HK40066532B - Active cancellation of a height-channel soundbar array's forward sound radiation - Google Patents

Description

Active cancellation of forward sound radiation in high-channel bar arrays

Priority claims and related application references:

This application claims priority to the related, jointly owned U.S. Provisional Patent Application No. 62/815,204, filed March 7, 2019, the entire disclosure of which is incorporated herein by reference. This application also relates to (a) jointly owned U.S. Patent No. 9,374,640, (b) jointly owned U.S. Patent No. 9,185,490, and (c) jointly owned U.S. Patent No. 7,231,053, the entire disclosure of which is also incorporated herein by reference for background information and naming purposes.

Technical Field

The present invention relates to sound reproduction in a multi-channel system commonly referred to as a “surround sound” or “home theater” system, and more specifically to a multi-driver loudspeaker system configured as a single-shell “soundbar” for use in front of a listening space.

Background Technology

Listeners use two-channel "stereo systems" and "surround stereo" or "home theater" audio systems for music playback and other types of audio reproduction. Surround stereo or home theater speaker systems are constructed for use with standardized home theater audio systems, which may include multiple playback channels, each typically served by an amplifier and speakers. In a basic Dolby ^™ home theater audio playback system, there are typically five or more channels of basic full-range material plus a subwoofer channel configured to reproduce band-limited low-frequency material. The five basic full-range channels in a basic Dolby Digital 5.1 ^™ system are typically center, front left, front right, left surround, and right surround (e.g., as shown in Figures 1A and 1B). The front left and right front channel speakers are typically positioned near the left and right sides of the video monitor or television in the home theater system, and the front left and right front channels are used by content creators for "stereo" signals (e.g., music) and sound effects.

Unfortunately, setup problems arise when typical surround sound (e.g., Du 5.1) speaker systems are installed in a listener's home, and many users struggle with speaker placement, component connections, and the associated complexities. As a result, many listeners have turned to "soundboard" style home theater speaker systems (e.g., 50), which combine at least the left, center, and right channels into a single enclosure (e.g., 60) configured for use near the user's video display (as shown in Figures 1C, 1D, and 1E) and a separate subwoofer (e.g., 70). Polk Audio has developed numerous soundboard speaker systems (e.g., 50), including those described and illustrated in (a) jointly owned U.S. Patent No. 9,374,640, (b) jointly owned U.S. Patent No. 9,185,490, and (c) jointly owned U.S. Patent No. 7,231,053, the entire disclosure of which is also incorporated herein by reference for background information and naming purposes.

These soundbar systems (“soundbars”) are easier to install and connect, and can be constructed as compact active speaker products for use in virtually any location. However, most soundbars do not provide satisfactory performance for listeners who want to enjoy movies and music from a listening position arranged in the typical user’s listening space. Traditional home theater setups (e.g., 10 shown in Figures 1A and 1B) require the use or installation of multiple pairs of speakers (e.g., a pair of front speakers 16, 18, and two pairs of surround stereo channel speakers placed to the sides (26, 28) and rear of seating area 24, conforming to industry standard Dolby Digital ^™ and compatible formats). Thus, a traditional home theater setup places the listener in listening position 24 in front of the screen or monitor 14 in room 12, with all speakers pointed at the listening position.

Unlike home theater systems, modern commercial cinemas are now equipped with sound systems designed to create an “immersive” or “3-D” sound field using speakers mounted above the listener, thus creating sound images from sources in front, behind, beside, and overhead. For example, the Atmos ^™ system places speakers in or on the ceiling of the cinema to provide overhead sound sources, and it is now possible to use speakers at home to reproduce Atmos ^™ “height” or upward-facing program material, as described in U.S. Patent 9,648,440, the entire disclosure of which is incorporated herein by reference for defining the background and “Atmos” height channel nomenclature. Consumers or home theater enthusiasts who cannot equip their homes with commercial cinema sound equipment but wish to recreate the immersive 3-D sound field experienced with an Atmos ^™ system can configure and install systems with “virtual height” speakers, such as those described and illustrated in Dolby’s U.S. Patent 9,648,440. A competitive height channel or vertical immersive up-angle audio reproduction loudspeaker system is marketed by DTS under the associated trademark.

However, height channel loudspeakers, or loudspeakers with upward-emitting tilting modules, such as those described in Dolby's U.S. Patent 9,648,440 (and those shown in Figure 1E, from which this information is primarily derived), are not entirely satisfactory in practical use because top-emitting height channel loudspeakers do not radiate sound 108 (for overhead sound images) solely toward the ceiling (at 104 in Figure 1E), and thus produce an audibly defective reproduced sound at the listening position (i.e., 24 in Figures 1A, 1B, 1D, and 1E). The applicant has identified an audible sound defect arising from the listener's perception of an unwanted direct radiated sound 113DS from height channel 110, which follows a generally horizontal line directly from height channel loudspeaker 110 toward listening position 24 (as shown in Figure 1E).

Therefore, there is a need for a more efficient, satisfactory, and unobtrusive system and method to provide high-fidelity reproduction of cinema sound in the listening space of a home theater user when the user attempts to recreate or simulate the immersive 3-D sound field experienced by a modern commercial cinema system (such as Atmos ^™ or a system) with high channel audio reproduction.

