   a ). The processed sound may, for example, provide acoustic transparency and/or active noise canceling. With acoustic transparency, the ambient sound from the real environment is generally reproduced without significant alteration as the processed sound, which may be referred to as processed ambient sound and is output by the speaker  136 . As a result, the user may still hear the real environment, for example, when the detachable speaker unit  132  is placed against the user&#39;s ear E and might otherwise hinder (e.g., by insulating and/or blocking) the ambient sound of the real environment from reaching the user&#39;s ear E directly. With active noise canceling, the ambient sound is processed to provide processed sound that generally cancels or counters the ambient sound (e.g., by having the same amplitude but inverted phase as the ambient sound), which may be referred to as the processed canceling sound and is output by the speaker  136 . 
     It should be noted that the speaker electronics  138  (e.g., the amplifier  138   a , the power electronics  138   b , the signal electronics  138   c , the sensing electronics  138   d , and/or the ambient sound electronics  138   e ), or different electronics performing similar functions, may instead or additionally be incorporated into the head-mounted display unit  110 . For example, the speaker  136  may have a wired connection to the head-mounted display unit  110  and/or the controller  150 , while amplification, power, sensing, and ambient sounds functions are performed by electronics of the head-mounted display unit  110  and/or the controller  150 . 
     In addition to the head-mounted display unit  110  and the audio headset  130 , the display system  100  additionally includes the controller  150 . As illustrated, the controller  150  may be external to the head-mounted display unit  110  and the audio headset  130  and is in communication therewith, such as with a wired or wireless connection. The controller  150  is generally configured to process various input information (e.g., signals), such as the location and/or orientation of the user, the head-mounted display unit  110 , and/or the audio headset  130 , process such information, and provide output signals for controlling the head-mounted display unit  110  (e.g., to output the visual content and the aural content) and the audio headset  130  (e.g., to output the aural content). A hardware configuration for the controller  150  is discussed below with reference to  FIG. 9 . While depicted as a singular unit separate from and external to the head-mounted display unit  110  and the audio headset  130 , the controller  150  may instead include multiple such controllers or be subdivided into separate units that cooperatively function as the controller  150 , and the controller  150  may be incorporated into one or more of the head-mounted display unit  110  and the detachable speaker units  132 . 
     As referenced above, the head-mounted display unit  110  and the audio headset  130  may be cooperatively configured provide mechanical, electrical, and/or data connections between the head-mounted display unit  110  and the audio headset  130 , cooperatively provide sound to the user, and/or provide cues and/or feedback to the user related to use of the audio headset  130  with the head-mounted display unit  110 . 
     Referring to  FIGS. 2A-4B , each of the detachable speaker units  132  of the audio headset  130  is detachable from the head-mounted display unit  110 . When attached to the head-mounted display unit  110 , each of the detachable speaker units  132  is physically supported thereby, and may further be in communication therewith and/or receive electric power therefrom. 
     Referring to  FIGS. 2A-2B , a display system  200  includes an audio headset  230  having detachable speaker units  232  that are releasably coupleable to a head-mounted display unit  210  with magnetic force. The head-mounted display unit  210  is configured as the head-mounted display unit  110 , while additionally including one or more magnetic attachments  224 , which may be referred to as HMD magnetic attachments. The detachable speaker unit  232  is configured as the detachable speaker unit  132 , while including one or more magnetic attachments  244  that correspond to the HMD magnetic attachments  224  of the head-mounted display unit  210 . The magnetic attachments  224 ,  244  of the head-mounted display unit  210  and the detachable speaker unit  232  may be referred to as HMD magnetic attachments  224  and speaker magnetic attachments  244 , respectively. The magnetic attachments  224 ,  244  are configured to attract each other with magnetic force, for example, with one of the magnetic attachments  224 ,  244  including a permanent magnetic and the other including ferromagnetic material or another permanent magnet of opposite orientation. 
     In the example shown in  FIGS. 2A-2B , the head-mounted display unit  210  includes two HMD magnetic attachments  224 , one being forward of and the other being rearward of the ear E of the user. As shown, the two HMD magnetic attachments  224  may be coupled to the support  112  of the head-mounted display unit  210 , for example, to flanges  212   a  (e.g., protrusions) that extend downward to positions forward and rearward of the ear E of the user. The two HMD magnetic attachments  224  include permanent magnets, which may be incorporated into or otherwise coupled to the support  112  of the head-mounted display unit  210 . 
     The detachable speaker unit  232 , such as the housing  134  or padding  246  thereof, may protrude (e.g., extend inward) of the support  112  (e.g., inward of the flanges  212   a ) to be positioned against the user, for example, engaging the head H around the ear E (e.g., over ear configuration) or engaging the ear E of the user (e.g., on ear configuration). As a result, the detachable speaker unit  232  may be considered to have an inner portion (e.g., the padding  246  and/or the housing  134 ) that extends laterally inward (e.g., toward the user) from an outer portion (e.g., formed by the speaker magnetic attachments  244 ) that is coupled to the head-mounted display unit  110 . The padding  246  may engage and/or circumscribe the ear E of the user (e.g., in an on ear and/or over ear configuration). 
     Each of the detachable speaker units  232  includes the two speaker magnetic attachments  244 , which are magnetically coupleable to the two HMD magnetic attachments  224  of the head-mounted display unit  210 . For example, the two speaker magnetic attachments  244  may extend forward and rearward of the ear E of the user, so as to be magnetically coupleable to the HMD magnetic attachments  224 . The speaker magnetic attachments  244  may, for example, be elongated and extend forward and rearward from the housing  134  of the detachable speaker unit  232 . As shown, the speaker magnetic attachments  244  may be configured as posts that include the ferromagnetic material or permanent magnets of opposite orientation for being attracted to the permanent magnets of the HMD magnetic attachments  224  of the head-mounted display unit  210 . Alternatively, the HMD magnetic attachments  224  may include ferromagnetic material, while the speaker magnetic attachments  244  include permanent magnets to be attracted thereto. 
     The head-mounted display unit  210  and the detachable speaker unit  232  may also be configured to guide the detachable speaker units  232  to a pre-determined position relative thereto (e.g., a coupling location of the head-mounted display unit  110  over the ear E of the user). For example, each set of the magnetic attachments  224 ,  244  (e.g., front and rear pairs of the magnetic attachments  224 ,  244 ) provide magnetic force to guide the speaker magnetic attachments  244  of the detachable speaker unit  232  to the HMD magnetic attachment  224  of the head-mounted display unit  210  corresponding. Additionally, the magnetic attachments  224 ,  244  that do not correspond to each other may also function to repel each other, for example, by having permanent magnets with the same orientation. As a result, the detachable speaker unit  232  is pushed away from non-predetermined positions. These attraction and/or repulsion forces may be useful to help the user guide the detachable speaker units  132  to their respective coupling locations on the head-mounted display unit  210 , which are outside the user&#39;s field of view, by providing tactile feedback to the user. 
     Instead of or in addition to using magnetic force to guide the detachable speaker units  232  to proper positions, the head-mounted display unit  210  and the detachable speaker unit  232  may include mechanically cooperative guide features. For example, the head-mounted display unit  210  may include detents in the support  112 , which receive and guide the speaker magnetic attachments  244  of the detachable speaker unit  232  to the predetermined location. 
