WO2011152044A1 - Sound-generating device - Google Patents

Abstract

In order to achieve natural surround sound field reproduction that is seamless in all three-dimensional directions, the disclosed sound-generating device is provided with a signal processor (102) that outputs a plurality of 7.1-channel input sound signals to a plurality of prescribed speakers prescribed as the output destinations of each 7.1 channel of the plurality of input sound signals, and that generates a virtual speaker at a position different from that of each of the plurality of prescribed speakers and outputs at least one of the plurality of 7.1-channel sound signals from the generated virtual speaker.

Description

Sound reproduction device

The present invention relates to a sound reproduction device for reproducing a three-dimensional diffuse sound field with a rich sound field feeling despite being a 5.1 channel speaker system composed of a set of surround channel speakers. is there.

Recently, with the advent of media that provide high-definition and multi-channel audio, such as digital broadcasting and Blu-ray Disc, it has become possible to enjoy high-quality and high-quality content easily at home. Furthermore, with the widespread use of thin large-screen TVs, home theaters for enjoying movies at home are in the spotlight. In particular, there is a demand for an audio playback system that can provide high-quality and realistic playback sound that is comparable to a large screen. In particular, the Blu-ray disc has a format for recording 13.1 channel audio signals (7.1 channel is the maximum in the current contents), and the expectation expands to the sound field full of presence that the reproduced sound brings. On the other hand, as the number of channels increases, the sense of reality increases, but the number of speakers for reproducing it increases, which is far from being easy at home theaters handled at home.

Therefore, a multi-channel sound field reproduction device having a multi-channel sound field reproduction method for reproducing a 7.1-channel signal with a 5.1-channel speaker has been proposed.

FIG. 13 is a diagram showing an example of a conventional multi-channel sound field reproduction device (see Patent Document 1).

Hereinafter, the operation of the conventional multi-channel sound field reproduction apparatus will be described with reference to FIG.

FIG. 13 shows an example of a multi-channel sound field reproduction method for reproducing a 7.1-channel signal with a 5.1-channel speaker, and an arithmetic unit F1a that generates a sum signal and a difference signal of the back surround signals BL and BR. The FIR filter F1b that processes the sum signal, the FIR filter F1c that processes the difference signal, the arithmetic unit F1d that generates the sum signal and the difference signal of the signals processed by the FIR filters F1b and F1c, and the arithmetic unit F1d The adder a and the adder b add the sum signal and the difference signal processed in step 1 to the side surround signals SL and SR, respectively.

For audio playback in 5.1 channel format, ITU-R BS. The loudspeaker arrangement recommended by 775-1 is recommended, and the back surround channel added as the 7.1 channel is set at around 150 degrees behind SL and SR. In this conventional example, the back surround channel audio signals BL and BR are signal-processed and added to the surround channel signals SL and SR, so that a 5.1 channel speaker configuration without a back surround channel speaker is provided. 7.1 The effect of the channel is produced.

First, the 5.1 channel surround speakers SL and SR are arranged in the direction of 90 degrees (right and left lateral direction of the viewer) rather than in the direction of 120 degrees (diagonal left and right backward of the viewer).

As shown in FIG. 13, the processing of the back surround signal is performed by calculating a pair of back surround signals BL and BR by the calculation unit F1a and generating a sum / difference component thereof, and then the sum signal is processed by the FIR filter F1b. The difference signal is processed by the FIR filter F1c, and the sum / difference signal is generated by the calculation unit F1d. The transfer characteristics P and N of the FIR filters F1b and F1c are
P = (F + K) / (S + A)
N = (F−K) / (SA)
Indicated by Here, S is the transfer characteristic from the actual speaker to the ear on the same side of the viewer, A is the transfer characteristic from the ear on the opposite side of the viewer, and F is the ear on the same side of the viewer from the position where the sound image is to be localized. Is a transfer characteristic from the position where the sound image is to be localized to the ear on the opposite side of the viewer, and uses the viewer's head-related transfer function.

In this way, the pair of back surround signals BL and BR are subjected to sound image localization processing, added to the SL and SR channel audio signals by the adder a and adder b, respectively, and left and right side surround speakers SL as output signals of the SL and SR channels. , Supplied to SR and played back. In this way, the back surround signal is subjected to sound image localization processing, added to the side surround speaker, and played back, so that 7.1 channel sound image localization and realism can be easily created in a general home. it can.

JP 2005-341208 A

However, in this conventional example, it is only possible to reproduce the surround back signal, and the sound field feeling between the front speakers and the surround speakers cannot be reproduced, so that a natural surround without a joint is felt. The sound field cannot be reproduced.

The present invention solves the problems of the prior art, and does not impair the surround feeling of the content, and furthermore, sounds that make the user feel a natural surround without being conscious of being played from the speaker. It is an object of the present invention to configure an acoustic reproduction device that realizes field reproduction.

In order to solve the above-described problem, an acoustic reproduction device according to an aspect of the present invention outputs a plurality of input acoustic signals to a plurality of prescribed speakers defined as output destinations of the plurality of input acoustic signals. And a signal processing unit that generates a virtual speaker at a position different from any of the defined speakers and outputs at least one of the plurality of acoustic signals from the generated virtual speaker.

As described above, according to the sound reproducing device of one embodiment of the present invention, the input sound signal is output to a plurality of specified speakers specified as the output destinations of the input sound signal, and is different from any of the specified speakers. Since virtual speakers are generated at positions, acoustic signals are reproduced from more than the number of speakers defined as the output destinations of the input acoustic signals. As a result, the viewer can view natural surround sound that cannot be tasted only with a plurality of prescribed speakers.

In addition, the signal processing unit may be a sound that is perceived as being reproduced by a predetermined prescribed speaker among the plurality of prescribed speakers defined as respective output destinations of the input acoustic signal when viewed from a predetermined viewing position. The acoustic signal is equalized with an equalizer characteristic that converts the characteristic of the signal into a characteristic that is perceived as being reproduced by the first virtual speaker when viewed from the viewing position, and the first virtual speaker is converted by the equalization. It may be generated at the same position as the prescribed speaker on a second horizontal plane located above or below the first horizontal plane where the prescribed speaker exists.

Thus, a virtual speaker can be generated on a horizontal plane that is different in the vertical direction from the horizontal plane on which the specified speaker is present, so that a surround space with a three-dimensional effect can be realized.

In addition, the signal processing unit uses the amplitude characteristic of the head-related transfer function from the position of the first virtual speaker to the viewing position as the amplitude characteristic of the head-related transfer function from the position of the specified speaker to the viewing position. The acoustic signal may be equalized with equalization characteristics obtained by dividing the sound signal.

Accordingly, the signal processing unit equalizes the amplitude characteristic of the head-related transfer function of the specified speaker to the amplitude characteristic of the head-related transfer function of the first virtual speaker by equalizing the acoustic signal to the first virtual speaker. A speaker can be generated.

In addition, the signal processing unit includes a plurality of transfer characteristic processing units that equalize the sound signals of the plurality of channels reproduced by the plurality of prescribed speakers arranged on the first horizontal plane with the equalization characteristics, respectively. The transfer characteristic processing unit generates a plurality of the first virtual speakers, and generates each of the first virtual speakers at the same position as each of the plurality of specified speakers on the second horizontal plane. It is good.

Thereby, acoustic signals of a plurality of channels reproduced by the plurality of prescribed speakers can be generated at the same position as the plurality of prescribed speakers on the second horizontal plane.

