JP2007142909A - Acoustic reproducing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic reproducing system capable of performing an acoustic output in various modes by a small-scale speaker array. <P>SOLUTION: Speaker arrays 222L, 222R are to be slidably supported by a rail 221, and an acoustic beam is made to be output from each of the speaker arrays at each appropriate position. At that time, control of a signal process for making the acoustic beam outputted from each of the speaker arrays is to be performed based on a position of each of the speaker arrays 222L, 222R. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound reproduction system suitable for sound reproduction in classrooms, lectures, concerts, and the like.

The speaker array is a sound output device in which a plurality of speakers are arranged in a line shape or a matrix shape. According to this speaker array, a sound beam with sharp directivity can be radiated by performing delay control of an audio signal applied to each speaker. For this reason, various techniques using a speaker array for a service that provides sound toward a specific area have been proposed (for example, Patent Documents 1 and 2). In addition, when an acoustic beam that converges to one focal point in space is generated, the sound pressure locally increases at that focal point, so that a listener near the focal point is as if there is a sound source at the focal point. Get a good impression. By paying attention to this point, various techniques using a speaker array as a sound field reproduction device for forming a virtual sound source have been proposed (for example, Non-Patent Document 1).
JP-A-11-27604 JP 2005-173137 A "3D sound reproduction using speaker array", NHK Science and Technology Research Laboratories Shigeru Nakayama, Hiroyuki Okubo, Satoshi Watanabe, Satoshi Komiyama, VMA Research Group Journal No. 9 pages 12-17, issued July 12, 2002

  By the way, in the speaker array, the mode of sound output, such as a range in which an acoustic beam can reach, is restricted by the manner of speaker arrangement and the size of the entire speaker array. Therefore, in order to perform sound output in various modes, for example, it is necessary to provide a large-scale speaker array that covers the entire surface of one wall of a room. However, such a large-scale speaker array is expensive. Further, if the entire surface of the wall is covered with the speaker array, there is a problem that the wall cannot be used for other purposes such as display of a display.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an acoustic reproduction system that can perform acoustic output in various modes by a small speaker array.

The present invention provides a sound output device having a speaker array having a plurality of speakers, and a support means for slidably supporting the speaker array, and performs signal processing including at least delay processing on an audio signal provided from a sound source, Signal processing means for generating a plurality of delayed audio signals for driving a plurality of speakers of the speaker array, input means for receiving an instruction of a sound output mode, and instructions given by the speaker array via the input means A sound reproduction system comprising: control means for controlling signal processing in the signal processing means based on the position of the speaker array so as to perform sound output in a mode.
According to this invention, since the position of the speaker array can be freely changed, it is possible to output sound in various modes with a small-scale speaker array.

Embodiments of the present invention will be described below with reference to the drawings.
<Configuration of Embodiment>
FIG. 1 is a diagram of a classroom 1 in which an acoustic reproduction system according to an embodiment of the present invention is installed as viewed from obliquely above, and FIG. 2 is a diagram of the classroom 1 as viewed from the side. Like a general classroom, a classroom 2 is arranged in front of the classroom 1, and a classroom 3 is arranged on the platform 2. The teacher 4 stands on the platform 2 and gives a lecture to a plurality of students 5 seated in front of the platform 2. The sound reproduction system in the present embodiment is a main body unit 100 that controls the entire system and processes audio signals, a microphone 210 that collects the voice of the teacher 4, and a means for transmitting the voice of the teacher 4 to the student 5. The sound output device 220 used and the operation display device 300 for receiving various instructions from the teacher 4 are provided.

  In the example shown in the figure, the main body 100 is housed in the teaching desk 3, and the operation display device 300 is placed on the teaching desk 3. The microphone 210 is fixed to the clothes of the teacher 4. The microphone 210 may be a microphone that transmits an audio signal representing the voice of the teacher 4 to the main body unit 100 via a signal line cable, or may be a wireless microphone. Although not shown in the figure, it is also possible to provide the main body unit 100 with a digital audio signal reproduced from a sound source such as a CD reproducing device or a tuner and perform the processing.

  The sound output device 220 includes a rail 221 fixed at a position near the ceiling of the front wall where the platform 2 is located, and two left and right speakers suspended on the rail 221 and movable in the horizontal direction along the rail 221. The arrays 222L and 222R are configured. These speaker arrays 222L and 222R may be a plurality of speakers SP arranged in a matrix as shown in FIG. 3, or a plurality of speakers SP arranged in a line as shown in FIG. .

  In a preferred embodiment, as shown in FIG. 5, the speakers SP are arranged at a constant pitch L in the two speaker arrays 222L and 222R. When both speaker arrays 222L and 222R are in contact with each other without a gap, the rightmost speaker SP of the speaker array 222L and the leftmost speaker SP of the speaker array 222R are arranged at a pitch L, and the speakers are passed through both speaker arrays 222L and 222R. The SPs are regularly arranged. That is, in this state, the speaker arrays 222L and 222R constitute a speaker array in which the width of the original speaker array is doubled.

  In the case of radiating human voice, it is only necessary that voice in a band of 300 Hz to 4 kHz can be radiated from the speaker arrays 222L and 222R. In addition, when used in a classroom, it is only necessary to have a directivity control capability that can radiate a 300 Hz acoustic beam in a direction inclined 60 degrees from the front. For that purpose, it is sufficient that the speaker arrays 222L and 222R each have a width of 1 m. Further, if the speaker SPs having a diameter of about 5.7 cm are arranged at intervals of 7 cm in the speaker arrays 222L and 222R, a reproduction band and a high frequency limit that do not cause a practical problem can be obtained.

  FIG. 6 is a block diagram showing the configuration of the sound reproduction system in the present embodiment. In FIG. 6, a speaker array driving device 223 is a device that moves the speaker arrays 222L and 222R along the rails 221. For example, a motor such as a pulse motor and the rotational motion of this motor are converted into a linear motion. And a transmission mechanism for transmitting to 222L or 222R. The speaker array driving device 223 in the present embodiment is configured to be capable of both an operation of moving one of the speaker arrays 222L and 222R alone and an operation of moving both the speaker arrays 222L and 222R in the same direction. . The speaker array position detection device 224 is a device that detects the position of each of the speaker arrays 222L and 222R.