     The detachable speaker unit  232  may be configured to pivot about the speaker magnetic attachments  244 , for example, to be biased toward or otherwise accommodate the ear E of the user. In one example, the speaker magnetic attachments  244  are cylindrical posts that extend forward and rearward (e.g., forming a pivot axis  244   a ). The cylindrical posts roll along surfaces of the HMD magnetic attachments  224  or the support  112  of the head-mounted display unit  210 , so as to pivot relative thereto. In another example, the housing  134  pivots relative to the speaker magnetic attachments  244  without the speaker magnetic attachments moving (e.g., without rolling) relative to the HMD magnetic attachments  224  of the head-mounted display unit  210 , thereby still allowing the housing  134  and the speaker  136  therein to pivot relative to the head-mounted display unit  210 . 
     The pivot axis  244   a  of the detachable speaker unit  232  is, for example, formed by the speaker magnetic attachments  244 . The pivot axis  244   a  may, as shown, be arranged in a central position of the detachable speaker unit  232  (e.g., horizontally and vertically), or may be biased vertically (e.g., toward an upper end of the detachable speaker unit  232 ) and/or horizontally (e.g., toward an inner or outer side of the detachable speaker unit  232 ). Additionally, the pivot axis  244   a  may, as shown, be arranged outward of the support  112  of the head-mounted display unit  210 . 
     The detachable speaker unit  232  may additionally be configured to biased toward the ear E of the user about the pivot axis  244   a , such as with a spring or magnets. In the example shown in  FIGS. 2A-2B , the detachable speaker unit  232  may be biased toward the ear E of the user with magnetic force. The head-mounted display unit  210  may include a magnet  228  of one orientation positioned above the ear E of the user, while the detachable speaker unit  232  includes another magnet  248  of opposite orientation above the ear E of the user, for example, by forming or being incorporated in an elongated member extending upward from the housing  134 . The magnets  228 ,  248  of the head-mounted display unit  210  and the detachable speaker unit  232  repel each other, so as to bias the detachable speaker unit  232  about the pivot axis  244   a  and toward the ear E of the user. 
     The head-mounted display unit  210  and the detachable speaker unit  232  are additionally configured for the head-mounted display unit  210  to provide electric power to the detachable speaker unit  232 . As shown, the magnetic attachments  224 ,  244  conduct electricity from the head-mounted display unit  210  to the detachable speaker unit  232 , so as to provide power to the amplifier  138   a  and other electronics (e.g., the signal electronics  138   c  and/or the sensing electronics  138   d ). For example, a first set of the magnetic attachments  224 ,  244  are for power (positive) and a second set of the magnetic attachments  224 ,  244  are for ground. The magnetic attachments  224 ,  244  may also transmit audio signals via conduction from the head-mounted display unit  210  to the detachable speaker unit  232  in conjunction with conducting electric power. 
     Alternatively, electric power may be conducted from the head-mounted display unit  210  to the detachable speaker unit  232  with electrical contacts that are independent of the magnetic attachments  224 ,  244 , which may also transmit audio signals. In other variations, audio signals may be transmitted independent of the electric power, such as with separate contacts and/or an optical connection. In embodiments of the detachable speaker units  232  having the sensing electronics  138   d , sensor signals may be transmitted from the detachable speaker unit  232  to the head-mounted display unit  210  with the magnetic attachments  224 ,  244 , the separate contacts, the optical connection, or wirelessly. Electrical power may also be provided from the head-mounted display unit  210  inductively. 
     Referring to  FIGS. 3A-3E , a display system  300  includes an audio headset  330  having a detachable speaker unit  332  that is releasably coupleable to a head-mounted display unit  310 . The head-mounted display unit  310  is configured as the head-mounted display unit  110 , and additionally includes a magnetic attachment  324  having a female configuration, such as a socket. The detachable speaker unit  332  is configured as the detachable speaker unit  132 , while additionally including a magnetic attachment  344  having a male configuration, such as a ball, which is received by the magnetic attachment  324  of the head-mounted display unit  310 . The magnetic attachments  324 ,  344  of the head-mounted display unit  310  and the detachable speaker unit  332  may be referred to as an HMD or female magnetic attachment, and a speaker or male magnetic attachment, respectively. 
     In the example shown in  FIGS. 3A-3E , the head-mounted display unit  310  includes one HMD magnetic attachment  324  positioned above the ear E of the user. As shown, the HMD magnetic attachment  324  is coupled to the support  112  of the head-mounted display unit  310  above the ear E of the user. The speaker magnetic attachment  344  is coupled to the housing  134  of detachable speaker unit  332 , for example, being formed at the end of an elongated protrusion (e.g., shaft) extending upward from the housing  134 . 
     The magnetic attachments  324 ,  344  have complementary profiles that allow receipt of the speaker magnetic attachment  344  by the HMD magnetic attachment  324 , such as a spherical shape. The magnetic attachments  324 ,  344  may also be configured to permit movement of the detachable speaker unit  332  relative to the head-mounted display unit  310 , while still being supported thereby. For example, the detachable speaker unit  332  may be permitted to displace inward and outward, forward and backward, and rotate, as illustrated by the arrows in  FIGS. 3A and 3B . 
     The head-mounted display unit  310  and the detachable speaker unit  332  are additionally configured for the head-mounted display unit  310  to provide electric power to the detachable speaker unit  332 . As shown, the magnetic attachments  324 ,  344  conduct electricity from the head-mounted display unit  310  to the detachable speaker unit  332 , so as to provide power to the amplifier  138   a  and/or other electronics  138  thereof. For example, each of the magnetic attachments  324 ,  344  are subdivided to provide power and ground contacts, which maintain physical contact for conducting electricity as the detachable speaker unit  332  moves relative to the head-mounted display unit  310 . 
     For example, as shown in  FIG. 3C , the HMD magnetic attachment  324  may include a first power contact  324   a  (e.g., positive) and a second power contact  324   b  (e.g., ground) that are spaced apart along the spherical surface of the HMD magnetic attachment  324  and are electrically isolated from each other. As shown in  FIG. 3D , the speaker magnetic attachment  344  is includes a first power contact  344   a  (e.g., positive) and a second power contact  344   b  (e.g., ground), which are electrically isolated from each other and have larger conductive surface areas than the first power contact  324   a  and the second power contact  324   b  of the HMD magnetic attachment  324  corresponding there to. As a result, as shown in  FIG. 3E , the detachable speaker unit  332  may move inward/outward, forward/backward, and/or rotate in limited ranges of motion, while still maintaining conductive contact between the power contacts  344   a ,  344   b  and  324   a ,  324   b  to conduct electric power therebetween. The magnetic attachments  324 ,  344  may also transmit audio signals from the head-mounted display unit  310  to the detachable speaker unit  332  in conjunction with conducting electric power. The power contacts  324   a ,  324   b  of the HMD magnetic attachment  324  may, for example, be permanent magnets or be made of or otherwise include ferromagnetic material, while the power contacts  344   a ,  344   b  of the speaker magnetic attachment  344  may be made of a ferromagnetic material or be permanent magnets of opposite orientation from those of the HMD magnetic attachment  324 . 
     While the detachable speaker units  232 ,  332  are discussed as being movable relative to the head-mounted display units  210 ,  310 , variations of the magnetic attachments  224 ,  244  and the magnetic attachments  324 ,  344  may instead be configured to prevent movement therebetween. 
     Further, while the detachable speaker units  232 ,  332  are discussed as being releasably coupleable to the head-mounted display units  210 ,  310  with magnetic force, they may instead be coupled to each other with other releasable mechanisms, such as buckles, clamps, or fasteners. In such cases, power and signals may be conducted through such releasable mechanisms or separate power connections and data connections. 
