JP2013062772A - Sound-reproducing device and stereoscopic video reproducer including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound-reproducing device including a directivity control unit controlling the directivity of speakers, which allows for excellent auditory localization remote from the actual positions of the speakers, by a simpler configuration, even of a monaural component common to the right and left channels, and to provide a stereoscopic video reproducer including the same.SOLUTION: The sound-reproducing device includes a front center speaker disposed at a position substantially forming an isosceles triangle together with a right speaker and a left speaker, and a directivity control unit including phase reversal means for radiating sound from the front center speaker while reversing the phase of right and left signals from that of a sum signal delayed by delay means, and producing single directional radiation characteristics by driving the right, left and front center speakers.

Description

  The present invention is an acoustic reproduction apparatus including a directivity control unit for controlling the directivity of a speaker, and is capable of obtaining a sound image localization far from the actual position of the speaker and a three-dimensional including the same. The present invention relates to a video playback device.

  As a method of controlling the change in acoustic radiation characteristics depending on the direction (hereinafter referred to as “directivity”) using a speaker that reproduces sound waves in the audible sound range, two non-directional speakers are connected in opposite phases and are bidirectional. For example, a method of providing a unidirectional or directional beam in a certain direction by using three or more speaker arrays has been proposed. For example, the applicant has proposed a directivity control device capable of obtaining a clear unidirectional radiation characteristic only by using two speakers and a gaming machine using the directivity control device (Patent Document 1).

  In the conventional method, the desired directivity is realized by applying a time delay to each speaker basically by the structure of the speaker and signal processing and utilizing the spatial phase interference of sound waves. In particular, when unidirectionality is realized, a direction in which the volume is reproduced at a high level (referred to as “beam direction”) and a direction in which the sound is reproduced at a low level (referred to as “zero point direction”) are generated. A sound reproduction system using the sound has been proposed. In this case, the area in the beam direction is normally used as an area where the listener is located, and the area in the zero point direction is mainly used for the purpose of lowering the volume.

  On the other hand, the applicant obtains a unidirectional characteristic by driving a set of two speakers that reproduce sound waves in the audible sound range, so that the sound image can be felt farther than the actual position of the speakers. And a sound reproducing device using the speaker device has been proposed (Patent Document 2). When a monaural sound is played back in a normal stereo playback device, if played back with a single speaker, the perceived sound image becomes the installation position of the speaker. On the other hand, if stereo sound is played equally between two speakers that are equidistant from the listener, that is, if monaural sound is fed to the left channel and right channel for playback, the phantom is placed in the center of the speakers for both channels. The monaural sound is localized and perceived as a sound image. However, in the case of Patent Document 2, if the monaural sound as described above is reproduced on the left and right channels, the phantom sound image is localized farther from the actual arrangement position of the speakers.

  However, in the conventional technique of Patent Document 2, when a standard stereo signal of two left and right channels is reproduced, a total of four speakers and an amplifier for four channels are required. There is a problem that two speakers and amplifiers for two channels cause a cost increase. In addition, it can be assumed that the prior art of Patent Document 2 is applied to a case where a stereo signal is reproduced with a total of two speakers and two-channel amplifiers. However, a monaural component common to the left and right channels is simply a comb filter. There is a problem that voice information is lost at the signal level stage. Further, due to the relationship between the positions of the speakers, it is impossible to give the listener a sense of localization in the depth direction of the sound image as in Patent Document 2.

JP 2003-87888 A (FIGS. 1 to 7) Japanese Patent Laid-Open No. 2003-87893 (FIGS. 1 to 12)

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is an acoustic reproduction device including a directivity control unit for controlling the directivity of a speaker, which is simpler. Therefore, it is an object of the present invention to provide an audio reproducing apparatus and a stereoscopic video reproducing apparatus including the same that can obtain a sound image localization far from the actual position of a speaker with respect to monaural components common to the left and right channels.