  The main body unit 100 includes a signal processing unit 110, a control unit 120, and a memory unit 130. In the present embodiment, the speaker array 222L includes m speakers SP-k (k = 1 to m), and the speaker array 222R also has similar m speakers SP-k (k = m + 1 to 2m). )have. The signal processing unit 110 drives the 2m speakers SP-k (k = 1 to 2 m) constituting the speaker arrays 222L and 222R based on the audio signal output from the microphone 210 or the like, and performs various acoustic beams and classrooms. 1 is a device for outputting the whole loud sound that reaches the whole in 1 from the speaker arrays 222L and 222R. The configuration of the signal processing unit 110 is as follows.

  The A / D converter 111 performs A / D conversion on the audio signal (analog signal) output from the microphone 210 and outputs a digital audio signal. The digital audio interface 117 is an interface that receives and outputs a digital audio signal reproduced from a sound source such as a CD reproducing device or a tuner. The audibility correction unit 112 is a device that performs audibility correction processing such as loudness correction and dynamic range compression on an audio signal output from the A / D converter 111 or the digital audio interface 117. In the present embodiment, the process of the audibility correction unit 112 is used when it is necessary to provide the voice of the teacher 4 to the deaf person.

  The n acoustic beam signal processing units 113-j (j = 1 to n) are means for performing signal processing for outputting an acoustic beam from the speaker arrays 222L and 222R or a speaker array in which both are combined. When each acoustic beam signal processing unit 113-j (j = 1 to n) outputs an acoustic beam having a focal point F by a speaker array in which the speaker arrays 222L and 222R are combined, for example, the A / D converter 111, The audio signal output from the digital audio interface 117 or the auditory correction unit 112 is subjected to delay processing and window function multiplication processing to drive 2m speakers SP-k (k = 1 to 2 m). Each delayed audio signal is output. Further, when an acoustic beam is output by only one of the speaker arrays 222L or 222R, each acoustic beam signal processing unit 113-j (j = 1 to n) uses the former speaker SP-k (k = 1 to m). A delayed audio signal to be driven or a delayed audio signal to drive the latter speaker SP-k (k = m + 1 to 2 m) is generated. At that time, the acoustic beam signal processing unit 113-j causes the sound wave output from the plurality of driven speakers SP-k to reach the focal point F in the same phase, and the sound pressure locally increases at the focal point F. , Delay processing for generating a plurality of delayed audio signals is executed. The window function multiplication processing is performed in order to suppress generation of side lobes from the speaker array 222L or 222R in a direction different from the direction of the focal point F.

  At the focal point F of the acoustic beam, the sound pressure increases locally, and the student 5 facing this recognizes as if there is a sound source at this position. In the present embodiment, a virtual sound source using this acoustic beam is used as a means for alerting a specific student 5. Note that the high-frequency sound can make the listener more clearly recognize the position of the sound source than the low-frequency sound. Therefore, when a virtual sound source using an acoustic beam is generated by a speaker array, the audio signal is output by a high-pass filter. May be extracted and given to the acoustic beam signal processing unit 113-j involved in the output of the acoustic beam. The acoustic beam signal processor 113-j (j = 1 to n) changes the width after being output from the speaker array 222L or 222R in addition to the acoustic beam that converges at the focal point F in front of the speaker array 222L or 222R. It is also used for signal processing for obtaining an acoustic beam propagating as a plane wave and an acoustic beam propagating while gradually increasing the width. In the signal processing for generating these acoustic beams, the direction of the acoustic beam output and the acoustic beam can be adjusted by adjusting the delay amount and window function value when obtaining the delayed audio signal that drives each speaker constituting the speaker array. The spread angle is adjusted.

  The audio signal output from the A / D converter 111 or the digital audio interface 117 is input to the overall loudspeaker signal processing unit 114. The overall loudspeaker signal processing unit 114 performs delay processing and window function multiplication processing on the input audio signal, similarly to the acoustic beam signal processing unit 113-j (j = 1 to n). This general loudspeaker signal processing unit 114 emits general loudspeaks from the speaker arrays 222L and 222R, that is, speaker groups SP-k (k = 1 to m) and virtual focal points behind each speaker array. Delay processing and window function multiplication processing are performed to output an acoustic beam that is radiated from each speaker as if it has passed through the speaker group SP-k (k = m + 1 to 2 m) and propagates while expanding the range.

The adders 115-k (k = 1 to 2m) are provided from each of the 2m delayed audio signals output from each of the acoustic beam signal processing units 113-j (j = 1 to n) and the overall sound signal processing unit 114. The output 2m delayed audio signals corresponding to the same speaker SP-k are added together and output. The D / A converter 116-k (k = 1 to 2m) converts each audio signal output from the adder 115-k (k = 1 to 2m) into an analog signal, and the speaker SP-k (k = 1 to 2 m).
The details of the configuration of the signal processing unit 110 have been described above.

  The control unit 120 includes a CPU, a ROM storing various programs executed by the CPU, a RAM used as a work area, and the like. The control unit 120 controls signal processing in the signal processing unit 110 in accordance with the positions of the speaker arrays 222L and 222R detected by the speaker array position detection device 224 and various information or instructions given via the operation display device 300. I do. In addition, the control unit 120 performs control for driving the speaker arrays 222L and 222R by the speaker array driving device 223 in accordance with an instruction or the like given through the operation display device 300. The memory unit 130 stores various control information that is referred to when the control unit 120 controls the signal processing unit 110. One of the control information is a seat position table 131 indicating the position coordinates of the seats of the students 5 in the classroom 1.

  The processes executed by the control unit 120 include an overall control process 121, a plurality of mode-specific control processes 122, and a speaker array drive process 123. The overall control process 121 is a so-called main routine, and the plurality of mode-specific control processes 122 and the speaker array driving process 123 are subroutines activated in this main routine.