     Referring to  FIGS. 4A-4C , a display system  400  includes an audio headset  430  having detachable speaker units  432 , such as a right detachable speaker unit  432   r  and a left detachable speaker unit  4321 , that are detachably coupleable to a head-mounted display unit  410  and to each other. Each of the detachable speaker units  432  is configured as one of the detachable speaker units  132 ,  232 ,  332  and additionally includes coupling features  449 . In one example, the coupling features  449  couple the detachable speaker units  432  to each other using magnetic force. For example, the coupling features  449  of the right detachable speaker unit  432   r  may be or may include permanent magnets or ferromagnetic material, while the coupling features  449  of the left detachable speaker unit  4321  are configured to be attracted magnetically thereto, for example, being or including permanent magnets (e.g., of opposite orientation) or ferromagnetic material. 
     The coupling features  449 , when configured to detachably couple the detachable speaker units  432  to each other with magnetic force, may be hidden from view (e.g., being contained within the housing  134  or the pad  246 ). 
     The coupling features  449  may, instead of or in addition to using magnetic force, be mechanical mechanisms (e.g., buckles, clamps, or fasteners) that detachably couple the detachable speaker units  432  to each other. 
     Referring additionally to  FIG. 4C , the coupling features  449  may also function to couple the detachable speaker units  432  to the head-mounted display unit  410 . For example, the head-mounted display unit  410  may be configured as the head-mounted display unit  110  and include coupling features  429  that correspond to the coupling features  449 . For example, as illustrated in  FIG. 4C , the coupling features  429  on a right side of the head-mounted display unit  410  may include one or more of the coupling features  429  in a similar arrangement (e.g., position, magnetic pole orientation if using magnetic force, or common male/female configuration if using mechanical engagement) to the coupling features  449  of the left detachable speaker unit  4321 . As a result, the right side of the head-mounted display unit  410  may couple to the right detachable speaker unit  432   r  in a similar manner to which the left detachable speaker unit  4321  couples to the right detachable speaker unit  432   r.    
     Referring  FIGS. 5-7B , for any one of the display systems  100 ,  200 ,  300 ,  400 , the head-mounted display unit  110 ,  210 ,  310 ,  410  and the audio headset  130 ,  230 ,  330 ,  430 , or both output sound according to a condition of the audio headset  130 ,  230 ,  330 ,  430 . For simplicity in the discussion that follows, only the display system  100  will be referred to, though it should be understood that the other display systems  200 ,  300 ,  400  may be configured as described with respect to  FIGS. 5-7B . As discussed in further detail below, the condition of the audio headset  130  according to which sound is output may be one or more of whether the detachable speaker units  132  are coupled to each other (i.e., forming an audio unit as described previously), or a position or relative movement of the audio headset  130  or the detachable speaker units  132  relative to the head-mounted display unit  110 . 
     Referring to  FIG. 5 , in one example, the HMD speakers  118  of the head-mounted display unit  110  output sound when the detachable speaker units  132  are decoupled from each other, for example, upon decoupling the detachable speaker units  132  from each other and a duration thereafter. In such cases, the sound output from the HMD speakers  118  of the head-mounted display unit  110  may represent activation of the audio headset  130  or the detachable speaker units  132  thereof, so as to provide an audio cue or feedback suggesting the sound output capability of the audio headset  130  (e.g., the detachable speaker units  132  thereof). 
       FIG. 5  illustrates a method  500  for outputting sound from HMD speakers  118  according to a decoupling of the detachable speaker units  132  from each other. The method may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . 
     In a first operation  510  decoupling of the detachable speaker units  132  from each other is determined. Decoupling of the detachable speaker units  132  may, for example, occur due to the user pulling apart the detachable speaker units  132 . Decoupling of the detachable speaker units  132  may be determined, for example, by the controller  150  using sensors of the head-mounted display unit  110 , such as by processing video received from a camera  116 , or the sensing electronics  138   d  of the detachable speaker units  132 , such as by detecting relative movement therebetween or change in proximity therebetween. 
     In a second operation  520 , based on decoupling of the detachable speaker units  132  having been determined, sound is output from the HMD speakers  118  of the head-mounted display unit  110 . For example, the controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  to output sound therefrom. The sound output from the HMD speakers  118  contains aural content. Such aural content may include an audio indicator related to the detachable speaker units  132 . 
     In a third operation  530 , sound is output from the detachable speaker units  132  of the audio headset  130 . For example, the controller  150  may cause audio signals and/or power to be sent to the detachable speaker units  132 . The sound output from the detachable speaker units  132  may contain aural content, such as pertaining to a virtual or mixed reality experience. 
     In the operations,  520 ,  530 , the sound may be output from the detachable speaker units  132  according to the manners described below with reference to  FIGS. 6A to 6B  and  FIGS. 7A to 7B . 
     Referring to  FIGS. 6A-6B and 7A-7B , audio signal processing is performed (e.g., by the controller  150 ), such that the HMD speakers  118  of the head-mounted display unit  110  and the detachable speaker units  132  output sounds according to the position of the audio headset  130  and/or the detachable speaker units  132  thereof. As discussed in further detail below, such audio signal processing or other audio controls may include adjusting the volume (see  FIGS. 6A-7B  and related discussion), equalization (see  FIGS. 8A-8B  and related discussion), and/or dynamic range (see  FIGS. 9A-9B ). 
     With reference to  FIGS. 6A-6B , the detachable speaker units  132  may be configured to not output sound until coupled to the head-mounted display unit  110 . For example, the detachable speaker units  132  may not have a power source independent of the head-mounted display unit  110  (e.g., do not have internal batteries, do not have a wired connection to a power source independent of the head-mounted display unit  110 , or are otherwise powered only when detachably coupled to the head-mounted display unit  110 ). In other examples, the detachable speaker units  132  may receive audio signals associated with the head-mounted display unit  110  (e.g., the virtual audio content) only when physically coupled thereto, such as via a conductive or optical data connection. In still further examples, the detachable speaker units  132  are otherwise configured to not output the sound until detachably coupled to the head-mounted display unit  110  (e.g., due to software programming). 
     In such scenarios, the HMD speakers  118  of the head-mounted display unit  110  may output sound so as to simulate or otherwise represent sound being emitted by the detachable speaker units  132 , while the detachable speaker units  132  are not coupled to the head-mounted display unit. Upon connecting the detachable speaker units  132  to the head-mounted display unit  110 , sound output from the detachable speaker units  132  increases to become the primary sound source (e.g., turning on), while sound output from the HMD speakers  118  may simultaneously or subsequently decrease substantially (e.g., to emit no sound). 
       FIG. 6A  depicts a plot of volume of sound output from the HMD speakers  118  of the head-mounted display unit  110  and the detachable speaker units  132  of the audio headset  130  as a function of distance of the detachable speaker units  132  to a predetermined coupling location at which the detachable speaker unit  132  is coupleable to the audio headset  130 . The zero distance (i.e., at the coupling location) is shown on the right of the plot, such that moving rightward on along the plots reflects moving the detachable speaker unit  132  toward the coupling location. The plot also depicts a coupled state indicated by C in which the detachable speaker unit  132  is coupled to the detachable speaker unit  132  at the coupling location. The coupled state C is illustrated after the zero distance, but should be understood as representing a change of state of the coupling state of the detachable speaker unit  132  and not necessarily a further change of distance between the detachable speaker unit  132  and the coupling location. As used herein, the term “volume” generally refers to the level of sound output by an audio output device, and may also be referred to as “sound output level.” 