  The sound reproducing device of the present invention includes a speaker mounting surface, a left speaker that is attached to the speaker mounting surface to reproduce a left signal, a right speaker that is attached to the speaker mounting surface to reproduce a right signal, and a left speaker on the speaker mounting surface. And a center front speaker disposed at a position on the middle position of the right speaker and forming a substantially isosceles triangle with the left speaker and the right speaker, and an adding means for adding the left signal and the right signal and outputting a sum signal The delay means for delaying the sum signal by a time corresponding to the distance between the left speaker and the right speaker and the center front speaker, and the left signal, the right signal, and the sum signal delayed by the delay means are out of phase with each other. Phase inversion means for allowing sound emission from the center front speaker at the left speaker and the right speaker. -A directivity control unit that drives the car and the center front speaker to obtain a unidirectional radiation characteristic, and the left speaker and the right speaker on the speaker mounting surface are arranged symmetrically toward the listener, and the center front speaker is The speaker is arranged in front of the left speaker and the right speaker toward the listener.

  Preferably, in the sound reproducing device of the present invention, the left speaker, the right speaker, and the center front speaker are elongated electrodynamic speakers having a short-diameter direction length shorter than a long-diameter direction length, The right speaker is disposed so that the major axis directions thereof coincide with each other, and is disposed in close proximity to the central front speaker so that the distance from the central near speaker and the minor axis direction length substantially coincide with each other.

  Also preferably, in the sound reproducing device of the present invention, the directivity control unit is canceled by the left speaker driven in the opposite phase and the left signal or the right signal canceled due to the separation distance between the right speaker and the center front speaker. Compensation means for relatively increasing the level of the low-frequency region of the

  Preferably, the sound reproduction device of the present invention further includes a level adjustment circuit in which the directivity control unit adjusts and outputs the relative level of the sum signal with respect to the left signal or the right signal.

  Preferably, in the sound reproducing device of the present invention, the speaker mounting surface is disposed along the horizontal direction, and the listener's head is positioned on the extended surface.

  In addition, a stereoscopic video playback device of the present invention includes at least the above-described sound playback device and a 3D display.

  The operation of the present invention will be described below.

  The sound reproducing device of the present invention drives a speaker mounting surface, a left speaker, a right speaker, and a center front speaker, and a left speaker, a right speaker, and a center front speaker that are mounted on the speaker mounting surface, and has a unidirectional radiation characteristic. And a directivity control unit for obtaining a sound image localization device that can give a listener a sound image localization farther from the actual position of the speaker. The left speaker and the right speaker that respectively reproduce the left signal and the right signal of the stereo signal are arranged symmetrically toward the listener. Further, the center front speaker is disposed on the middle position of the left speaker and the right speaker on the speaker mounting surface and at a position forming a substantially isosceles triangle with the left speaker and the right speaker, and the left speaker and the speaker toward the listener. It is arranged in front of the right speaker.

  The directivity control unit adds the left signal and the right signal and outputs a sum signal, and outputs the sum signal by delaying the sum signal by a time corresponding to the distance between the left speaker and the right speaker and the center front speaker. Delay means, and phase inversion means for allowing the left signal and the right signal and the sum signal delayed by the delay means to be acoustically radiated from the center front speaker in opposite phases to each other. That is, the directivity control unit outputs a left signal to the left speaker, outputs a right signal to the right speaker, and adds a sum signal of the left signal and the right signal to the left speaker, the right speaker, and the center front speaker. It is delayed by a time corresponding to the separation distance and output to the center front speaker in an antiphase relationship.

  As a result, for the left signal, unidirectional acoustic radiation characteristics with the left speaker and the center front speaker set the listener side as the zero point direction and the left speaker along the side of the isosceles triangle as the beam direction With respect to the right signal, the right speaker and the center front speaker make the listener side the zero point direction, and the unidirectional acoustic radiation with the back side of the right speaker along one side of the isosceles triangle being the beam direction Characteristics are realized. Therefore, the listener can obtain the sound image localization farther than the actual position of the left speaker with respect to the left signal, and can obtain the sound image localization farther than the actual position of the right speaker with respect to the right signal. Even when monaural sound in which the left signal and the right signal have substantially the same amplitude and phase relationship is reproduced, the phantom sound image is localized farther from the actual speaker placement position. When reproducing standard left and right two-channel stereo signals, only three speakers and a three-channel amplifier are required. Compared with the prior art disclosed in Patent Document 2, the cost of the stereo sound is reduced. The same effect that the field spreads far away can be obtained. Further, since the left signal and the right signal are respectively reproduced by the left speaker and the right speaker, there is an advantage that there is no problem that main audio information is lost by the comb filter.