Further, the signal processing unit further reproduces an acoustic signal with a first prescribed speaker that is one of the plurality of prescribed speakers, so that the acoustic signal is a second virtual speaker on the first horizontal plane. A first transfer characteristic processing unit that equalizes the acoustic signal reproduced by the first prescribed speaker with a first equalizer characteristic that is converted into a characteristic that is perceived as being reproduced by the first prescribed speaker; and the plurality of prescribed speakers And the acoustic signal is perceived as being reproduced by the second virtual speaker by reproducing the acoustic signal using a second prescribed speaker different from the first prescribed speaker. A second transfer characteristic processing unit for equalizing the acoustic signal reproduced by the second prescribed speaker with a second equalizer characteristic to be converted into the first transmission, and the first transmission for the acoustic signal. The ratio of the reproduction levels when the outputs of the sex processing unit and the second transfer characteristic processing unit are reproduced is the distance from the first prescribed speaker to the second virtual speaker, and the second A first level adjusting unit for adjusting an output level of the first transfer characteristic processing unit so as to correspond to a ratio with a distance from a prescribed speaker to the second virtual speaker; and the first level with respect to the acoustic signal. When the outputs of the transfer characteristic processing unit and the second transfer characteristic processing unit are reproduced, the ratio of the reproduction levels is the distance from the first prescribed speaker to the second virtual speaker, and the second A second level adjusting unit that adjusts an output level of the second transfer characteristic processing unit so as to correspond to a ratio with a distance from the second prescribed speaker to the second virtual speaker, and the signal processing Part is the second The virtual speakers may generate a position between the said first of said viewed from the viewing position on the horizontal plane first prescribed speaker second prescribed speakers.

As described above, the second virtual speaker is generated between the first specified speaker and the second specified speaker by using the first specified speaker and the second specified speaker on the first horizontal plane. Can do. At this time, it is possible to generate the second virtual speaker with higher accuracy by combining the equalization of the head-related transfer function and the level adjustment.

In addition, the first transfer characteristic processing unit and the second transfer characteristic processing unit, when viewed from the viewer at the viewing position, have a head-related transfer function with respect to the ear on the side where the second virtual speaker is located. The conversion is performed using the amplitude characteristic, and the amplitude characteristic of the head-related transfer function from the position of the second virtual speaker to the viewing position is determined as the position of each of the first specified speaker and the second specified speaker. The acoustic signal may be equalized by each of the first equalization characteristic and the second equalization characteristic obtained by dividing by the amplitude characteristic of the head-related transfer function from to the viewing position.

Thus, since the acoustic signal is equalized using the amplitude characteristic of the head-related transfer function for one ear, the second virtual speaker can be generated in a position having a vaguely broadened area. This makes it possible to perceive the approximate position of the second virtual speaker even when the viewer views at a position deviated from the predetermined viewing position, and a plurality of second virtual speakers are continuously connected. If it is arranged, it becomes possible to experience a natural surround sound without a joint between sounds. In addition, since the equalization characteristic is calculated using the head-related transfer function for one ear, the amount of calculation can be reduced compared to the case where the head-related transfer function for both ears is used, and the processing of the sound reproduction device There is an effect that the load can be reduced.

In addition, the signal processing unit further reproduces an acoustic signal with a third virtual speaker that is one of the plurality of first virtual speakers, so that the acoustic signal is the second virtual speaker as viewed from the viewing position. A third equalizer characteristic that equalizes the acoustic signal reproduced by the third virtual speaker with a first equalizer characteristic that is converted into a characteristic that is perceived as being reproduced by the fifth virtual speaker on the horizontal plane The acoustic signal is reproduced by the fourth virtual speaker that is one of the processing unit and the plurality of first virtual speakers and is different from the third virtual speaker, so that the acoustic signal is the fifth virtual speaker. A fourth transfer characteristic processing unit that equalizes the acoustic signal reproduced by the fourth virtual speaker with a second equalizer characteristic that is converted into a characteristic perceived as being reproduced by the virtual speaker; A ratio of reproduction levels when the outputs of the third transfer characteristic processing unit and the fourth transfer characteristic processing unit with respect to the audio signal are reproduced is from the third virtual speaker to the fifth virtual speaker. Level adjustment unit that adjusts the output level of the third transfer characteristic processing unit so as to correspond to the ratio of the distance from the fourth virtual speaker to the distance from the fourth virtual speaker to the fifth virtual speaker And the ratio of the reproduction level when the outputs of the third transfer characteristic processing unit and the fourth transfer characteristic processing unit with respect to the acoustic signal are reproduced from the third virtual speaker to the fifth A fifth level for adjusting the output level of the fourth transfer characteristic processing unit so as to correspond to the ratio of the distance to the virtual speaker and the distance from the fourth virtual speaker to the fifth virtual speaker Adjustment section The signal processing unit generates the third virtual speaker on the second horizontal plane at the same position as the first specified speaker, and the fourth virtual speaker on the second horizontal plane. And generating the fifth virtual speaker from the viewing position on the second horizontal plane with the third virtual speaker and the fourth virtual speaker. It may be generated at a position between.

Thus, the fifth virtual speaker can be generated at a position sandwiched between the third virtual speaker and the fourth virtual speaker on a horizontal plane different from the horizontal plane where the plurality of specified speakers exist. At this time, the signal processing unit equalizes transfer characteristics between the third virtual speaker and the fourth virtual speaker, and adjusts the playback level according to the distance from each virtual speaker to the fifth virtual speaker. Therefore, the fifth virtual speaker can be localized at a desired position with higher accuracy than in the case where the fifth virtual speaker is generated using only either equalization or level adjustment.

Furthermore, the signal processing unit is further on the first horizontal plane or the second horizontal plane, and two speakers at the same level at the same level with respect to the front direction of the viewing position are the same. A third level adjuster that causes the sound signal to be reproduced by a sixth virtual speaker on the first horizontal plane or the second horizontal plane by reproducing the acoustic signal; The processing unit may generate the sixth virtual speaker at a position in the front direction when viewed from the viewing position on the first horizontal plane or when viewed from the viewing position on the second horizontal plane. Good.

Thus, the signal processing unit uses the two speakers located on the first horizontal plane or the second horizontal plane and located symmetrically with respect to the front direction, on the first horizontal plane or the second horizontal plane. It is possible to generate a virtual center channel speaker on the top. As a result, the center channel signal can be viewed in a three-dimensional surround space.

Further, the signal processing unit may equalize the acoustic signal with an approximate equalizer characteristic that satisfies at least one peak or dip feature point on the equalizer characteristic curve obtained by the conversion.

As a result, when an acoustic signal is equalized with an equalizer characteristic that completely matches the equalizer characteristic curve obtained by division, the amount of computation increases, but the characteristic points such as the peak or dip of the equalizer characteristic curve are satisfied. By approximating with the equalizer characteristic, there is an effect that the acoustic signal can be equalized with a small amount of calculation.

Note that the present invention can be realized not only as an apparatus but also as a method using steps as processing units constituting the apparatus, as a program for causing a computer to execute the steps, or as a computer read recording the program. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet.

With the above configuration, the sound field control device of the present invention has a wide service area as an audio environment by using a limited number of speakers, and is further reproduced from the speakers without impairing the surround feeling of the content. This makes it possible to realize sound field reproduction with a simple configuration that makes the user feel natural surround without any connection in all three-dimensional directions.

FIG. 1 is a block diagram showing a configuration of a sound reproducing device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of speaker arrangement in the embodiment of the present invention. FIG. 3 is an explanatory diagram of speaker arrangement in the embodiment of the present invention. FIG. 4 is an explanatory diagram of speaker arrangement in the embodiment of the present invention. FIG. 5 is a block diagram showing the overall configuration of the signal processor according to the embodiment of the present invention. FIG. 6 is a block diagram showing a detailed hardware configuration of a signal processor for constructing a speaker group in a plane including real speakers in the embodiment of the present invention. FIG. 7 is a block diagram showing a detailed hardware configuration of the signal processor for constructing the speaker group in the second plane located above the plane including the actual speaker in the embodiment of the present invention. FIG. 8 is a diagram illustrating an example of signal processing for constructing one virtual speaker between two real speakers in the embodiment of the present invention. FIG. 9 is a diagram illustrating another example of signal processing for constructing one virtual speaker between two real speakers in the embodiment of the present invention. FIG. 10 is a characteristic diagram showing an example of head-related transmission characteristics when the presentation angle of the sound source is changed. FIG. 11 is a characteristic diagram showing the frequency characteristics of the equalizer in the embodiment of the present invention shown in FIGS. 6 and 7. FIG. 12 shows ITU-R BS. It is a speaker arrangement diagram of 775-1 recommendation. FIG. 13 is a block diagram showing a configuration of a conventional audio playback apparatus. FIG. 14 is a diagram illustrating an external appearance of a sound reproducing apparatus using a 5.1 channel speaker system.

