Embodiments herein relate generally to sound reproduction systems and methods and more specifically to providing an immersive listening area for a plurality of listeners using a rear sound bar.
Systems and methods are described for providing an immersive listening area. In an embodiment of a method for a providing an immersive listening area, a rear virtualizer receives a first set of rear audio signals. The rear virtualizer processes the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar. This processing uses a first virtualization algorithm. In addition, a first set of front audio signals suitable for playback on a front set of speakers is created.
In an embodiment of the method, the first virtualization algorithm accounts for: a speaker configuration of the rear sound bar, an intended location of the rear sound bar being behind a listener, and an intended distance of the listener from the rear sound bar.
In an embodiment of the method, the intended location of the rear sound bar includes being adjacent to a rear wall, and the intended distance of the listener from the rear sound bar is within a pre-determined distance.
An embodiment of the method further includes: providing the second set of rear audio signals to the rear sound bar, and providing a first set of front audio signals to a front set of speakers, creating a rear sound stage by the rear sound bar upon playback of the second set of rear audio signals, and creating a front sound stage by the front set of speakers upon playback of the first set of front audio signals. In this embodiment, the front sound stage combines with the rear sound stage to create an overall sound stage.
In an embodiment of the method, processing, by the rear virtualizer, the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar includes: decorrolating the received first set of rear audio signals to create a decorrolated set of rear audio signals based on a number of channels in the rear sound bar; gain-adjusting the decorrolated set of rear audio signals to create a gain-adjusted set of rear audio signals, and cross-mixing the gain-adjusted set of rear audio signals to create the second set of rear audio signals.
In an embodiment of the method, processing, by the rear virtualizer, the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar includes: processing, by a rear height virtualizer, a subset of the received first set of rear audio signals; not processing, by the rear height virtualizer, the remainder of the received first set of rear audio signals. The embodiment then includes, using the first virtualization algorithm to: decorrolate the processed subset and the remainder of the received first set of rear audio signals to create a decorrolated set of rear audio signals based on a number of channels in the rear sound bar; gain-adjust the decorrolated set of rear audio signals to create a gain-adjusted set of rear audio signals; and cross-mix the gain-adjusted set of rear audio signals to create the second set of rear audio signals.
In an embodiment of the method, the front set of speakers is included within a front sound bar, and the first set of front audio signals are front audio signals suitable for playback on the front sound bar. In this embodiment, the first set of front audio signals are created by processing, by a front virtualizer, an initial set of front audio signals to create the first set of front audio signals. This processing uses a second virtualization algorithm that accounts for: a speaker configuration of the front sound bar, and an intended distance of the listener from the front sound bar.
In an embodiment of the method, the first virtualization algorithm employs at least one of: cross talk cancellation, binauralization, and diffuse panning.
According to another embodiment, an audio processing unit includes a memory and a processor, the memory including instructions which when executed by the processor perform a method for providing an immersive listening area. In this embodiment, the method comprises: receiving, by a rear virtualizer, a first set of rear audio signals; processing, by the rear virtualizer, the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar, the processing using a first virtualization algorithm; and creating a first set of front audio signals suitable for playback on a front set of speakers.
In an embodiment of the audio processing unit, the first virtualization algorithm accounts for: a speaker configuration of the rear sound bar, an intended location of the rear sound bar being behind a listener, and an intended distance of the listener from the rear sound bar.
In an embodiment of the audio processing unit, the intended location of the rear sound bar includes being adjacent to a rear wall, and the intended distance of the listener from the rear sound bar is within a pre-determined distance.
In an embodiment of the audio processing unit, the audio processing unit further includes the rear sound bar and the method further comprises: providing, by the audio processing unit, the second set of rear audio signals to the rear sound bar.
In an embodiment of the audio processing unit, the processing, by the rear virtualizer component, the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar includes: decorrolating the received first set of rear audio signals to create a decorrolated set of rear audio signals based on a number of channels in the rear sound bar; gain-adjusting the decorrolated set of rear audio signals to create a gain-adjusted set of rear audio signals, and cross-mixing the gain-adjusted set of rear audio signals to create the second set of rear audio signals.
In an embodiment of the audio processing unit, the processing, by the rear virtualizer component, the first set of rear audio signals to create a second set of rear audio signals suitable for playback on a rear sound bar includes: processing, by a rear height virtualizer, a subset of the received first set of rear audio signals; and not processing, by the rear height virtualizer, the remainder of the received first set of rear audio signals. The embodiment then includes, using the first virtualization algorithm to: decorrolate the processed subset and the remainder of the received first set of rear audio signals to create a decorrolated set of rear audio signals based on a number of channels in the rear sound bar; gain-adjust the decorrolated set of rear audio signals to create a gain-adjusted set of rear audio signals; and cross-mix the gain-adjusted set of rear audio signals to create the second set of rear audio signals.