  It is particularly preferable that the left speaker, the right speaker, and the center front speaker be an elongated electrodynamic speaker whose length in the minor axis direction is shorter than that in the major axis direction. The short elongated electrodynamic speaker is preferably a speaker including a rectangular flat diaphragm, and in the sound reproducing device of the present invention, the left speaker and the right speaker are arranged so that their major axis directions coincide with each other. In addition, the central front speaker is disposed in proximity to the central front speaker so that the separation distance from the central front speaker and the length in the minor axis direction substantially coincide with each other. In the case of realizing a planar diaphragm speaker having a short minor axis direction and a long major axis direction, the distance between the speakers can be narrower than that of a round normal speaker. The substantial separation distance between the center front speaker arranged on the front side, the left speaker, and the right speaker can be approximated by the length in the minor axis direction. When the substantial separation distance is shortened, the delay time in the delay means can be shortened, and unidirectional control can be performed up to a high frequency. Furthermore, since the width can be increased in the direction of the zero point in the unidirectionality, it is possible to enhance the effect that the sound image can be felt far away.

  In addition, the directivity control unit relatively increases the level of the left signal or the right signal in the low frequency region that is canceled due to the separation between the left speaker and the right speaker and the center front speaker driven in opposite phases. If the compensation means is further included, the bass component lost by the unidirectional control can be compensated. It is possible to improve the balance of the sound image that is felt far away for the listener by relatively emphasizing the low frequency component that cancels the low frequency component between the left speaker and the center front speaker arranged close to the right speaker. . In addition, with respect to the anti-phase component (for example, (left signal-right signal)) of the stereo signal, the bass component is easily canceled between the left speaker and the right speaker arranged in close proximity, but the low frequency component is relatively Since the compensation circuit for emphasizing is provided, it is possible to maintain a sense of spread of the stereo sound field.

  The speaker mounting surface only needs to be arranged along the horizontal direction, and if the listener's head is positioned on the extended surface, the speaker mounting surface is unidirectional with the listener side as the zero point direction. Therefore, the listener can easily obtain the sound image localization farther from the actual position of the speaker.

  In addition, the sound reproduction device can provide a sense of localization in the depth direction of the sound image if the directivity control unit further includes a level adjustment circuit that adjusts and outputs the relative level of the sum signal with respect to the left signal or the right signal. Can be changed. If the output level of the sum signal from the directivity control circuit is reduced, the sound image can be localized on the front side, and if the output level of the sum signal is increased, the sound image can be localized on the back side. In particular, a stereoscopic video playback device including this sound playback device and a 3D display can realize video and audio playback with higher presence.

  The sound reproduction device of the present invention and the stereoscopic video reproduction device including the same include a directivity control unit for controlling the directivity of the speaker, and with a simpler configuration, the monaural component common to the left and right channels is also favorable. Sound image localization can be obtained farther than the actual position of the speaker.

It is a figure explaining the sound reproduction apparatus 1 by preferable embodiment of this invention. Example 1 It is a figure explaining the speaker part 3 which comprises the sound reproduction apparatus 1 by preferable embodiment of this invention. Example 1 It is a figure which illustrates notionally the unidirectional radiation characteristic and reproduction | regeneration sound field which are reproduced | regenerated with the sound reproduction apparatus 1 by preferable embodiment of this invention. Example 1 It is a figure which illustrates notionally the omnidirectional radiation characteristic and reproduction | regeneration sound field which are reproduced | regenerated by the speaker part 30 of the sound reproduction apparatus of a comparative example. (Comparative Example 1) It is a figure explaining the elongate electrodynamic type speaker 20 which comprises the speaker part 3 of the sound reproduction apparatus 1 by other preferable embodiment of this invention. (Example 2) It is a figure explaining the speaker part 3 which comprises the sound reproduction apparatus 1 by other preferable embodiment of this invention. (Example 2)

  Hereinafter, a sound reproducing device and a stereoscopic video reproducing device including the same according to preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

  1 and 2 are diagrams for explaining a sound reproducing device 1 according to a preferred embodiment of the present invention. Specifically, FIG. 1 is a block diagram illustrating a configuration of the sound reproducing device 1. 2 is a diagram for explaining the speaker unit 3 constituting the sound reproducing device 1. FIG. 2 (a) is a plan view, and FIG. 2 (b) is a side sectional view. Further, FIG. 3 is a diagram for conceptually explaining the unidirectional radiation characteristic and the reproduced sound field reproduced by the sound reproducing device 1, FIG. 3 (a) is a plan view, and FIG. 3 (b). Shows a side view. In addition, illustration and description of a part of the structure unnecessary for the description, an internal structure, and the like are omitted.

