Computer-implemented method of generating an audio signal

Abstract

The present disclosure relates to a computer-implemented method of generating audio signals. A computer-implemented method of generating audio signals for a low frequency unit array and a high frequency unit array housed in a computing device is disclosed, the method comprising: receiving a plurality of input audio signals to be reproduced by the low frequency unit array and the high frequency unit array at a respective plurality of control points in an acoustic environment; and generating a respective output audio signal for each low frequency unit and each high frequency unit by applying one or more crosstalk cancellation algorithms to the plurality of input audio signals to control a pressure at each of the plurality of control points, wherein the low frequency unit array comprises two low frequency units and the high frequency unit array comprises at least three high frequency units.

Description

Technical Field

[0001] This disclosure relates to a computer-implemented method for generating audio signals for computing devices such as laptops or laptops. Background Technology

[0002] Crosstalk cancellation can be used to generate binaural audio signals for 3D audio. Crosstalk cancellation allows the binaural signal to be reproduced through loudspeakers. This is typically achieved using crosstalk cancellation algorithms. These algorithms help deliver two signals at the listener's ears that are designed to match the desired binaural signal. This can be achieved using a system that includes two loudspeakers, or by using a multi-channel linear loudspeaker array that includes more than two loudspeakers. The motivation for moving towards loudspeaker arrays stems from the proven robustness of loudspeaker arrays to the inaccuracies of algorithmic responses and the limited interaction of loudspeaker arrays with room acoustics.

[0003] Marcos F. Simon Gálvez et al.'s "Arobustness study for low-channel-count cross-talk cancellation systems" (Audio Engineering Society Conference: 2019, Immersive & Interactive Audio Conference, July 2019) describes the use of multi-channel miniature speaker arrays to reproduce 3D audio through crosstalk cancellation in a laptop computer. Additionally, Daniel... Booth et al.'s "Speaker driver arrangement for implementing cross-talk cancellation," US2023077689A1, has attempted a system for reproducing 3D audio on a PC screen. However, the known methods offer suboptimal performance across the entire audible frequency range. Summary of the Invention

[0004] The invention is set forth in the claims. Attached Figure Description

[0005] An example of this disclosure will now be explained with reference to the accompanying drawings, in which: Figure 1 A top view shows the layout of the computing device, as well as the bass and tweeter units, in the proposed two-way system; Figure 2 The operating frequency ranges of the woofer array and tweeter array are shown; Figure 3The crosstalk cancellation performance of a combined system using a 2-channel down-firing woofer pair and a multi-channel up-firing tweeter array is shown. Figure 4 The crosstalk cancellation performance of a pair of down-firing woofers is shown, comparing the large spacing (outer) and small spacing (inner) between the speakers. Figure 5 A side view of a laptop computing device is shown, along with the calculation of the positions of the woofer and tweeter relative to the user's head based on the geometry of the fixed laptop and the instantaneous head position detected by a listener position sensing mechanism. Figure 6 The crosstalk cancellation performance of a multi-channel up-firing tweeter array is compared to that of a 2-channel down-firing woofer pair. Figure 7 The frequency response of the down-firing woofer and the up-firing tweeter is shown. Figure 8 The crosstalk cancellation performance of a multi-channel down-firing woofer array is shown compared to that of a 2-channel down-firing woofer pair. Figure 9 A side view of a laptop design with a down-firing woofer and a front-firing tweeter for a multi-channel array is shown, wherein the woofer and tweeter are at different heights. Figure 10 A front view of a laptop computer with a down-firing subwoofer is shown. Figure 11 A front view of a laptop computer with a side-fired bass unit is shown. Figure 12 A side view of a laptop computer with a front-firing bass unit is shown. Figure 13 A top view shows the layout of the woofer and tweeter in an array system with a shared array axis; Figure 14 A top view shows the layout of the woofer and tweeter in an array system with different array axes (the woofer has a woofer array axis and the tweeter has a tweeter array axis). Figure 15 A flowchart illustrating a method for generating audio signals is shown; and Figure 16 The diagram shows the generation that can be used to implement Figure 15 A device for transmitting audio signals using a method. Detailed Implementation

[0006] Overview

[0007] In summary, a computer-implemented method for generating audio signals for a computing device is provided, wherein the computing device comprises an array of first and second woofers and an array of tweeters, which in turn comprises a larger number of woofers. For example, L can be configured... w = 2 bass unit arrays and L t > 2 Tweeter arrays. By applying crosstalk cancellation algorithms, multiple input audio signals are reproduced by an array at control points in the acoustic environment.

[0008] In the field of audio reproduction systems for laptops and notebook computers using crosstalk cancellation to reproduce 3D sound, a 2-way speaker system has been realized that combines, for example, a 2-channel woofer array and a high-frequency multi-channel (greater than 2) tweeter array for crosstalk cancellation within a notebook-size specification, with minimal spatial coverage and high performance across the entire audible frequency range. Specifically, while multi-channel speaker arrays require multiple speakers, this is difficult to achieve in a notebook-size specification due to the significant space required for speaker and enclosure installation. However, by using the combination of woofers and multi-channel tweeters in the disclosed manner, acceptable crosstalk cancellation can be provided for high-performance 3D audio reproduction across the entire spectrum, while minimizing the speaker volume coverage required for the driver-cabinet speaker module. Therefore, the speaker arrangement can be optimized based on the audio reproduction algorithm used. For example, low-frequency control requires a large speaker spacing for crosstalk cancellation, while high-frequency control requires a small speaker spacing, both of which can be achieved in the disclosed arrangement.

[0009] background

[0010] In general, this disclosure relates to computer-implemented methods for generating audio signals for computing devices such as laptops or laptops.

[0011] Some audio systems provide 3D spatial audio for audio programs (e.g., video or video game audio content). To generate 3D audio, the audio system can provide binaural audio signals to drive speakers, such as loudspeakers. Loudspeakers may include one or more speaker drivers. Crosstalk can occur when sound from one set of speaker drivers interferes with another set of speaker drivers in a separate location (or is mixed with that other set of speaker drivers). To avoid this, crosstalk cancellation (CTC) algorithms can be applied to the audio to provide 3D spatial audio with minimized crosstalk.