(Embodiment)
The operation and components of the sound reproducing device according to the embodiment of the present invention will be described in detail below.

FIG. 14 is a diagram showing an external appearance of a sound reproducing device using a 5.1 channel speaker system. The home theater system shown in the figure includes a monitor 10, a deck 11, a center channel speaker 12, a front L channel speaker 13, a front R channel speaker 14, a side L channel speaker 15, a side R channel speaker 16, a bass effect (SW (subwoofer)). Speaker) A channel speaker 17 and a sofa 18 are provided. The sofa 18 is an example of a viewing space where the user uses the home theater system. The sound reproducing device according to the present embodiment in FIG. 14 is, for example, a set top box or the like and is stored in the deck 11. Note that the sound reproducing device of the present invention does not need to include the above-described speaker, and may simply perform signal processing on the sound signal and output the signal processed sound signal to an externally connected speaker.

FIG. 1 is a block diagram showing a configuration of a sound reproducing device according to an embodiment of the present invention.

FIG. 2 is a visual representation of a specific arrangement in an actual viewing space of six actual speakers and 23 generated virtual speakers of the sound reproducing device according to the embodiment of the present invention.

1 uses a 5.1 channel speaker system to create a sound field in which 7.1 channel signals are reproduced by 29 speakers. For example, in the present embodiment, virtual speakers are generated for 21 speakers that exceed 7.1 channels out of 29 speakers. More specifically, the actual speakers actually provided in the sound reproducing device are six speakers constituting 5.1 channels. On the other hand, the 7.1-channel signal input to the sound reproduction device includes a signal in which two speakers not provided in the sound reproduction device are defined as output destinations. In the following example, there are a surround back L channel signal (BL signal) and a surround back R channel signal (BR signal). The two speakers (specified speakers) defined for the input signal are virtually generated using other real speakers, but the virtual speaker that is a feature of the sound reproducing device of the present embodiment. It is distinguished from That is, the sound reproducing device of the present embodiment is a plurality of speakers that are preliminarily defined as 7.1 channel signals, which are a plurality of input audio signals, as respective output destinations of the 7.1 channel signals. The apparatus outputs to eight virtual speakers that are virtually generated, and outputs to the virtual speakers generated at 21 speaker positions different from any of the eight predetermined speakers.

In FIG. 1, a signal generator 101 generates a 7.1-channel multi-channel audio signal. That is, front L channel signal (FL signal), front R channel signal (FR signal), surround L channel signal (SL signal), surround R channel signal (SR signal), surround back L channel signal (BL signal), surround back An R channel signal (BR signal), a center channel signal (C signal) and a bass effect channel signal (LFE signal) are generated. Specific examples of the signal generator 101 include a Blu-ray disc having 7.1-channel audio signal content and its playback player. With respect to content having a channel number less than 7.1 channels, a channel having no content generates a signal as no signal, or the signal is expanded to a channel having no content, and a 7.1 channel signal is generated. Will either occur. For example, in the case of 5.1 channel which is very general content, the signal level of the surround signal (SL, SR) is set to −3 dB, and the SL signal is changed from SL and BL to SR The signal is output from SR and BR.

The signal processor 102 performs signal processing for reproducing the sound field corresponding to the reproduction by the 29 speaker system on the output signal of the signal generator 101 by the 5.1 channel speaker system. The power amplifier 103 amplifies the output signal of the signal processor 102. The front L speaker 104 is a front L channel speaker (FL speaker) arranged on the front left side when viewed from the viewing position. The front R speaker 105 is a front R channel speaker (FR speaker) arranged on the front right side when viewed from the viewing position. The surround L speaker 106 is a surround L channel speaker (SL speaker) disposed on the rear left side when viewed from the viewing position. The surround R speaker 107 is a surround R channel speaker (SR speaker) arranged on the rear right side when viewed from the viewing position. The center speaker 108 is a center channel speaker (C speaker) disposed in front of the viewing position. The subwoofer speaker 109 is a speaker for a bass sound effect channel (SW (subwoofer) speaker). In the sound reproduction apparatus of the present embodiment, the front L speaker 104, the front R speaker 105, the surround L speaker 106, the surround R speaker 107, the center speaker 108, and the subwoofer speaker 109 constitute a 5.1 channel speaker system. .

The speaker arrangement shown in FIG. 2 is generated and arranged on the same horizontal plane as the actual speakers 104 to 109, and on the horizontal plane (elevation angle) above the horizontal plane where the actual speakers 104 to 109 are installed. It consists of two layers of virtual speakers 301-314.

FIG. 3 shows a planar arrangement of the virtual speakers 201 to 209 to be reproduced and the speakers 104 to 109 actually existing when viewed from vertically above the viewing point in the sound reproduction apparatus according to the embodiment of the present invention.

FIG. 4 shows a planar arrangement of the virtual speakers 301 to 314 to be reproduced as seen from above the viewing point vertically in the sound reproduction apparatus according to the embodiment of the present invention.

FIG. 5 shows a specific configuration of the signal processor 102, and the signal processing block 501 generates and processes the speaker shown in FIG. The signal processing block 502 generates and processes the speaker shown in FIG. The level adjuster 503 adjusts the output level of the signal processing block 501. The level adjuster 504 adjusts the output level of the signal processing block 502. The level adjuster 505 adjusts the signal level of the LFE channel. Adders 506 to 510 add the outputs of level adjusters 503 and 504 for each channel.

FIG. 6 is a block diagram showing a specific configuration of the signal processing block 501 for generating a virtual speaker on a plane where a real speaker exists. The signal processing block 501 includes level adjusters 601 to 627, 648 to 659, and an adder 628. ˜635, 660˜663, and equalizers 636˜647.

FIG. 7 is a block diagram showing a specific configuration of the signal processing block 502 for generating a virtual speaker on a virtual plane located vertically above a plane where the real speaker exists, and level adjusters 701 to 727 and 755 to 770. , Adders 728 to 737, 771 to 774, and equalizers 738 to 754 are provided.

8 and 9 are explanatory diagrams regarding the generation of virtual speakers.

FIG. 10 is an example of head-related transmission characteristics when the presentation angle of the sound source is changed.

FIG. 11 is an example of frequency characteristics of the equalizer shown in FIG. 6 or FIG.

The operation of the embodiment of the present invention configured as described above will be described in detail.

The 7.1-channel audio signal output from the signal generator 101 is input to the signal processor 102. In the embodiment of the present invention, a 5.1-channel speaker system generates a sound field equivalent to a 7.1-channel content reproduced by 29 speaker systems including the real speakers and virtual speakers shown in FIG. To perform signal processing for reproduction. Here, the arrangement of the 5.1 channel speaker system is the speaker arrangement as defined in ITU (International Telecommunication Union) -R BS10 TG10 / 1 recommendation 775-1 shown in FIG. The center speaker is arranged on a concentric circle of 0 degrees, the front speaker is arranged on the left and right 30 degrees, and the surround speaker is arranged on the left and right 120 degrees).

On the other hand, a virtual speaker 203 for surround back channel that reproduces a surround back channel L signal (BL signal) included in the playback content on the same horizontal plane where the real speaker is installed as a virtual speaker to be reproduced in addition to the real speaker. VBL speakers) and surround back channel virtual speakers 206 (VBR speakers) for reproducing surround back channel R signals (BR signals) are arranged.

Also, in the 5.1-channel and 7.1-channel speaker arrangement, the left and right speaker intervals are 90 degrees between the front channel and the surround channel, so there is a lack of seamless sound field between the front channel and the surround channel. In order to improve this, the virtual speaker 201 (VFL speaker) and the SL signal for localizing the FL signal at positions of 60 degrees and 90 degrees between the speaker 104 (FL speaker) and the speaker 106 (SL speaker). And a virtual speaker 202 (VSL speaker) for localizing the sound signal, and similarly, the FR signal is localized at positions of 60 degrees and 90 degrees between the speaker 105 (FR speaker) and the speaker 107 (SR speaker). A virtual speaker 204 (VFR speaker) for positioning and a virtual speaker 205 (VSR speaker) for localizing the SR signal are arranged.