     As shown, a volume  118   v  of the HMD speaker  118  increases as the detachable speaker unit  132  is moved closer to the coupling location and reaches a peak volume when the detachable speaker unit  132  is at or near the coupling location. A volume  132   v  of the detachable speaker unit  132  stays at zero until the detachable speaker unit  132  reaches the coupling location and/or is coupled to the head-mounted display unit  110 . 
     At the coupling location or upon being in the coupled state C, a volume  132   v  of the detachable speaker unit  132  is increased, for example, to become the primary sound source to the user. Sound output from the speaker unit  132  is maintained while in the coupled state C. 
     Coincident with the volume  132   v  of the detachable speaker unit  132  increasing (e.g., when the detachable speaker unit  132  is moved into the coupling location or upon coupling to the head-mounted display unit  110 ), the volume  118   v  of the HMD speaker  118  decreases. For example, the volume  118   v  of the HMD speaker  118  may go to and/or be maintained at zero when the detachable speaker unit  132  is in the coupled state C. 
       FIG. 6B  illustrates a method  600  for outputting sound from the HMD speakers  118  according to a position of the audio headset  130  and/or the detachable speaker units  132  individually relative to the head-mounted display unit  110  (e.g., to a coupling location on the head-mounted display unit  110 ). The method  600  may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . While discussed in conjunction with respect to one of the detachable speaker units  132 , the method  600  should be understood to be applicable to each of the detachable speaker units  132  and the audio headset  130 . 
     In a first operation  610 , a change of position of the detachable speaker unit  132  relative to the head-mounted display unit  110  (e.g., the coupling location thereon) is determined. The position of the detachable speaker unit  132  may be changed relative to the head-mounted display unit  110 , for example, as the user moves relative to the detachable speaker unit  132  (e.g., toward, away, rotating head) or as the user moves the detachable speaker unit  132  (e.g., moving the detachable speaker unit  132  to the coupling location). The change of position or relative motion of the detachable speaker unit  132  may be determined, for example, by the controller  150  using sensors of the head-mounted display unit  110 , such as by processing video received from the camera  116 , or the sensing electronics  138   d  of the detachable speaker units  132  (e.g., if the detachable speaker units  132  are powered independent of being coupled to the head-mounted display unit  110 ), such as by detecting movement toward the head-mounted display unit and or change in proximity therebetween. 
     In a second operation  620 , based on the change of the position of the detachable speaker unit  132  relative to the head-mounted display unit  110 , the volume  118   v  of the HMD speaker  118  is changed. For example, as shown in  FIG. 6A , the volume  118   v  is increased or decreased as the detachable speaker unit  132  is, respectively, moved toward or away from the head-mounted display unit  110  (e.g., the coupling location thereon). The controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  to output sound therefrom at the volume  118   v . The sound output from the HMD speaker  118  contains the aural content, such as that pertaining to the virtual or mixed reality experience. 
     In a third operation  630 , based on determining that the detachable speaker unit  132  is at a zero distance relative to the head-mounted display unit  110  or upon coupling the detachable speaker unit  132  to the head-mounted display unit  110  at the predetermined location, the volume  132   v  of the detachable speaker unit  132  is substantially increased. For example, the controller  150  may determine that the detachable speaker unit  132  is at the zero distance using the sensors of the head-mounted display unit  110  and/or the detachable speaker unit  132  as described above with respect to the second operation  620 , and/or by determining that the detachable speaker unit  132  is coupled to the head-mounted display unit  110 . The controller  150  may cause audio signals and/or power to be sent to the detachable speaker unit  132  to output sound therefrom at the substantially increased volume  132   v . For example, the volume  132   v  of the detachable speaker unit  132  may be increased from zero to provide the primary or only sound output to the user. 
     In a fourth operation  640 , based the determination of the zero distance, coupling of the detachable speaker unit  132 , or according to the volume  132   v  of the detachable speaker unit  132  having been substantially increased, the volume  118   v  of the HMD speaker  118  is substantially reduced (e.g., to zero). For example, the controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  to reduce the volume  118   v  or to not be sent to the HMD speaker  118  to reduce the volume  118   v  to zero. The fourth operation  640  may occur coincident with the third operation  630 , such as simultaneously therewith or shortly thereafter. 
     In a fifth operation  650 , while the detachable speaker unit  132  is coupled to the head-mounted display unit  110  (e.g., is in the coupled state shown in  FIG. 6A ), the detachable speaker unit  132  continues to provide sound output to the user, while the HMD speaker  118  provides secondary or no sound to the user. 
     In a sixth operation  660 , acoustic transparency of the detachable speaker unit  132  may be activated. Acoustic transparency is implemented by the ambient sound electronics  138   e  (e.g., the microphone  138   e ′ and signal processor  138   e ″), so as to produce the processed ambient sound as described above. Acoustic transparency may be activated automatically upon coupling of the detachable speaker unit  132  to the head-mounted display unit  110 , for example, if the display system  100  is operating in a mixed reality mode or by default, or may be activated by selection of the user. Acoustic transparency may provide a mixed reality experience by transmitting the processed ambient sound to the user despite the detachable speaker unit  132  physically hindering passage of ambient sound directly to the user&#39;s ear E. 
     In a seventh operation  670 , noise cancellation of the detachable speaker unit  132  may be activated. Noise cancellation is implemented by the ambient sound electronics  138   e , so as to produce the processed cancelling sound as described above. Noise cancellation may be activated automatically upon coupling of the detachable speaker unit  132  to the head-mounted display unit  110 , for example, if the display system  100  is operating in a virtual reality mode (e.g., when providing virtual visual content with no visual pass through), or by default (e.g., after passage of a predetermined time period after connecting the detachable speaker unit  132  to the head-mounted display unit  110 , or after a predetermined time of operating the acoustic transparency), or may be activated by selection of the user. Noise cancellation may provide a virtual reality experience by further inhibiting hearing of sounds from the real environment by the user. It should be noted that noise cancellation may not be activated or may be activated without activating acoustic transparency (e.g., one, the other, or both of the sixth operation  660  and the seventh operation  670  may be performed). 
     In a variation of the method  600 , the first operation  610  and the second operation  620  of determining the position of the detachable speaker unit  132  (i.e., the first operation  610 ) and changing the volume  118   v  of the HMD speaker  118  (i.e., the second operation  620 ) based thereon may be omitted. In such cases, the third operation  630  and the fourth operation  640  of increasing the volume  132   v  of the detachable speaker unit  132  based on determining the zero position or upon coupling (i.e., the third operation  630 ) and decreasing the volume  118   v  of the HMD speaker  118  (i.e., the fourth operation  640 ) are still performed. 
     The method  600  and the aforementioned variation thereof may be used in conjunction with the method  500  described previously, for example, in the third operation  530 . 
     With reference to  FIGS. 7A-7B , the detachable speaker units  132  may be configured output sound prior to being coupled to the head-mounted display unit  110 . For example, the detachable speaker units  132  may be powered independent of being coupled the head-mounted display unit (e.g., by having internal batteries or a wired connection to a power source). In such scenarios, the HMD speakers  118  of the head-mounted display unit  110  and the detachable speaker units  132  may blend sound output to limit fluctuating volume experienced by the user, such as prior to the detachable speaker unit  132  being coupled to the head-mounted display unit  110 . 