[0012] CTC enables the reproduction of binaural audio through loudspeakers. This is typically achieved using a digital signal processing network that controls the sound pressure level at the listener's ear by creating specific loudspeaker signals to minimize crosstalk. While this can be achieved using only two loudspeakers, there has recently been a trend towards using loudspeaker arrays, which increases robustness to source errors and reduces the impact of room response.

[0013] The effectiveness of the CTC algorithm is affected by the arrangement (and / or number) of speaker drivers integrated within an audio device. For larger audio devices, the effectiveness of the sweet spot can change at different frequencies as the spacing between the built-in speakers increases, where the sweet spot is the area where the user most effectively focuses and receives the desired audio. As the spacing between speaker drivers increases, the sweet spot for lower frequencies (e.g., below 1 kHz) can provide sufficient space, while the size of the sweet spot for higher frequencies (e.g., above 1 kHz) can decrease. To avoid this problem, a multi-channel array of high-frequency speaker drivers (tweeters) outputting high-frequency audio and an array of low-frequency speaker drivers (woofers) outputting low-frequency audio can be used. The tweeter and woofer arrays receive the input audio signals to be reproduced at corresponding control points in the acoustic environment, and generate corresponding output audio signals for each woofer and each tweeter by applying the CTC algorithm to the input audio signals to control the pressure at the control points.

[0014] The details of how this CTC algorithm works are described, for example, in EP3920557 and are well known to those skilled in the art, but are briefly summarized here. A listener-adaptive CTC 3D audio system can rely on multiple control filters to generate sound that drives one or more speakers. The parameters of these filters are adapted in real time according to the instantaneous position of one or more listeners, estimated using listener tracking devices (e.g., cameras, GPS devices, or wearable devices). This filter parameter adaptation requires high computational resources, thus making the use of this audio reproduction method difficult for small embedded devices. Part of the computational resource consumption comes from the need for multiple inverse filters, stemming from the use of complex and accurate transfer function models between the system speakers and the ears of a given listener.

[0015] Listener-adaptive CTC systems can be based on stereo speaker arrangements. Alternatively, they can utilize multi-channel speaker arrays. These examples of listener-adaptive CTC systems can employ time-varying signal processing control methods to adapt to time-varying listener position and head orientation. Control filters can be read from a database or computed on the fly at a significant computational cost. When using more than two speakers, CTC-based 3D audio systems exhibit improved response.

[0016] This technique, also described in WO 2017 / 158338 A1, allows for efficient listener-adaptive audio reproduction using speaker arrays employing two or more loudspeakers. The main reduction in CPU overhead (or consumption) introduced by this technique is due to the decomposition of the filtered signal processing audio stream into a combination of loudspeaker-dependent filters (DF) and loudspeaker-independent filters (IF). In this technique, the IF is implemented as a set of time-varying finite impulse response (FIR) filters, while the DF is implemented as a set of time-varying gain delay elements. Due to this decomposition, only M×M control filters and M delay lines are needed, each with L readout points, where M is the number of sound pressure control points (typically one per listener's ear), and L is the number of loudspeakers in the loudspeaker array. The CTC algorithm requires that the acoustic transfer function between each loudspeaker and sound pressure control point can be represented by a linear phase- and frequency-independent gain, for example, assuming a free-field point monopole propagation model.

[0017] Crosstalk cancellation methods

[0018] The CTC algorithm can be implemented via a controller that executes a computer-implemented method having the following steps.

[0019] First, the woofer array and tweeter array receive multiple input audio signals to be reproduced at corresponding control points (or listening positions, such as the user's ears) in the acoustic environment. Position sensors can be used to receive these control points. Specifically, the position of each control point can be received or determined.

[0020] The corresponding output audio for each woofer and each treble unit can be generated by applying one or more CTC algorithms to multiple input audio signals to control the pressure at multiple M control points (hereinafter referred to as control points). This algorithm can be applied in the frequency domain. In this case, a transform such as a Fast Fourier Transform (FFT) is applied to the input audio signals, the algorithm is applied, and then an inverse transform is applied to obtain the output audio signals.

[0021] The CTC algorithm can be based on filters derived from approximations of the transfer functions of each control point and the corresponding transfer functions of the woofer and tweeter, where the transfer functions lie between the audio signal applied to the corresponding woofer or tweeter and the audio signal received from the corresponding woofer or tweeter at the corresponding control point. CTC can also be based on predetermined positions and / or orientations of each woofer and tweeter, and the received position estimation at each of the multiple control points.

[0022] The position of each of the multiple control points is estimated relative to a reference point, and the crosstalk cancellation algorithm is also based on the predetermined positions of each woofer and each tweeter relative to the reference point.

[0023] The CTC algorithm can be applied to different sets of parameters that have the same steps but are based on different estimates for each of the multiple control points.

[0024] The following is for reference. Figure 15 Describe other features of this method.

[0025] An exemplary computing device for implementing any of the methods described herein may include a computer program, a sound reproduction device, a controller, a woofer array and a tweeter array, and a housing having woofers and tweeters. The controller is configured to output a corresponding output audio signal for the woofers to the woofer array and a corresponding output audio signal for the tweeters to the tweeter array, and implements the method. References are made in the “Example Implementations” section below and in the “Alternative Implementations” section below. Figure 16 The device will be described in more detail.

[0026] Explanatory Design

[0027] exist Figure 1 An example system combining two woofers and a multi-channel tweeter array can be seen in the figure. The figure also shows a schematic representation of a laptop 100 having a set of two woofers 104 and a multi-channel tweeter array containing more than two tweeters 102.