Summary of the Invention

Therefore, the object of the present invention is to overcome the aforementioned difficulties by providing a method and system for implementing a new speaker configuration and signal processing approach, which overcomes the problems of existing home theater products equipped with ATMOS ^™ or compatible high-channel speakers, and provides high-fidelity reproduction of cinema sound in the listening space of the home theater user when the user attempts to recreate or simulate the immersive 3-D sound field experienced by modern commercial cinema systems (such as ATMOS ^™ or systems).

In the system of this invention, the ATMOS or enabled soundbar and subwoofer home theater audio system (somewhat similar to 50 in Figures 1C and 1D) is modified to include a forward-facing mid-bass transducer in the soundbar housing to reproduce a bandpass phase-inverted copy of the ATMOS or height channel signal, and this forward-facing mid-bass transducer is configured to work in conjunction with left and right height channel sound projection speaker arrays configured and driven to provide phased array beam manipulation of the upward-aligned height channel (e.g., ATMOS or) signal. For nomenclature purposes, the term ATMOS or may be used interchangeably in this application to generally describe the height channel or virtual height signal and the speaker designed to produce the desired vertical immersive tilt effect.

The system and method of the present invention have two main aspects. The first aspect describes a system for significantly reducing forward-radiated sound associated with a height-channel (e.g., ATMOS) speaker array (e.g., 113DS) in a height-channel-enabled soundbar system over a limited bandwidth. By design, the height-channel signal is intended to be sent toward the ceiling of the media room or space (e.g., 102, at point 104) in a prescribed radiation pattern (e.g., 108) so as to reflect downwards into the listening area (e.g., at 24). Any significant direct radiation from the speaker system (such as a soundbar, e.g., 60) toward the listener is detrimental to the height-channel effect, partly due to something experienced by the listener known as the “priority” or “Haas” effect. Due to this Haas effect, the directly radiated sound (113DS) will significantly detract from the expected height cues provided by the sound that appears to originate from above (the actual expected ceiling reflection from 104). During the applicant's development work, it was discovered that by employing a forward-facing mid-bass transducer in the soundbar to reproduce a bandpass phase-inverted copy of the height channel (e.g., ATMOS) signal, a height channel-enabled soundbar with left and right height channel speaker arrays can be constructed and driven to provide significantly better performance. The radiation pattern of the height channel array can be effectively improved in a measurable manner.

Another aspect of the systems and methods of the present invention relates to manipulating sound projected from a height-channel array in such a way that the principal axis of its radiation is selectable or manipulatory within an angular range and can generally deviate from the principal axis typically expected based on the geometry of the transducer array. Array manipulation and the control associated with phased array manipulation control the radiation principal axis of the acoustic transducers and are achieved, in part, by determining the time delay between array elements. According to generally accepted practice regarding phased array design (e.g., as described and illustrated in U.S. Patent 9,736,977 to Yamamoto et al.), directivity can be improved by increasing the number of array elements (which is functionally analogous to increasing the array size relative to the acoustic wavelength). During the applicant's development work on a height-channel (e.g., ATMOS) enabled soundbar, it was found that the front-to-back dimensions are particularly important for manipulating the directivity of the array.

Most importantly, the advantages of the system and method of the present invention include improved radiation patterns for each height channel array of a height channel-enabled soundbar by effectively eliminating some portions of the forward radiation component (e.g., 113DS as shown in FIG. 1E) through a remarkably efficient method of using mid-bass drivers mounted on the front panel of the soundbar. Preferably, appropriate signal processing, typically including bandpass filtering, parametric equalization, and delay, is applied to the left and right height channel arrays (but it can also be applied to only one array). In this way, the “secondary source” (direct radiation signal cancellation) transducer is the mid-bass driver of the soundbar that has been found to provide optimal performance. Another important advantage of the invention relates to the requirements for the height channel array in the presence of a secondary cancellation source. Without a secondary cancellation source, the height channel array must be relatively large (in the front-to-back dimension) and typically includes acoustic shielding forms designed to block or absorb sound radiation that would otherwise radiate directly into the listening area. Partly due to the use of cancellation in the system of the present invention, the front-to-back dimensions of the height channel array itself can be smaller than they would otherwise be. This means that, due to the inclusion of a transducer elimination, the need to physically block or absorb unwanted direct sound (113DS) to mitigate its arrival at the seating area 24 via the direct path is significantly reduced. Numerous advantages are gained in the phased array and manipulation aspects of the system and method according to the invention. Including phased array manipulation allows for a wider range of seating positions without compromising audio performance. Superior audio performance is achieved through an automated calibration scheme that determines the optimal steering angle for the selected listening position, compared to a conventional height-channel (e.g., ATMOS) enabled soundbar (where the ATMOS array is fixed relative to the steering angle).

The upward orientation helps to make more efficient use of the enclosure volume and allows for more possibilities in industrial design as a means of differentiating this new product from regular ATMOS ^™ compatible soundbars.

The above and further objects, features and advantages of the invention will become apparent after considering the following detailed description of specific embodiments of the invention, and especially when taken in conjunction with the accompanying drawings, wherein the same reference numerals in the various drawings are used to denote the same parts.

Attached Figure Description

Figures 1A and 1B illustrate conventional home theater sound systems with multi-speaker enclosures in a home theater environment, including the listening position, based on prior art.