     The HMD speakers  118  of the head-mounted display unit  110  and the detachable speaker units  132  output sounds according to movement of the audio headset  130  (e.g., when the detachable speaker units  132  are coupled to each other) and/or movement of the detachable speaker units  132  individually. For example, when the detachable speaker unit  132  is a relatively far distance from the head-mounted display unit  110 , sound be output from only the HMD speakers  118 . As the detachable speaker units  132  are moved closer to the head-mounted display unit  110 , the detachable speaker units  132  may increase in volume, such that the user hears sound being simultaneously emitted from both the HMD speakers  118  of the head-mounted display unit  110  and the detachable speaker units  132 . As the detachable speaker units  132  are moved still closer to the head-mounted display unit  110 , such as for coupling the detachable speaker units  132  thereto, the HMD speakers  118  and the detachable speaker units  132  may cooperatively provide sound output to limit volume fluctuation by decreasing volume from the HMD speakers  118 , while simultaneously increasing and then decreasing volume from the detachable speaker unit  132 . This may help limit fluctuation in volume perceived by the user fluctuations in volume perceived by the user 
       FIG. 7A  depicts a plot of volume of sound output from the HMD speakers  118  and the detachable speaker units  132  as a function of distance of the detachable speaker units  132  to a predetermined coupling location at which the detachable speaker unit  132  is coupleable to the audio headset  130 . The zero distance (i.e., at the coupling location) is shown on the right of the plot, such that moving rightward along the plot reflects moving the detachable speaker unit  132  toward the coupling location. 
     As shown, at relatively far distances between the detachable speaker unit  132  and the coupling location on the head-mounted display unit  110 , the HMD speaker  118  outputs sound at the volume  118   v , while the detachable speaker unit  132  outputs no sound. At such relatively far distances, the volume  118   v  of the HMD speaker  118  may be independent of such distance and/or be constant. As the detachable speaker unit  132  is moved still closer to the coupling location, the volume  118   v  of the HMD speaker  118  may decrease, while the volume  132   v  of the detachable speaker unit  132  increases. At such closer distances, the user may hear sound from output from both the HMD speaker  118  and the detachable speaker unit  132 . At close distances, such as when moving to the zero distance at which the detachable speaker unit couples to the head-mounted display unit  110  over the user&#39;s ear E, the volume  118   v  output by the HMD speaker  118  reduces to zero, while the volume  132   v  of the detachable speaker unit  132  may reduce to a final output level. The reduction in the volume  132   v  of the detachable speaker unit  132  may, for example, account for an increase in volume that might otherwise be perceived by the user due to reduced distances and/or sound isolation that might be perceived from the real environment due to the housing  134  or the padding  246  of the detachable speaker unit  132  engaging the ear E of the user. 
       FIG. 7B  illustrates a method  700  for outputting sound from the HMD speakers  118  and the detachable speaker units  132  according to a position of the audio headset  130  and/or the detachable speaker units  132  individually relative to the head-mounted display unit  110  (e.g., to a coupling location on the head-mounted display unit  110 ). The method  700  may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . While discussed in conjunction with respect to just one of the detachable speaker units  132 , the method  700  should be understood to be applicable to each of the detachable speaker units  132  and the audio headset  130 . 
     In a first operation  710 , a position of the detachable speaker unit  132  relative to the head-mounted display unit  110  (e.g., the predetermined coupling location thereon) is determined, which may be performed in the manner described above for the first operation  610  of the method  600 . 
     In a second operation  720 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being relatively far (e.g., greater than a threshold distance), the HMD speaker  118  outputs sounds (i.e., the volume  118   v  is greater than zero), while the detachable speaker unit  132  outputs no sound (i.e., the volume  132   v  is zero). The controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  to output the sound therefrom. The sound output from the HMD speaker  118  contains the aural content, such as that pertaining to the virtual or mixed reality experience. 
     In a third operation  730 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being in intermediate range (e.g., below the threshold distance and above a second threshold) and reducing, the volume  118   v  of the HMD speaker  118  is reduced, while the volume  132   v  of the detachable speaker unit  132  is simultaneously increased. The controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  and the detachable speaker unit  132 . 
     In a fourth operation  740 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being in close proximity (e.g., below the second threshold distance to the zero distance) and reducing to the zero distance, the volume  118   v  of the HMD speaker  118  is reduced to zero and the volume  132   v  of the detachable speaker unit  132  is reduced slightly to a non-zero value. The controller  150  may cause audio signals and/or power to be sent to the HMD speaker  118  to output the sound therefrom. 
     In a fifth operation  750 , while the detachable speaker unit  132  is coupled to the head-mounted display unit  110 , the detachable speaker unit  132  continues to provide sound output to the user with the volume  132   v  being greater than zero, while the HMD speaker  118  provides no sound to the user. 
     In a sixth operation  760 , acoustic transparency of the detachable speaker unit  132  may be activated, as described previously for the sixth operation  670  of the method  600 . 
     In a seventh operation  770 , noise cancellation of the detachable speaker unit  132  may be activated, as described previously for the seventh operation  670  of the method  600 . 
     It should be noted that aspects of the method  600  may be incorporated into the method  700  in which case the volume  118   v  of the HMD speaker  118  may change to simulate movement of the detachable speaker unit  132  with sound being emitted therefrom. For example, in the second operation  720 , the volume  118   v  may increase to simulate the detachable speaker unit  132  being moved closed to the coupling location on the head-mounted display unit  110 , and in the third operation  730  may increase or stay constant. Further, the method  700  may be used in conjunction with the method  500  described previously, for example, in the third operation  530 . 
     With reference to  FIGS. 8A-8B , for the detachable speaker units  132  that are configured to output sound when detached from the head-mounted display unit  110 , equalization of the sound output by the detachable speaker units  132  may be varied according to the distance from the detachable speaker unit  132  to the head-mounted display unit  110  (e.g., the coupling location thereon). For example, the gain of low frequency sounds (e.g., in a bass range) may increase and the gain of higher frequency sounds may decrease as the detachable speaker unit  132  is moved close to the head-mounted display unit  110 . Decreasing the gain at the low frequency and increasing the gain at the higher frequencies concentrates power output on the higher frequency sounds, which generally consume less power than low frequency sounds for a given volume output. Since power output of the detachable speaker units  132  may be limited due to the portable/detachable nature (e.g., being battery powered) and/or primary use case (e.g., being held in close proximity to the user&#39;s ear E), equalization in this manner may allow the user to experience louder sound while the detachable speaker units  132  are at relatively far distances than if equalization were not performed. 
     Referring to  FIG. 8A , the gain of low frequency sound that is to be output by the detachable speaker unit  132  is referred to as the low frequency gain  832 L, while the gain of the higher frequency sound that is to be output by the detachable speaker unit  132  is referred to as the high frequency gain  832 H. The low frequency gain  832 L and the high frequency gain  832 H are represented by plots with the Y-axis being gain and the X-axis being distance between the detachable speaker unit  132  and the head-mounted display unit  110  (e.g., the coupling location thereon) with the zero distance on the right (i.e., the detachable speaker unit  132  moves closer to the coupling location moving rightward along the plots). 
     At relatively far distances between the detachable speaker unit  132  and the head-mounted display unit  110 , the low frequency gain  832 L is below one, for example, starting at zero. As the distance decreases, such as when the user moves the detachable speaker unit  132  toward the head-mounted display unit  110  (e.g., to the coupling location over the user&#39;s ear E), the low frequency gain increases, for example, ending at one. Conversely, the high frequency gain  832 H is above one at relatively far distances and decreases as the distance decreases, for example, ending at one. As a result, at relatively far distances, the low frequency gain  832 L is below one and the high frequency gain  832 H is above one, and the difference between the low frequency gain  832 L and the high frequency gain  832 H decreases as the distance decreases, for example, with the difference ending at zero. 