  Each of the plurality of mode-specific control processes 122 performs control to form a signal transmission path of the audio signal in the signal processing unit 110, calculates parameters used for signal processing, and sets the parameters in each unit in the signal processing unit 110. It is processing. The sound reproduction system according to the present embodiment emits an overall loud sound into the classroom 1 by using, for example, two speaker arrays 222L and 222R, and forms a virtual sound source at a designated position, or two There are a plurality of modes for sound output using the two speaker arrays 222L and 222R, such as a mode for providing stereo reproduction sound to a specific area using the speaker arrays 222L and 222R. Here, which output signal of the A / D converter 111, the audibility correction unit 112, and the digital audio interface 117 is to be processed, the acoustic beam signal processing unit 113-j (j = 1 to n) and the whole Which of the loudspeaker signal processing units 114 performs processing of the audio signal differs depending on the sound output mode. Therefore, it is necessary to form a signal transmission path for the audio signal in the signal processing unit 110 in accordance with the sound output mode. Further, the signal processing of the signal processing unit 110 for causing the speaker arrays 222L and 222R to perform sound output needs to have contents corresponding to the mode. Therefore, in this embodiment, a mode-specific control process 122 for controlling the state of the signal processing unit 110 in association with various modes is prepared. Note that the sound output modes prepared in the present embodiment will be clarified in detail in the operation description of the present embodiment in order to avoid overlapping description.

  In the overall control process 121, the sound output mode to be executed is determined according to an instruction given via the operation display device 300, and the mode-specific control process 122 corresponding to the mode is activated. In the mode-specific control processing 122 corresponding to each mode, a signal transmission path is formed in the signal processing unit 110 corresponding to the mode. The speaker arrays 222L and 222R are determined based on the positions of the speaker arrays 222L and 222R detected by the speaker array position detection device 224 and other necessary parameters (for example, the target position when a virtual sound source is formed). Parameters used for signal processing such as a delay amount when generating a delayed audio signal to be driven, a window function value, and the like are calculated, and the acoustic beam signal processing unit 113-j (j = 1 to n) or the overall loudspeaking signal processing unit 114 Set to the one in charge of signal processing. The speaker array driving process 123 is a process of moving the speaker array 222L or 222R by the speaker array driving device 223 in accordance with an instruction given via the operation display device 300. In the present embodiment, an instruction to automatically optimize the position of the speaker array 222L or 222R may be generated. In the speaker array drive processing 123, drive control of the speaker array 222L or 222R in such a case is performed.

  FIG. 7 is a plan view showing a configuration example of the operation display device 300. The operation display device 300 is a touch panel. A seat designation area 301 and a guidance message display area 302 are provided in the right half region of the operation surface of the operation display device 300. In the seat designation area 301, a rectangle representing the teaching desk 3 and a plurality of rectangles representing the seats of the student 5 are displayed. The teacher 4 can touch the rectangle corresponding to the seat of the desired student 5 and specify the seat. Based on the designated seat position, for example, the position of the virtual sound source is determined. In the guidance message display area 302, a guidance message for assisting the operation of the operation display device 300 by the teacher 4 is displayed.

  The following various soft buttons are provided in the left half area of the operation surface of the operation display device 300. The move buttons 311 to 316 are soft buttons for instructing to move the speaker array 222L or 222R. When one of the move buttons 311 to 316 is pressed, the control unit 120 executes the speaker array driving process 123, and while the soft button is pressed, the control unit 120 moves the speaker array designated by the soft button. The driving device 223 is caused to perform this. The move buttons 311 and 314 are soft buttons for instructing to move the speaker array 222R on the right side as viewed from the student 5 in the direction of the arrow shown in the figure, and the move buttons 312 and 315 are the speakers on the left side as viewed from the student 5. This is a soft button for instructing to move the array 222L in the direction of the arrow shown in the figure. On the operation surface, the movement buttons 311 and 314 are provided on the left side, and the movement buttons 312 and 315 are provided on the right side when the teacher 4 operates the operation display device 300 with his back to the speaker arrays 222L and 222R. This is to improve operability. The move buttons 313 and 316 are soft buttons for instructing to move the two speaker arrays 222L and 222R together in the direction of the arrow shown in the drawing without changing the distance between them.

  The plurality of mode buttons 320 are soft buttons for designating a sound output mode desired by the teacher 4. Here, each mode button 320 is a toggle type soft button, and the state is reversed from OFF to ON and from ON to OFF each time it is pressed. Each mode button 320 is exclusive, and when one mode button 320 is ON, when another mode button 320 is turned ON, the mode button 320 that was originally ON is turned OFF. The mode button 320 that is ON has a different appearance from the mode button 320 that is OFF, for example, the display color changes. The teacher 4 can instruct the controller 120 to output sound in that mode by turning on the mode button 320 of the desired mode. In order for the teacher 4 to easily find the mode button 320 corresponding to the desired mode, each mode button 320 schematically displays the mode of sound output in that mode, as illustrated in FIG.

  The automatic optimization button 331 is a soft button that instructs to optimize the positions of the speaker arrays 222L and 222R. This automatic optimization button 331 is also a toggle type soft button similar to the mode button 320. When the automatic optimization button 331 is ON, the controller 120 executes the speaker array driving process 123, and the speaker arrays 222L and 222R are positions where the sound output can be performed under the best conditions (for example, a certain student 5 When the virtual sound source is formed in front of, the student 5 is moved to a position in front of the student 5. In the mode-specific control process 122 by the control unit 120 at this time, signal processing parameters are calculated based on the positions of the speaker arrays 222L and 222R after the movement. When the automatic optimization button 331 is OFF, the speaker arrays 222L and 222R are not moved, and the mode-specific control process 122 calculates signal processing parameters based on the current positions of the speaker arrays 222L and 222R. The

The set button 332 is a soft button for instructing to confirm one or a plurality of positions designated by the touch operation of the seat designation area 301. For example, when a plurality of virtual sound sources are formed in front of a plurality of students 5, the teacher 4 may press the position of the seat of each student 5 in the seat designation area 301 with a finger and then press the set button 332. Thereby, each position in front of the seat of each student 5 pressed by the finger is determined as the position of the virtual sound source. The clear button 333 is a soft button for instructing the set button 332 to cancel the confirmation of one or more positions made by operation.
The above is the configuration of the present embodiment.