Figures 1C and 1D illustrate a soundbar/subwoofer home theater sound system in an environment including the listening position of a home theater user, based on prior art.

Figure 1E is a diagram illustrating a Dolby ATMOS home theater sound system (as shown in U.S. Patent 9,648,440) in an environment including a home theater user at a listening position, according to the method of the present invention, with an additional representation of the problematic direct radiated sound paths from one or more height channel speakers.

Figure 2 is a perspective view of a soundbar loudspeaker system according to the present invention, equipped with a virtual height or height channel (e.g., ATMOS ^™ or compatible height loudspeaker) array, which implements an active cancellation method for forward sound radiation from the soundbar height channel array, employing a transducer in the soundbar front panel and manipulating sound from the height channel array via phased array technology.

Figure 3 is a front view of the soundbar loudspeaker system equipped with a height channel array according to Figure 2 of the present invention, showing the transducer of the soundbar front baffle.

Figure 4 is a right-side view of a soundbar loudspeaker system equipped with a height channel array according to Figures 2 and 3 of the present invention, showing the orientation of the transducer of the soundbar front panel and the top-mounted height channel array.

Figure 5 is a top side plan view of a soundbar loudspeaker system equipped with a height channel array according to Figures 2, 3 and 4 of the present invention, showing the inner sub-shell and the orientation of the transducer of the soundbar front baffle relative to the top-mounted height channel array, indicated by dashed lines.

Figure 6 is a signal flow block diagram according to the present invention, illustrating a method for actively eliminating forward sound radiation from the height channel array of a soundbar using a front baffle transducer (e.g., those in Figures 2-5) and manipulating the height channel array signal via phased array technology.

Figure 7 is a diagram illustrating a method for manipulating high-channel array signals via phased array technology according to the present invention.

Figure 8 is a diagram illustrating the enhanced height channel enabled soundbar system of the present invention (when viewed along the speaker axis SA) in a user environment including the listening position, according to the method of the present invention. It shows the orientation of the soundbar system components and a representation of the eliminated, undesirable direct radiated sound paths.

Detailed Implementation

Turning now to Figures 2-8, the system and method of the present invention includes a height channel (e.g., ATMOS or) enabled multi-driver soundbar loudspeaker system 260 having a housing 270 with a forward-facing mid-bass transducer 312 to reproduce “master” and “surround” signals, as well as a bandpass inverted copy of the height channel (e.g., ATMOS virtual height) signal. The front-mounted mid-bass transducer 312 is configured to work in conjunction with left and right height channel loudspeaker arrays (310L, 310R), which are constructed and driven to provide phased array beam manipulation of the upward-pointing height channel signal (308, best observed in Figure 8). In order to define a broad descriptive nomenclature, the term height channel is generally used in this application to describe channels used for virtual height signals and loudspeakers designed to produce the desired vertical immersive tilt effect in popular commercial (e.g., ATMOS ^™ or systems) systems. Therefore, the left and right height channel sound projection loudspeaker arrays (310L, 310R) are referred to as virtual height loudspeaker arrays or height channel arrays, respectively.

According to the structure and method of the invention, the lower portion of the bandwidth of the height channel is acoustically eliminated, which would otherwise be part of an undesirable direct radiated signal (213DS) directly radiated forward into the listening area 24. The cancellation signal is generated and radiated from the front emitter speaker 312 of the soundbar. As shown in Figures 6 and 8, the direct signal cancellation signal is generated by receiving the height channel (e.g., ATMOS) channel content, the bandpass-filtered height channel signal, the phase-inverted height channel signal, and then delaying the phase-inverted bandpass-filtered height channel signal to amplify it for the front emitter speaker 312 of the soundbar.

In the initial signal processing step, a bandpass filter is applied to each height channel signal (left and right height channels, whether discrete for Dolby Atmos program material or when using non-Atmos program material such as Dolby Digital 5.1 or 7.1 with discrete channels or derived height channel DTS equivalent program material) in the higher bass range (e.g., approximately 200 to 400 Hz or higher). In the next step, a phase reversal or polarity reversal is applied to each bandpass height channel signal. Depending on the product configuration (of the soundbar system 260), the signal can then be attenuated by 3 to 9 dB, and product-dependent amplitude shaping (parametric equalization) can be present to complete the signal processing in order to derive a corrected secondary source for significantly reducing the direct room radiation (e.g., 213DS) from the height channel speaker arrays 310L and 310R, as perceived by the listener at listening position 24.

Without applying a delay to the height channel cancellation signal for the front emitter speaker 312 of the soundbar, the resulting secondary source radiation will reach the listener before the direct radiation from the height channel speakers 310L, 310R (i.e., signal 213DS, which is assumed to be acoustically canceled). Therefore, an appropriate delay should be applied to the height channel direct signal cancellation signal relative to the front channel speaker radiation to ensure optimal synchrotron radiation and performance from the secondary sources in the listening area. The delay can be simply calculated by considering the distance between the acoustic center of the secondary source (i.e., the front-facing soundbar speaker 312) and the acoustic center of the upward-facing height channel speakers in the array 310L, 310R.

