阅读说明：本技术 无上发和环绕扬声器的条形音箱中的虚拟高度和环绕效果 (Virtual height and surround effect in a bar-shaped loudspeaker enclosure without up-and surround speakers ) 是由 J.郑 于 2019-03-06 设计创作，主要内容包括：一种用于实现虚拟高度和环绕效果的装置。所述装置至少包括输入源、处理器和前置扬声器。所述输入源在输入到所述处理器的前声道、环绕声道和高度声道上提供输入信号,其中分别对源声道中的每一个应用波束成形、声道分离和/或虚拟高度效果。在处理之后,由所述处理器输出的所有所产生输出声道排列并组合到条形音箱的现有扬声器中。(An apparatus for achieving a virtual height and surround effect. The apparatus includes at least an input source, a processor, and a front-facing speaker. The input source provides input signals on a front channel, a surround channel, and a height channel that are input to the processor, wherein beamforming, channel separation, and/or virtual height effects are applied separately to each of the source channels. After processing, all of the generated output channels output by the processor are aligned and combined into existing speakers of the sound bar.)

1. An apparatus for achieving virtual height and surround effects with front speakers, comprising:

an input source configured to provide an input signal through at least one of a front channel, a surround channel, and a height channel;

a processor configured to perform an optimization process on the at least one of a front channel, a surround channel, and a height channel of the input source; and

a front speaker comprising a plurality of speakers;

wherein the output signal after processing by the processor is fed to the front speaker.

2. The apparatus of claim 1, wherein the front channel of the input source comprises at least one of a left channel/a right channel, and the processor further comprises a beamforming processor that applies beamforming to the at least one of the left channel/the right channel to produce at least one of a virtual left channel/a right channel, respectively.

3. The apparatus of claim 2, wherein the beamforming comprises setting a transfer function.

4. The apparatus of claim 1, wherein the surround channels of the input source comprise at least one of left surround channels/right surround channels, and the processor further comprises a surround effect processor that applies channel separation to the at least one of the left surround channels/right surround channels to produce at least one of virtual left surround channels/right surround channels, respectively.

5. The apparatus of claim 4, wherein the channel separation comprises setting a crosstalk cancellation function.

6. The apparatus of claim 1, wherein the elevation channel of the input source comprises at least one of a left elevation channel/a right elevation channel, and the processor comprises an elevation effect processor that applies both channel separation and head related transfer functions to the at least one of the left elevation channel/right elevation channel to generate at least one of a virtual left elevation channel/right elevation channel, respectively.

7. The apparatus of claim 6, wherein the channel separation comprises setting a crosstalk cancellation function, and the head-related transfer function comprises setting a measured head-related transfer function.

8. The apparatus of claim 1, wherein the apparatus further comprises a channel-speaker matrix, the output signals being arranged and combined to the plurality of speakers by the channel-speaker matrix.

9. The apparatus of claim 1, wherein the front speakers are integrated into a soundbar.

10. The apparatus of claim 1, wherein the plurality of speakers included in the front speakers include neither a top speaker nor a surround speaker.

11. A method for achieving virtual height and surround effect with front speakers, the steps of the method comprising:

receiving an input signal from at least one of a front channel, a surround channel, and a height channel of an input source

Performing, by a processor, optimization processing on the input signals from the at least one of a front channel, a surround channel, and a height channel of the input source, respectively; and

the output signal after processing by the processor is fed to a front speaker.

12. The method of claim 11, wherein performing the optimization process further comprises applying a beamforming process to at least one of left/right channels of the front channel of the input source to produce at least one of virtual left/right channels, respectively.

13. The method of claim 12, wherein applying the beamforming process comprises setting a transfer function.

14. The method of claim 11, wherein performing the optimization process further comprises applying channel separation to at least one of left/right surround channels of the input channels to produce at least one of virtual left/right surround channels, respectively.

15. The method of claim 14, wherein applying the channel separation comprises setting a crosstalk cancellation function.

16. The method of claim 11, wherein performing the optimization process further comprises applying both channel separation and head related transfer functions to at least one of a left elevation channel/a right elevation channel of the elevation channels of the input source to produce at least one of a virtual left elevation channel/elevation channel, respectively.

17. The method of claim 16, wherein applying the channel separation comprises applying a crosstalk cancellation function, and applying the head-related transfer function comprises applying a measured head-related transfer function.

18. The method of claim 11, further comprising arranging and combining all of the generated virtual channels into a plurality of speakers by a channel-speaker matrix.