[0028] In the illustrated embodiment, it can be seen that the four-channel tweeter unit 102 or speaker array is arranged on a line parallel to the long axis of the laptop base 110, on the upper surface of the base 110 and along the rear edge of the base 110, i.e., behind the keyboard 108 and near and below the screen 106. The tweeter unit 102 is rectangular in shape, with its long axis aligned with the long axis of the laptop base 110. Furthermore, two woofer units 104 are arranged at the front of the base 110, i.e., in front of the keyboard 108, at two opposite corners. The woofer units 104 are rectangular in shape, with their long axes perpendicular to the long axis of the laptop base 110. In the illustrated embodiment, the woofer units 104 are arranged on the lower surface of the base 110, but in other embodiments, the woofer units 104 may be arranged on the upper surface, as discussed in more detail below. Furthermore, since the CTC algorithm controls acoustic interference between drivers, it is preferable that the path between the speaker and the listener's ear is not obstructed, for example, by the listener's hand. The illustrated arrangement satisfies this requirement. Note that the arrangement of the tweeter array here is exemplary, and the tweeter array can also be placed on the underside of the laptop lid and below the laptop screen 106, or inside the keyboard 108. More generally, any layout of the tweeters 102 can be adopted, with regular or irregular spacing and orientation, and in any desired location, and the CTC algorithm can be implemented accordingly.

[0029] This arrangement further considers that CTC is achieved through a combination of constructive wave interference and destructive interference, realized using beamforming. The former is more robust to errors and can be increased by increasing the number of drivers, while the latter is sensitive to modeling errors. These errors can be more severe at high frequencies (especially due to speaker directivity and acoustic diffraction). Therefore, it is preferable to maximize constructive / beamforming CTC at high frequencies. Both effects are achieved at high frequencies through the proposed arrangement, which includes a large number of closely spaced high-frequency drivers (tweeters 102). Furthermore, tweeters 102 have minimal volume requirements, and multiple tweeters 102 can be more easily adapted to the size specifications of the laptop 100 than multiple woofers 104 / full-range speakers.

[0030] Figure 2 This is a 2-way (crossover) design. A set of two woofers is used for low-frequency crosstalk cancellation. Since the woofers are capable of exciting sound at a low-frequency range of 202 with a higher dynamic range than full-range speakers, it is desirable to use only the woofers to handle and deliver the low-frequency portion of the spectrum. (As shown in...) Figure 3 As can be seen in the image, and described in more detail below, the CTC Response 300 thus achieves an acceptable level across the audible spectrum. This is achieved through a 2-way design (i.e., separate tweeter and woofer), as... Figure 3As shown. Because a set of two woofers is used for crosstalk cancellation at low frequencies, this set of woofers is able to excite sound within the low-frequency range 302, where the dynamic range is higher than that of a full-range speaker. Therefore, it is desirable to use only the woofers to handle and deliver the low-frequency portion of the spectrum, while the high-frequency components 304 are provided by the tweeters.

[0031] Figure 3 The response 300, primarily provided by the woofer in the low-frequency range (shaded light gray 302) and by the tweeter in the high-frequency range (shaded dark gray 304), is shown in more detail. Specifically, the combination of two woofers and a multi-channel tweeter array provides high crosstalk cancellation, ensuring the CTC level remains above 10 dB at all relevant frequencies, while requiring a minimal volumetric coverage area for the speaker enclosure, and also optimizing the overall system frequency response at the listener's ear without requiring significant corrected equalization (EQ). This is also relevant in new artificial intelligence (AI) laptop designs, where large batteries are required and little space is available for additional speakers.

[0032] While any suitable spacing can be used, a wider spacing between the woofers is preferred to provide enhanced low-frequency performance for the crosstalk cancellation system; the lower the frequency performance of the CTC, the greater the distance between the drivers. This reduces the amount of disruptive wave interference required and allows for a higher dynamic range in the speaker drivers. Figure 4 The text compares two pairs of woofers using different speaker spacings, with the outer pair corresponding to the outer pair of the array (28 cm spacing, corresponding to a normal-sized laptop) and the inner pair corresponding to the inner pair of the array (10 cm spacing). This shows that reducing the spacing results in a decrease in the level of crosstalk cancellation achievable at low frequencies below 3000 Hz. Therefore, preferably, considering the limitations of a physical laptop, the two woofers are spaced as wide as possible, that is, less than 8 cm from the edge of the laptop's housing (in the longitudinal direction) at opposite edges of the laptop's base relative to the laptop's chassis, and / or at least 10 cm apart from each other. Other arrangements are also possible; for example, the woofer 104 can be placed at opposite diagonal corners on the top or bottom surface (or one of either surface) of the laptop's chassis to achieve greater spacing.

[0033] In operation, the described woofer 104 and tweeter 102 speaker audio system works using listener position adaptive audio DSP software to provide user position adaptive 3D audio using techniques well known to those skilled in the art but briefly summarized herein. Both woofer 104 and tweeter 102 are software-controlled, taking into account that the array of two woofers and the array of multiple tweeters can share different array axes, i.e., can be placed at different distances from the user's head. Figure 1 As shown, if the bass unit 104 is located on the lower side, the shaft can be separated by the length of the laptop base 110 along its short axis and / or by the height of the laptop base 110.

[0034] refer to Figure 5 Due to the geometry of the laptop, the distance between the elements of the two woofer array and the tweeter array is fixed, while the exact position of the user's head 502 is estimated by listener position sensing software (e.g., using the laptop's webcam 504 or other sensors placed in the laptop), so that the exact position of the user's head relative to each speaker is always known. Figure 5 An example of this real-time estimation is shown, in which the three-dimensional vector d of the listener's head position 510 is obtained in real time. The listener's head position vector d can be estimated using a listener position sensing mechanism based on a laptop-based webcam 504 or another laptop-based sensor. For reference, in Figure 5 In this design, the listener position sensing mechanism is positioned on the top of the laptop's bezel, but it can also be placed elsewhere along the laptop. Given the precise location of the speaker array as described above, any suitable position estimation system can be employed, as is well known to those skilled in the art. Alternatively, the listener's head position can be estimated based on known typical user positioning data to provide a fixed, non-adaptive implementation.

