JP2013077977A - Speaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker device which has high directivity and can be downsized.SOLUTION: First and second speaker units 101 and 102 have their diaphragms directed to the front and are separated to the left and right by a distance w of 0.3λ and over to less than 0.8λ where λ is a wavelength of an acoustic signal with a frequency f. Third and fourth speaker units 103 and 104 have their diaphragms directed to the back and are separated to the back side by a distance d from the first and second speaker units 101 and 102. A shield plate is installed between the front and the rear speaker units. A supply part supplies an acoustic signal to the first and second speaker units 101 and 102, and supplies an inverse phase acoustic signal to the third and fourth speaker units 103 and 104. A band division part outputs an acoustic signal centering around the frequency f, and, when the half-value angle of the frequency response of the speaker units to an acoustic signal at a frequency 2mf (m=integer equal to or greater than 2) is 60° or less, it also outputs an acoustic signal in a frequency band of (2m-1)f or more.

Description

The present invention relates to a speaker device having directivity.

  In public facilities such as stations and large-scale stores, commercial facilities, and the like, PAs (Public Addresses, broadcasting facilities) that provide voice guidance broadcasting are widely used. In PA, since a guidance broadcast reaches outside the facility, noise is generated. Therefore, a directional speaker device is used so that the guidance broadcast reaches only the target area.

  As a speaker device having directivity, a tone Zoise type speaker in which a plurality of speakers are arranged linearly is known. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2-239795

  The speaker device described in Patent Document 1 is known to have high directivity in the front-rear direction for an audio signal having a wavelength that is approximately twice the distance between the left and right units. However, the tone Zoire type speaker device needs to increase the number of speakers in order to increase directivity, and there is a problem that the size of the device increases because many speakers are arranged in a straight line.

  Accordingly, an object of the present invention is to provide a speaker device that has high directivity and can be miniaturized.

In order to solve the above problems, the present invention provides the following apparatus.
1) Frequency division of an input acoustic signal, a divided acoustic signal that is an acoustic signal in a frequency band centered on the frequency f, and a frequency band of (2m-1) f or more (m is an integer of 2 or more) A band dividing unit (91) for outputting an acoustic signal, a first speaker unit (8Bnfr) having a diaphragm directed in a predetermined direction, and a speaker unit having a diaphragm directed in a predetermined direction, having a frequency f Where the distance of the center of the diaphragm with respect to the first speaker unit is separated by a distance wn of 0.3λ or more and less than 0.8λ in a direction orthogonal to a predetermined direction, where λ is the wavelength of the acoustic signal. Speaker unit (8Bnfl) and a speaker unit in which the diaphragm is directed in a direction opposite to a predetermined direction, and the distance between the center of the diaphragm and the first speaker unit is determined in a direction opposite to the predetermined direction. Distance of A speaker unit having a third speaker unit (8Bnrr) separated from each other and a speaker unit in which a diaphragm is directed in a direction opposite to a predetermined direction, the diaphragm being in contact with the second speaker unit in a direction opposite to the predetermined direction Between the fourth speaker unit (8Bnrl), the first speaker unit and the second speaker unit, and the third speaker unit and the fourth speaker unit separated by a predetermined distance d. And the third speaker unit and the fourth speaker unit while supplying the sound signal divided by the band dividing unit to the first speaker unit and the second speaker unit in the same phase. An acoustic signal having a phase opposite to that of the acoustic signal output to the first speaker unit and the second speaker unit. Speaker apparatus characterized by comprising a supply unit for feeding (92n).
2) m is m in which the half-value angle of the frequency characteristics of the first, second, third and fourth speaker units with respect to an acoustic signal having a frequency of 2 mf is 60 ° or less. Speaker device.
3) The speaker device according to 1) or 2), wherein the distance w is set to 0.45λ or more and less than 0.75λ.
4) The speaker device according to 1), 2) or 3), wherein the first, second, third and fourth speaker units are speaker units having the same characteristics.

  ADVANTAGE OF THE INVENTION According to this invention, the directivity can provide the speaker apparatus which can be reduced in size.

It is a perspective view of 1st Example of the speaker apparatus of this invention. It is a block block diagram of 1st Example of the speaker apparatus of this invention. It is a figure which shows the directional characteristic of 1st Example of the speaker apparatus of this invention. It is a perspective view of 2nd Example of the speaker apparatus of this invention. It is a block block diagram of 2nd Example of the speaker apparatus of this invention. It is a figure which shows the directional characteristic when the acoustic signal of a different frequency is input in 1st Example of the speaker apparatus of this invention. It is an example of directivity when an acoustic signal having a different frequency is input to the speaker unit. It is a perspective view of 3rd Example of the speaker apparatus of this invention. It is a block block diagram of 3rd Example of the speaker apparatus of this invention. It is a figure which shows the frequency characteristic of the acoustic signal which the supply part in 3rd Example of the speaker apparatus of this invention supplies.