19. The method of claim 11, wherein the front speakers are integrated into a soundbar.

20. The method of claim 11, wherein the plurality of speakers included in the front speakers include neither upper speakers nor surround speakers.

Technical Field

One or more embodiments relate to an apparatus and method for achieving virtual height and surround effect, and more particularly, for achieving virtual height and surround effect through front speakers in a bar-shaped speaker without a pop-up or surround speaker.

Background

Currently in home theaters, the input source of a movie typically includes multiple channels, such as a front channel, a surround channel, and a height channel. Typically, the front speakers (left, right and center) reproduce the main content of the movie, while the other speakers generate the surround sound and immersive listening experience. With prior art speaker products, to achieve a surround or height effect, the speakers need to be physically placed in different locations in the room, such as around and on the ceiling of the room, which can increase the installation difficulty of the speakers and reduce the aesthetics of the room. Even the integrated sound speaker, in order to increase the high effect, a speaker must be used therein, which limits the thickness of the speaker design, and such sound speaker cannot be designed in a slim style to meet aesthetic trends and practical applications.

Today, soundbar systems are widely used in home theatres due to their simplified loudspeaker configuration. However, by size limitation, soundbars typically have only front speakers, and they are all located in small cavities. Thus, the sound field is narrow and the immersive experience is poor. Soundbars employ some digital signal processing methods, but each of the input channels is simply mixed rather than processed individually, so the sound field is neither natural nor improves the immersive experience. Unlike discrete 5.1/7.1 channel speaker systems, conventional one-piece soundbars have little or no surround effect. In contrast, conventional soundbars do not produce any high degree of effect. Some soundbars can be designed with some upper speakers, but these speakers introduce many stringent directivity requirements and the appearance of the product is limited.

Disclosure of Invention

The present disclosure overcomes some of the aforementioned disadvantages by providing an apparatus and method for achieving a virtual height and surround effect with front speakers in a bar-shaped loudspeaker enclosure. In particular, the soundbar of the present invention may comprise front speakers or side speakers, but no up-or surround speakers are present.

According to one aspect, an apparatus for implementing virtual height and surround effect through front speakers includes: an input source comprising at least one of a front channel, a surround channel, and a height channel; a processor configured to perform an optimization process on input signals from the at least one of a front channel, a surround channel, and a height channel of the input source, respectively; and a front speaker including a plurality of speakers. After processing by the processor, the output signal from the processor is fed to the front-facing speaker.

The front channel of the input source comprises at least one of a left channel/a right channel. The surround channels of the input source comprise at least one of left surround channels/right surround channels. The elevation channel of the input source comprises at least one of a left elevation channel/a right elevation channel.

The processors include a beamforming processor to apply beamforming to the at least one of the left/right channels, a surround effect processor to apply channel separation to the at least one of left/right surround channels, and a height effect processor to apply both channel separation and a Head Related Transfer Function (HRTF) to the at least one of the left/right height channels.

Alternatively, the processor further comprises a channel-speaker matrix for arranging and combining all the generated virtual channels into an existing plurality of speakers of the front speakers.

The front speakers are integrated into a bar-shaped sound box without any upper speakers or surround speakers.

Alternatively, the beamformer processor further applies a transfer function during application of the beamforming.

Alternatively, the surround effect processor further applies a cross-cancellation function during application of the channel separation.

Alternatively, the height effect processor applies the measured head related transfer function both during application of the channel separation and further during application of the cross-cancellation function(s) and during application of the Head Related Transfer Function (HRTF).

According to another aspect, a method for achieving virtual height and surround effect through front speakers includes the steps of: receiving an input signal from at least one of a front channel, a surround channel, and a height channel of an input source; performing, by a processor, an optimization process on the signal from the input source; and feeding an output signal output by the processor after processing by the processor to a front speaker.

Alternatively, performing the optimization process comprises applying a transfer function to the at least one of the left/right channels to produce at least one of virtual left/right channels, respectively.

Alternatively, performing the optimization process comprises applying the channel separation to the at least one of the left/right surround channels by preferably setting a crosstalk cancellation function to produce at least one of virtual left/right surround channels, respectively.

Alternatively, performing the optimization process comprises applying the channel separation process to the at least one of the left/right elevation channels by setting the crosstalk cancellation function and applying the head-related transfer function to the at least one by setting the measured head-related transfer function to generate at least one of virtual left/right elevation channels, respectively.