In addition, virtual center speakers 207 (VC1), 208 (VC2), and 209 (VC3) are arranged in order to improve the density of the sound field near the viewer formed by the center channel.

Furthermore, virtual speakers 301 (VFLH1), 302 (VFLH2), 306 (VFRH1), and 307 (VFRH2) that reproduce front channel signals on a plane that is higher in elevation than the horizontal plane where the actual speakers are installed, and surround channel signals. Virtual speakers 303 (VSLH1), 304 (VSRH2), 308 (VSRH1), and 309 (VSRH2) that reproduce the sound, virtual speakers 305 (VBLH) and 310 (VBRH) that reproduce the surround back channel signal, and the center channel signal. Virtual speakers 311 (VCH0), 312 (VCH1), 313 (VCH2), and 314 (VCH3) to be reproduced are arranged.

Therefore, in the embodiment of the present invention, C (0 degree), FL (left 30 degrees), FR (right 30 degrees), SL (left 120 degrees), SR (right 120 degrees), SW 5.1 channel The sound field to be reproduced with 29 speakers is realized by this speaker system.

Next, a method for reproducing a reproduction sound (particularly sound source localization) from a virtual speaker that does not exist using a real speaker will be described.

Realization of the virtual speakers 201, 202, 204, 205, 302, 303, 307, 308 will be described. As an example, the virtual speaker 201 illustrated in FIG. 8 is generated using the real speakers 104 and 106. That is, the reproduction is performed with two real speakers sandwiching the virtual speaker to be generated.

人間 Humans feel the sound with their ears, but the sound transmitted to the ear is not only the direct sound from the sound source but also via the human body, especially the head. Therefore, the sound transmission characteristic from the sound source to the ear is affected by the human body, particularly the head and pinna, and has a frequency characteristic, which varies depending on the presentation position of the sound source. This is called head-related transfer characteristics. The reason that humans can specify the position of the sound source is that they understand the head-related transfer characteristics and their angular dependence. The head-related transfer characteristic is determined by the direction of the sound source relative to the ear, but can be specified by two angles, a horizontal angle and an elevation angle.

An example of the head transfer characteristic is shown in FIG. FIG. 10 shows the case where the speaker and the ear are located at the same height of 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees counterclockwise when viewed from the front of the viewer. The frequency characteristic of the transfer function from the speaker to the viewer's left ear is shown.

In the embodiment of the present invention, by applying this human sound localization position specifying mechanism, the head from the virtual speaker is determined based on the relative relationship of the installation angle as viewed from the viewing position of the virtual speaker and the actual speaker to be realized. By controlling the frequency characteristics from the actual speaker so that the transfer characteristics are given to the viewer, it is possible to feel as if the sound comes from the virtual speaker to be realized (the sound is localized).

On the other hand, humans have ears on the left and right. Therefore, the head-related transfer characteristic exists for each of the left and right ears. However, in the present invention, the head-related transfer characteristics of the ear on the direction side where the virtual speaker desired to be realized from the viewpoint of the viewer is utilized. The reason is that it is sufficient to control this side because the sound pressure applied to the ear on the side where the speaker exists is larger.

That is, in the case where the real speakers A and B (not shown) that exist in a form sandwiching the installation angle of the virtual speaker V (not shown) to be reproduced are used, viewing on the side where the virtual speaker V to be realized is viewed The transmission characteristics of the person's head. Here, the installation angle of the speaker means an angle measured counterclockwise with the viewer's viewing position as the center and the front of the viewer as the reference direction. HA is the head transfer characteristic at the viewer accompanying the playback sound of the real speaker A, HB is the head transfer characteristic at the viewer accompanying the playback sound of the real speaker B, and the playback sound of the virtual speaker V is actually Assuming that the head transfer characteristic at the viewer is HV (assuming that there is a real speaker at the position), the real speaker A performs frequency characteristics processing of HV / HA, and the real speaker B performs processing of frequency characteristics of HV / HB.

When the same sound source is reproduced from two speakers, a synthesized sound of reproduced sounds from the two speakers can be generated so that the sound source is localized at a position where the vectors are synthesized by weighting of the level ratio. That is, when the angle between the real speaker A and the virtual speaker V viewed from the viewing position is a and the angle between the real speaker B and the virtual speaker V is b, the levels PA and PB of the speakers A and B are respectively

It becomes.

However, since the actual speakers A and B are processed with different frequency characteristics, it is necessary to consider the level change due to the frequency characteristics processing. Therefore, (Expression 1) and (Expression 2) become (Expression 3) and (Expression 4), respectively.

In the specific example shown in FIG. 8, the virtual speaker 201 (60 ° left direction when viewed from the front of the viewer) to be realized is the real speaker 104 (30 ° left when viewed from the front of the viewer) and 106 (viewed from the front of the viewer). To the left 120 degrees). The reason is that the virtual speaker 201 to be realized is located on the left side of the viewer, and therefore uses the left ear's head transmission characteristics. HFL is the head transfer characteristic of the viewer's left ear associated with the playback sound of the real speaker 104, HSL is the head transfer characteristic of the viewer's left ear associated with the playback sound of the real speaker 106, and the playback sound of the virtual speaker 201 HVFL / HFL from the real speaker 104 and HVFL / HSL from the real speaker 106, where HVFL is a head-related transfer characteristic in the left ear of the viewer (assuming that a real speaker actually exists at this position). Apply the process. The reproduction levels of the actual speakers 104 and 106 are determined by (Expression 3) and (Expression 4).

That is, the speaker 104 is

The speaker 106

It becomes.

The virtual speaker 202 can be realized in exactly the same manner. The virtual speakers 204 and 205 are the same as the virtual speakers 201 and 202 and correspond to the right channel.

The virtual speakers 302, 303, 307, and 308 use head-related transfer characteristics that have the same horizontal angle as the virtual speakers 201, 202, 204, and 205, and the upward elevation direction (based on the height of the viewer's ears). This can be achieved.

The realization of the virtual speakers 203, 206, 305, 310 will be described. In this case as well, the same is true for the virtual speakers 201, 202, 204, 205, 302, 303, 307, and 308, but there are real speakers on both sides of the viewer that sandwich the virtual speaker to be realized. However, the head-related transfer characteristics used are those for the ear on the side where the virtual speaker to be realized exists.

In this way, by using only the head-related transfer function for the ear on the side where the virtual speaker that is desired to be realized is used, the individual virtual speakers are not localized at distinct positions so that they can be distinguished from each other, but gently. It can be located at a position with a wide spread. And the surround sound space where a sound spreads continuously is realizable by arrange | positioning the virtual speaker each localized in this way continuously without leaving a space | interval. As a result, there is an effect that a viewer can enjoy a natural three-dimensional acoustic space without any problem, even when the viewer views at a position deviated from a predetermined viewing position. Further, by performing control using the head-related transfer function for one ear, the processing load of the sound reproducing device can be reduced.

FIG. 9 shows an example in which the virtual speaker 203 is realized using the actual speakers 106 and 107.

Realization of the virtual speakers 301, 306, 304, 309, 311 will be described. These are sound images localized above the elevation angles of the actual speakers 104, 105, 106, 107, and 108, respectively. In this case, it is realized only by controlling the frequency characteristics. That is, taking the virtual speaker 301 as an example, it can be realized by processing the head transmission characteristic by the virtual speaker 301 / the head transmission characteristic by the real speaker 104 into a signal reproduced from the virtual speaker 301 and reproducing from the real speaker 104. .

Realization of the virtual speakers 207, 208, 209, 312, 313, 314 will be described. From these virtual speakers, the center channel signal is reproduced. Here, it is utilized that the sound image is localized at the center when a signal of the same level is reproduced on a speaker installed symmetrically. Therefore, the virtual speaker 207 uses the real speakers 104 and 105, the virtual speaker 208 uses the virtual speakers 201 and 204, the virtual speaker 209 uses the virtual speakers 202 and 205, and the virtual speaker 312 uses the virtual speakers 312. Using the speakers 301 and 306, the virtual speaker 313 is implemented using the virtual speakers 302 and 307, and the virtual speaker 314 is implemented using the virtual speakers 303 and 308.