Hereinafter, a speaker device of the present invention will be described based on an embodiment with reference to the accompanying drawings.
[First embodiment]
<Configuration>
FIG. 1 is a perspective view showing a speaker device 1 according to a first embodiment of the present invention. In FIG. 1, for ease of understanding, the housing and circuit portion of the speaker device 1 are not shown, and only the arrangement of the speaker units is shown. The speaker device 1 of the present embodiment is mainly used for the purpose of public announcements such as announcements in a PA, and amplifies and outputs a voice uttered by a human having a frequency band of 250 Hz to 600 Hz centering on a frequency of 500 Hz. To do.

  In FIG. 1, the speaker unit is arranged so that the center of the diaphragm comes to the vertices V1 to V4 of a rectangle having a width w and a depth d. Specifically, when A is the front direction of the speaker device 1, the front speaker unit 101 is placed at the position of the vertex V1 on the front side (front side in FIG. 1) and the right side (right side in FIG. 1) of the diaphragm. Position the diaphragm in the forward direction so that the center comes. The front speaker unit 102 is arranged with the direction of the diaphragm as the front direction so that the center of the diaphragm comes to the position of the vertex V2 that is a distance w away from the left side of the front speaker unit 101.

  In addition, the rear speaker unit 103 is arranged with the direction of the diaphragm in the rear direction so that the center of the diaphragm comes to the position of the vertex V3 that is separated by the distance d in the rear direction of the front speaker unit 101. Further, the rear speaker unit 104 is arranged with the direction of the diaphragm in the rear direction so that the center of the diaphragm comes to the position of the vertex V4 that is separated from the front speaker unit 102 by the distance w in the rear direction.

  The front speaker units 101 and 102 and the rear speaker units 103 and 104 are speaker units having substantially the same aperture and the same frequency characteristics, and are used in a state in which sound from the back is cut off by being attached to an enclosure. To do.

  A shielding plate 105 is provided between the front speaker units 101 and 102 and the rear speaker units 103 and 104. Note that a structure that serves as both the shielding plate 105 and the enclosure may be employed.

FIG. 2 is a block configuration diagram of the speaker device 1. As shown in FIG. 2, the input unit 20 sends the input audio signal to the supply unit 21. The supply unit 21 supplies the audio signal sent from the input unit 20 to the front speaker units 101 and 102, and inverts the phase of the audio signal supplied to the front speaker units 101 and 102 to the rear speaker units 103 and 104. Supply a sound signal.
<Action>
In the speaker device 1 of the present embodiment, FIG. 3 shows directivity characteristics when the left and right distance w between the front speaker units 101 and 102 and the rear speaker units 103 and 104 is changed. FIG. 3 shows the sound pressure of the sound wave output in each direction of the speaker device 1 when the reference sound signal having the wavelength λ is input to the speaker device 1, using the speaker unit as a point sound source, and is shown in a pie chart. Is. In FIG. 3, the interval w is a multiple of λ. In the directional characteristic pie chart of FIG. 3, the downward direction is the front direction of the speaker device 1. In addition, twice the sound pressure of the output sound wave when the reference audio signal is input to one speaker unit is set to 0 dB (the maximum value of the scale of the pie chart). As an index representing directivity, the half-value angle, which is the angle from the front when the output sound pressure is ½ of the maximum sound pressure, is known. Hereinafter, the half-value angle will be described.

  As shown in FIGS. 3a), b), and c), when w <0.3λ, the half-value angle is about 65 ° or more, and the waveform of the directivity characteristic is a figure of 8 that spreads horizontally. At this time, the directivity of the speaker device 1 is low.

  As shown in FIGS. 3d), e), and f), when 0.3λ ≦ w <0.45λ, the half-value angle is 55 ° or less, and the waveform of the directivity is slightly wide, but it has an 8-shaped shape. At this time, the directivity of the speaker device 1 is high.

  As shown in FIGS. 3g), h), i), j), k), and l), when 0.45λ ≦ w <0.75λ, the half-value angle is 35 ° or less and the waveform of the directivity is an 8-shaped waveform. It has become. At this time, the directivity of the speaker device 1 is quite high.