  The sound reproducing device 1 includes a directivity control circuit 2 and a speaker system 3. As shown in FIG. 3, the sound reproducing device 1 is a sound reproducing device that can give the listener 4 a sound image localization farther than the actual position of the speaker system 3. The directivity control circuit 2 receives a stereo signal (left signal L and right signal R) and performs signal processing on the DSP (digital signal processor) 5, and receives three-channel output from the DSP 5 and converts it into an analog signal. A / A converter 6 and an amplifier circuit 7 for amplifying these analog signals and outputting them to the speaker system 3 at least. The directivity control circuit 2 has input terminals Lin and Rin that receive the left signal L and the right signal R, and output terminals Lout, Rout, and Fout that output the outputs of the three amplifier circuits 7. Specifically, the directivity control circuit 2 can be configured by a DSP that supports multi-channel audio and an AV receiver that incorporates a multi-channel amplifier circuit.

  The speaker system 3 includes a speaker mounting surface 32 on the top surface side of a cabinet 31 formed of resin or the like, and includes a left speaker Lsp, a right speaker Rsp, and a center front speaker Fsp that are mounted on the speaker mounting surface 32. . The left speaker Lsp, the right speaker Rsp, and the center front speaker Fsp of the present embodiment are electrodynamic speakers having a circular outer shape cone diaphragm having an aperture of 8 cm, and each cone diaphragm has the same top surface. It is attached to the speaker attachment surface 32 so as to be aligned in the direction. These three speakers preferably have substantially the same acoustic radiation characteristics, and most preferably the same. The three speakers need to have positive and negative terminals for supplying signals to the magnetic circuit and the voice coil so that at least the audio signal is radiated in the same phase.

  The cabinet 31 has a space for defining an acoustic capacity in the interior thereof in order to increase the vicinity of the lowest resonance frequency of each speaker and the following bass range. The interior of the cabinet 31 is preferably partitioned for each speaker so that sound waves radiated to the back side of the cone diaphragm do not interfere with each other. As the cabinet 31, various types of cabinets such as a sealed type, a bass reflex type, and a kelton type can be adopted. The cabinet 3 of the speaker system 2 may be provided with a front grill (not shown), a punching net, or the like so as to protect the exposed speaker 10.

  As illustrated, the left speaker Lsp and the right speaker Rsp are arranged symmetrically toward the listener 4. The center front speaker Fsp is disposed on the speaker mounting surface 32 at an intermediate position between the left speaker Lsp and the right speaker Rsp and at a position forming a substantially isosceles triangle with the left speaker Lsp and the right speaker Rsp. 4 is arranged in front of the left speaker Lsp and the right speaker Rsp. That is, when viewed from three speakers, the listener 4 is positioned in a direction in which a perpendicular bisector passing through a vertex constituted by two sides of equal length of an isosceles triangle is extended. In the case of this embodiment, the three speakers are arranged at positions that form a substantially equilateral triangle, and the separation distance d between the respective speakers is about 10 cm. The separation distance d between the speakers can be calculated from the distance between the center positions of the respective diaphragms. The speaker mounting surface 32 is arranged along the horizontal direction, and the head of the listener 4 is located on the extended surface.

  The DSP 5 of the directivity control circuit 2 performs signal processing and outputs a left signal L and a right signal R that are digital signals. The DSP 5 adds the left signal L and the right signal R and outputs a sum signal (L + R), a delay device 12 that delays and outputs the sum signal (L + R), and a delayed sum signal (L + R). ) At least in phase, and a compensation filter 14 that relatively increases the level of the low frequency region of the left signal L or the right signal R. The input left signal L and right signal R are respectively input to the compensation filter 14. The output of each compensation filter 14 is output to the D / A converter 6 as an output signal of the left signal L or the right signal R from the DSP 5. The outputs of the respective compensation filters 14 are input to the adder 11 and output to the delay unit 12 as a sum signal (L + R). The delay unit 12 delays the sum signal (L + R) by a time corresponding to the left speaker Lsp and the distance d between the right speaker Rsp and the center front speaker Fsp, and outputs the delayed signal. That is, when the sound speed is about 343 m / sec, the delay unit 12 of this embodiment gives a delay of about 0.29 msec to the sum signal (L + R). The phase inverter 13 inverts the phase of the output signal from the delay unit 12 and outputs it to the D / A converter 6 as the output signal of the sum signal (L + R) from the DSP 5. The phase inverter 13 has a range of −1.0 to 0 so as to further include a level adjustment circuit for adjusting the output level of the output of the sum signal (L + R), as will be described in other embodiments described later. It may be a multiplier that multiplies the numerical values. Further, the phase inverter 13 is omitted from the DSP 5 when the front speaker Fsp is connected to the left speaker Lsp and the right speaker Rsp by connecting them in a relatively reverse phase. May be.