The specific configuration of the signal processing blocks 501 and 502 for generating the virtual speaker described above will be described with reference to FIGS.

FIG. 6 shows a specific configuration of the signal processing block 501, which performs processing for the speaker shown in FIG. Here, since the same processing is performed on the left and right, only the L channel will be described. Here, the front channel signal is reproduced from the real speaker 104 and the virtual speaker 201, the surround channel signal is reproduced from the real speaker 106 and the virtual speaker 202, and the back surround signal is reproduced from the virtual speaker 203.

Realization of the virtual speaker 201 is realized using the real speakers 104 and 106 as described above.

The signal for localization to the virtual speaker 201 (VFL speaker) is processed by the equalizer 636, the equalizer 638, the level adjuster 648, and the level adjuster 650.

The equalizer characteristic PEQ101 of the equalizer 636 realizes (left ear head transmission characteristic in the direction of 60 degrees left) ÷ (left ear head transmission characteristic in the direction of 30 degrees left), and is calculated using the head transmission characteristics themselves. It is also possible to use only the amplitude characteristic calculated using the head transfer characteristic itself, or to simply implement the amplitude characteristic only calculated using the head transfer characteristic itself. Good. As a simple realization method, a graphic equalizer such as a 1/3 oct bandwidth may be used, or about 5 feature points in order of increasing or decreasing amplitude level in a band of 1 kHz or more of the calculated amplitude characteristic. Extracted from the characteristic curve and realized individual feature points using a parametric equalizer (PEQ) that can determine the characteristics as the center frequency, Q value, and amplitude level in the band obtained by further subdividing the band above 1 kHz. May be. FIG. 6 shows an example using PEQ. Further, in order to reduce the configuration scale of the equalizer to the maximum, it may be realized by extracting characteristics at at least one peak or dip. Similarly, the equalizer characteristic PEQ103 of the equalizer 638 realizes (left ear head transmission characteristic in the direction of 60 degrees left) ÷ (left ear head transmission characteristic in the direction of 120 degrees left). Based on (Equation 3) and (Equation 4) described above, the coefficients of the level adjuster 648 and the level adjuster 650 are calculated. FIG. 11 shows the frequency characteristics of the equalizer characteristics PEQ101 and PEQ103. The level adjusters 603 and 607 adjust the playback level of the front channel signal from the virtual speaker 201. Normally, the levels of the level adjusters 602 and 607 are the same. Similarly, the playback level of the front channel signal from the actual speaker 104 is adjusted by the level adjuster 602.

Similarly, the signal for localizing the virtual speaker 202 (VSL speaker) is processed by the equalizer 637, the equalizer 639, the level adjuster 649, and the level adjuster 651. The equalizer characteristic PEQ102 of the equalizer 637 realizes (left ear head transmission characteristic in the direction of 90 degrees left) ÷ (left ear head transmission characteristic in the direction of 30 degrees left), and the equalizer characteristic PEQ104 of the equalizer 639 is (left 90 degrees Left ear head transmission characteristics in the direction of degrees) ÷ (left ear head transmission characteristics in the direction of 120 degrees left), and based on the above (Equation 3) and (Equation 4), the level adjuster 649, the level adjuster A 651 coefficient is calculated. The level adjusters 605 and 609 adjust the playback level of the surround channel signal from the virtual speaker 202. Normally, the level adjusters 605 and 609 have the same level. Similarly, the reproduction level of the surround channel signal from the actual speaker 106 is adjusted by the level adjuster 611.

Further, since the virtual speaker 203 (VBL speaker) is sandwiched between the speaker 106 (SL speaker) and the speaker 107 (SR speaker), it is reproduced by these two speakers.

A signal for localization to the virtual speaker 203 (VBL speaker) is processed by the equalizer 640, the equalizer 642, the level adjuster 652, and the level adjuster 654. The equalizer characteristic PEQ105 of the equalizer 640 realizes (left ear head transmission characteristic in the direction of 150 degrees left) ÷ (left ear head transmission characteristic in the direction of 120 degrees left), and the equalizer characteristic PEQ106 of the equalizer 642 is (left 150 head transmission characteristics). Left ear head transmission characteristics in the direction of degrees) / (left ear head transmission characteristics in the direction of 120 degrees to the right), and based on the above-described (Equation 3) and (Equation 4), the level adjuster 652 and the level adjuster A coefficient of 654 is calculated. The playback level of the back surround channel signal is adjusted by level adjusters 612 and 613. Usually, the same value is sufficient for both.

The signals processed as described above are added by adders 660 to 663 to generate an output signal.

The adder 660 outputs a signal to the FL channel output of the signal processing block 501, and performs processing for reproducing the output signal of the level adjuster 602 that adjusts the level of the input FL signal and the VFL speaker. The output signal of the level adjuster 648 that has been applied, the output signal of the level adjuster 649 that has been processed to reproduce the VSL speaker, and the output signal of the level adjuster 601 that generates the virtual speaker 207 (VC1) Is added.

Similarly, the adder 661 outputs a signal to the SL channel output of the signal processing block 501, and reproduces the output signal of the level adjuster 611 that adjusts the level of the input SL signal and the VFL speaker. The output signal of the level adjuster 650 that has been processed, the output signal of the level adjuster 651 that has been processed to reproduce the VSL speaker, and the output of the level adjuster 652 that has been processed to reproduce the VBL speaker The signal is added to the output signal of the level adjuster 654 that has been processed to reproduce the VBR speaker. Here, the level adjusters 648 to 659 are calculated using (Expression 3) and (Expression 4), but may be changed according to the subjective effect level of the sound field feeling. The level adjusters 601 to 627 that determine the reproduction level of each channel signal basically adjust the acoustic characteristics at the viewing point so that the sound pressure is the same in each channel. You may change according to the subjective effect degree of a sound field feeling. In the configuration shown in FIG. 6, the front channel signal is reproduced from the FL and VFL speakers, the surround channel signal is reproduced from the SL and VSL speakers, and the back surround channel signal is reproduced from the VBL. The structure of the signal to be reproduced may be changed according to the subjective effect level of the sound field feeling, such as from the VFL speaker and from the VSL speaker. In that case, it can be realized by adding a level adjuster capable of adjusting the signal level and inputting it to an adder in front of the equalizer.

Similarly, FIG. 7 shows a specific configuration of the signal processing block 502, which performs processing for the speaker shown in FIG. Here, since the same processing is performed on the left and right, only the L channel will be described.

Realization of the virtual speaker 301 is processed (equalizer 738) based on the head transmission characteristic to the real speaker 104 and adjusted by the level adjusters 701 and 755 as described above. The equalizer characteristic 201 of the equalizer 738 is to realize (left ear head transmission characteristic in the upward direction of 30 ° left angle) ÷ (left ear head transmission characteristic in the 30 ° real speaker 104 elevation angle direction). The level adjuster 701 determines the signal level of the front channel signal reproduced by the virtual speaker 301, and the level adjuster 755 determines the reproduction level of the virtual speaker 301.

Realization of the virtual speaker 302 is realized by using the real speakers 104 and 106 as described above.

The signal for localizing the virtual speaker 302 (VFLH2 speaker) is processed by the equalizer 739, the equalizer 741, the level adjuster 756, and the level adjuster 758.