<Operation of Embodiment>
Next, the operation of this embodiment will be described.
(1) Whole loudspeaking mode When the teacher 4 speaks to all the students, the mode button 320 for the whole loudspeaking mode is turned ON and the sound output mode is set to the whole loudspeaking mode. Here, when the automatic optimization button 331 is OFF, in the overall control process 121, the mode-specific control process 122 corresponding to the overall loudspeaking mode is activated. In this mode-specific control process 122, a predetermined group of delay amounts for overall loudness and a set of window function values are set in the overall loudspeaker signal processing unit 114. The overall loudspeaker processing unit 114 generates 2m delayed audio signals based on the output signal of the A / D converter 111. The 2m delayed audio signals pass through the adder 115-k (k = 1 to 2m), and are then converted into an analog signal by the D / A converter 116-k (k = 1 to 2m), and the speaker SP. -K (k = 1 to 2 m). As a result, the whole loud sound is output from the speaker arrays 222L and 222R. FIG. 9 shows an example of the radiation pattern of the overall loud sound 401 radiated from the speaker arrays 222L and 222R in this way. In this example, when the speaker arrays 222L and 222R are located at the center of the front wall of the classroom 1, the mode button 320 of the overall loudspeaking mode is turned ON, and the loudspeaker of the teacher 4's voice is being performed. As shown in the figure, in the overall loudspeaking mode, the overall loudspeaking sound 401 of the voice of the teacher 4 output from the speaker arrays 222L and 222R propagates while expanding the range and reaches a wide range in the classroom 1.

  When the automatic optimization button 331 is ON, the overall control process 121 activates the speaker array drive process 123 and the mode-specific control process 122 corresponding to the overall loudspeaker mode. At this time, information about the optimum positions of the speaker arrays 222 </ b> L and 222 </ b> R determined in advance for the whole loudness is delivered to the speaker array driving process 123. As a result, the speaker array driving process 123 moves the speaker arrays 222L and 222R to the optimum positions by the speaker array driving device 223 as illustrated in FIG. The processing content of the mode-specific control processing 122 is the same as when the automatic optimization button 331 is OFF.

(2) Virtual sound source mode The virtual sound source mode is a mode in which an acoustic beam is output, a virtual sound source is formed at the focal point of the acoustic beam, and audio is provided only to listeners in the nearby area. When the teacher 4 wishes to provide sound in this mode, the mode button 320 in the virtual sound source mode is turned ON, and the seat of the student 5 who places the focal point of the acoustic beam by touching the seat designation area 301 and the set button 332 is arranged. Is specified. The operation in this case will be described separately when the automatic optimization button 331 is OFF and when it is ON.

  When the automatic optimization button 331 is OFF in the virtual sound source mode, the overall control process 121 obtains the position of the seat designated by the teacher 4 by referring to the seat position table 131, and the focus position based on this position. Ask for. Then, based on the position of the focal point and each position of the speaker arrays 222L and 222R detected by the speaker array position detection device 224, a speaker array that outputs an acoustic beam is selected. In the example shown in FIG. 11, one focal point F1 is obtained, and the speaker array 222R is close to this focal point F1. Therefore, in the overall control process 121, the speaker array 222R is selected. Then, the mode-specific control process 122 corresponding to the virtual sound source mode is started, and an instruction to output the acoustic beam having the focal point F1 to the speaker array 222R, the position of the focal point F1, and the position of the speaker array 222R for the process. Give information about.

  In the control processing by mode 122, a signal transmission path for supplying the output signal of the A / D converter 111 to the acoustic beam signal processing unit 113-1 is formed in the signal processing unit 110. Further, m delay amounts and m windows for obtaining each delayed audio signal applied to each speaker SP-k (k = m + 1 to 2m) of the speaker array 222R based on the positional relationship between the focal point F1 and the speaker array 222R. Calculate the function value. Then, the calculated delay amount and window function value are set in the acoustic beam signal processing unit 113-1. The acoustic beam signal processing unit 113-1 generates m delayed audio signals from the output signal of the A / D converter 111 using the set delay amount and window function value, and adds the adder 115-k ( k = m + 1 to 2m) and the D / A converter 116-k (k = m + 1 to 2m), and then applied to the speaker SP-k (k = m + 1 to 2m). As a result, as shown in FIG. 11, an acoustic beam 501 having a focal point F1 is output from the speaker array 222R, and a virtual sound source is formed at the focal point F1.

  On the other hand, when the automatic optimization button 331 is ON in the virtual sound source mode, the overall control process 121 is performed after selecting the speaker array 222R close to the focus F1 by the same process as when the automatic optimization button 331 is OFF. The optimum position of the speaker array 222R for outputting the acoustic beam having the focal point F1 is obtained. In this example, the position of the speaker array 222R that captures the focal point F1 directly in front is obtained. In the overall control process 121, a mode-specific control process 122 and a speaker array driving process 123 corresponding to the virtual sound source mode are activated. At that time, information regarding the optimum position of the speaker array 222R is delivered to the speaker array driving process 123. As a result, the speaker array driving process 123 moves the speaker array 222R to the optimum position where the focal point F1 is captured directly in front as illustrated in FIG. In the overall control process 121, an instruction to output the acoustic beam having the focal point F1 to the speaker array 222R and information regarding the position of the focal point F1 and the position of the speaker array 222R are given to the control process 122 for each mode. As a result, in the mode-specific control process 122, a signal transmission path formation and parameter calculation process for outputting the acoustic beam having the focal point F1 to the speaker array 222R in the same procedure as when the automatic optimization button 331 is OFF. And the calculated parameters are set in the acoustic beam signal processing unit 113-1. As a result, as illustrated in FIG. 12, the acoustic beam 501 having the focal point F1 is output from the speaker array 222R, and a virtual sound source is formed at the focal point F1.

  In the virtual sound source mode, the teacher 4 can generate a plurality of acoustic beams with different focal points by touching the plurality of positions in the seat designation area 301 and touching the set button 332. 13 and 14 show examples of such acoustic beam generation.

  In the example illustrated in FIG. 13, a touch operation for designating four seats is performed in a state where the automatic optimization button 331 is OFF. In this case, in the overall control process 121, the positions of the four seats are obtained by referring to the seat position table 131, and the positions of the four focal points F1 to F4 are obtained based on the positions. Then, based on the positions of the focal points F1 to F4 and the positions of the speaker arrays 222L and 222R detected by the speaker array position detecting device 224, a speaker array for outputting each acoustic beam having each focal point is selected. To do. In the example shown in FIG. 13, the speaker array 222R close to these focal points is selected as means for outputting the acoustic beams 501 and 502 having the focal points F1 and F2, and the acoustic beams 503 and 504 having the focal points F3 and F4 are outputted. As a means, the speaker array 222L close to these focal points is selected. Then, in the overall control process 121, a mode-specific control process 122 corresponding to the virtual sound source mode is activated, and an instruction to output the acoustic beams 501 and 502 having the focal points F1 and F2 to the speaker array 222R for the same process. , An instruction to output the acoustic beams 503 and 504 having the focal points F3 and F4 to the speaker array 222L, and information on the positions of the focal points F1 to F4 and the positions of the speaker arrays 222L and 222R are given.