In an embodiment, the method further comprises creating a first set of front audio signals for a front set of speakers.
In an embodiment, the front set of speakers includes a front sound bar, and the first set of front audio signals are front audio signals suitable for playback on the front sound bar. In this embodiment, the method further comprises processing, by a front virtualizer component, an initial set of front audio signals to create the first set of front audio signals, where the processing uses a second panning algorithm that accounts for: a speaker configuration of the front sound bar, and an intended distance of the listener from the front sound bar.
In an embodiment, the first virtualization algorithm uses at least one of: cross talk cancellation, binauralization, and diffuse panning.
In another embodiment, a system for a providing an immersive listening area comprises: a decoder configured to provide a front set and a rear set of signals; a front plurality of speakers configured to provide a front sound stage upon receiving the front set of signals; a rear virtualizer configured to receive the rear set of signals and to provide a set of virtualized rear signals; and a rear sound bar configured to receive the set of virtualized rear signals and provide a rear sound stage upon playback of the virtualized rear signals.
In an embodiment of the system, the first virtualization algorithm accounts for: a speaker configuration of the rear sound bar, an intended location of the rear sound bar being behind a listener, and an intended distance of the listener from the rear sound bar.
In an embodiment of the system, the intended location of the rear sound bar includes being adjacent to a rear wall, and the intended distance of the listener from the rear sound bar is within a pre-determined distance.
In an embodiment of the system, the rear virtualizer includes a height virtualizer, a decorrolator, and a gain-adjusted cross-mixer, and the height virtualizer is configured to receive the rear height signals and provide a set of virtualized height signals to the decorrolator, the decorrolator is configured to receive the rear surround signals and the virtualized height signals and provide a decorrolated set of signals to the gain-adjusted cross-mixer, and the gain-adjusted cross-mixer is configured to provide the set of virtualized rear signals to the rear sound bar.
In an embodiment of the system, the rear virtualizer includes a first decorrolator, a second decorrolator, and a gain-adjusted cross-mixer, and the first decorrolator is configured to receive a first rear signal and provide a first decorrolated set of signals to the gain-adjusted cross-mixer, the second decorrolator is configured to receive a second rear signal and provide a second set of decorrolated signals to the gain-adjusted cross-mixer, and the gain-adjusted cross-mixer is configured to provide the third set of signals using the first and second sets of decorrolated signals.
In an embodiment of the system, to provide a virtualized set of rear signals, the rear virtualizer uses at least one of: cross talk cancellation, binauralization, and diffuse panning.
This disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which:
Discrete multichannel surround sound systems may provide a large immersive listening area (or “sweet spot”) in which a listener may have an immersive listening experience because the speakers may be placed around the listeners' position. In other words, a spatially encompassing sound stage (an “immersive listening area”) may be created using an unrestricted set of speakers. Regarding “unrestricted,” the speaker set is “unrestricted” in the sense that the speakers may be located freely around the listener, including, for example, speakers in the listener plane (e.g. left/right surround speakers) or above and below the listeners (e.g. ceiling speakers). In contrast, a front sound stage is an example of a non-encompassing sound stage (a “non-immersive listening area”) that may be created using a restricted set of speakers, where “restricted” means that the speakers are all located in front of the listener. Auditory scenes created using any of the sets of, e.g.: mono/front; left and right; left, right, and center; or a sound bar in front of the listener virtualizing such channels would be considered front sound stages.