The equalizer characteristic PEQ202 of the equalizer 739 realizes (the left ear head transmission characteristic of the left 60 degrees elevation angle upward direction) ÷ (left ear head transmission characteristic of the left 30 degrees real speaker 104 elevation angle direction). It may be calculated using the characteristic itself, or only the amplitude characteristic calculated using the head-related transfer characteristic itself, or simply the amplitude characteristic calculated using the head-related transfer characteristic itself. It may be realized. As a simple realization method, a graphic equalizer such as a 1/3 oct bandwidth may be used, or about 5 feature points in order of increasing or decreasing amplitude level in a band of 1 kHz or more of the calculated amplitude characteristic. It may be realized by a parametric equalizer (PEQ) that can extract and determine characteristics with a center frequency, a Q value, and an amplitude level. FIG. 7 shows an example using PEQ. Further, when the configuration scale of the equalizer is reduced to the maximum, it may be realized by extracting at least one peak or dip characteristic. Similarly, the equalizer characteristic PEQ 204 of the equalizer 741 realizes (left ear head transmission characteristic in the direction of 60 degrees left elevation) / (left ear head transmission characteristic in the direction of elevation of the left 120 degrees real speaker 106). Based on (Equation 3) and (Equation 4) described above, the coefficients of the level adjuster 756 and the level adjuster 758 are calculated. The head-related transfer characteristics used here are obtained by determining the horizontal angle with reference to the front of the viewer and the elevation angle with reference to the ears of the viewer. The localization position of the virtual speaker 302 desired to be realized here is the horizontal angle of 60 Degrees and elevation angles are determined to be preferable angles (for example, 30 degrees) due to subjective effects. The head-related transfer characteristic for the real speaker 104 is determined by the relative relationship with the viewer. The equalizer 741 is similarly determined. Here, the head transmission characteristics for the virtual speaker 302 used when determining the characteristics of the equalizers 739 and 741 are basically the same, but priority is given to the subjective effect. The equalizer 741 may use different head transmission characteristics such as a horizontal angle of 60 degrees and an elevation angle of 30 degrees, such as a head transmission characteristic of a horizontal angle of 60 degrees and an elevation angle of 40 degrees. The level adjusters 703 and 707 are for adjusting the playback level of the front channel signal from the virtual speaker 302. Normally, the levels of the level adjusters 703 and 707 are the same.

Similarly, the signal for localization to the virtual speaker 303 (VSLH2 speaker) is processed by the equalizer 740, the equalizer 742, the level adjuster 757, and the level adjuster 759. The equalizer characteristic PEQ 203 of the equalizer 740 realizes (left ear head transmission characteristic in the upward direction of 90 ° left elevation) ÷ (left ear head transmission characteristic in the 30 ° left real speaker 104 elevation angle direction), and the equalizer characteristic of the equalizer 742 The PEQ 205 realizes (left ear head transmission characteristic in the upward direction of the left 90 ° elevation angle) ÷ (left ear head transmission characteristic in the elevation direction of the left 120 ° real speaker 106), and the above-described (Equation 3) and (Equation 4). ) And level adjuster 757 and level adjuster 759 coefficients are calculated. The level adjusters 705 and 709 adjust the playback level of the surround channel signal from the virtual speaker 303. Normally, the levels of the level adjusters 705 and 709 are the same.

Realization of the virtual speaker 304 (VSLH1) is performed by the processing (equalizer 743) based on the head transmission characteristic to the real speaker 106 (SL) and adjusted by the level adjusters 711 and 760 as described above. The equalizer characteristic 206 of the equalizer 743 realizes (left ear head transmission characteristic in the upward direction of 120 degrees left elevation) ÷ (left ear head transmission characteristic in the elevation direction of the left 120 degrees real speaker 106). The level adjuster 711 determines signal level adjustment of the surround channel signal reproduced by the virtual speaker 304, and the level adjuster 760 determines the reproduction level of the virtual speaker 304.

Further, since the virtual speaker 305 (VBLH speaker) is sandwiched between the speaker 106 (SL speaker) and the speaker 107 (SR speaker), it is reproduced by these two speakers.

The signal for localization to the virtual speaker 305 (VBLH speaker) is processed by the equalizer 744, the equalizer 745, the level adjuster 761, and the level adjuster 762. The equalizer characteristic PEQ 207 of the equalizer 744 realizes (left ear head transmission characteristic in the upward direction of the left 150 degrees elevation angle) ÷ (left ear head transmission characteristic in the elevation direction of the left 120 degrees actual speaker 106), and the equalizer characteristics of the equalizer 208 The PEQ 106 realizes (left ear head transmission characteristics in the upward direction of 150 degrees left elevation) ÷ (left ear head transmission characteristics in the direction of 120 degrees right), and based on the above (Equation 3) and (Equation 4), The coefficients of the level adjuster 761 and the level adjuster 762 are calculated. The playback level of the back surround channel signal is adjusted by level adjusters 712 and 713. Usually, the same value is sufficient for both.

Also, as described above, the virtual speaker 311 (VCH0) is realized by the processing (equalizer 746) based on the head transmission characteristics to the real speaker 108 and adjusted by the level adjuster 714. The equalizer characteristic 209 of the equalizer 746 realizes (left ear head transmission characteristic in the front elevation angle upward direction) / (left ear head transmission characteristic in the elevation direction of the front real speaker 108). Here, the head transfer characteristic of the left ear is used, but since it is the front of the viewer, the same is true even if the head transfer characteristic of the right ear is used. The level adjuster 714 determines the reproduction level of the center channel signal reproduced by the virtual speaker 311.

Also, the virtual speaker 312 (VCH1) is realized by inputting the center channel signal of the same level to the virtual speakers 301 (VFLH1) and 306 (VFRH1). That is, the signal level (same value) is adjusted by the level adjusters 702 and 726 and output to the adders 728 and 737.

Similarly, the virtual speaker 313 (VCH2) is realized by inputting the center channel signal of the same level to the virtual speakers 302 (VFLH2) and 307 (VFRH2). That is, the level adjusters 704, 708, 725, and 721 adjust the signal level (same value), and output it to the adders 729, 731, 736, and 734.

The virtual speaker 314 (VCH3) is realized by inputting a center channel signal of the same level to the virtual speakers 303 (VSLH2) and 306 (VSRH2). That is, the level adjusters 706, 710, 723, and 718 adjust the signal level (same value) and output it to the adders 730, 732, 735, and 733.

The signals processed as described above are added by adders 771 to 774 to generate an output signal.

The adder 771 outputs a signal to the FL channel output of the signal processing block 502. The adder 771 outputs the signal from the level adjuster 755 that has undergone processing for realizing the VFLH1 speaker, and processing for realizing the VFLH2 speaker. The output signal of the level adjuster 756 that has been subjected to the above and the output signal of the level adjuster 757 that has undergone processing for reproducing the VSLH2 speaker are added.

Similarly, the adder 772 outputs a signal to the SL channel output of the signal processing block 502, and reproduces the output signal of the level adjuster 760 subjected to processing for reproducing the VSLH1 speaker and the VSLH2 speaker. Of the level adjuster 759 subjected to the above process, the output signal of the level adjuster 761 subjected to the process for reproducing the VBLH speaker, and the level adjuster 763 subjected to the process for reproducing the VBRH speaker. The output signal is added to the output signal of the level adjuster 758 that has been processed to reproduce the VFLH2 speaker.

Here, the level adjusters 756 to 769 are calculated using (Expression 3) and (Expression 4), but may be changed according to the degree of subjective effect of the sound field feeling. The level adjusters 701 to 727 for determining the reproduction level of each channel signal are basically adjusted so that the acoustic characteristics at the viewing point, particularly the sound pressure, are the same in each channel. You may change according to the degree of the subjective effect of a sound field feeling. In the configuration shown in FIG. 7, the front channel signal is reproduced from the VFLH1 and VFLH2 speakers, the surround channel signal is reproduced from the VSLH1 and VSLH2 speakers, and the back surround channel signal is reproduced from VBLH. May be reproduced by extending the configuration of the signal to be reproduced from the VFLH2 speaker, the front channel signal from the VSLH2 speaker, or the like to other adjacent virtual speakers in accordance with the subjective effect of the sound field feeling. In that case, the movement of the virtual speaker in the direction of expansion of the sound field can also be realized by adding a level adjuster that can adjust the level of the signal and inputting it to the adder in front of the equalizer.

The signal processing blocks 501 and 502 configured as described above are level-adjusted by level adjusters 503 and 504, respectively, and then added and output by adders 506 to 510 for each channel. The values of the level adjusters 503 and 504 are based on the fact that the sound pressure characteristics of each channel at the viewing point are the same, and the distribution of the signal processing blocks 501 and 502 and the distribution between the channels take into account the subjective effect. To decide.