  In the control processing by mode 122, a signal transmission path for supplying the output signal of the A / D converter 111 to the acoustic beam signal processing units 113-1 to 113-4 is formed in the signal processing unit 110. Further, based on the positional relationship between the focus F1 and the speaker array 222R, m delay amounts and m window function values necessary to obtain the acoustic beam 501 having the focus F1 are calculated, and the acoustic beam signal processing unit 113- Set to 1. Through similar processing, m delay amounts and m window function values for obtaining the acoustic beam 502 having the focal point F2 are sent to the acoustic beam signal processing unit 113-2 to obtain the acoustic beam 503 having the focal point F3. m delay amounts and m window function values are input to the acoustic beam signal processing unit 113-3, and m delay amounts and m window function values for obtaining the acoustic beam 504 having the focal point F4 are input to the acoustic beam signal. Set in the processing unit 113-4. As a result, as shown in FIG. 13, acoustic beams 501 to 504 having focal points F1 to F4 are output from the speaker arrays 222R and 222L, and a virtual sound source is formed at the focal points F1 to F4.

  In the example shown in FIG. 14, in the state where the automatic optimization button 331 is ON, the touch operation for designating four seats similar to the case of FIG. 13 is performed. Also in this case, in the overall control processing 121, the speaker array 222R is selected as a means for outputting the acoustic beams 501 and 502 having the focal points F1 and F2, and the speaker as the means for outputting the acoustic beams 503 and 504 having the focal points F3 and F4. Array 222L is selected. Thereafter, in the overall control process 121, it is determined whether or not the positions of the speaker arrays 222R and 222L are deviated from the optimum positions for outputting the respective acoustic beams. There are various methods for determining the optimum position of each speaker array. For example, the center of gravity of each focal point of each acoustic beam for each speaker array is obtained, and the position at which the center of gravity is seen directly in front is used as the optimum position of the speaker array. Good. If at least one of the positions of the speaker arrays 222L and 222R is deviated from the optimum position, the overall control process 121 activates the speaker array driving process 123, passes the information on the optimum position to the process, and moves to the optimum position. The speaker array that has not been moved is moved to the optimum position. In the example shown in FIG. 14, since the speaker array 222R is not located at the optimum position, the movement to the optimum position is performed. In the overall control process 121, as in the case where the automatic optimization button 331 is OFF, the mode-specific control process 122 corresponding to the virtual sound source mode is activated, and the acoustic beams 501 to 504 are output to the speaker arrays 222R and 222L. Instructions and information necessary to do this are given to the process. As a result, as shown in FIG. 14, acoustic beams 501 to 504 having focal points F1 to F4 are output from the speaker arrays 222R and 222L, and a virtual sound source is formed at the focal points F1 to F4.

(3) Whole loudspeaker and acoustic beam combined mode In this mode, as illustrated in FIG. 15, the loudspeaker arrays 222L and 222R output the loudspeaker 401 and the acoustic beam 500 having the focal point F. A virtual sound source is formed at the position of the focal point F. In the example shown in FIG. 15, one acoustic beam 500 is output to form one virtual sound source, but a plurality of acoustic beams may be output to form a plurality of virtual sound sources. In this mode, both the process for outputting the overall loud sound 401 clarified in the explanation of the overall loudness mode and the process for forming the virtual sound source clarified in the explanation of the virtual sound source mode are performed in the main body 100. Is called. When the automatic optimization button 331 is ON, the position of the speaker array (speaker array 222R in the example shown in FIG. 15) that outputs the acoustic beam 500 is optimized in accordance with the focal point F of the acoustic beam 500. Is called.

(4) Integrated expansion mode In this mode, as illustrated in FIG. 16, a speaker array having a width twice as large as the original width is constituted by the speaker arrays 222L and 222R whose ends are in contact with each other. To output an acoustic beam 510 having a focal point F, and form a virtual sound source at the position of the focal point F. In this mode, the effect of the virtual sound source can be expressed in the fan-shaped area centered on the focal point F, and the fan-shaped spread angle at that time can be increased, so that the sound can be provided in a wider range. is there.

  When the teacher 4 desires to provide sound in this mode, the student arranges the focus F of the acoustic beam 510 by turning on the mode button 320 of the integrated expansion mode and touching the seat designation area 301 and the set button 332. Specify 5 seats.

  In this case, the operation when the automatic optimization button 331 is OFF is as follows. First, the overall control process 121 determines whether or not the ends of the speaker arrays 222L and 222R are in contact with each other. When the ends of the speaker arrays 222L and 222R are not in contact with each other, the overall control process 121 displays a message rejecting the operation in the integrated expansion mode in the guidance message display area 302. On the other hand, when the ends of the speaker arrays 222L and 222R are in contact with each other, in the overall control process 121, the mode-specific control process 122 corresponding to the integrated expansion mode is activated, and the sound having the focal point F for the same process. An instruction to output the beam 510 to a speaker array in which the speaker arrays 222L and 222R are integrated, and information on the position of the focal point F and the positions of the speaker arrays 222L and 222R are given.

  In the control processing by mode 122, a signal transmission path for supplying the output signal of the A / D converter 111 to the acoustic beam signal processing unit 113-1 is formed in the signal processing unit 110. Further, based on the positional relationship between the focal point F and the speaker arrays 222L and 222R, 2m delay amounts for obtaining the delayed audio signals to be given to the speakers SP-k (k = 1 to 2m) of the speaker arrays 222L and 222R, and 2m window function values are calculated. Then, the calculated delay amount and window function value are set in the acoustic beam signal processing unit 113-1. The acoustic beam signal processing unit 113-1 generates 2 m delayed audio signals from the output signal of the A / D converter 111 using the set delay amount and window function value, and adds the adder 115-k ( k = 1 to 2m) and the D / A converter 116-k (k = 1 to 2m), and then applied to the speaker SP-k (k = 1 to 2m). As a result, as shown in FIG. 16, the acoustic beam 510 having the focal point F is output from the speaker array in which the speaker arrays 222L and 222R are integrated, and a virtual sound source is formed at the focal point F.