     Instead or additionally, at relatively close distances, the gain for low frequency sound may be increased to above one at relatively close distances, such as when the detachable speaker unit  132  is in the user&#39;s hand and being moved toward the head-mounted display unit  110  to be coupled thereto. Such low frequency sound may have a tendency to roll off (e.g., be attenuated) when the detachable speaker unit  132  is held by the user, and increasing the gain for such low frequency sound may provide flatter sound, or the perception of flatter sound, to the user. Thus, referring again to  FIG. 8A , an alternative gain of low frequency sound that is to be output by the detachable speaker unit  132  is referred to as the low frequency gain  832 L′. At relatively close distances between the detachable speaker unit  132  and the head-mounted display unit  110 , the low frequency gain  832 L′ may increase to above one and, as the distance decreases, decrease in a gradual (as shown) or stepped manner, for example, toward and/or to one. At relatively far distances, the low frequency gain  832 L′ may be the same as the low frequency gain  832 L (e.g., starting below one, such as at zero, and increasing as the distance decreases) or other value (e.g., being one). 
       FIG. 8B  illustrates a method  800  for outputting sound from the detachable speaker units  132  using equalization audio signal processing according to a position of the audio headset  130  and/or the detachable speaker units  132  individually relative to the head-mounted display unit  110  (e.g., to a coupling location on the head-mounted display unit  110 ). The method  800  may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . While discussed in conjunction with respect to just one of the detachable speaker units  132 , the method  800  should be understood to be applicable to each of the detachable speaker units  132  and the audio headset  130 . The method  800  may be referred to as an equalization method or an equalization audio signal processing method, and may be used alone and/or in conjunction with the method  700 . 
     In a first operation  810 , a position of the detachable speaker unit  132  relative to the head-mounted display unit  110  (e.g., the predetermined coupling location thereon) is determined, which may be performed in the manner described above for the first operation  610  of the method  600 . 
     In a second operation  820 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being relatively far (e.g., greater than a threshold distance), the low frequency gain  832 L is below one and/or the high frequency gain  832 H is above one, and sound is output from the detachable speaker unit  132  according to the low frequency gain  832 L and/or the high frequency gain  832 H. The controller  150  may adjust the low frequency gain  832 L and the high frequency gain  832 H, for example as shown in  FIG. 8A , and cause audio signals and/or power to be sent to the detachable speaker unit  132  to output the sound therefrom according to such adjusted gains. The output sound may contain the aural content, such as that pertaining to the virtual or mixed reality experience. 
     In a third operation  830 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being in an intermediate range (e.g., below the threshold distance and above a second threshold) and reducing, the low frequency gain  832 L is increased and/or the high frequency gain  832 H is decreased, and sound is output from the detachable speaker unit  132  according to the low frequency gain  832 L and/or the high frequency gain  832 H (as adjusted). The controller  150  may adjust the low frequency gain  832 L and the high frequency gain  832 H, for example as shown in  FIG. 8A , and cause audio signals and/or power to be sent to the detachable speaker unit  132  to output the sound therefrom according to such adjusted gains. 
     In a fourth operation  840 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being in a relatively close range (e.g., below the second threshold) and reducing, the low frequency gain may optionally be increased to above one and may thereafter further optionally decease toward one as the distance reduces to zero. The controller  150  may adjust the low frequency gain  832 L′, and cause audio signals and/or power to be sent to the detachable speaker unit  132  to output the sound therefrom according to such gain. 
     With reference to  FIGS. 9A-9B , for the detachable speaker units  132  that are configured output sound when detached from the head-mounted display unit  110 , the dynamic range of the sound output by the detachable speaker units  132  may be varied according to the distance of the detachable speaker unit  132  relative to the head-mounted display unit  110  (e.g., the coupling location thereon). The dynamic range generally refers to the range of volume between loud and soft sounds, while dynamic range compression refers to audio signal processing of decreasing the volume of the louder sounds and/or amplifying the quieter sounds. For example, dynamic range compression may be applied at decreasing levels as the detachable speaker unit  132  is moved closer to the head-mounted display unit  110 , thereby resulting in a lower dynamic range at relatively far distances and higher dynamic range at lower distances. Applying dynamic range compression in this manner may, for example, allow the user to hear more sounds and/or experience a consistent louder volume from the detachable speaker unit  132  at relatively far distances. 
     Referring to  FIG. 9A , the dynamic range  932 R of the sound that is to be output by the detachable speaker unit is illustrated as a function of the distance between the detachable speaker unit  132  and the head-mounted display unit  110  (e.g., the coupling location thereon). As the distance decreases, less dynamic compression is applied, such that the dynamic range  932 R increases. 
       FIG. 9B  illustrates a method  900  for outputting sound from the detachable speaker units  132  using dynamic range compression audio signal processing according to a position of the audio headset  130  and/or the detachable speaker units  132  individually relative to the head-mounted display unit  110  (e.g., to a coupling location on the head-mounted display unit  110 ). The method  900  may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . While discussed in conjunction with respect to just one of the detachable speaker units  132 , the method  900  should be understood to be applicable to each of the detachable speaker units  132  and the audio headset  130 . The method  900  may be referred to as a dynamic range compression method or a dynamic range compression audio signal processing method, and may be used alone and/or in conjunction with the method  700  and/or the method  800 . 
     In a first operation  910 , a position of the detachable speaker unit  132  relative to the head-mounted display unit  110  (e.g., the predetermined coupling location thereon) is determined, which may be performed in the manner described above for the first operation  610  of the method  600 . 
     In a second operation  920 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being relatively far (e.g., greater than a threshold distance), a relatively high level of dynamic range compression is applied to achieve a relatively low dynamic range. The controller  150  may apply dynamic range compression, for example, to achieve the dynamic range  932 R shown in  FIG. 9A , and cause audio signals and/or power to be sent to the detachable speaker unit  132  to output the sound therefrom according to such dynamic range. The output sound may contain the aural content, such as that pertaining to the virtual or mixed reality experience. 
     In a third operation  930 , based on the position of the detachable speaker unit  132  relative to the head-mounted display unit  110  being in intermediate range (e.g., below the threshold distance) and reducing, the level of dynamic range compression applied is reduced to achieve a relatively high dynamic range. The controller  150  may apply dynamic range compression, for example, to achieve the dynamic range  932 R shown in  FIG. 9A , and cause audio signals and/or power to be sent to the detachable speaker unit  132  to output the sound therefrom according to such dynamic range. 
     Referring to  FIGS. 10A-10D , the display system  100  may be configured to display a visual indicator  1060  associated with the audio headset  130 . For example, prior to the detachable speaker units  132  being coupled to the head-mounted display unit  110 , the head-mounted display unit  110  may provide visual content that includes the visual indicator  1060 , such as an animation, icon, or other indicator, which may be in spatial proximity to the audio headset  130 . The visual indicator  1060  may suggest or otherwise indicate the sound output capability of the audio headset  130  and/or provide instructions for use thereof. While discussed in conjunction with the display system  100  and the components thereof (e.g., the head-mounted display unit  110  and the audio headset  130 ), the concepts and method discussed with respect to  FIGS. 10A-10D  are applicable to the display systems  200 ,  300 ,  400 . 