[0035] Once the user's location is known, and given the fixed relationships of the speaker components in the laptop, a series of geometric transformations are used to determine the relative position of each speaker with respect to the listener 502 (or the listener's ear), thereby obtaining the positions of all tweeters. X T 512 and bass unit position X w 514 is a separate vector relative to the listener 502. Note this. X T，wEach contains the 3D position of all tweeters 506 and woofers 508. These individual three-dimensional vectors of position are then used as input to a crosstalk cancellation algorithm that calculates a digital signal processing filter in real time based on the instantaneous user position, as known to those skilled in the art and described, for example, in EP3920557 and GB2616073.

[0036] Speaker position X W 514 and X T The 512 three-dimensional vector is then used as input to the crosstalk cancellation algorithm. The speaker position, represented by the position vector, can then be used to retrieve the speaker-to-ear transfer function forming a planar matrix, as defined in GB2616073, which is used to create the crosstalk cancellation filter.

[0037] An example of a speaker-to-ear transfer function is the head-dependent transfer function. In this case, the head-dependent transfer function can be derived for each element of a two-woofer array and for each ear of a user at a given position relative to a laptop device.

[0038] The speaker-to-ear transfer function can be loaded from a database storing head-related transfer functions measured for predefined positions, modeled using acoustic delay and gain elements, or generated using a mathematical model, as is well known to those skilled in the art.

[0039] To evaluate the frequency response of a speaker array, the ability of a crosstalk cancellation system to render 3D audio is typically measured using the crosstalk cancellation level. The crosstalk cancellation level (CTC) is the absolute squared voltage difference of the signal delivered to the binaural (left and right) ears of a user listening to a CTC device, averaged over two specific test signals (10 and 01), which include a target signal that reproduces the Dirac pulse only in the left ear (10) or only in the right ear (01). This is defined in Equation 1.

[0040] (1)

[0042] To deliver 3D audio via binaural reproduction through loudspeakers, a system with crosstalk cancellation capability is preferably configured to achieve a CTC level above 10 dB between 300 Hz and 8 kHz. This will produce sufficient 3D audio performance and good spatial audio localization. A CTC level below 10 dB in this frequency range will result in inaccurate localization and poor spatial audio performance.

[0043] like Figure 3As shown, the hardware design described in this paper achieves a large CTC level within the frequency range of interest. This can be referenced... Figures 6 to 8 To understand in more detail. Figure 6 This shows a comparison with the up-firing 5-channel array 602 of the tweeter 102. Figure 1 The crosstalk cancellation level of the down-firing external pair 600 of the woofer 104 is shown. This indicates that above 3 kHz, in the gray shaded area 604, the performance of the tweeter array 102 is significantly better than the 2-channel down-firing woofer pair 104. This demonstrates the particular benefit of using an array of relatively large numbers of speakers in a laptop-sized specification at the high frequencies, and therefore allows for the inclusion of tweeters 102 to save space and be oriented as up-firing drivers to ensure proper high-frequency reconstruction.

[0044] Figure 7 The figure shows measurements of a typical down-firing woofer 700 and an up-firing tweeter 702, demonstrating how the woofer response drops significantly above 1.8 kHz. Based on this figure and analysis of many different woofer types and designs, the likely suitable operating range for a down-firing woofer in a laptop is approximately up to 1 kHz – 4 kHz. The tweeter exhibits a higher resonant frequency, meaning it is less useful for low-frequency content, but it maintains a better response at higher frequencies. A typical up-firing tweeter in a laptop has a starting operating frequency of 1 kHz.

[0045] Figure 8 The crosstalk cancellation performance of two system combinations is shown: a 5-channel down-firing woofer array 800 located at the front of a laptop, and a 2-channel down-firing woofer pair using an array 802 of the same width. Crosstalk cancellation level is a measure of system spatial performance. The 2-channel pair performs identically up to 1 kHz and is very similar between 1 kHz and 3 kHz. The acceptable matching performance range is shown in gray shading. While above 3 kHz, a multi-channel woofer array can provide better spatial performance (higher crosstalk cancellation level) due to the presence of more closely spaced speakers, this indicates that a multi-channel woofer array is not necessary below 1 kHz – 3 kHz, where a single woofer pair can be effectively used, with the crossover frequency between the low-frequency pair and the high-frequency array in the 1 kHz – 4 kHz range. Woofers typically require large cabinet volumes to provide a good frequency response. Therefore, reducing the number of required woofers or full-range drivers from five to two introduces many space-saving advantages, which can then be used for other important laptop components.

[0046] Figure 9The diagram shows in more detail the pairing of the down-firing woofer 904 with the up-firing tweeter 902, taking into account... Figures 6 to 8 The diagram illustrates how the woofer and tweeter are oriented in the laptop design 900. Sometimes, due to space constraints, the low-frequency woofer / full-range speaker is oriented downwards or sideways on the laptop (as described below). Figure 11 (As discussed), however, these speakers exhibit significant high-frequency attenuation in their frequency response because they are not oriented towards the listener. In the mid-to-high frequencies, this complicates modeling the speaker acoustic interference required to perform CTC. Using an up-firing tweeter 902 in this scenario simplifies modeling, resulting in better performance of the CTC algorithm, and the use of multiple speakers improves CTC performance at higher frequencies.

[0047] It's important to note that using a relatively small number of woofers alleviates the problem of needing a large amount of physical space to install multiple woofer enclosures, especially in laptops where physical space is crucial for different component groups. This is because, in addition to the space for the speaker drivers, the speakers are housed in modules with both drivers and enclosures, and these enclosures typically require several cubic centimeters in volume, making each module bulky relative to the total available space in a laptop. The addition of speaker enclosures increases the speaker's resonant frequency, thereby reducing the speaker's bass response. Therefore, a larger enclosure is required for low-frequency woofers than for high-frequency tweeters. This, in turn, means that a multi-channel array of woofers occupies significantly more space than an equivalent number of tweeters. Since the speakers are optimized to reproduce only high frequencies, tweeters can have smaller enclosures and smaller physical drivers.