  The operation when the automatic optimization button 331 is ON is as follows. First, in the overall control process 121, the positions of the speaker arrays 222L and 222R that are optimal for outputting an acoustic beam having the focal point F are obtained. In this example, the optimum positions of the speaker arrays 222L and 222R are obtained so that the focal point F is located in front of the speaker array in which the speaker arrays 222L and 222R are integrated. In the overall control process 121, a mode-specific control process 122 and a speaker array drive process 123 corresponding to the integrated expansion mode are activated. At this time, information regarding the optimum positions of the speaker arrays 222L and 222R is delivered to the speaker array driving process 123. As a result, the speaker array driving process 123 moves the speaker array 222L or 222R so that the speaker array in which the speaker arrays 222L and 222R are integrated captures the focal point F directly as illustrated in FIG. In the overall control processing 121, an instruction to output an acoustic beam having a focal point F to a speaker array in which the speaker arrays 222L and 222R are integrated, and information on the position of the focal point F and the positions of the speaker arrays 222L and 222R are set in the mode. This is given to another control process 122.

  As a result, in the mode-specific control process 122, the formation of the signal transmission path and the parameters for outputting the acoustic beams having the focus F to the speaker arrays 222L and 222R in the same procedure as when the automatic optimization button 331 is OFF. Calculation processing is performed, and the calculated parameters are set in the acoustic beam signal processing unit 113-1. As a result, as illustrated in FIG. 17, the acoustic beam 510 having the focal point F is output from the speaker array in which the speaker arrays 222L and 222R are integrated, and a virtual sound source is formed at the focal point F.

  The case where one virtual sound source is formed has been described above as an example, but it is of course possible to form a plurality of virtual sound sources by a speaker array in which the speaker arrays 222L and 222R are integrated. In that case, the same number of acoustic beam signal processing units 131-k as the number of virtual sound sources may be used, and signal processing for obtaining acoustic beams for virtual sound source formation may be performed on them. When the automatic optimization button is ON, the optimum positions of the speaker arrays 222L and 222R are determined so that the speaker array in which the two speaker arrays are integrated captures the center of gravity of the positions of the plurality of virtual sound sources directly in front. Just do it.

(5) Separation-type expansion mode In this separation-type expansion mode, as illustrated in FIG. 18, two acoustics having the same focal point F from both speaker arrays 222 </ b> L and 222 </ b> R are arranged at a predetermined distance or more. Beams 511L and 511R are output to form a virtual sound source at the position of the focal point F. Here, between the propagation ranges of the acoustic beams 511L and 511R after passing through the focal point F, a non-expression area where the effect of the virtual sound source is not expressed and the sound cannot be heard well is generated. Therefore, in the separation-type expansion mode, interpolation acoustic beams 511La and 511Ra for distributing sound to the non-expression area are output from the speaker arrays 222L and 222R. This separation-type expansion mode has an effect that it is possible to further widen the region where the sound can be heard more than the integrated expansion mode.

  When the teacher 4 desires to provide sound in this mode, the mode button 320 in the separation-type extended mode is turned on, and the common focus of the acoustic beams 511 </ b> L and 511 </ b> R is operated by touching the seat designation area 301 and the set button 332. The seat of the student 5 who arranges F is designated.

  In this case, the operation when the automatic optimization button 331 is OFF is as follows. First, the overall control process 121 determines whether or not the distance between the speaker arrays 222L and 222R exceeds a predetermined threshold that can obtain the effect as the separation type expansion mode. If the distance between the speaker arrays 222L and 222R does not exceed the threshold value, the overall control process 121 displays a message rejecting the operation in the separation type expansion mode in the guidance message display area 302. On the other hand, when the distance between the speaker arrays 222L and 222R exceeds the threshold value, the overall control process 121 activates the mode-specific control process 122 corresponding to the separation type expansion mode, and the sound having the focal point F for the same process. An instruction to output the beams 511L and 511R and the interpolating acoustic beams 511La and 511Ra to the speaker arrays 222L and 222R, and information on the position of the focal point F and the positions of the speaker arrays 222L and 222R are given.

  In the control processing by mode 122, a signal transmission path for supplying the output signal of the A / D converter 111 to the acoustic beam signal processing units 113-1 to 113-4 is formed in the signal processing unit 110. Then, parameter setting processing for outputting the acoustic beam 511L from the speaker array 222L is performed. In this parameter setting process, m delay amounts and m windows for obtaining each delayed audio signal to be given to each speaker SP-k (k = 1 to m) based on the positional relationship between the focal point F and the speaker array 222L. A function value is calculated and set in the acoustic beam signal processing unit 113-1. Also, parameter setting processing for outputting the acoustic beam 511R from the speaker array 222R is performed. In this parameter setting process, m delay amounts and m windows for obtaining each delayed audio signal to be given to each speaker SP-k (k = m + 1 to 2m) based on the positional relationship between the focus F and the speaker array 222R. A function value is calculated and set in the acoustic beam signal processing unit 113-2.

  Next, a non-expression region sandwiched between the propagation ranges of the acoustic beams 511L and 511R that have passed through the focal point F is obtained. Of these non-expressing areas, an area within a predetermined distance from the focal point F is determined as a target area for the interpolation acoustic beams 511La and 511Ra. Then, a parameter setting process for outputting the interpolating acoustic beam 511La from the speaker array 222L is performed. In this parameter setting process, m delay amounts and m pieces for obtaining each delayed audio signal to be given to each speaker SP-k (k = 1 to m) based on the positional relationship between the target area and the speaker array 222L. A window function value is calculated and set in the acoustic beam signal processing unit 113-3. In addition, parameter setting processing for outputting the interpolating acoustic beam 511Ra from the speaker array 222R is performed. In this parameter setting process, m delay amounts and m pieces for obtaining each delayed audio signal to be given to each speaker SP-k (k = m + 1 to 2m) based on the positional relationship between the target area and the speaker array 222R. The window function value is calculated and set in the acoustic beam signal processing unit 113-4.