     For example, in  FIG. 10A , the user may view the display screen  114  of the head-mounted display unit  110  and see the audio headset  130  within the field of view as a real object in a mixed reality experience (e.g., via video or optical pass-through as described above), or as a virtual object in a virtual reality experience, wherein the audio headset  130  is depicted by rendered graphics. For illustrative purposes, the audio headset  130  is positioned on a table of the real environment. As shown in  FIG. 10B , the display screen  114  may also display the visual indicator  1060 , which may be visually associated with the audio headset  130 , for example, by being depicted in close proximity thereto, such as by surrounding and/or overlaying the audio headset  130 . 
     The visual indicator  1060  suggests or otherwise communicates the audio capabilities and/or use of the audio headset  130 . In one example, the visual indicator is an audio-related icon, such as sound waves (as shown), a depiction of traditional headphones, or other icon suggestive of the audio capabilities or use of the audio headset  130 . Instead or additionally, the visual indicator  1060  may be an animation, such as sound waves emitting from the audio headset  130 . The motion and/or intensity of the visual indicator  1060  (e.g., animation of sound waves) may be correlated to the sound related thereto, for example, by changing appearance in accordance with the sound being output. For example, the visual indicator  1060  may visually pulsate according to a beat of the sound or music (e.g., faster or slower according to a faster or slower beat, respectively, of the sound) or intensity of a sonic event (e.g., increasing in size and/or pulsating faster coincident with a real or virtual event expected to produce a loud and/or intense sound, such as an explosion). 
     The visual indicator  1060  may be positioned in spatial proximity (e.g., in close proximity, overlaying, and/or surrounding) to the audio headset  130  and/or the detachable speaker units  132  individually. The location of the audio headset  130  may be determined in the manners described above, for example, by using the sensors of the head-mounted display unit  110  (e.g., the camera  116  for video recognition of the audio headset  130 , or the motion sensors  120 ) and/or the sensing electronics  138   d  of the detachable speaker units  132  (e.g., camera, motion sensors, etc.). 
     The visual indicator  1060  or variations thereof may suggest or otherwise communicate how to use the audio headset  130 , for example, displaying one or more diagrams illustrating how to use the audio headset  130 . Referring to  FIG. 10C , for example, when the detachable speaker units  132  are not in the field of view of the user, a visual indicator  1070  may guide the user in moving the detachable speaker unit  132  to the coupling location on the head-mounted display unit  110 . The visual indicator  1070  includes an illustration  1070   a  representing the detachable speaker unit  132  and another illustration  1070   b  representing the coupling location. The illustrations  1070   a ,  1070   b  may be displayed in a spatial relationship to each other representing the physical spatial arrangement between the detachable speaker unit  132  and the coupling location on the head-mounted display unit  110 , thereby communicating to the user required movement for coupling the detachable speaker unit  132 . For example, as shown, the illustration  1070   a  (i.e., representing the detachable speaker unit  132 ) is positioned downward and rightward of the illustration  1070   b  (i.e., representing the coupling location on the head-mounted display unit  110 ), which may represent the right detachable speaker unit  132  being forward of and lower than the coupling location. The visual indication  1070  may instead or additionally include iconography (e.g., arrows), text (e.g., written text), and/or animations (e.g., depicting movement of the illustration  1070   a  toward the illustration  1070   b ) instructing the user where to move the detachable speaker unit  132  for being coupled to the head-mounted display unit  110 . 
     Referring to  FIG. 10D , a method  1000  for providing visual content with a display system and, in particular, for providing a visual indicator related to an audio output device. The display system may, for example, be one of the display systems  100 ,  200 ,  300 ,  400 . The method  1000  may, for example, be implemented with the controller  150  and the various sensors of the head-mounted display unit  110  and the detachable speaker units  132 . For simplicity, the method  1000  is discussed in conjunction with the display system  100  but should be understood as being applicable to the display systems  200 ,  300 ,  400 . Additionally, while discussed generally with respect to the detachable speaker unit  132  below, the method  1000  should be understood to be applicable to each of the detachable speaker units  132 , the audio headset  130 , or another audio output device, such as an external speaker. 
     In a first operation  1010 , a position of the audio output device (e.g., the audio headset  130 , the detachable speaker unit  132 , or other audio output device) is determined. The position of the audio output device may be determined, for example, by the controller  150  using sensors of the head-mounted display unit  110 , such as by processing video received from the camera  116 , or the sensing electronics  138   d  of the detachable speaker units  132  (e.g., if the detachable speaker units  132  are powered independent of being coupled to the head-mounted display unit  110 ), such as by detecting movement toward the head-mounted display unit  110  and or change in proximity therebetween. 
     In a second operation  1020 , while the audio output device is in the field of view of the head-mounted display unit, a visual indicator  1060  is displayed in spatial proximity to the audio output device. For example, the controller  150  may send display signals to the head-mounted display unit  110  for displaying the visual indicator  1060  with the display screen  114  according to the position determined in the first operation  1010 . The visual indicator  1060  may, as described above, visually communicate to the user an audio characteristic of the audio output device (e.g., showing an icon or animation resembling sound waves or type of audio device, such as headphones) and/or instructions for using the audio output device (e.g., for coupling the detachable speaker unit  132  to the head-mounted display unit  110 ). The field of view of the head-mounted display unit  110  is that portion of the real environment which is viewable by the user at a given time. 
     In a third operation  1030 , when the audio output device is outside the field of view of the display screen  114 , the visual indicator  1070  is displayed to illustrate the physical proximity of the audio output device to the head-mounted display unit (e.g., of the detachable speaker unit  132  to the coupling location). For example, the controller  150  may send display signals to the head-mounted display unit  110  for displaying the visual indicator  1070  with the display screen  114  according to the position determined in the first operation  1010 . As discussed above, the visual indicator  1070  may include the illustration  1070   a  representing the detachable speaker unit  132 , and the illustration  1070   b  representing the coupling location in spatial relationship thereto representing the physical spatial relationship (e.g., the physical proximity) of the detachable speaker unit  132  to the coupling location on the head-mounted display unit  110 . It should be noted that one, the other, or both of the second operation  1020  and the third operation  1030  may be performed. 
     In a fourth operation  1040 , which may occur simultaneous to the second operation  1020  (i.e., when the audio output device is within the field of view) and/or the third operation  1030  (i.e., when the audio output device is outside the field of view), the virtual aural content may be output by the HMD speakers  118 , which may spatially simulate sound being emitted from the audio output device (e.g., being spatially balanced left-to-right and/or changing in volume to represent the left-right orientation and/or distance, respectively, of the audio output device). The virtual aural content may correspond to the visual indicator  1060  or the visual indicator  1070 , for example, coinciding in time with display thereof. 
     While the method  1000  is discussed as providing both of the visual indicators  1060 ,  1070 , the method  1000  may instead include operations for providing only one of the visual indicators  1060 ,  1070 . 
     As referenced above, the method  1000  may be used with an audio output device other than the audio headset  130  or the detachable speaker units  132 , which is associated with the display system  100 . For example, another audio output device may be an external speaker that is not physically coupleable to the head-mounted display unit. 
     Furthermore, the method  1000  may be used in conjunction with the methods  500 ,  600 ,  700  discussed above. For example, the visual indicators  1060 ,  1070  may be displayed simultaneous with the sound output from the HMD speakers  118  and/or the detachable speaker units  132  as described with the methods  500 ,  600 ,  700 ,  800 ,  900 . 