[0048] Another issue with using a larger array of full-range or woofer speakers is speaker orientation. Sometimes, to house such large speakers within a laptop enclosure, the speaker enclosure vents are oriented downwards, towards the surface where the laptop rests, or alternatively, laterally. This is because the top surface of the laptop dock is covered by other components, such as the touchpad and keyboard. Installing full-range / woofer speakers with upward-facing vents would reduce the top surface space significantly more than the currently accepted 2-channel laptop design. As mentioned above, if the speakers are oriented downwards, this affects the speaker's frequency response at the listener's ear, resulting in significant high-frequency attenuation. While this can be compensated for to some extent with equalization (EQ), this design can lead to crosstalk cancellation problems, which require accurate knowledge of the acoustic transfer function from the speaker to the listener's ear. Tweeters are actually better suited to the design of the top surface of a laptop dock because they are physically much smaller, as they are optimized solely for reproducing high frequencies.

[0049] In implementations, the speaker can be located on the upward-facing or downward-facing surface of the base, or on a lateral edge such as the front edge, rear edge, or side edge. For example, in Figure 10 In the down-firing configuration, two subwoofers 1000 are placed on the lower side of the laptop stand 1002, near the front edge. Figure 11 In another embodiment shown, the subwoofer unit can be placed on the side edge of the laptop dock 1102, near the front edge, but in a side-firing configuration 1100 to minimize obstruction of the speaker's transmission function by the user's hand. Figure 12 In another embodiment shown, the subwoofer unit can be positioned on the front edge of the laptop base 1202 and project forward perpendicular to the front edge 1200 of the laptop. It will be apparent to those skilled in the art that the subwoofer unit can also be positioned in other configurations not described herein. For example, the subwoofer unit can also be positioned on the side front edge of the laptop and project sound towards the user. The subwoofer unit element can consist of a single speaker driver, or it can be constructed using more than one driver, such as using, for example, a back-to-back type subwoofer unit element structure well known to those skilled in the art.

[0050] The line that divides the positions of all array elements (woofer 1300 or tweeter 1302) in half is defined as array axis 1304. For example... Figure 13 As shown, the two-channel woofer pair is positioned along a "woofer array axis" defined as parallel to the laptop screen, at a certain distance along the laptop body. Similarly, the tweeter array speakers are positioned along a "tweeter array axis" also parallel to the laptop screen. That is, each of the woofer 1300 / tweeter array 1302 follows a linear geometry. Note that in the illustrated embodiment, the speakers are arranged symmetrically, i.e., symmetrical about the sagittal plane (the center line that divides the laptop 1306 in two), thereby providing improved CTC performance. Figure 13 In the illustrated embodiment, the woofer array 1300 and the tweeter array 1302 share the same array axis 1304. It will be apparent to those skilled in the art that the woofers and tweeters can also be placed in other configurations not described herein, wherein the woofers and tweeters are arranged asymmetrically with respect to the sagittal plane, thereby providing a more flexible layout of the components of the computing device.

[0051] Reference Figure 1 Describe and Figure 14In the implementation shown in more detail, for example, due to space constraints in a laptop computer, the woofer 1400 and tweeter 1402 are placed in different locations. This results in the woofer array 1400 having its own array axis, namely the woofer array axis 1404, and the tweeter array 1402 having its own array axis, namely the tweeter array axis 1406. The crosstalk cancellation system can take into account the physical positions of the different axes differently, and it will be noted that any desired geometric configuration can be adapted through appropriate CTC modeling. Specifically, with each array having a different coordinate center, this needs to be taken into account when finding the relative array positions derived from the listener position sensing system, and this needs to be appropriately handled by the crosstalk cancellation algorithm when calculating real-time parameters.

[0052] While implementations have been presented with respect to laptop computers, it should be noted that the methods disclosed herein can be implemented in any suitable computing device, such as a laptop, tablet, or other computing device or peripheral with a fixed physical layout, especially where space constraints exist. Any particular form of speaker and layout geometry can be employed within the space constraints of the device, and any suitable CTC algorithm can be implemented, which may be the same for each array or different crosstalk algorithms for different frequency ranges, as will be apparent to the reader in the art.

[0053] Therefore, the proposed method incorporates a loudspeaker system that provides effective crosstalk cancellation across the desired frequency range for accurate 3D audio reproduction, while encapsulating it with minimal physical coverage. This allows the technology to be used in laptop platforms where there is insufficient space to install multi-channel loudspeaker arrays with woofers or full-range speakers.

[0054] Alternative implementation methods

[0055] It should be understood that the above methods and designs can be implemented in various ways. The following is a general description of the characteristics common to the many implementations of the above methods and designs. Of course, it should be understood that, unless otherwise stated, any characteristic of the above methods and designs can be combined with any of the common characteristics listed below.

[0056] A computer-implemented method is provided for generating audio signals for a woofer array and a tweeter array.

[0057] The “woofer” can be a speaker driver configured to reproduce audio in a first frequency range, and the “tweeter” can be a speaker driver configured to reproduce audio in a second frequency range, wherein the lower end of the first frequency range is lower than the lower end of the second frequency range, and the upper end of the second frequency range is higher than the upper end of the first frequency range.

[0058] The woofer array and tweeter array can be housed in computing devices, such as... Figure 1 , Figure 5 or Figures 9 to 14 Computing devices.

[0059] The selected steps of this method are in Figure 15 As shown in the image.

[0060] The method includes receiving a plurality of input audio signals at step S100. A corresponding input audio signal of the plurality of input audio signals can be reproduced by a woofer array and a tweeter array at each of a plurality of control points (or "listening positions") in an acoustic environment (or "acoustic space").

[0061] Each of the multiple input audio signals can be different.

[0062] At least one of the multiple input audio signals may be different from at least one other input audio signal among the multiple input audio signals.

[0063] The method may also include receiving an estimate of the position of each of the multiple control points at step S110.

[0064] Multiple control points can correspond to the positions of multiple listeners.

[0065] Multiple control points can be the location of one or more listeners' ears.