When using multiple speakers, for the purpose of this delay calculation, it is preferable to derive the average position:

Delay = (A _{C, A} – _{A C, f} )/c Equation 1

Where A _{_C,A} = the position of the acoustic center of the Atmos transducer, A _{_C,f} = the position of the acoustic center of the front baffle secondary source, and c = the speed of sound in air at sea level, room temperature = 343 m/s. It can be noted that in some cases, due to the industrial design of height channel (e.g., ATMOS ^™ or) compatible soundbars, the calculated delay can approach zero. This is especially true for shallow soundbars, where the height channel arrays 310L, 310R are positioned approximately above transducers 312 mounted on the front baffle and aligned along the speaker axis SA. In this case, the transducer mounted on the front baffle (e.g., 312L, 312R) that is physically closest to or closest to the height channel arrays 310L, 310R is selected as the secondary (cancellation) source.

A second aspect of the invention relates to manipulating a multi-element array of electroacoustic transducers projecting upwards from a soundbar 260 into a listening space. The combined output of the array (e.g., 310L and 310R) (see, for example, a figure in FIG7) can be manipulated by delaying the acoustic output of adjacent array elements or adjacent speaker driver transducers by an appropriate amount of time. In principle, this phased beam manipulation method is analogous to the operation of a phased array radar. Typically, the inter-element delay depends on the element spacing, the desired swivel angle, and the speed of sound in air (e.g., in the air of listening room 100). For example, for a multi-element array (e.g., a three-element array 310L) with a center-to-center spacing of 2.25 inches between adjacent elements between its three identical 25mm drivers, the time delay is calculated from the following formula to achieve a swivel angle of 5.0 degrees from the axis directly between the center of the soundbar and the listener:

t = l * tan(theta) / c Equation 2

Where l is the spacing between elements (2.25 inches), θ is the turning angle (5 degrees), and c is the speed of sound and air (343 m/s). For this exemplary embodiment, the time delay t of the 5-degree turning angle is equal to 14.6 microseconds. Further improvements to the radiation pattern can be achieved by applying a specific finite impulse response (“FIR”) filter to the amplitude response of each element in a manner commonly referred to as amplitude shaping, thereby combining both phase and amplitude shaping to obtain an optimized controlled array response. According to the invention, for beamform acoustic arrays, the signal processing method using FIR filters is improved for applications including the bar speaker structure shown in Figures 2-8. While the exemplary embodiments described and shown herein include multiple (e.g., three) element arrays 310L and 310R, arrays comprising 2 to 5 elements can also be used to efficiently implement the structure and method of the invention.

Referring again to Figures 2-5, the multi-channel single-shell height channel (e.g., ATMOS ^™ or) enabled soundbar loudspeaker system 260 is preferably configured to be used with digital signal processing methods to reproduce height channel audio program material with very high fidelity for listeners in listening space 100 (e.g., including listening position 24), regardless of the position of each listener relative to the loudspeakers within the listening space.

The multi-driver, multi-channel, single-casing-height-channel (e.g., ATMOS ^™ or) enabled soundbar system 260 preferably has a single base frame including a flat bottom and left and right sidewall members that also support a generally vertical front wall section or flat baffle, the front wall section or flat baffle defining the speaker axis SA and having a proximal or front surface defined by opposing left and right ends. In the illustrated embodiment, the housing of the single-casing-height-channel enabled soundbar system is preferably configured with a forward-facing first driver 312L and a forward-facing second driver 312R, the first driver 312L being positioned more closely to the left of the housing center on the lateral left, and the second driver 312R being positioned more closely to the right of the housing center on the lateral right. As best shown in Figures 2 and 3, the housing also aligns and supports other forward-mounted and aligned mid-bass and tweeter drivers.

The multi-driver, multi-channel, single-shell height-channel enabled soundbar loudspeaker system 260 also has an upper surface or a shell wall section with a left and a right distal end, the left and right distal ends carrying a left-side upward-emitting array of three drivers 310L configured to generate audio for the left height channel (virtual height) and a right-side upward-emitting array of three drivers 310R configured to generate audio for the right height channel (virtual height).

The forward-facing first driver 312L is driven using a signal modified according to the invention to eliminate any unwanted horizontally projected direct sound from the left-side height channel array 310L (e.g., 213DS, best observed in FIG8). The distance (DL _-AC ) separating the acoustic centers of the height channel array 310L and the forward-facing driver 312L is preferably less than 5.5 inches (but the distance from the acoustic center of the driver array 310L to the acoustic center of the forward-facing driver 312L can be 2-8 inches). The “acoustic center” of the driver or array is the point where the radiated sound of the driver or array originates and can vary with frequency, but generally coincides with the junction where the voice coil frame of the driver is connected to its diaphragm. Similarly, the forward-facing second driver 312R is driven using a signal modified according to the invention to eliminate any unwanted horizontally projected direct sound from the right-side height channel array 310R (e.g., similar to 213DS). The distance (DR _-AC ) separating the acoustic centers of the height channel array 310R and the forward-facing driver 312R is preferably less than 5.5 inches (but the distance from the acoustic center of the driver array 310R to the acoustic center of the forward-facing driver 312R can be 2-8 inches). These spacings, along with the signal processing 400 used for signal cancellation as described above and in Figure 6, have been found to have remarkable effectiveness in the applicant's development work.