Alternatively, the output signals of at least all the generated virtual channels are arranged and combined to the plurality of loudspeakers by a channel-loudspeaker matrix.

Drawings

Fig. 1 is a schematic diagram illustrating a virtual sound field applying beamforming in a front channel of an input source according to an embodiment of the present invention.

Fig. 2 is a diagram illustrating a directivity pattern of a target beamformer at 1kHz in the beamforming process of fig. 1.

Fig. 3 is a schematic diagram showing how a listener positions a virtual sound source to the side in a virtual sound field with application of channel separation in a front channel according to another embodiment of the present invention.

Fig. 4 is a diagram showing one example of channel separation with respect to a ratio of a signal received at a right ear to a left ear when only a left signal is input.

Fig. 5 is a schematic diagram illustrating a virtual sound field applying a virtual height effect in a front channel of an input source according to another embodiment of the present invention.

Fig. 6 is an exemplary block diagram of an apparatus or method for implementing the virtual height and surround effect of the present invention.

Detailed Description

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

The object of the present invention is to apply different optimization processes to different input source channels to generate corresponding virtual channels, respectively, and to combine all generated channels reasonably into existing loudspeakers of a soundbar that has neither a loudspeaker nor a surround speaker, so that the virtual sound field can be expanded and an immersive experience can be created.

The loudspeaker provided by the invention only comprises the front-emitting loudspeaker and the possible side-emitting loudspeaker, but no upper loudspeaker and no surround loudspeaker, so that the loudspeaker device can be realized as a single-piece bar-shaped sound box, and the bar-shaped sound box loudspeaker can be designed in an ultrathin form while realizing virtual surround and virtual height effects. In the present invention, the most appropriate and effective processing is applied to each channel to achieve a sound effect of high virtual sense and small distortion.

A. The front channel of the source is input.

The front channels of the input source typically include a left channel, a right channel, and a center channel. In the prior art, the signals from these channels are fed directly to the front speakers in a bar-shaped sound box, so the listener receives direct sound from these speakers and a relatively low level of sound reflections from the walls of the listening room. Since the left/right channels received by a listener indicate the width of the sound field, the listener mostly locates the sound source from front speakers with an extremely narrow sound field, which almost depends on the length of the soundbar.

Referring to fig. 1-2, in order to expand the sound field, some beamforming process is used on the left/right channel of the input source, as shown in fig. 1. Let p (r) denote the total sound pressure at position r,

wherein q is_kIs the loudspeaker strength of the kth loudspeaker in the bar, K is the number of loudspeakers, H (r)_k) Is the transfer function between the kth loudspeaker and the optimum position r, which is determined by the width over which the sound field is intended to be expanded. Transfer function H (r)_k) It can be calculated based on theoretical models or measured under ideal conditions. Preferably, the transfer function H (r)_k) The measurement can be carried out on the site where the bar-shaped sound box is actually used. In one aspect, the virtual sound field defined by the generated virtual channels may be a target region, for example, having a radius of about 3m-4 m. The sound pressure can be rewritten in matrix form as

P＝Hq (2)

Using some beamforming process (e.g., pressure matching method), the speaker intensity may be calculated and the beamformer w may be obtained_k，

q＝H^Hp (3)

w_k＝A_kq_k (4)

Wherein A is_kIs the tuning parameter of the improved frequency response and the superscript H denotes the conjugate transpose of the matrix.

After beamforming, virtual left/right channels are generated and received by the listener, indicating a virtual sound field having a wider width from which the listener can locate the sound source, as shown in fig. 1.

Fig. 2 shows a typical directivity pattern of a target beamformer which determines the sound pressure p (r). B. Surround channels of the input source.

Conventional surround speakers are placed on both sides of a listener. When listeners use the one-piece sound bar, they experience little or even no surround effect because the surround signal is also reproduced by the front speakers and therefore the interaural level and time differences are minimal. These two parameters are the main clues to the perceived sound position.

Referring to fig. 3-4, in order to enhance cues, a higher channel separation should be obtained, which is the difference in received signal between the left/right ear per input channel. Therefore, the listener can receive sound virtually from the side, since at higher channel separation the interaural level difference can be larger and the listener will be misdirected to locate the sound source at the side.