  The three D / A converters 6 are each connected to an amplifier circuit 7, and each amplifier circuit 7 outputs a power amplified signal to output terminals Lout, Rout, and Fout. The three D / A converters 6 and the amplifier circuit 7 have substantially the same output characteristics. In this way, the directivity control circuit 2 outputs the left signal L in which the level in the low frequency region is relatively increased to the output terminal Lout, and the right signal in which the level in the low frequency region is relatively increased to the output terminal Rout. In addition to outputting the signal R, the sum signal (L + R) obtained by adding the left signal L and the right signal R is delayed by a time corresponding to the separation distance d in the speaker system 3 and output to the output terminal Fout in an inverse phase relationship. To do.

  The output terminal Lout of the directivity control circuit 2 is connected to the left speaker Lsp of the speaker system 3. The output terminal Rout of the directivity control circuit 2 is connected to the right speaker Rsp of the speaker system 3. The output terminal Fout of the directivity control circuit 2 is connected to the center front speaker Fsp of the speaker system 3. Accordingly, the left signal L is acoustically radiated as sound waves from the left speaker Lsp, the right signal R is acoustically radiated as sound waves from the right speaker Rsp, and the sum signal (delayed and reversed in phase) is output from the center front speaker Fsp. L + R) is acoustically emitted as sound waves.

  As a result, as shown in the conceptual diagram of FIG. 3, with respect to the left signal L, the left speaker Lsp and the center front speaker Fsp make the listener 4 side the zero point direction and the left speaker Lsp along one side of the isosceles triangle. Unidirectional acoustic radiation characteristics with the back side as the beam direction are realized. The radiated sound wave due to the left signal L and the radiated sound wave due to the L signal component of the delayed sum signal (L + R) interfere with each other in one direction determined by the left speaker Lsp and the center front speaker Fsp. This is because a unidirectional zero point is created. Similarly, for the right signal R, the right speaker Rsp and the center front speaker Fsp make the listener 4 side as the zero point direction, and the unidirectionality with the back side of the right speaker Rsp along one side of the isosceles triangle as the beam direction. The acoustic radiation characteristics are realized. Therefore, the listener 4 located in the zero point direction of the unidirectional acoustic radiation characteristic can obtain the sound image localization farther from the actual position of the left speaker with respect to the left signal L, and the right speaker R with respect to the right signal R. Sound image localization can be obtained far from the actual position.

  The sound reproduction device 1 of the present embodiment also reproduces monaural sound in which the left signal L and the right signal R are in the same amplitude and phase relationship than the actual arrangement position of the left speaker Lsp and the right speaker Rsp. The phantom sound image can be localized in the distance. In a normal stereo audio signal such as music or broadcast, the left signal L and the right signal R have a high ratio of including a common monaural component M. Therefore, the listener 4 located in the zero point direction of the unidirectional acoustic radiation characteristic can obtain the sound image localization farther than the actual position of the left and right speakers with respect to the monaural component M.

  Further, in the DSP 5 of the directivity control circuit 2 of the present embodiment, the input left signal L and right signal R are respectively input to the compensation filter 14, but the compensation filter 14 is applied to each of the three output signals. It can replace with what is provided. The compensation filter 14 preliminarily determines the level of the low frequency region of the left signal L or the right signal R that is canceled due to the left speaker Lsp driven in the opposite phase and the distance d between the right speaker Rsp and the center front speaker Fsp. What is necessary is just to increase relatively. The compensation filter 14 can enhance the balance of the sound image that is felt far away for the listener 4 by relatively emphasizing the low-frequency component for which the low-frequency component is canceled between the three speakers arranged in close proximity. Since the compensation filter 14 also compensates for a reverse phase component (for example, (LR)) in which a bass component is easily canceled between the left speaker Lsp and the right speaker Rsp that are arranged in proximity to each other, the sense of spread of the stereo sound field is sensed. Can be kept.