The multi-channel, single-shell, height-enabled bar speaker system 260 preferably includes several dedicated amplifiers, each driving a corresponding speaker driver (e.g., 312L, 312R), each dedicated amplifier being mounted and acoustically sealed into one of five (5) sub-shells (as shown in FIG. 5), and the system 260 includes signal processing circuitry with signal processing algorithms programmed into a microprocessor and DSP circuitry contained in dedicated power amplifiers.

Figure 8 illustrates an enhanced height-channel enabled soundbar system 260 as observed along the speaker axis SA in a user environment 100 including listening position 24, showing the orientation of the soundbar system components and a representation of the eliminated, undesirable direct radiation sound path 213DS. The radiation pattern of each height channel array (310L, 310R) of the enhanced soundbar system 260 is improved by employing at least one of the front-panel mounted mid-bass drivers (e.g., 312L) of the soundbar to effectively eliminate a significant portion of the forward radiation component (e.g., 213DS). Preferably, appropriate signal processing, typically including bandpass filtering, parametric equalization, and delay, is applied to the left and right height channel arrays (but it is also possible to apply it to only one). In this way, the "secondary source" (direct radiation signal cancellation) transducer is the mid-bass driver of the soundbar, which has been found to provide optimal performance. Another important advantage of the invention relates to the requirements of the height channel array in the presence of a secondary cancellation source. Without a secondary cancellation source, the height channel array must be relatively large (in the front-to-back dimension) and typically includes acoustic shielding designed to block or absorb sound radiation that would otherwise radiate directly into the listening area. Partly due to the use of cancellation in the system of this invention, the height channel array itself (e.g., 310L, 310R) can be constructed to be remarkably small in the front-to-back dimension (e.g., as shown in Figures 2-5). This means that the need to physically block or absorb unwanted direct sound (e.g., 213DS) to mitigate its arrival at the seating area 24 via the direct path is greatly reduced due to the inclusion of cancellation transducers (e.g., 312L, 312R). Therefore, the phased array and manipulation aspects of the system and method of this invention offer numerous advantages. Including phased array manipulation allows for a wider range of seating positions (e.g., 24) without compromising audio performance. Compared to conventional height-channel enabled soundbars (e.g., ATMOS ^™ or), where the height channel array is fixed relative to the steering angle, an automatic calibration scheme that determines the optimal steering angle (e.g., θ as shown in Figure 7) for a selected listening position achieves superior audio performance.

Those skilled in the art will recognize that the present invention makes available a system and method for actively eliminating forward sound radiation (e.g., 213DS) from a height channel array: the system and method employs a transducer in the front baffle of a soundbar and manipulates sound projected from the height channel array via phased array technology. The invention also includes a multi-channel, single-shell height channel (e.g., ATMOS ^™ or) enabled soundbar loudspeaker system 260, comprising a first shell 270 having a front baffle surface 270F aligned along the loudspeaker axis SA and terminating on opposing lateral sides having a generally transverse left sidewall surface 270L and a right sidewall surface 270R, and terminating along its upper edge on a top sidewall surface 270T.

Preferably, the soundbar 270 has multiple acoustically isolated sub-shells, and in Figure 5, height channel arrays 310L, 310R are shown, each radiating upwards from a dedicated sub-shell with a selected volume of 10 cubic inches (cu.in) (for a group of three 25mm drivers per array). The internal volume of the exemplary soundbar shell 270 also includes three additional sub-shells corresponding to internal volumes dedicated to the left, center, and right channel speaker drivers, each having a selected internal volume of 1.33L. Each of the left, center, and right sub-shells is defined behind the front baffle surface 270F and provides an opening (as best shown in Figure 5) for a pair of mid-bass drivers arranged laterally along the speaker axis SA around a dedicated 25mm tweeter.

The soundbar loudspeaker system housing 270 supports and aligns loudspeaker drivers or transducers including: a first left main height channel direct signal cancellation loudspeaker driver 312L, mounted on the front baffle 270F near the left side wall 270L; a second right main height channel direct signal cancellation loudspeaker driver 312R, mounted on the front baffle 270F near the right side wall 270R; and a first left three-driver height channel loudspeaker array 310L, aligned upwards from the top wall surface 270T near the left side wall 270L and with its acoustic center spaced from the left main height channel direct signal cancellation loudspeaker driver 312L by a selected distance DL _-AC ranging from 2 to 6 inches (e.g., 2-3 inches, and preferably less than 5.5 inches). The housing 270 of the soundbar system 260 also supports and aligns a second right height channel speaker array 310R, which is aligned upwards from the top wall, close to the right side wall, and whose acoustic center is spaced 2 to 6 inches (e.g., 2-3 inches, and preferably less than 5.5 inches) from the _right main height channel direct signal cancellation speaker driver 312R.