Fig. 3 shows the theory of how a listener locates a sound source on the side. Theoretically, the higher the channel separation, the larger the rotation angle can be, as shown in fig. 3. In one aspect, the rotation angle of the virtual surround channel may be, for example, up to 120 degrees. Preferably, the virtual sound field having the larger virtual surround channel gives the listener a sense that the sound source is located behind. In another aspect, the virtual surround channels may be rotated by an amount less than 120 degrees, but a rotation angle of 60-70 degrees is necessary.

To achieve higher channel separation, one of the methods is to apply crosstalk cancellation. Let G (r)_k) Becomes the crosstalk cancellation function between the kth loudspeaker and the optimum position r. The signal received by both ears is given by s,

s＝Hq (5)

q＝Gd (6)

e-d-s (7) wherein G is G (r)_k) And d is the desired received signal received by both ears of the listener. To minimize the error signal e, G is given by:

G＝[H^HH]-¹H^H (8)

using the channel separation method, high channel separation can be obtained, as shown in fig. 4.

C. The height channel of the source is input.

There are generally two types of height channel speakers in the prior art: a lower loudspeaker located on the ceiling and an upper loudspeaker located in the bar box. The lower speaker plays back the high channel signal of the input source directly to the listener, while the upper speaker reflects the sound off the ceiling. Whichever type of speaker is used, it is recommended that the listener feel the sound source coming from the ceiling.

When using a conventional one-piece soundbar, the upper speaker is the only option, but may not be allowed due to limitations in industrial design and system configuration.

Referring to fig. 5, some virtual height processing may be used on front speakers in a soundbar without any upper speakers. Our hearing system is less sensitive to interaural time differences from elevation angle differences of sound source positions than azimuth angle differences, because our ears are placed horizontally on both sides of our head. However, the difference in frequency response due to the asymmetry of our ears in the vertical direction can produce more clues to perceive the location of the sound source. Therefore, when the front speaker plays back the height channel signal by applying the head-related transfer function, a virtual height effect can also be provided.

Fig. 5 shows the principle of the virtual height method, where "HRTF" refers to the head-related transfer function between the ceiling and the ear with elevation angle. In one aspect, the elevation angle of the virtual height effect channel may range, for example, from 30 degrees to 90 degrees. Preferably, a virtual sound field with an appropriate virtual high effect channel causes a listener to perceive the sound source as being located on the ceiling of the listening room. In another aspect, an elevation angle of 60 degrees is preferred. To increase the virtual height effect, channel separation methods are also used to reduce crosstalk confusion. The HRTF can be measured in an anechoic chamber by using the desired elevation angle. With respect to the height channel, equation (8) can be modified as:

G_height＝C_HRTF[H^HH]^-1H^H (9)

wherein, C_HRTFIs the measured head related transfer function assuming ideal conditions in the anechoic chamber.

By applying the channel separation process and the HRTF, a virtual left height channel/right height channel that brings about a virtual height effect is generated.

D. Combination of all sound channels

Fig. 6 shows a block diagram of the present invention. "L/R", "Ls/Rs", "Lh/Rh", and "C/LFE" indicate a left/right channel, a left/right surround channel, and a center/low frequency extension channel, respectively. After the virtual processing, the channel-speaker matrix arranges and combines all of these channels to different speakers. Due to the limited number of loudspeakers in a bar-shaped loudspeaker box, it may be necessary to arrange and combine output signals from different virtual channels into the same loudspeaker. For example, there are four speakers in a soundbar. After processing the beamforming on the L/R channels, the number of virtual channels produced is four per input channel, while for the Ls/Rs and Lh/Rh channels, the number of virtual channels produced after processing is two per input channel. One example of a channel-speaker matrix may be described as table 1.

Since the signals of different channels are mostly not correlated with each other, the influence between different channels on the same loudspeaker will be minimal. Thus, signals from different channels may be mixed with each other. Combining these three approaches can expand the sound field and can produce an immersive listening experience with virtual height and surround effect.

TABLE 1 one example of a channel-loudspeaker matrix

	Loudspeaker 1	Loudspeaker 2	Loudspeaker 3	Loudspeaker 4
					Left side of	●	●	●	●
Right side	●	●	●	●
					Left surround	●	●
Right surround			●	●
					Left height	●	●
Right height			●	●
					Center (C)		●	●
LFE	●	●	●	●

To complete the apparatus, it is contemplated that after output from the channel-speaker matrix of the processor, at least a digital-to-analog converter and a power amplifier, for example, may be further applied to the processed channels in sequence, before entering the speakers.

While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. In addition, features of various implementing embodiments may be combined to form further embodiments of the invention.