[0066] The method may also include determining multiple control points using a position sensor prior to step S110.

[0067] The method also includes, at step S120, generating (or “determining”) the corresponding output audio signal for each woofer and each treble unit by applying one or more crosstalk cancellation algorithms to multiple input audio signals to control the pressure at each of the multiple control points.

[0068] A woofer array can contain two woofers. A tweeter array can contain at least three tweeters. This provides a balance between speaker coverage and system performance.

[0069] The generation may include generating a corresponding output audio signal for each of the woofers by applying a first crosstalk cancellation algorithm to a plurality of input audio signals, and generating a corresponding output audio signal for each of the tweeters by applying a second crosstalk cancellation algorithm to a plurality of input audio signals.

[0070] The first and second crosstalk cancellation algorithms can be the same or different.

[0071] Crosstalk cancellation algorithms can generate output audio signals such that when the output audio signals are fed to the woofer array and tweeter array, at each of the multiple control points, essentially only one of the multiple input audio signals is reproduced.

[0072] Applying one or more crosstalk cancellation algorithms may include applying a set of crosstalk cancellation filters. This set of crosstalk cancellation filters may be digital filters. A set of crosstalk cancellation filters may be applied in the frequency domain. This set of crosstalk cancellation filters may be based on multiple filter elements, including corresponding filter elements for each of the control points and the loudspeakers.

[0073] Filter elements can be filter weights. Multiple filter elements can be any set of filter weights. Filter elements can be any component of filter weights. Multiple filter elements can be multiple components of the corresponding weights of the filter.

[0074] A set of crosstalk cancellation filters can be time-varying. Alternatively, a set of crosstalk cancellation filters can be fixed or time-invariant, for example, when the listener's position and head orientation are considered relatively static.

[0075] One or more crosstalk cancellation algorithms or a set of crosstalk cancellation filters may be based on approximations of the transfer functions of each control point and each woofer and each treble unit, the transfer functions being between the audio signal applied to the corresponding woofer or treble unit and the audio signal received from the corresponding woofer or treble unit at the corresponding control point.

[0076] Approximations can be based on free-field acoustic propagation models and / or point-source acoustic propagation models. Approximations can consider one or more of the following: reflection, refraction, diffraction, or scattering of sound in the acoustic environment. Approximations may alternatively or additionally consider scattering from the heads of one or more listeners. Approximations may alternatively or additionally consider one or more of the frequency response of each loudspeaker or the directional modes of each loudspeaker. Approximations can be based on one or more head-related transfer functions (HRTFs). One or more HRTFs can be measured HRTFs. One or more HRTFs can be simulated HRTFs. One or more HRTFs can be determined using a head boundary element model.

[0077] One or more crosstalk cancellation algorithms or a set of crosstalk cancellation filters can be based on a predetermined position and / or predetermined orientation of each woofer and each tweeter. As a result, the output audio signal generated by this method can be a function of calculating the position and / or orientation of each woofer and each tweeter within the device.

[0078] One or more crosstalk cancellation algorithms or a set of crosstalk cancellation filters can be based on the received estimates of the position of each of the multiple control points.

[0079] The position of each control point among multiple control points can be estimated relative to a reference point, and one or more crosstalk cancellation algorithms or a set of crosstalk cancellation filters can also be based on the predetermined positions of each woofer and each tweeter relative to the reference point.

[0080] Generating the corresponding output audio signal may include using a filter bank to apply at least one or more crosstalk cancellation algorithms or a set of crosstalk cancellation filters in multiple frequency subbands (e.g., one subband for the woofer and one subband for the treble).

[0081] The generation of the corresponding output audio signal for each woofer and each tweeter can be based on a crossover frequency of 1 kHz to 4 kHz.

[0082] The method may further include receiving a set of crosstalk cancellation filters, for example, from another processing device or from a filter determination module, before step S120. The method may also include determining a set of crosstalk cancellation filters before step S120.

[0083] The method may further include, at step S130, outputting the output audio signal to the tweeter array and the woofer array.

[0084] The method can be repeated. In other words, the position estimate of each of the multiple control points can be received at a first time, and one or more crosstalk cancellation algorithms applied in the generation can be based on a first set of crosstalk cancellation algorithm parameters. The method can further include: at a second time, receiving the position estimate of each of the multiple control points; and repeatedly generating the data by applying one or more crosstalk cancellation algorithms based on a second set of crosstalk cancellation algorithm parameters, which are based on the position estimate of each of the multiple control points received at the second time.

[0085] The bass unit can be positioned away from the bottom of the computing device (e.g., as shown below). Figure 9 (As shown). In other words, the bass unit can be down-firing or downward-facing. The bass unit can be positioned on the lower side of the computing device.

[0086] The bass unit can be positioned away from the corresponding side of the computing device (e.g., as shown in the image). Figure 11 (As shown). In other words, the bass unit can be side-fired or side-facing. The bass unit can be positioned on the corresponding side of the computing device.

[0087] The bass unit can be positioned away from the front edge of the computing device (e.g., as shown in the image). Figure 12 (As shown). The bass unit can be positioned on the front edge of the computing device.

[0088] The tweeter can be positioned away from the top of the computing device (e.g., as shown in the image). Figure 9 (As shown). In other words, the tweeter can be upward-firing or face-up. The tweeter can be positioned on the upper side of the computing device. Specifically, the tweeter can be positioned away from the upper side of the computing device's base. The tweeter can be positioned on the upper side of the computing device's base.

[0089] The woofer and tweeter can be positioned facing opposite sides of the computing device (e.g., as shown in the image). Figure 9 (As shown).

[0090] The bass unit can be positioned at two opposite edges of the computing device (e.g., as shown in the image). Figure 10 and Figure 11 (As shown).

[0091] Each woofer can be positioned less than 8 centimeters from the edge of the computing device's housing.

[0092] Each subwoofer can be positioned at a corresponding distance from the edge of the computing device housing, which is less than 30% of the width of the computing device’s visible display area or less than 30% of the width of the housing.