  The sound reproducing apparatus 1 of this embodiment only requires a total of three speakers and an amplifier for three channels when reproducing a standard left and right two-channel stereo signal. As compared with the above, it is possible to obtain the same effect that the stereo sound field spreads far away while suppressing an increase in cost. In the sound reproducing device 1, the left signal L and the right signal R are reproduced by the left speaker Lsp and the right speaker Rsp, respectively. The DSP 5 of the directivity control circuit 2 performs signal processing such as delaying and dividing the sum signal (L + R) from the left signal L, or delaying and summing the sum signal (L + R) from the right signal R. Therefore, the problem that the common monaural component M is lost as if it has passed through the comb filter does not occur.

In the sound reproducing apparatus 1 of the present embodiment, the phase inverter 13 is provided in the DSP 5 of the directivity control circuit 2. However, the sum is delayed from the center front speaker Fsp by the other means and the method, and the phase is reversed. The signal (L + R) only needs to be acoustically emitted as a sound wave. For example, instead of providing the phase inverter 13, phase inversion is performed by connecting the positive and negative polarity of the output terminal of the amplifier circuit that amplifies the sum signal (L + R) and the positive and negative polarity of the input terminal of the front speaker Fsp to the opposite phase. It may be realized.
(Comparative Example 1)

  FIG. 4 is a diagram for conceptually explaining the omnidirectional radiation characteristic and the reproduced sound field reproduced by the speaker unit 30 of the sound reproducing device of the comparative example. As in FIG. 3, FIG. ) Shows a plan view, and FIG. 4B shows a side view. The speaker unit 30 of the sound reproducing device of the comparative example is an example in the case of reproducing only the left speaker Lsp and the right speaker Rsp when reproducing a standard left and right two-channel stereo signal. As shown in the conceptual diagram of FIG. 4, when sound is played back by a normal sound playback device, sound waves are radiated in all directions if played back by a single speaker. It becomes. The same applies to the monaural component M common to the left signal L and the right signal R.

  FIG. 5 is a diagram for explaining an elongated electrodynamic speaker 20 constituting the speaker unit 3 of the sound reproducing device 1 according to another preferred embodiment of the present invention. FIG. 6 is a diagram for explaining the speaker unit 3 using the electrodynamic speaker 20 constituting the sound reproducing device 1. Similar to FIG. 2, FIG. 6A shows a plan view of the speaker unit 3, and FIG. 6B shows a side sectional view. The speaker system 3 of the present embodiment is different from the speaker system 3 of the previous embodiment except that the left speaker Lsp, the right speaker Rsp, and the center front speaker Fsp and the configuration of the cabinet 3 including the arrangement relationship thereof are different. It is common. Therefore, the same parts as those in the previous embodiment are denoted by the same reference numerals, and the description and illustration are omitted.

  As shown in FIG. 5, the electrodynamic speaker 20 of this embodiment includes a thin rectangular planar diaphragm 25, an edge 26 that supports the periphery of the planar diaphragm 25 so as to vibrate, and a back surface of the planar diaphragm 25. A flat-type thin speaker that is driven on the entire surface, including a voice coil assembly 21 fixed to the side, a damper 24 that supports the voice coil assembly 21 so as to vibrate, a frame 27, and a plurality of magnetic circuits 28 including magnets. is there. The voice coil assembly 21 has three voice coils 23 connected in a lattice pattern by bobbins 22, and the speaker 20 includes three magnetic circuits 28 corresponding to the three voice coils 23. The thin rectangular speaker 20 has a length daL in the major axis direction da of about 12.5 cm and a length dbL in the minor axis direction db of about 4.8 cm.