As shown in Figures 3 and 6, the soundbar loudspeaker system 260 has left (“L”) and right (“R”) height channel (e.g., ATMOS ^™ or) signal inputs, signal processing, and a first amplifier and a second amplifier connected to the left main and right main height channel direct signal cancellation loudspeaker drivers 312L, 312R. Signal processing 400 is used for the left and right height channel signal inputs, and a first amplifier and a second amplifier (e.g., 420) are connected to the left and right main height channel direct signal cancellation speaker drivers 312L, 312R. A selected bandpass filter 404 (e.g., 200-400Hz or higher) is used to generate filtered left and right height channel signals 406. A phase inversion 408 is configured to invert the phase of the filtered left and right height channel signals to generate filtered inverted left and right height channel signals 410. Attenuation (and optionally, delay in block 412) is configured to provide an attenuation of about 3-9 dB to generate level-adjusted (and optionally delayed) filtered inverted left and right direct height channel cancellation signals 414. In certain product configurations, it is desirable that the signal processing method of the present invention may also include some correction (compensation) parameter equalization (“EQ”) not shown in FIG. 6, but it may also be incorporated into the method for generating level-adjusted (and optionally delayed and EQ’d) filtered inverted left and right direct height channel cancellation signals 414. The processing steps shown in FIG. 6 are exemplary, and using analog or digital signal processing, there are other sequences for combining these method steps or processes to achieve the generation of the desired level-adjusted (and optionally delayed and EQ’d) filtered inverted left and right direct height channel cancellation signals 414.

For sound from a high-channel array (e.g., 310L, 310R, see Figure 6), in an alternative prototype with the beam turned in the "beam" direction, the acoustic centers of the three drivers (e.g., in array 310L) span a distance "l" of 4.5 inches, so for a beam turned to a desired angle θ ("θ") of 5 degrees:

d = l tanθ = 0.394” (Equation 3)

therefore,

Therefore, t = 2.924 ( ^10⁻⁵ ) seconds or about 0.03 ms (for θ = 5 degrees). As described above, although the exemplary embodiments described and shown herein include three-element height channel arrays 310L and 310R, the structure and beam control method of the present invention can also be effectively implemented by utilizing each array to include 2 to 5 elements with slightly different spacing.

In a multi-driver, multi-channel, single-enclosure height channel (e.g., ATMOS ^™ or) enabled soundbar loudspeaker system 260, each height channel array is turned at a selected ceiling bounce angle (e.g., between 5 and 20 degrees, depending in part on where the soundbar 270 is mounted and how deep the soundbar is at the front and back, and what the enclosure will look like). Thus, the turning delay “t” can be selected to correspond to the desired ceiling bounce angle and can be in the range of 0.03 ms to more than 1.3 ms, depending on the arrangement and size of the drivers in each height channel array (e.g., 310L). Referring to Figures 3, 5, and 7, a multi-channel, single-shell height-channel enabled soundbar system 260 is shown, having a flat, horizontal top wall surface 270T supporting a first left ATMOS speaker array 310L. The first left ATMOS speaker array 310L includes an array of three drivers aligned along an axis parallel to the shell sidewall 270L, and this array is signal-driven to project height-channel sound upward from the top wall surface of the shell at a selected first ceiling bounce angle in the range of 5 to 20 degrees. The second right height-channel speaker array 310R also includes an array of three drivers aligned along an axis, and is aligned upward to project height-channel sound at the same bounce angle as the selected first ceiling bounce angle.

Referring again to Figures 2-5 and 8, the loudspeaker system 260 includes a first up-signal-dependent sound source and a second up-signal-dependent sound source, namely (a) a top-emitting up-signal loudspeaker (i.e., transducer or array) 310L and (b) a cancelling loudspeaker (i.e., transducer or array) 312L. The cancelling loudspeaker 312L is driven by a bandpass-filtered signal to limit cancellation to a mid-range frequency range (e.g., 200-400 Hz), a strategy that relies on the fact that low frequencies are less localizable to the listener. An all-pass filter allows the cancelling loudspeaker 312L to amplify low frequencies, while high frequencies are adequately controlled by the top-mounted up-signal loudspeaker 310L. Preferably, the directivity of the cancelling loudspeaker 312L is selected to reduce unwanted reflections, particularly from the floor and ceiling. Therefore, a larger transducer is preferable for the cancelling loudspeaker 312L. The distance from the cancelling loudspeaker 312L to the listener L is preferably approximately equal to or as close as possible to the distance from the top-emitting loudspeaker 310L to the listener L in order to reduce phase errors (which result in less efficient cancellation). As mentioned above, the Haas effect helps the listener L focus the sound reflected from the top speaker (from 308).

As stated above, in order to define a broad descriptive nomenclature, the terms ATMOS or DTS-X are not used as trademarks in this application, but rather as a naming convention and are generally used interchangeably to describe virtual height signals and loudspeakers intended to produce a desired vertical immersive tilt effect. Thus, the left and right virtual height sound projection loudspeaker arrays (310L, 310R) are referred to differently as height channel arrays or ATMOS arrays, and therefore the term ATMOS broadly refers to height channels or virtual height signals, loudspeakers, signal processing circuitry, or DSP methods intended to facilitate or produce a desired vertical immersive tilt effect.

Preferred embodiments of the new and improved loudspeaker systems and signal processing methods have been described, and it is believed that other modifications, variations, and alterations will be proposed by those skilled in the art in light of the teachings set forth herein. Therefore, it should be understood that all such variations, modifications, and alterations are considered to fall within the scope of this invention.