See, for example,
In contrast, small living spaces typically require that at least some of the speakers of discrete multichannel surround sound setups be placed very close to the listener's position—the room does not allow the unrestricted placement of the speakers. This results in a very small area providing an immersive experience, or reduces or prevents the ability of the system to provide an immersive listening area at the listeners' location. See, for example,
Furthermore listener 114 is much closer to speaker 110 than is listener 116. Similarly, listener 116 is much closer to speaker 112 than listener 114. Thus, each may have a significantly different listening experience—one which is very probably not ideal since neither listener is within immersive listening area 202. It should be noted that the relative sizes of immersive listening areas 118 (
One known solution to surround sound in small home theatre space 200 is to use a sound bar at the front of the room, under TV screen 102, with post-processing to virtualize the presence of a complete home theatre installation with discrete speakers. These systems can be very effective at creating a wide and high soundstage for the listener. However, virtualization effects of such systems are insufficient to make a listener believe that sound is coming from behind the listener. The result of listening to content, which is intended to be immersive, using only a sound bar at the front of the room is that the rear auditory sound stage disappears, leaving only the front sound stage. The overall sound stage (i.e., the locations from which the sound may appear to originate) is thus limited to, at best, the 180 degrees in front of the listeners, and cannot completely envelope them. A current solution to this limitation is to pair a front sound bar with rear satellite speakers, e.g., speakers 110, 112 (
An object of the disclosed subject matter is to overcome these limitations by using a rear speaker array that receives virtualized speaker input signals (e.g., a sound bar that receives virtualized speaker input signals) to provide an immersive listening area. Thus, embodiments may provide an immersive listening experience to a plurality of listeners. To provide the immersive experience embodiments pair a rear sound bar, placed behind the listeners, with a front sound bar or discrete front speakers or both, placed at the front of the room. In an embodiment, the surround channels of the rear sound bar undergo customized processing to create a virtualized rear sound stage, which, when combined with the sound stage created by the front sound bar or discrete speakers or both, creates an overall sound stage large enough to encompass the listeners, providing each listener an immersive listening experience.
In an embodiment, an immersive listening area may be realized in a small home theater room using a rear sound bar with relatively small drivers, making the sound bar small and narrow enough to fit, for example, behind a chair in the room. Advantages of using such a form factor include that the sound bar occupies less space than discrete satellite speakers and that the rear sound bar provides a rear sound stage representation—one that, when combined with a front sound stage, may provide listeners with an immersive listening experience.
Generally, the speakers of rear sound bar 306 may be oriented to direct sound toward the locations of the intended listeners, e.g., if floor-located, rear sound bar 306 may have upward firing speakers, or a combination of upward, forward, and side firing speakers; if ear-level located, rear sound bar 206 may have forward firing speakers, or a combination of forward, upward, downward, and side-firing speakers; and if ceiling-located, rear sound bar 306 may have downward-firing speakers, or a combination of downward, forward, and side-firing speakers.
In
Rear sound bar 306 may process, e.g., left rear surround (Lrs) and right rear surround (Rrs) input signals (not shown), to provide virtualized signals for speakers 308a . . . 308m. In an embodiment, rear sound bar 306 may also process additional inputs signals such as left rear top (Lrt) and right rear top (Rrt). For virtualization, rear sound bar 306 receives input signals based on standard audio coding and performs additional audio processing such that, when used to drive speakers 308a . . . 308m, the virtualized speaker signals distribute and render a rear sound stage. In other words, a panning algorithm is applied to the standard audio coding that takes into account: the rear sound bar speaker configuration and orientation; the rear sound bar position in the environment; and the rear sound bar position with respect to the intended listener location. In the example of
Similarly a front sound stage is created as a result of the virtualization of the front speaker signals using front sound bar 302, by using discrete speakers, or with a combination of the two. The combination of the front and rear sound stages results in an immersive listening area 310 that may encompass both listeners 114, 116, providing an immersive listening area for each. When each listener is within the immersive listening area, each listener receives, more or less, an equivalent listening experience, which is preferably to the different listening experiences received by listeners 114, 116 in
In
In
In embodiments, front sound bar 408 and rear sound bar 412 may be positioned within room 200 (
In
In
In
Virtualization for Speaker Arrays
In embodiments, a sound stage may be created by an array of discrete speakers, by virtualized signals sent to a soundbar, or by a combination of these. Generally, an array of discrete speakers and a speaker bar may each be called a type of “speaker array.” Embodiments may virtualize a sound stage from a speaker array that is positioned in front of, behind, or a combination of in front of and behind the listeners, i.e., “about” the listeners. Embodiments may virtualize a sound stage where a speaker array is intended to be close to (e.g., less than one meter) or far from (e.g., typically greater than one and a half meters) the listeners. Embodiments may virtualize signals for a speaker array using discrete channels in a multichannel playback or using single objects in an object-based playback (such as Dolby Atmos®). In addition to the following methods of virtualization, it is envisioned that other methods of virtualization may achieve similar effects.
Cross talk cancellation algorithms (or “cross talk cancellers”) are effective at creating a wider stereo image from a small device. They are employed as part of the virtualization on many consumer electronic devices—including TVs, mobile phones, laptops, and soundbars.