  In the case of the present embodiment, the left speaker Lsp, the right speaker Rsp, and the center front speaker Fsp using the electrodynamic speaker 20 are arranged so that the planar diaphragms 25 are aligned in the same top surface direction as shown in the figure. Is attached to the speaker mounting surface 32. The left speaker Lsp, the right speaker Rsp, and the center front speaker Fsp are arranged on the speaker mounting surface 32 in close proximity so as to form a substantially isosceles triangle. The left speaker Lsp and the right speaker Rsp are arranged symmetrically toward the listener 4. In addition, the center front speaker Fsp is disposed at a position between the left speaker Lsp and the right speaker Rsp on the speaker mounting surface so as to form a substantially isosceles triangle with the left speaker Lsp and the right speaker Rsp. It is arranged in front of the left speaker Lsp and the right speaker Rsp. When viewed from three speakers, the listener 4 is positioned in the apex direction of the isosceles triangle.

  In the case of the present embodiment, since the elongated electrodynamic speaker 20 having a shorter short-axis length dbL than the long-diameter length daL is used for the three speakers, these are formed at positions where substantially isosceles triangles are formed. , The left speaker Lsp and the right speaker Rs are arranged so that the major axis directions da thereof coincide with each other, and the center front speaker Fsp is arranged at an intermediate position in the direction in which these minor axis directions coincide. For example, the separation distance d (= 5.0 cm) from the center front speaker Fsp can be shortened to an extent that substantially coincides with the minor diameter direction length dbL (= 4.8 cm). In other words, if the frames 27 of the elongated electrodynamic speakers 20 are adjacent to each other in the minor axis direction so as not to interfere with each other, they can be separated from the center front speaker Fsp to realize unidirectional acoustic radiation characteristics. Since the distance d can be shortened and placed close to the left speaker Lsp and the right speaker Rs, the distance between the speakers can be made narrower compared to a round normal speaker as in the previous embodiment.

  When the substantial separation distance d between the speakers in the speaker system 3 can be shortened as in this embodiment, the delay time in the delay unit 12 of the DSP 5 of the directivity control circuit 2 can be shortened, and the high frequency Unidirectional control is possible. The delay unit 12 of this embodiment gives a delay of about 0.15 msec to the sum signal (L + R). Compared to the case of the previous embodiment, since the separation distance d is about ½ in this embodiment, the frequency band in which unidirectional control is possible is about twice (frequency at which dip occurs: about 1). .7 kHz → about 3.4 kHz). In addition, since the elongated flat diaphragm 25 of the electrodynamic speaker 20 has the minor axis direction db directed in the direction toward the listener 4, the major axis direction da is a lateral direction, so that the relatively lateral diaphragm is relatively long. become. Therefore, in the sound reproducing apparatus 1 of the present embodiment, the width can be increased in the direction of the zero point in the unidirectionality, so that the effect that the sound image can be felt far away can be enhanced for the listener 4.

  In addition, the sound reproducing device 1 according to the present embodiment uses three electrodynamic speakers 20 including the planar diaphragm 25 and the voice coil assembly 21 in the speaker system 3. The voice coil assembly 21 of the electrodynamic speaker 20 has three voice coils 23 connected in a lattice pattern by bobbins 22 and can suppress the divided vibration on the flat diaphragm 25. The piston vibration regeneration range is extremely wide. As a result, it is possible to obtain the sound image localization farther than the actual position of the speaker, with a simpler configuration, as compared with the conventional technique such as Patent Document 2.

  The sound reproduction apparatus 1 of the above embodiment changes the sense of localization in the depth direction of the sound image so as to correlate with the video displayed on the 3D display stereoscopically viewed in the depth direction of the screen, thereby realizing more realistic sound reproduction. It becomes possible. That is, the audio reproduction device 1 can realize video / audio reproduction with higher presence by combining with the 3D display. The sound playback device 1 may be used in combination with a 3D display, or may be incorporated in a stereoscopic video playback device (not shown).

  For example, in a stereoscopic video playback device including at least the sound playback device 1 and a 3D display (not shown), when viewed on a 3D display, audio linked to a video located on the near side of the 3D screen is on the near side. The sound image is localized, and the sound linked to the video located on the back side of the 3D screen can be located on the back side. In this case, the audio signal that is localized on the far side is a monaural component common to the left signal L and the right signal R. For example, when a naked eye liquid crystal display (not shown) such as a parallax barrier method is used, the 3D display is on the front side of the cabinet 31 constituting the speaker system 3 in the above embodiment, and is in front of the listener 4 and the center. What is necessary is just to attach to the position between the speakers Fsp. In addition, when using a frame sequential type liquid crystal display (not shown) in which a listener wears glasses that open and close the left and right shutters at high speed, the arrangement of the 3D display may be the same.