  As a result of the above processing, as shown in FIG. 18, the acoustic beams 511L and 511R having a common focal point F, and the interpolating acoustic beams 511La and 511Ra that provide sound to the non-expressing region between the two acoustic beams are converted into the speaker array 222L The voice of the teacher 4 is transmitted to the fan-shaped area centered on the focal point F.

  Various modes are conceivable for the operation when the automatic optimization button 331 is ON. In a preferable aspect, in the overall control process 121, the speaker array driving process 123 is driven, and the speaker arrays 222L and 222R are moved to the left end and the right end of the classroom 1 as shown in FIG. Maximize distance. Then, in the overall control process 121, as in the case where the automatic optimization button 331 is OFF, the mode-specific control process 122 corresponding to the separation-type extended mode is activated, and the acoustic beam 511L having the focal point F and An instruction to output 511R and interpolating acoustic beams 511La and 511Ra to the speaker arrays 222L and 222R, and information on the position of the focal point F and the positions of the speaker arrays 222L and 222R are given.

  According to this aspect, in the case where the voice of the teacher 4 is transmitted to the focus F and the fan-shaped region having the center, the fan-shaped spread angle can be maximized. On the other hand, in this embodiment, when the focal point F is near the front wall of the classroom 1 where the speaker arrays 222L and 222R are arranged, the crossing angle of the acoustic beams 511L and 511R at the focal point F becomes large, and the non-expression region Has the disadvantage of becoming larger. Therefore, as illustrated in FIG. 20, when the distance from the front wall of the classroom 1 to the focal point F is short, the distance between the speaker arrays 222L and 222R is shortened, while the classroom as shown in FIG. When the distance from the front wall of 1 to the focal point F is long, the distance between the speaker arrays is adjusted according to the distance to the focal point F, such as increasing the distance between the speaker arrays 222L and 222R. Also good. According to this aspect, regardless of the position of the focal point F, the acoustic beams 511L and 511R can always be intersected at an optimum angle, and the voice of the teacher 4 can be transmitted to a relatively wide range near the focal point F.

  In the above example, the interpolation acoustic beam is output from both the speaker arrays 222L and 222R. However, when the non-expression area is narrow, the interpolation acoustic beam is output from only one speaker array. Also good.

(6) Whole Loudness and Hearing Correction Sound Beam Combined Mode In this mode, the loudspeaker array 222L and 222R allow the loudspeaker 401 and the acoustic beam 500 to be reproduced by the speaker arrays 222L and 222R, as in the whole loudspeaker and acoustic beam combined mode described with reference to FIG. Output both. In this mode, the object providing the acoustic beam 500 is a deaf person. In the mode-specific control processing 122 corresponding to this mode, the hearing correction unit 112 is operated so that the hearing-impaired person can hear the voice of the teacher 4 well, and the output signal of the A / D converter 111 is converted into the overall loudness signal processing unit. 114, and a signal transmission path for supplying the output signal of the audibility correction unit 112 to the acoustic beam signal processing unit 113-1. Except for using the auditory sensation correction unit 112, the operation in this mode is the same as that in the overall loudspeaker and acoustic beam combined mode.

(7) Sweet Spot Stereo Playback Mode In this mode, L and R2 channel digital audio signals played back from a CD playback device or the like are received by the digital audio interface 117, and the stereo playback is performed in the classroom 1.

  Prior to this stereo reproduction, the speaker arrays 222L and 222R are moved to appropriate predetermined positions as illustrated in FIG. In addition, the number of acoustic beam signal processing units 113-k corresponding to the number of acoustic beams to be output is operated to process the output signal of the digital audio interface 117. Then, the L channel audio signal is output as, for example, three acoustic beams 521L, 522L, and 523L from the speaker array 222L. Further, an R channel audio signal is output from the speaker array 222R as, for example, an acoustic beam 520R. Here, the acoustic beam 520R is output in a direction that intersects the acoustic beams 521L, 522L, and 523L. In addition, the delay amount of the delayed audio signal that is the source of each acoustic beam is adjusted so that each acoustic beam propagates with a wider width.

  When the acoustic beams are output in this way, the area A1 that is the common part of the propagation ranges of the acoustic beams 521L and 520R, the area A2 that is the common part of the propagation ranges of the acoustic beams 522L and 520R, the acoustic beam 523L and An area A3 that is a common part of the propagation ranges of 520R is generated in the classroom 1. These areas A1 to A3 serve as sweet spots where the L channel and R channel sounds can be heard in a balanced manner.

  In the above example, an acoustic beam corresponding to a two-channel audio signal is output from two speaker arrays. However, an acoustic beam corresponding to a three-channel audio signal is used by using three or more speaker arrays. The speaker array may be used for output.

  The details of the operation of the present embodiment have been described above. According to the present embodiment, since the speaker array is slidable and the signal processing is controlled to obtain a desired acoustic beam based on the position of the speaker array, the speaker array is small-scale. However, it is possible to radiate an acoustic beam to various places in the room under optimum conditions. In addition, since the speaker array is a slide type, this embodiment also has an advantage that the speaker array can be moved to a position where howling does not occur due to the relationship with the microphone 210 used by the teacher 4, for example. Further, according to the present embodiment, since two slide-type speaker arrays are used, the acoustic beam can be output to the speaker array that can output the acoustic beam under the optimum condition of the two. Also, an acoustic beam is output by a wide speaker array in which two speaker arrays are integrated, or two acoustic beams having a common focal point and an interpolating acoustic beam are output from the two speaker arrays. The range of voice can be expanded. Furthermore, according to the present embodiment, the sweet spot that can output the sound beam of the stereo reproduction sound of the L and R2 channels using the two speaker arrays and can listen to the sound of the L and R channels in a balanced manner. It can be formed in the classroom 1.

<Other embodiments>
Although one embodiment of the present invention has been described above, other embodiments are possible for the present invention. For example:
(1) The number of speaker arrays supported by the rails may not be two, but may be one or three or more.
(2) In the above embodiment, the slide type speaker array is provided on the front wall of the room. However, the same slide type speaker array is provided on the side wall and the rear wall of the room so that the acoustic beam is transmitted. You may make it output.
(3) You may comprise so that a speaker array can be moved manually.