Because a cross talk canceller may be configured to use any HRTF they are suitable for speaker arrays (soundbars, discrete arrays, or combinations thereof) that are intended to be used in front of, behind, or above the listener. When the speaker array is closer to the listener, the variation in the HRTF approximation is more sensitive to perceivable “errors” in the cross talk cancellation. For this reason, cross talk cancellers are more suitable for providing virtualization in situations when the speaker array is intended to be further away from the listeners, such that variations in the listener's position are relatively small compared to the listening distance. Cross talk cancellers, however, may be employed effectively for virtualization when the speaker array is in close proximity to the listener when the listener is relatively stationary.
A binauralization algorithm compensates for the real location by applying, to an output signal, an inverse of the actual HTRF (from the speaker to the listener) and applying an additional HRTF to create a virtualized signal to simulate the sound of the sound source as if it were in the intended location. A binauralization algorithm may be added to, or used in combination with, a cross talk cancellation algorithm.
A rear virtualizer 1200 using a diffuse panning algorithm may create an array of decorrolated outputs, e.g., outputs 1212, from a single original sound source, e.g., signal 1210, and pan them around the listeners. The result is that each listener within the immersive listening area has a general sense of spatial direction for the source. The single sound source could be a single channel in a multichannel playback or a single object in an object-based playback (such as Dolby Atmos®).
A sense of general spatial direction may be achieved by scaling the array of decorrolated outputs along the length of a speaker array with a linear ramping of gains. The linear ramp may cause some of the spatial accuracy of the sound source to become more diffuse. However, ramped, decorrolated, and cross-mixed output 1228 may provide a significant increase in the size of the immersive zone for the listeners.
Because diffuse panning increases the size of an immersive listening area, it is ideal for a speaker array positioned close to (e.g., less than one meter from) a group of listeners. The diffuse panning virtualizer may be used in front or behind the listeners however it may be more appropriate to use this setup behind the listeners when paired with a discrete speaker or cross talk cancelling and binaruralizing front sound bar. For these reasons, the embodiments described with reference to
Returning to
In the various embodiments, the number and configuration of the speakers and sound bars are provided as examples and should not be understood as limiting. Other embodiments may include more or fewer speakers and different configurations, e.g., forward, upward, and side-firing drivers, and may have the soundbar located at different heights and directed at different points in a room.
The embodiments show that the functions performed by the various components of embodiments may be divided and re-located. These embodiments are exemplary of the multitude of potential configurations for any embodiment and do not limit the potential configurations in any way.
The bus 1514 may comprise any type of bus architecture. Examples include a memory bus, a peripheral bus, a local bus, etc. The processing unit 1502 is an instruction execution machine, apparatus, or device and may comprise a microprocessor, a digital signal processor, a graphics processing unit, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. The processing unit 1502 may be configured to execute program instructions stored in memory 1504 and/or storage 1506 and/or received via data entry module 1508.
The memory 1504 may include read only memory (ROM) 1516 and random access memory (RAM) 1518. Memory 1504 may be configured to store program instructions and data during operation of device 1500. In various embodiments, memory 1504 may include any of a variety of memory technologies such as static random access memory (SRAM) or dynamic RAM (DRAM), including variants such as dual data rate synchronous DRAM (DDR SDRAM), error correcting code synchronous DRAM (ECC SDRAM), or RAMBUS DRAM (RDRAM), for example. Memory 1504 may also include nonvolatile memory technologies such as nonvolatile flash RAM ( ) or ROM. Memory 1504 may include non-printed material. In some embodiments, it is contemplated that memory 1504 may include a combination of technologies such as the foregoing, as well as other technologies not specifically mentioned. When the subject matter is implemented in a computer system, a basic input/output system (BIOS) 1520, containing the basic routines that help to transfer information between elements within the computer system, such as during start-up, is stored in ROM 1516.
The storage 1506 may include a flash memory data storage device for reading from and writing to flash memory, a hard disk drive for reading from and writing to a hard disk, a magnetic disk drive for reading from or writing to a removable magnetic disk, and/or an optical disk drive for reading from or writing to a removable optical disk such as a CD ROM, DVD or other optical media. The drives and their associated computer-readable media provide nonvolatile storage of computer readable instructions, data structures, program modules and other data for the hardware device 1500.
It is noted that the methods described herein can be embodied in executable instructions stored in a non-transitory computer readable medium for use by or in connection with an instruction execution machine, apparatus, or device, such as a computer-based or processor-containing machine, apparatus, or device. It will be appreciated by those skilled in the art that for some embodiments, other types of computer readable media may be used which can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, RAM, ROM, and the like may also be used in the exemplary operating environment. As used here, a “computer-readable medium” can include one or more of any suitable media for storing the executable instructions of a computer program in one or more of an electronic, magnetic, optical, and electromagnetic format, such that the instruction execution machine, system, apparatus, or device can read (or fetch) the instructions from the computer readable medium and execute the instructions for carrying out the described methods. A non-exhaustive list of conventional exemplary computer readable medium includes: a portable computer diskette; a RAM; a ROM; an erasable programmable read only memory (EPROM or flash memory); optical storage devices, including a portable compact disc (CD), a portable digital video disc (DVD), a BLU-RAY disc; and the like.