  In order to change the sense of localization in the depth direction of the sound image, the level of the delayed sum signal (L + R) output from the output terminal Fout of the directivity control circuit 2 to the center front speaker Fsp is adjusted (illustrated). No) A level adjustment circuit may be further provided. If the output level of the sum signal (L + R) from the output terminal Fout of the directivity control circuit 2 is reduced, the sound image can be localized on the front side, and if the output level of the sum signal (L + R) is increased, the sound image on the back side. Can be localized. As described in the above embodiment, the level adjustment circuit may be any circuit that adjusts and outputs the relative level of the sum signal with respect to the left signal or the right signal.

  Further, a decoder circuit (not shown) for extracting a signal component for sound image localization on the back side from the left signal L and the right signal R is further provided, and the output of the decoder circuit is replaced with the output signal of the adder 11 in the above embodiment. You may input into the delay device 12. Since the signal component for sound image localization is output from the output terminal Fout of the directivity control circuit 2 to the back side delayed to the center front speaker Fsp and reversed in phase, some of the left signal L and the right signal R are output. Only the signal component is localized on the far side. If the output level of the decoder circuit is reduced, the sound image can be localized on the front side, and if the output level of the decoder circuit is increased, the sound image can be localized on the back side.

  The sound reproducing device of the present invention is not only a stereo device that reproduces a stereo sound signal alone, or a multi-channel surround sound reproducing device, but also a speaker built in a video / audio device such as a display, or a speaker that reproduces sound. The present invention can also be applied to a game machine having a cabinet with a built-in and a game machine such as a slot machine.

DESCRIPTION OF SYMBOLS 1 Sound reproduction apparatus 2 Directivity control circuit 3, 30 Speaker system 31 Cabinet 32 Speaker mounting surface 4 Listener 5 DSP
6 D / A converter 7 Amplifier circuit 11 Adder 12 Delayer 13 Phase inverter 14 Compensation filter 20 Speaker 21 Voice coil assembly 22 Bobbin 23 Voice coil 24 Damper 25 Planar diaphragm 26 Edge 27 Frame 28 Magnetic circuit Lsp Left speaker Rsp Right speaker Fsp Center front speaker

Claims (6)

A speaker mounting surface; a left speaker that is attached to the speaker mounting surface to reproduce a left signal; a right speaker that is attached to the speaker mounting surface to reproduce a right signal; and the left speaker and the right speaker on the speaker mounting surface A center front speaker disposed at a position on the middle position of the left speaker and the right speaker to form a substantially isosceles triangle;
Summing means for adding the left signal and the right signal to output a sum signal, and outputting the sum signal delayed by a time corresponding to the distance between the left speaker and the right speaker and the center front speaker. Delay means; and phase inversion means for causing the left signal and the right signal and the sum signal delayed by the delay means to be radiated from the center front speaker in opposite phases with each other, and A directivity control unit that obtains a unidirectional radiation characteristic by driving the left speaker, the right speaker, and the center front speaker, and
The left speaker and the right speaker on the speaker mounting surface are arranged symmetrically toward the listener, and the central front speaker is arranged on the front side of the left speaker and the right speaker toward the listener. Yes,
Sound playback device. The left speaker, the right speaker, and the center front speaker are elongated electrodynamic speakers having a short-diameter direction length shorter than a long-diameter direction length, and the left speaker and the right speaker are respectively It is arranged so that the major axis direction matches, and is arranged close to the center front speaker so that the separation distance from the center front speaker and the length in the minor axis direction substantially match.
The sound reproducing device according to claim 1. The directivity control unit is configured to cancel the left signal or the right signal in a low-frequency region level that is canceled due to the separation distance between the left speaker and the right speaker and the center front speaker that are driven in opposite phases. Further comprising compensation means for relatively increasing
The sound reproducing device according to claim 1 or 2. The directivity control unit further includes a level adjustment circuit that adjusts and outputs a relative level of the sum signal with respect to the left signal or the right signal.
The sound reproducing device according to claim 1. The speaker mounting surface is disposed along the horizontal direction, and is disposed such that the listener's head is positioned on the extended surface.
The sound reproducing device according to claim 1.   A stereoscopic video reproduction apparatus including at least the sound reproduction apparatus according to claim 1 and a 3D display.