In the above embodiment, the virtual speakers 301, 306, 302, 307, 303, and 308 in the center channel virtual speakers 312, 313, and 314 are located at the same level with respect to the front direction of the viewing position. Realized by reproducing the center channel signal. However, the present invention is not limited to this, and the virtual speakers 312 and 313 may be realized by adjusting the output levels of the virtual speakers 311 and 314. Furthermore, the virtual speaker 314 can be realized by using a virtual speaker at a symmetrical position, or may be realized by using a virtual speaker located in a facing direction across the viewing position.

Furthermore, in the above-described embodiment, the example in which the virtual speakers 301 to 314 are realized upward (in the elevation angle direction) with respect to the horizontal plane where the real speakers are located has been described, but the present invention is not limited to this, and the virtual speakers are not limited to this. You may implement | achieve on the horizontal surface below (a depression angle direction) with respect to the horizontal surface in which a real speaker is located.

In the above embodiment, the virtual speaker 301 is realized by reproducing the front channel signal equalized in the elevation direction with the real speaker 104. However, the present invention is not limited to this. For example, the virtual speaker 301 may be realized by using the virtual speaker 311 and the virtual speaker 302, or the virtual speaker 311 and the virtual speaker 303 or the virtual speaker 311. You may implement | achieve using the virtual speaker 304. FIG. As described above, the virtual speaker can be realized in any combination by using the equalizer that equalizes the transfer characteristics and the level adjuster that distributes the outputs of the two speakers sandwiching the virtual speaker.

Note that in the localization of the virtual speaker by level adjustment, the virtual speaker tends to be localized on a straight line connecting the two speakers whose levels are adjusted. Therefore, if the localization position has a further depth, the sound spreads more naturally. You may be able to get Conversely, there may be a case where the localization position of the virtual speaker should be closer to the viewing position depending on the viewer's feeling. For this reason, it goes without saying that the distance between the speaker and the viewer may be relatively changed by inserting a delay device in the equalizer constituting FIGS. 6 and 7 and controlling the arrival time of the signal. There is no.

As described above, according to the sound reproduction device according to the present embodiment, a 5.1-channel speaker configuration generates speakers everywhere in three dimensions without being influenced by the positional relationship between the speaker and the viewer. be able to. This also makes it possible to feel a natural surround without any joints in all three-dimensional directions without impairing the surround feeling of the content and without making it conscious of being reproduced from the speaker. In addition, according to the sound reproducing apparatus of the present embodiment, it is possible to reproduce a full-scale sound field with a small number of speakers (sound field reproduction equivalent to that of a movie theater or a movie production site). This is particularly effective as a sound reproducing apparatus for a home theater where it is desired to install a plurality of speakers in a designated space.

(Other embodiments)
In the above embodiment, a three-dimensional stereoscopic speaker system is configured by using 5.1-channel real speakers, but the present invention is not limited to this. For example, it is also possible to construct the three-dimensional speaker system of the above-described embodiment by using two real speakers normally provided in a television or the like, that is, the front L speaker 104 and the front R speaker 105.

In this case, the surround L speaker 106, the surround R speaker 107, and the center speaker 108, which are configured by real speakers in the above embodiment, are virtual speakers. The virtual speakers, that is, the surround L speaker 106, the surround R speaker 107, and the center speaker 108 are generated by using conventional technology, and an input signal that is treated in the same manner as the actual speaker in the above embodiment and subjected to signal processing is generated. , The virtual speakers can be generated at 21 speaker positions different from any of the eight speakers defined in advance as the respective output destinations of the 7.1 channel signal.

The center speaker 108, which is a virtual speaker, can be realized in the same manner as the virtual speakers 207, 208, 209, 312, 313, 314 described with reference to FIG. That is, the center speaker 108 can be realized by reproducing the center channel signal of the same level and the same phase by using the front L speaker 104 and the front R speaker 105 installed symmetrically. At this time, when a center channel signal of the same level and phase is reproduced from the front L speaker 104 and the front R speaker 105, a position at the center of a line segment connecting the front L speaker 104 and the front R speaker 105, that is, a virtual speaker. The sound image is localized at the same position as 207. Therefore, a delay is added to the reproduced center channel signal in order to localize the virtual center speaker 108 at a position predetermined as the installation position of the center speaker 108 (further deeper as viewed from the viewing position). In this way, when the delayed center channel signal reaches the ear later than the virtual speaker 207, the virtual center speaker 108 is heard so as to be located at a position deeper than the virtual speaker 207. become.

Further, the virtual surround R speaker 107 and the virtual surround L speaker 106 are realized by using the front L speaker 104 and the front R speaker 105 in the same manner as in the past. Here, the front L speaker 104, the front R speaker 105, the surround L speaker 106, and the surround R speaker 107 are all arranged at the positions shown in FIG. A method for realizing the virtual surround R speaker 107 and the virtual surround L speaker 106 will be described.

When the virtual surround R speaker 107 is realized, the surround channel SR signal is equalized with the equalizer characteristic G1 and reproduced from the front L speaker 104, and the surround channel SR signal is equalized with the equalizer characteristic G2 and reproduced from the front R speaker 105. At this time, the equalizer characteristics G1 and G2 are
H1 = C1 * G1 + C3 * G2,
H2 = C2 * G1 + C4 * G2
When the condition is satisfied, it is detected as if the surround channel SR signal is being reproduced from the virtual surround R speaker 107 at the viewing position.

In the above formula, H1 is the amplitude characteristic of the head-related transfer function from the left ear to the surround R speaker 107, H2 is the amplitude characteristic of the head-related transfer function from the right ear to the surround R speaker 107, and C1 Is the amplitude characteristic of the head-related transfer function from the left ear to the front L speaker 104, C2 is the amplitude characteristic of the head-related transfer function from the right ear to the front L speaker 104, and C3 is the front R speaker 105 from the left ear. C4 is the amplitude characteristic of the head-related transfer function from the right ear to the front R speaker 105.

Similarly, when the virtual surround L speaker 106 is realized, the surround channel SL signal is equalized with the equalizer characteristic G3 and reproduced from the front L speaker 104, and the surround channel SL signal is equalized with the equalizer characteristic G4 to be reproduced from the front R speaker 105. Reproduce. At this time, the equalizer characteristics G3 and G4 are
H3 = C1 * G3 + C3 * G4,
H4 = C2 * G3 + C4 * G4
Is satisfied as if a surround channel SL signal is being reproduced from the virtual surround L speaker 106 at the viewing position.

In the above formula, H3 is the amplitude characteristic of the head related transfer function from the left ear to the surround L speaker 106, H4 is the amplitude characteristic of the head related transfer function from the right ear to the surround L speaker 106, and C1 Is the amplitude characteristic of the head-related transfer function from the left ear to the front L speaker 104, C2 is the amplitude characteristic of the head-related transfer function from the right ear to the front L speaker 104, and C3 is the front R speaker 105 from the left ear. C4 is the amplitude characteristic of the head-related transfer function from the right ear to the front R speaker 105.

With the configuration described above, the center speaker 108, the surround L speaker 106, and the surround R speaker 107 can be virtually realized by using the two real speakers, the front L speaker 104 and the front R speaker 105. Therefore, it is possible to construct the home theater system shown in FIG. 2 using two real speakers provided in a television or the like.

In the above embodiment, the number of defined speakers defined as the output destination of the multi-channel input signal (for example, eight speakers of 7.1 channel) is the number of actual speakers (six of 5.1 channel). Virtual speakers 203 for reproducing the surround back channel L signal (BL signal) and virtual speakers 206 for reproducing the surround back channel R signal (BR signal). However, the present invention is not limited to this, and the present invention is applied even when the above speaker system is provided with more than the number of actual speakers. can do.

For example, when the number of actual speakers is the same as the number of specified speakers, a signal assigned to each actual speaker may be output as it is from the corresponding specified speaker. That is, a surround back channel R signal may be output from an existing surround back channel R speaker, and a surround back channel L signal may be output from an existing surround back channel L speaker. Further, when a speaker actually exists but there is no signal defined to be output from the actual speaker, the corresponding signal is generated using the conventional technique. For example, using a technology that generates virtual stereo signals to be output from the left and right speakers based on a real monaural signal, a signal as if it is a signal corresponding to that real speaker is used. Generate.