Claims (27)

1. A multi-channel single-shell soundbar loudspeaker system (260), comprising: A first housing having a front baffle surface that terminates along its upper edge at a top wall surface; The first left main front emitter speaker driver (312L) is mounted on the surface of the front baffle; The second right main front emitter speaker driver (312R) is mounted on the surface of the front baffle; A first left-upward emitting loudspeaker driver or multi-element loudspeaker array (310L) is aligned upward from the top wall surface, and the acoustic center of the first left-upward emitting loudspeaker driver or multi-element loudspeaker array (310L) is spaced 2 to 8 inches from the first left main front emitting loudspeaker driver (312L) by a distance D _L-AC ; and A second right-upward emitting loudspeaker driver or multi-element loudspeaker array (310R) is aligned upward from the top wall surface, and the acoustic center of the second right-upward emitting loudspeaker driver or multi-element loudspeaker array (310R) is spaced 2 to 8 inches from the second _right main front emitting loudspeaker driver (312R). The soundbar speaker system includes a signal processing circuit, which comprises: A bandpass filter for generating filtered left- and right-up transmitted signals; and a phase inversion method configured to invert the phases of the filtered left- and right-up transmitted signals to generate filtered, inverted left- and right-up signals. The soundbar speaker system is configured as follows: The first left-upward transmitting speaker driver or multi-element speaker array is driven based on the generated left-upward transmitting signal; The second right-upward transmitting loudspeaker driver or multi-element loudspeaker array is driven based on the generated right-upward transmitting signal; and The front-emitting speaker driver is driven by a direct cancellation drive signal generated based on the generated, filtered, inverted left and right signals. 2. The multi-channel single-shell bar speaker system according to claim 1, wherein the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced 2-3 inches apart from the first left main front emitting speaker driver (312L) by a distance D _L-AC . 3. The multi-channel single-shell bar speaker system according to claim 1, wherein the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced from the first left main front emitting speaker driver (312L) by a distance D _L-AC less than 5.5 inches. 4. The multi-channel single-shell bar speaker system according to claim 1, wherein the acoustic center of the second right-upward emitter driver or multi-element speaker array (310R) is spaced 2-3 inches from the second right main front emitter driver (312R) DR _-AC . 5. The multi-channel single-shell bar speaker system of claim 1, wherein the acoustic center of the second right-upward emitter driver or multi-element speaker array (310R) is spaced less than 5.5 inches from the second right main front emitter driver (312R) DR _-AC . 6. The multi-channel single-shell bar speaker system according to claim 1, wherein the front baffle surface of the first shell is aligned along the speaker axis SA and terminates on opposite lateral sides having a generally transverse left wall surface and a right wall surface, and the front baffle surface of the first shell terminates along its upper edge on the top wall surface. The first left main front emitter speaker driver (312L) is mounted on the front baffle surface, near the left side wall; and the second right main front emitter speaker driver (312R) is mounted on the front baffle surface, near the right side wall. 7. The multi-channel single-shell bar speaker system according to claim 1 further includes L and R upward transmitting signal inputs, signal processing circuitry, and a first amplifier and a second amplifier connected to the first left main front transmitting speaker driver and the second right main front transmitting speaker driver (312L, 312R). 8. The multi-channel single-shell soundbar loudspeaker system according to claim 7, wherein the L and R upward emitters are ATMOS ^™ or 9. The multi-channel single-shell soundbar loudspeaker system according to claim 1, wherein the signal processing circuit further includes... Attenuation (412), which is configured to provide 3-9 dB attenuation to generate level-regulated, filtered, inverted L and R signals (414). 10. The multi-channel single-shell bar speaker system according to claim 9, wherein the signal processing circuit further comprises: a delay configured to generate level-adjusted, delayed, filtered, inverted L and R signals (414). 11. The multi-channel single-shell bar speaker system of claim 1, wherein the first left-upward emitting speaker driver or multi-element speaker array (310L) comprises a multi-element array of two to five drivers aligned along the axis and aligned upward from the top wall surface at a selected first ceiling bounce angle in the range of 5 to 20 degrees; and the second right-upward emitting speaker driver or multi-element speaker array (310R) comprises a multi-element array of two to five drivers aligned along the axis and aligned upward at the selected first ceiling bounce angle. 12. The multi-channel single-shell bar speaker system of claim 11, wherein the first left-upward emitting speaker driver or multi-element speaker array (310L) comprises a phased array of drivers aligned along an axis, and the first left-upward emitting speaker driver or multi-element speaker array (310L) is aligned upward from the top wall surface via a selected first ceiling bounce angle in the range of 5 to 20 degrees after a selected delay process. 13. The multi-channel single-shell bar speaker system of claim 12, wherein the first left-upward emitting speaker driver or multi-element speaker array (310L) comprises a phased array of drivers aligned along the axis, and the first left-upward emitting speaker driver or multi-element speaker array (310L) is aligned upward from the top wall surface at a selected first ceiling bounce angle of 15 degrees via a selected delay process. 14. The multi-channel single-shell soundbar loudspeaker system of claim 6, wherein the first left-upward emitting loudspeaker driver or multi-element loudspeaker array (310L) is aligned upward from the top wall surface, close to the left side wall, and the acoustic center of the first left-upward emitting loudspeaker driver or multi-element loudspeaker array (310L) is spaced from the first left main front emitting loudspeaker driver (312L) by a distance of less than 8 inches (D _L-AC) ; and The second right-upward emitting speaker driver or multi-element speaker array (310R) is aligned upward from the top wall surface, close to the right side wall, and the acoustic center of the second right-upward emitting speaker driver or multi-element _speaker array (310R) is spaced less than 8 inches from the second right main front emitting speaker driver (312R). 