A number of program modules may be stored on the storage 1506, ROM 1516 or RAM 1518, including an operating system 1522, one or more applications programs 1524, program data 1526, and other program modules 1528. A user may enter commands and information into the hardware device 1500 through data entry module 1508. Data entry module 1508 may include mechanisms such as a keyboard, a touch screen, a pointing device, etc. Other external input devices (not shown) are connected to the hardware device 1500 via external data entry interface 1530. By way of example and not limitation, external input devices may include a microphone, joystick, game pad, satellite dish, scanner, or the like. In some embodiments, external input devices may include video or audio input devices such as a video camera, a still camera, etc. Data entry module 1508 may be configured to receive input from one or more users of device 1500 and to deliver such input to processing unit 1502 and/or memory 1504 via bus 1514.
The hardware device 1500 may operate in a networked environment using logical connections to one or more remote nodes (not shown) via communication interface 1512. The remote node may be another computer, a server, a router, a peer device or other common network node, and typically includes many or all of the elements described above relative to the hardware device 1500. The communication interface 1512 may interface with a wireless network and/or a wired network. Examples of wireless networks include, for example, a BLUETOOTH network, a wireless personal area network, a wireless 802.11 local area network (LAN), and/or wireless telephony network (e.g., a cellular, PCS, or GSM network). Examples of wired networks include, for example, a LAN, a fiber optic network, a wired personal area network, a telephony network, and/or a wide area network (WAN). Such networking environments are commonplace in intranets, the Internet, offices, enterprise-wide computer networks and the like. In some embodiments, communication interface 1512 may include logic configured to support direct memory access (DMA) transfers between memory 1504 and other devices.
In a networked environment, program modules depicted relative to the hardware device 1500, or portions thereof, may be stored in a remote storage device, such as, for example, on a server. It will be appreciated that other hardware and/or software to establish a communications link between the hardware device 1500 and other devices may be used.
It should be understood that the arrangement of hardware device 1500 illustrated in
In the description above, the subject matter may be described with reference to acts and symbolic representations of operations that are performed by one or more devices, unless indicated otherwise. As such, it will be understood that such acts and operations, which are at times referred to as being computer-executed, include the manipulation by the processing unit of data in a structured form. This manipulation transforms the data or maintains it at locations in the memory system of the computer, which reconfigures or otherwise alters the operation of the device in a manner well understood by those skilled in the art. The data structures where data is maintained are physical locations of the memory that have particular properties defined by the format of the data. However, while the subject matter is being described in the foregoing context, it is not meant to be limiting as those of skill in the art will appreciate that various of the acts and operation described hereinafter may also be implemented in hardware.
For purposes of the present description, the terms “component,” “module,” and “process,” may be used interchangeably to refer to a processing unit that performs a particular function and that may be implemented through computer program code (software), digital or analog circuitry, computer firmware, or any combination thereof.
It should be noted that the various functions disclosed herein may be described using any number of combinations of hardware, firmware, and/or as data and/or instructions embodied in various machine-readable or computer-readable media, in terms of their behavioral, register transfer, logic component, and/or other characteristics. Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, physical (non-transitory), non-volatile storage media in various forms, such as optical, magnetic or semiconductor storage media.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “hereunder,” “above,” “below,” and words of similar import refer to this application as a whole and not to any particular portions of this application. When the word “or” is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.
In the description above and throughout, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. It will be evident, however, to one of ordinary skill in the art, that the disclosure may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate explanation. The description of the preferred an embodiment is not intended to limit the scope of the claims appended hereto. Further, in the methods disclosed herein, various steps are disclosed illustrating some of the functions of the disclosure. One will appreciate that these steps are merely exemplary and are not meant to be limiting in any way. Other steps and functions may be contemplated without departing from this disclosure.
This application claims priority to U.S. Provisional Patent Application No. 62/572,103, filed on Oct. 13, 2017, the disclosure of which is incorporated herein by reference in its entirety.
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Can I daisy chain multiple sound bars together to create a surround sound from all angles in the room? http://www.tomsguide.com/answers/id-2965440/daisy-chain-multiple-sound-bars-create-surround-sound-angles-room.html. |
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20190116445 A1 | Apr 2019 | US |
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