[0093] The bass units can be spaced at least 10 centimeters apart.

[0094] The bass unit may be spaced at least 35% of the width of the visible display area of ​​the computing device or at least 35% of the width of the housing of the computing device.

[0095] The bass unit array and the tweeter array can be linear arrays.

[0096] The woofer and tweeter can be positioned along the same axis (e.g., as shown in the image). Figure 13 (As shown).

[0097] The woofer and tweeter can be positioned along different axes (e.g., as shown in the image). Figure 14 (As shown).

[0098] The woofer and / or tweeter can be arranged symmetrically (i.e., substantially symmetrically) with respect to the central latitude axis of the computing device (e.g., as shown in the image). Figure 13 and Figure 14 (As shown).

[0099] The woofer and / or tweeter can be arranged asymmetrically with respect to the central latitude axis of the computing device (e.g., as shown in the image). Figure 13 and Figure 14 (As shown).

[0100] Each woofer may include multiple drivers.

[0101] An apparatus is provided, specifically a controller for a computing device, configured to perform any of the methods described herein.

[0102] The device or controller may include a processor or digital signal processor configured to perform any of the methods described herein.

[0103] The device can be coupled to, or can be configured to be coupled to, a woofer array and a tweeter array.

[0104] A computer program comprising instructions that, when executed by a controller, cause the controller to perform any of the methods described herein.

[0105] A data carrier signal including instructions is provided, which, when executed by a controller, cause the controller to perform any of the methods described herein.

[0106] A (non-transitory) computer-readable medium or data carrier signal including a computer program is provided.

[0107] A sound reproduction device for a computing device is provided, including a controller, a bass unit array, and a tweeter array.

[0108] The controller can be configured to output the corresponding output audio signal for the woofer to the woofer array and the corresponding output audio signal for the tweeter to the tweeter array.

[0109] A computing device is provided, the computing device including a housing and a controller or sound reproduction device within the housing.

[0110] Computing devices can be mobile devices.

[0111] The computing device may also include a rechargeable energy storage device configured to power the processor within the housing.

[0112] The computing device can be a laptop or a tablet computer.

[0113] Controller implementation

[0114] Figure 16 The document illustrates any methods used to implement the methods described herein (such as...). Figure 15 A block diagram of an exemplary apparatus 1600 (the method). Apparatus 1600 can be used to implement at least a portion of a controller, and by extension, to implement at least a portion of a sound reproduction apparatus and / or a computing device.

[0115] Device 1600 may include processor 1610 (e.g., digital signal processor) configured to execute computer-readable instructions that may be provided to device 1600 via one or more of memory 1620, network interface 1630, or input interface 1650.

[0116] Memory 1620 (e.g., random access memory (RAM)) is arranged to retrieve, store, and provide instructions and data already stored in memory 1620 to processor 1610. Network interface 1630 is arranged to enable processor 1610 to communicate with a communication network such as the Internet. Input interface 1650 is arranged to receive user input provided via an input device (not shown) such as a mouse, keyboard, or touchscreen. Processor 1610 may also be coupled to display adapter 1640, which in turn is coupled to a display device (not shown). Processor 1610 may also be coupled to audio interface 1660, which can be used to output audio signals to one or more audio devices, such as a speaker array. Audio interface 1660 may include a digital-to-analog converter (DAC) (not shown), for example, for use with audio devices having analog inputs.

[0117] In some implementations, the various methods described above are implemented by a computer program. In some implementations, the computer program includes computer code arranged to instruct a computer to perform one or more of the various methods described above. In some implementations, the computer program and / or proxy for performing such methods is provided to a device (such as a computer) on one or more computer-readable media, or more generally, to a computer program product. The computer-readable medium may be transient or non-transient. One or more computer-readable media may be, for example, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, or may be a propagation medium for data transmission, such as for downloading code via the Internet. Alternatively, one or more computer-readable media may take the form of one or more physical computer-readable media, such as semiconductor or solid-state memory, magnetic tape, removable computer floppy disk, random access memory (RAM), read-only memory (ROM), rigid disk, or optical disk, such as CD-ROM, CD-R / W, or DVD.

[0118] In the implementation, the modules, components and other features described herein are implemented as discrete components or integrated into the functionality of hardware components such as ASICs, FPGAs, DSPs or similar devices.

[0119] A "hardware component" is a tangible (e.g., non-transitory) physical component (e.g., a group or more processors) capable of performing certain operations and configured or arranged in a physical manner. In some implementations, a hardware component includes dedicated circuitry or logic circuitry permanently configured to perform certain operations. In some implementations, a hardware component is or includes a dedicated processor, such as a field-programmable gate array (FPGA) or an ASIC. In some implementations, a hardware component also includes programmable logic or circuitry temporarily configured by software to perform certain operations.

[0120] Therefore, the term "hardware component" should be understood as a tangible entity that is physically constructed, permanently configured (e.g., hardwired), or temporarily configured (e.g., programmed) to operate or perform certain operations described herein in a certain way.

[0121] Additionally, in some implementations, modules and components are implemented as firmware or functional circuitry within a hardware device. Furthermore, in some implementations, modules and components are implemented as any combination of hardware devices and software components, or solely as software (e.g., code stored or otherwise embodied in a machine-readable or transportable medium).

[0122] explain

[0123] The chapter titles provided above are for the purpose of understanding this disclosure and should not be construed as limiting the scope of this disclosure.