15. A method for generating an enhanced vertically enveloping listening experience for a listener at a listening position (24) in a room (100), the method comprising: A multi-channel, single-shell soundbar loudspeaker system (260) is provided, the system (260) including an elongated shell having a front baffle surface terminating at its upper edge at a top wall surface; the single-shell soundbar loudspeaker system (260) further includes a first left main front emitter loudspeaker driver (312L) mounted on the front baffle surface; A first left-upward emitting speaker driver or multi-element speaker array (310L) is disposed on the single housing, the first left-upward emitting speaker driver or multi-element speaker array (310L) being aligned upward from the top wall surface, and the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) being spaced from the first left main front emitting speaker driver (312L) by a distance D _L-AC in the range of 2 to 8 inches; The first signal (402) is received in the single-shell bar speaker system (260), and a phase-reversed first signal (410) is generated in response to the first signal (402); Based on the first signal, drive the first left-upward transmitting loudspeaker driver or multi-element loudspeaker array; and The first left main front emitter speaker driver (312L) is driven by a first direct cancellation drive signal (422) generated in response to the first signal of phase reversal, thereby reducing the adverse effects of direct sound (213DS) from the first left upward emitter speaker driver or multi-element speaker array (310L) at the listening position (24) during operation. 16. The method of claim 15 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced 2-3 inches (D _L-AC) from the first left main front emitting speaker driver (312L). 17. The method of claim 15 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced less than 5.5 inches (D _L-AC) from the first left main front emitting speaker driver (312L). 18. The method of claim 15 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the driving of the first left main front emitter speaker driver (312L) using a first direct cancellation drive signal (422) comprises: receiving the first signal (402) and bandpass filtering the first signal to generate a bandpass filtered first signal (406). 19. The method of claim 18 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the driving of the first left main front emitter speaker driver (312L) using a first direct cancellation drive signal (422) further includes: reversing the phase of the bandpass-filtered first signal to generate a phase-reversed bandpass-filtered first signal (410). 20. The method of claim 19 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the driving of the first left main front emitter speaker driver (312L) using a first direct cancellation drive signal (422) further includes attenuating the inverted phase bandpass filtered first signal at a selected attenuation level of 3-9 dB to generate level-adjusted filtered inverted L and R signals (414). 21. The method of claim 20 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the level-adjusted, filtered, inverted L and R signals (414) are delayed. 22. The method of claim 20 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the driving of the first left main front emitter speaker driver (312L) using a first direct cancellation drive signal (422) further includes: amplifying the level-adjusted, filtered, inverted L and R signals (414) to generate the first direct cancellation drive signal (422). 23. The method of claim 22 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the level-adjusted, filtered, inverted L and R signals (414) are delayed. 24. The method of claim 18 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the multi-channel single-shell soundbar system (260) is provided with an elongated shell having a front baffle surface aligned along the speaker axis SA and terminating on opposing lateral sides having a generally transverse left side wall surface and a right side wall surface, and the front baffle surface terminating along its upper edge at a top side wall surface; wherein the soundbar system (260) further includes a first left main front emitter speaker driver (312L) mounted on the front baffle surface near the left side wall and a second right main front emitter speaker driver (312R) mounted on the front baffle surface near the right side wall; The method includes: A first left-upward emitting speaker driver or multi-element speaker array (310L) and a second right-upward emitting speaker driver or multi-element speaker array (310R) are disposed on the single housing. The first left-upward emitting speaker driver or multi-element speaker array (310L) is aligned upward from the top wall surface, close to the left side wall, and the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced DL-AC from the first left main front emitting speaker driver (312L) by a distance ranging from 2 to 8 inches. The second right-upward emitting speaker driver or multi-element speaker array (310R) is aligned upward from the top wall surface, close to the right side wall, and the acoustic center of the second right-upward emitting speaker driver or multi-element speaker array (310R) is spaced DR-AC from the second right main front emitting speaker driver (312R) by a distance ranging from 2 to 8 inches. The soundbar loudspeaker system (260) receives a left-up transmitted signal and generates a phase-reversed left signal in response to it; and The first left main front emitter speaker driver (312L) is driven by a first direct cancellation drive signal generated in response to the phase reversal of the left signal, thereby reducing the adverse effects of direct sound (213DS) from the first left upward emitter speaker driver or multi-element speaker array (310L) at the listening position (24) during operation. 25. The method of claim 24 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the acoustic center of the first left-upward emitting speaker driver or multi-element speaker array (310L) is spaced 2 to 3 inches from the first left main front emitting speaker driver (312L). 26. The method of claim 24 for generating an enhanced vertical surround listening experience for a listener at a listening position (24) in a room (100), wherein the acoustic center of the second right-upward emitter driver or multi-element speaker array (310R) is spaced less than 5.5 inches from the second right main front emitter driver (312R) DR-AC. 27. The method of claim 24 for generating an enhanced vertically enveloping listening experience for a listener at a listening position (24) in a room (100), comprising: The second right signal is received in the soundbar loudspeaker system (260), and a phase-reversed right signal is generated in response to it; and The second right main front emitter driver (312R) is driven by a second direct cancellation drive signal generated in response to the phase reversal of the right signal, thereby reducing the adverse effects of direct sound (213DS) from the second right upward emitter driver or multi-element speaker array (310R) at the listening position (24) during operation.