The sound reproducing device of this embodiment is useful as sound equipment for movie theaters, movie production / editing studios, home theaters, and the like.

10 monitor 11 deck 12 center channel speaker 13 front L channel speaker 14 front R channel speaker 15 side L channel speaker 16 side R channel speaker 17 bass sound effect channel speaker 101 signal generator 102 signal processor 103 power amplifier 104 to 109 speaker 201 to 209, 301-314 Virtual speaker

Claims (11)

1. Outputting a plurality of input acoustic signals to a plurality of prescribed speakers defined as respective output destinations of the plurality of input acoustic signals, and generating a virtual speaker at a position different from any of the plurality of prescribed speakers; A sound reproduction device comprising: a signal processing unit that outputs at least one of the plurality of sound signals from the generated virtual speaker.
2. The signal processing unit is configured to transmit an acoustic signal perceived as being reproduced by a predetermined specified speaker among the plurality of specified speakers defined as respective output destinations of the input acoustic signal when viewed from a predetermined viewing position. Equalizing the acoustic signal with an equalizer characteristic that converts the characteristic into a characteristic that is perceived as being reproduced by the first virtual speaker when viewed from the viewing position;
   The first virtual speaker is generated at the same position as the prescribed speaker on a second horizontal plane located above or below the first horizontal plane where the prescribed speaker exists by the equalization. Sound reproduction device.
3. The signal processing unit divides the amplitude characteristic of the head-related transfer function from the position of the first virtual speaker to the viewing position by the amplitude characteristic of the head-related transfer function from the position of the specified speaker to the viewing position. The sound reproduction device according to claim 1, wherein the sound signal is equalized with equalization characteristics obtained in the above manner.
4. The signal processing unit includes a plurality of transfer characteristic processing units that equalize acoustic signals of a plurality of channels reproduced by the plurality of prescribed speakers arranged on the first horizontal plane with the equalization characteristics,
   The plurality of transfer characteristic processing units generate a plurality of the first virtual speakers, and generate each of the first virtual speakers at the same position as each of the plurality of prescribed speakers on the second horizontal plane. The sound reproducing device according to claim 1 or 3.
5. The signal processing unit further includes:
   A characteristic that the sound signal is perceived as being reproduced by a second virtual speaker on the first horizontal plane by reproducing an acoustic signal by a first prescribed speaker which is one of the plurality of prescribed speakers. A first transfer characteristic processing unit that equalizes the acoustic signal reproduced by the first prescribed speaker with a first equalizer characteristic to be converted into:
   The acoustic signal is reproduced by the second virtual speaker by reproducing the acoustic signal with a second prescribed speaker that is one of the plurality of prescribed speakers and different from the first prescribed speaker. A second transfer characteristic processing unit that equalizes the acoustic signal reproduced by the second prescribed speaker with a second equalizer characteristic that is converted into a perceived characteristic;
   A ratio of reproduction levels when the outputs of the first transfer characteristic processing unit and the second transfer characteristic processing unit with respect to the acoustic signal are reproduced is from the first prescribed speaker to the second virtual speaker. The first level adjustment unit that adjusts the output level of the first transfer characteristic processing unit so as to correspond to the ratio of the distance from the second specified speaker to the second virtual speaker When,
   A ratio of reproduction levels when the outputs of the first transfer characteristic processing unit and the second transfer characteristic processing unit with respect to the acoustic signal are reproduced is from the first prescribed speaker to the second virtual speaker. A second level adjustment unit that adjusts the output level of the second transfer characteristic processing unit so as to correspond to the ratio of the distance from the second specified speaker to the second virtual speaker And
   The signal processing unit generates the second virtual speaker at a position between the first prescribed speaker and the second prescribed speaker when viewed from the viewing position on the first horizontal plane. 4. The sound reproducing device according to 4.
6. The first transfer characteristic processing unit and the second transfer characteristic processing unit are amplitude characteristics of the head-related transfer function with respect to the ear on the side where the second virtual speaker is viewed as viewed from the viewer at the viewing position. To convert the amplitude characteristics of the head-related transfer function from the position of the second virtual speaker to the viewing position from the respective positions of the first specified speaker and the second specified speaker. The sound reproduction apparatus according to claim 5, wherein the sound signal is equalized by each of the first equalization characteristic and the second equalization characteristic obtained by dividing by an amplitude characteristic of a head-related transfer function up to a viewing position.
7. The signal processing unit further includes:
   By reproducing an acoustic signal with a third virtual speaker that is one of the plurality of first virtual speakers, the acoustic signal is transmitted from the fifth virtual speaker on the second horizontal plane as viewed from the viewing position. A third transfer characteristic processing unit that equalizes the acoustic signal reproduced by the third virtual speaker with a first equalizer characteristic that is converted into a characteristic that is perceived as being reproduced;
   The acoustic signal is reproduced on the fifth virtual speaker by reproducing the acoustic signal on a fourth virtual speaker that is one of the plurality of first virtual speakers and different from the third virtual speaker. A fourth transfer characteristic processing unit that equalizes the acoustic signal reproduced by the fourth virtual speaker with a second equalizer characteristic that is converted into a characteristic that is perceived as being performed;
   A ratio of reproduction levels when the outputs of the third transfer characteristic processing unit and the fourth transfer characteristic processing unit with respect to the acoustic signal are reproduced is from the third virtual speaker to the fifth virtual speaker. Level adjustment unit that adjusts the output level of the third transfer characteristic processing unit so as to correspond to the ratio of the distance from the fourth virtual speaker to the distance from the fourth virtual speaker to the fifth virtual speaker When,
   A ratio of reproduction levels when the outputs of the third transfer characteristic processing unit and the fourth transfer characteristic processing unit with respect to the acoustic signal are reproduced is from the third virtual speaker to the fifth virtual speaker. A fifth level adjustment unit that adjusts the output level of the fourth transfer characteristic processing unit so as to correspond to the ratio of the distance from the fourth virtual speaker to the fifth virtual speaker And
   The signal processing unit generates the third virtual speaker at the same position as the first specified speaker on the second horizontal plane, and the fourth virtual speaker on the second horizontal plane. Generated at the same position as the second specified speaker, and the fifth virtual speaker is located between the third virtual speaker and the fourth virtual speaker when viewed from the viewing position on the second horizontal plane. The sound reproducing device according to claim 5 or 6, wherein the sound reproducing device is generated at a position.
8. The signal processing unit further includes:
   By reproducing the same acoustic signal at the same level with two speakers located on the first horizontal plane or the second horizontal plane and symmetrical with respect to the front direction of the viewing position, the acoustic signal is reproduced. A third level adjustment unit that makes it perceived that the image is being reproduced by a sixth virtual speaker on the first horizontal plane or the second horizontal plane,
   The signal processing unit generates the sixth virtual speaker at a position in the front direction when viewed from the viewing position on the first horizontal plane or when viewed from the viewing position on the second horizontal plane. The sound reproducing device according to any one of claims 1 to 7.
9. The signal processing unit equalizes the acoustic signal with an approximate equalizer characteristic that satisfies at least one peak or dip feature point on the equalizer characteristic curve obtained by the conversion. The sound reproducing device according to item.
10. A program recorded on a computer-readable non-transitory recording medium,
    Outputting a plurality of input acoustic signals to a plurality of prescribed speakers defined as respective output destinations of the plurality of input acoustic signals, and generating a virtual speaker at a position different from any of the plurality of prescribed speakers; A program that functions as a signal processing unit that outputs at least one of the plurality of acoustic signals from the generated virtual speaker.
11. Outputting a plurality of input acoustic signals to a plurality of prescribed speakers defined as respective output destinations of the plurality of input acoustic signals, and generating a virtual speaker at a position different from any of the plurality of prescribed speakers; An integrated circuit comprising: a signal processing unit that outputs at least one of the plurality of acoustic signals from the generated virtual speaker.

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