It is the figure which looked at the classroom where the sound reproduction system which is one Embodiment of this invention was installed from diagonally upward. It is the figure which looked at the classroom from the side. It is a figure which shows the structural example of the speaker array in the sound reproduction system. It is a figure which shows the other structural example of the speaker array in the sound reproduction system. It is a figure which shows the example of the arrangement | positioning aspect of the speaker in the speaker array. It is a block diagram which shows the structure of the sound reproduction system. It is a top view which shows the structure of the operation display apparatus in the sound reproduction system. It is a figure which illustrates the display mode of the mode button in the same operation display device. It is a figure which shows the aspect of the sound output in the whole loud sound mode in the sound reproduction system. In the same sound reproduction system, it is a figure which shows the aspect of a sound output when it is the whole loud sound mode and the automatic optimization button is ON. It is a figure which shows the aspect of the sound output in the virtual sound source mode in the sound reproduction system. In the same sound reproduction system, it is a figure which shows the aspect of a sound output when it is a virtual sound source mode and the automatic optimization button is ON. In the same sound reproduction system, it is a figure which is a virtual sound source mode, and shows the aspect of an acoustic output in case there exist multiple virtual sound sources. In the same sound reproduction system, it is a figure which shows the aspect of a sound output when it is virtual sound source mode, there are multiple virtual sound sources, and the automatic optimization button is ON. It is a figure which shows the aspect of the sound output in the whole sound amplification and sound beam combined use mode in the sound reproduction system. It is a figure which shows the aspect of the sound output in the integrated expansion mode in the sound reproduction system. In the same sound reproduction system, it is a figure which shows the aspect of an acoustic output when it is integrated expansion mode and the automatic optimization button is ON. It is a figure which shows the aspect of the sound output in the isolation | separation type expansion mode in the sound reproduction system. In the same sound reproduction system, it is a figure which shows the aspect of a sound output when it is separation-type expansion mode and the automatic optimization button is ON. In the same sound reproduction system, it is a figure showing other examples of the mode of sound output when it is separation type expansion mode and the automatic optimization button is ON. It is a figure which shows the aspect of the sound output in the stereo reproduction | regeneration mode for sweet spots in the sound reproduction system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Classroom, 4 ... Teacher, 5 ... Student, 100 ... Main part, 210 ... Microphone, 220 ... Sound output device, 221 ... Rail, 222L, 222R ... Speaker array, SP-k ( k = 1 to 2 m) …… Speaker, 110 …… Signal processing unit, 111 …… A / D converter, 112 …… Hearing correction unit, 117 …… Digital audio interface, 113-j (j = 1 to n) …… Acoustic beam signal processing unit, 114 …… Overall loudspeaker signal processing unit, 120 …… Control unit, 300 …… Operation display device, 224 …… Speaker array position detection device, 223 …… Speaker array driving device, 130 …… Memory unit 121... Overall control processing 122. Mode-specific control processing 123 123 Speaker array driving processing 131.

Claims (11)

A sound output device having a speaker array having a plurality of speakers, and a support means for slidably supporting the speaker array;
Signal processing means for performing signal processing including at least delay processing on an audio signal provided from a sound source, and generating a plurality of delayed audio signals for driving a plurality of speakers of the speaker array;
Input means for receiving an indication of the mode of acoustic output;
Control means for controlling signal processing in the signal processing means based on the position of the speaker array so that sound output is performed by the speaker array in a manner instructed via the input means. Sound reproduction system.   The sound reproduction system according to claim 1, wherein the sound output device includes a plurality of speaker arrays that can move independently as the speaker array.   The sound reproduction system according to claim 1, further comprising speaker array driving means for moving the speaker array.   The sound reproduction system according to claim 2, further comprising speaker array driving means for independently moving the plurality of speaker arrays.   When an instruction to output an acoustic beam to a specific location is given via the input unit, the control unit selects a speaker array suitable for the output of the acoustic beam to the location, and selects the selected speaker array. 5. The sound reproduction system according to claim 2, further comprising means for controlling signal processing of the signal processing means so that an acoustic beam is output from the head toward the place.   The control means is suitable for outputting the acoustic beam to the location by the loudspeaker array driving means when the instruction to output the acoustic beam to a specific place is given through the input means. The sound reproduction according to claim 3, further comprising means for controlling the signal processing of the signal processing means so that the sound beam is output to the position from the speaker array after the movement. system.   When an instruction to output an acoustic beam to a specific location is given via the input unit, the control unit selects a speaker array suitable for the output of the acoustic beam to the location, and selects the selected speaker array. Is moved to a position suitable for the output of the acoustic beam to the location by the speaker array driving means, and the signal processing of the signal processing means is performed so that the acoustic beam is output from the speaker array to the location after the movement. The sound reproduction system according to claim 4, further comprising a control unit.   The control means, when an instruction to output an acoustic beam to a specific location by a speaker array in which a plurality of speaker arrays are integrated is given via the input means, from the integrated speaker array. 5. The sound reproduction system according to claim 2, further comprising means for controlling signal processing in the signal processing means based on the positions of the plurality of speaker arrays so that an acoustic beam is output to a place. .   When the instruction to provide sound to a specific place is given via the input means by the two speaker arrays that are separated from each other, the control means includes the first and second speakers in the plurality of speaker arrays. The first and second acoustic beams traveling from the second speaker array toward the specific location and the first and second acoustic beams after intersecting the first and second acoustic beams from at least one of the first and second speaker arrays. Of the first and second speaker arrays so that an interpolating acoustic beam directed to a range sandwiched between the propagation ranges of the first and second acoustic beams is output by the first and second speaker arrays. 5. The sound reproduction system according to claim 2, further comprising means for controlling signal processing in the signal processing means based on a position.   The control means, when an instruction to output a stereo audio signal composed of a plurality of channels is given via the input means, a plurality of acoustic beams respectively corresponding to the plurality of channels of the audio signal and intersecting each other. 5. The sound reproduction according to claim 2, further comprising: means for controlling signal processing in the signal processing means based on positions of the plurality of speaker arrays so that a signal is output from the plurality of speaker arrays. system. The signal processing means includes audibility correction means for performing audibility correction processing on the audio signal,
When the instruction to output the audible correction acoustic beam to a specific location is given via the input means, the control means generates an acoustic beam based on the audio signal that has undergone the audibility correction processing of the audibility correction means. The sound reproduction system according to claim 1, further comprising means for controlling signal processing in the signal processing means based on a position of the speaker array so that the speaker array is output to the specific location.

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