     Referring to  FIG. 11 , the controller  150  may have the hardware configuration as shown and described, or other suitable configuration. The controller  150  may include a processor  1151 , memory  1152 , storage  1153 , a communications interface  1154 , and a bus  1155  connecting such components or devices for communication therebetween. The processor  1151  is operable to execute computer program instructions and perform operations described by such instructions. As an example, the processor  1151  may be a central processing unit or o other conventional processing device. The memory  1152  may be a volatile, high-speed, short-term information storage device (e.g., random-access memory module). The storage  1153  may be a non-volatile information storage device (e.g., a hard drive). The communications interface  1154  is configured to send and/or receive signals (e.g., wired or wirelessly), such as to and/or from the head-mounted display unit  110  and/or the audio headset  130 . 
     A physical environment refers to a physical world that people can sense and/or interact with without aid of electronic systems. Physical environments, such as a physical park, include physical articles, such as physical trees, physical buildings, and physical people. People can directly sense and/or interact with the physical environment, such as through sight, touch, hearing, taste, and smell. 
     In contrast, a computer-generated reality (CGR) environment refers to a wholly or partially simulated environment that people sense and/or interact with via an electronic system. In CGR, a subset of a person&#39;s physical motions, or representations thereof, are tracked, and, in response, one or more characteristics of one or more virtual objects simulated in the CGR environment are adjusted in a manner that comports with at least one law of physics. For example, a CGR system may detect a person&#39;s head turning and, in response, adjust graphical content and an acoustic field presented to the person in a manner similar to how such views and sounds would change in a physical environment. In some situations (e.g., for accessibility reasons), adjustments to characteristic(s) of virtual object(s) in a CGR environment may be made in response to representations of physical motions (e.g., vocal commands). 
     A person may sense and/or interact with a CGR object using any one of their senses, including sight, sound, touch, taste, and smell. For example, a person may sense and/or interact with audio objects that create 3D or spatial audio environment that provides the perception of point audio sources in 3D space. In another example, audio objects may enable audio transparency, which selectively incorporates ambient sounds from the physical environment with or without computer-generated audio. In some CGR environments, a person may sense and/or interact only with audio objects. 
     Examples of CGR include virtual reality and mixed reality. 
     A virtual reality (VR) environment refers to a simulated environment that is designed to be based entirely on computer-generated sensory inputs for one or more senses. A VR environment comprises a plurality of virtual objects with which a person may sense and/or interact. For example, computer-generated imagery of trees, buildings, and avatars representing people are examples of virtual objects. A person may sense and/or interact with virtual objects in the VR environment through a simulation of the person&#39;s presence within the computer-generated environment, and/or through a simulation of a subset of the person&#39;s physical movements within the computer-generated environment. 
     In contrast to a VR environment, which is designed to be based entirely on computer-generated sensory inputs, a mixed reality (MR) environment refers to a simulated environment that is designed to incorporate sensory inputs from the physical environment, or a representation thereof, in addition to including computer-generated sensory inputs (e.g., virtual objects). On a virtuality continuum, a mixed reality environment is anywhere between, but not including, a wholly physical environment at one end and virtual reality environment at the other end. 
     In some MR environments, computer-generated sensory inputs may respond to changes in sensory inputs from the physical environment. Also, some electronic systems for presenting an MR environment may track location and/or orientation with respect to the physical environment to enable virtual objects to interact with real objects (that is, physical articles from the physical environment or representations thereof). For example, a system may account for movements so that a virtual tree appears stationery with respect to the physical ground. 
     Examples of mixed realities include augmented reality and augmented virtuality. 
     An augmented reality (AR) environment refers to a simulated environment in which one or more virtual objects are superimposed over a physical environment, or a representation thereof. For example, an electronic system for presenting an AR environment may have a transparent or translucent display through which a person may directly view the physical environment. The system may be configured to present virtual objects on the transparent or translucent display, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. Alternatively, a system may have an opaque display and one or more imaging sensors that capture images or video of the physical environment, which are representations of the physical environment. The system composites the images or video with virtual objects, and presents the composition on the opaque display. A person, using the system, indirectly views the physical environment by way of the images or video of the physical environment, and perceives the virtual objects superimposed over the physical environment. As used herein, a video of the physical environment shown on an opaque display is called “pass-through video,” meaning a system uses one or more image sensor(s) to capture images of the physical environment, and uses those images in presenting the AR environment on the opaque display. Further alternatively, a system may have a projection system that projects virtual objects into the physical environment, for example, as a hologram or on a physical surface, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. 
     An augmented reality environment also refers to a simulated environment in which a representation of a physical environment is transformed by computer-generated sensory information. For example, in providing pass-through video, a system may transform one or more sensor images to impose a select perspective (e.g., viewpoint) different than the perspective captured by the imaging sensors. As another example, a representation of a physical environment may be transformed by graphically modifying (e.g., enlarging) portions thereof, such that the modified portion may be representative but not photorealistic versions of the originally captured images. As a further example, a representation of a physical environment may be transformed by graphically eliminating or obfuscating portions thereof. 
     An augmented virtuality (AV) environment refers to a simulated environment in which a virtual or computer generated environment incorporates one or more sensory inputs from the physical environment. The sensory inputs may be representations of one or more characteristics of the physical environment. For example, an AV park may have virtual trees and virtual buildings, but people with faces photorealistically reproduced from images taken of physical people. As another example, a virtual object may adopt a shape or color of a physical article imaged by one or more imaging sensors. As a further example, a virtual object may adopt shadows consistent with the position of the sun in the physical environment. 
     There are many different types of electronic systems that enable a person to sense and/or interact with various CGR environments. Examples include head mounted systems, projection-based systems, heads-up displays (HUDs), vehicle windshields having integrated display capability, windows having integrated display capability, displays formed as lenses designed to be placed on a person&#39;s eyes (e.g., similar to contact lenses), headphones/earphones, speaker arrays, input systems (e.g., wearable or handheld controllers with or without haptic feedback), smartphones, tablets, and desktop/laptop computers. A head mounted system may have one or more speaker(s) and an integrated opaque display. Alternatively, a head mounted system may be configured to accept an external opaque display (e.g., a smartphone). The head mounted system may incorporate one or more imaging sensors to capture images or video of the physical environment, and/or one or more microphones to capture audio of the physical environment. Rather than an opaque display, a head mounted system may have a transparent or translucent display. The transparent or translucent display may have a medium through which light representative of images is directed to a person&#39;s eyes. The display may utilize digital light projection, OLEDs, LEDs, uLEDs, liquid crystal on silicon, laser scanning light source, or any combination of these technologies. The medium may be an optical waveguide, a hologram medium, an optical combiner, an optical reflector, or any combination thereof. In one embodiment, the transparent or translucent display may be configured to become opaque selectively. Projection-based systems may employ retinal projection technology that projects graphical images onto a person&#39;s retina. Projection systems also may be configured to project virtual objects into the physical environment, for example, as a hologram or on a physical surface. 
     As described above, one aspect of the present technology is the gathering and use of data available from various sources to display visual content and output audio content, which may include varying content based on movement or conditions of the head or eyes of the user. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to output content. Accordingly, use of such personal information data enables users an enhanced user experience. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of observing conditions or movements of the head or eyes of the user, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide user movement or condition data or can select to limit the length of time user observation data is observed or maintained. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be provided to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, or publicly available information.

Metadata:
Filing Date: 20180927
Publication Date: 20201124
Grant Date: 20201124
Priority Date: 20180614
Inventors: EVANS, NEAL D.
VANDYKE, James W.
HULVA, Andrew M.
SILFVAST, ROBERT D.
EUBANK, Christopher T.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/26", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/012", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03G5/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04815", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1083", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2460/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1066", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2430/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/0335", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03G5/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/0335", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B27/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 64017441