[0124] Unless otherwise stated, the orientation and position described in this disclosure assume that the computing device (e.g., a laptop) is placed on a horizontal support surface and that the user of the computing device is using the computing device in its default physical operating configuration (e.g., for a laptop, the lid is open and the user is approximately...). Figure 5 The device is oriented in landscape mode (as shown for laptops), and if there is a choice of device orientation (e.g., for tablet computers), the device is landscape-oriented. Therefore: Terms such as "upward," "facing upward," "facing top," or "upward-firing" refer to the direction away from the supporting surface, that is, essentially in direction X3, such as... Figure 5 As shown; Terms such as "downward," "facing downward," "bottom-facing," "bottom-firing," or "downward-firing" refer to the direction facing the supporting surface; that is, essentially in... Figure 5 In the opposite direction of X3; Terms such as "forward," "facing forward," or "forward-firing" refer to a direction that is substantially parallel to the support surface and towards the user, that is, substantially along direction X1, such as... Figure 5 As shown; The term "front" refers to the side of a computing device that is closest to the user (for example, for a laptop, the side closest to the touchpad). The term "rear" or "rear" refers to the side of a laptop furthest from the user (for example, the side closest to the hinge in the case of a laptop). The term "lower side" or "bottom surface" refers to the surface that is closest to and substantially parallel to the supporting surface; and The term "top side" or "top surface" refers to the surface furthest from the support surface and substantially parallel to it (e.g., the surface on which the keyboard is located in a laptop).

[0125] It should be understood that although the various methods described above can be implicitly or explicitly described as "optimal," engineering involves trade-offs, so a method that is optimal from one perspective may not be optimal from another. Furthermore, a slightly suboptimal method may still be useful. Therefore, both optimal and suboptimal solutions should be considered within the scope of this disclosure.

[0126] Those skilled in the art will recognize that various modifications, alterations, and combinations can be made to the examples described above without departing from the scope of the disclosed concepts, and such modifications, alterations, and combinations should be considered within the scope of this disclosure.

[0127] Those skilled in the art will also recognize that the scope of the invention is not limited by the examples described herein, but is defined by the appended claims.

Claims

1. A computer-implemented method for generating audio signals for a woofer array and a tweeter array housed in a computing device, the method comprising: At corresponding multiple control points in the acoustic environment, multiple input audio signals to be reproduced are received through the bass unit array and the tweeter array; as well as By applying one or more crosstalk cancellation algorithms to the plurality of input audio signals to control the pressure at each of the plurality of control points, a corresponding output audio signal is generated for each woofer and each tweeter. The bass unit array contains two bass units, and the tweeter array contains at least three tweeters.

2. The method of claim 1, wherein, The generation includes: A corresponding output audio signal is generated for each of the bass units by applying a first crosstalk cancellation algorithm to the plurality of input audio signals; as well as A second crosstalk cancellation algorithm is applied to the multiple input audio signals to generate a corresponding output audio signal for each tweeter.

3. The method according to any one of claims 1 to 2, wherein: The bass unit faces away from the lower side of the computing device; or The bass unit is positioned away from the corresponding side of the computing device, optionally, wherein the bass unit is positioned away from the front edge of the computing device.

4. The method of any one of claims 1 to 2, wherein, At least one of the following: The tweeter unit faces away from the upper side of the computing device; The bass unit and the tweeter face opposite sides of the computing device; or The bass units are positioned at opposite edges of the computing device. Optionally, each bass unit is positioned less than 8 cm from the edge of the housing of the computing device, and / or alternatively, the bass units are positioned at least 10 cm apart from each other.

5. The method according to any one of claims 1 to 2, wherein, The woofer array and the tweeter array are linear arrays. Optionally, the woofers and the tweeters are positioned along the same axis, or alternatively, the woofers and the tweeters are positioned along different axes.

6. The method according to any one of claims 1 to 2, wherein, The bass unit and the tweeter are arranged symmetrically with respect to the central latitude axis of the computing device.

7. The method according to any one of claims 1 to 2, wherein, At least one of the following: Each of the bass units includes multiple drivers; A corresponding output audio signal is generated for each of the bass units and each of the tweeters based on a crossover frequency of 1 kHz to 4 kHz; The one or more crosstalk cancellation algorithms are based on approximations of the transfer functions of each of the control points and each of the woofers and treble units, the transfer functions being between an audio signal applied to one of the woofers or treble units and an audio signal received from one of the woofers or treble units at a corresponding control point in the control points. or The one or more crosstalk cancellation algorithms are based on a predetermined position and / or predetermined orientation of each of the woofers and each of the tweeters.

8. The method according to any one of claims 1 to 2, further comprising: Optionally, an estimate of the position of each of the plurality of control points can be received from a position sensor on the computing device. The one or more crosstalk cancellation algorithms are based on the received estimates of the position of each of the plurality of control points.

9. The method according to claim 8, wherein, The estimated position of each of the plurality of control points is relative to a reference point, and the one or more crosstalk cancellation algorithms are further based on a predetermined position of each of the bass units and each of the treble units relative to the reference point.

10. The method according to any one of claims 8 to 9, wherein, The method involves receiving an estimated position of each of the plurality of control points in a first-time manner, applying one or more crosstalk cancellation algorithms during generation based on a first set of crosstalk cancellation algorithm parameters, and further comprising: In the second time, the estimated position of each of the plurality of control points is received; and The system is repeatedly generated by applying one or more crosstalk cancellation algorithms based on a second set of crosstalk cancellation algorithm parameters, which are based on an estimated position of each of the plurality of control points received at the second time.

11. A controller for a computing device, the controller being configured to perform the method according to any one of claims 1 to 10.

12. A computer program comprising instructions that, when executed by a controller, cause the controller to perform the method according to any one of claims 1 to 10, or A computer-readable medium includes instructions that, when executed by a controller, cause the controller to perform the method according to any one of claims 1 to 10, or A data carrier signal includes an instruction that, when executed by a controller, causes the controller to perform the method according to any one of claims 1 to 10.

13. A sound reproduction apparatus for a computing device, comprising: The controller according to claim 11; Bass unit array; as well as Tweeter array, The controller is configured to output a corresponding output audio signal for the bass unit to the bass unit array and to output a corresponding output audio signal for the treble unit to the treble unit array.

14. A computing device comprising a housing and a controller according to claim 11 or a sound reproduction device according to claim 13 within the housing.

15. The method according to any one of claims 1 to 10, the controller according to claim 11, the sound reproduction apparatus according to claim 13, or the computing device according to claim 14, wherein, The computing device is a mobile device, optionally a laptop computer or a tablet computer.

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