  As shown in FIG. 3m), when 0.75λ ≦ w <0.8λ, the half-value angle is about 20 ° and the directivity is an 8-shaped pattern. Further, when looking at the waveform of the directivity, although the side lobe is generated, the size is about −16 dB, and the directivity of the speaker device 1 is quite high.

  As shown in FIGS. 3n), o), and p), when 0.8λ ≦ w, the half-value angle is about 18 ° or less and the directivity is an 8-letter shape. Further, when looking at the waveform of the directivity characteristics, a large side lobe of −8 dB or more is generated in a substantially lateral direction, and the directivity of the speaker device 1 is low.

  In summary, the speaker device 1 of this embodiment has low directivity when w <0.3λ. Directivity is high when 0.3λ ≦ w <0.8λ. Furthermore, when 0.45λ ≦ w <0.75λ, the directivity is considerably high. When 0.8λ ≦ w, directivity is low.

  In addition, as described above, the speaker device 1 according to the present embodiment is mainly used for the purpose of sound amplification such as announcements in the PA, and outputs sound composed of sound wave signals in a frequency band centered on a frequency of 500 Hz. . If the speed of sound is 340 m / s, the wavelength of a sound wave having a frequency of 500 Hz is 0.68 m. At this time, 0.3λ ≦ w <0.8λ corresponds to 0.204 m ≦ w <0.544 m, and 0.45λ ≦ w <0.75λ corresponds to 0.306 m ≦ w <0.51 m.

  The speaker device 1 of the present embodiment is characterized in that the distance w between the left and right speaker units is 0.204 m ≦ w <0.544 m. More preferably, 0.306 m ≦ w <0.51 m.

  In the speaker device 1 according to the present embodiment, the front speaker units 101 and 102 constitute a tone Zoise type speaker. Similarly, the rear speaker units 103 and 104 constitute a tone Zoise type speaker.

  In general, the directivity of a tone Zoise type speaker changes depending on the frequency of an input audio signal. When an audio signal having a wavelength approximately twice as long as the left-right unit interval is input, the audio signals in the front-rear direction are enhanced and the audio signals in the left-right direction cancel each other, so that the directivity is high. When the frequency of the input audio signal is further increased, the directivity characteristics in the front-rear direction gradually become sharper, but the sound pressure increases because the sound pressure (side lobe) in the left-right direction is weakened. When the frequency of the input audio signal increases and the wavelength reaches a frequency that is the same as the left and right unit intervals, the side lobes also increase, and the directivity is four-directional. Further, when the frequency is gradually lowered from an audio signal having a wavelength that is approximately twice the interval between the left and right units, the directivity approaches omnidirectionality.

  On the other hand, in the speaker device of the present embodiment, the front speaker unit 101 and the rear speaker unit 103 constitute a dipole speaker. Similarly, the front speaker unit 102 and the rear speaker unit 104 constitute a dipole speaker. The side lobes of the front speaker units 101 and 102, which are tone zeile speakers, cancel each other out with the side lobes of the rear speaker units 103 and 104 that are also tone zeile speakers and are driven in opposite phases. Thereby, the speaker apparatus of a present Example exhibits high directivity. Moreover, even if the wavelength of the output audio signal deviates to some extent from approximately twice the interval between the left and right units, high directivity can be exhibited.

In addition, the speaker device 1 according to the present embodiment exhibits high directivity using four speaker units, and only needs to arrange two speaker units in a width of approximately ½ wavelength in the horizontal direction. Compared to other speaker devices, the size can be reduced.
[Second Embodiment]
<Configuration>
Next, the speaker device of the second embodiment will be described. The second embodiment is an example of a speaker device having high directivity over a wider frequency band than the first embodiment. The speaker device 4 according to the second embodiment includes the speaker device 1 according to the first embodiment as a set of speaker sets, and n sets (n is an integer equal to or greater than 2) of speaker sets 4B1 to 4Bn with different intervals. Is provided.

  Hereinafter, an example in which n = 6 will be described. FIG. 4 is a perspective view showing the arrangement of the speaker device 4 of the second embodiment of the speaker device of the present invention. In FIG. 4, for ease of understanding, the housing and circuit portion of the speaker device 4 are not shown, and only the arrangement of the speaker units is shown. In FIG. 4, C is the front direction of the speaker device 4.

  In the present embodiment, as shown in FIG. 4, the front speaker unit is arranged such that the center of the diaphragm is located at a position symmetrical to the center and having a width wn on a straight line X1 extending in the left-right direction orthogonal to the front-rear direction. 4Bnfr is arranged on the right side (right side in FIG. 4), the front speaker unit 4Bnfl is arranged on the left side (left side in FIG. 4), and the direction of the diaphragm is arranged in the front direction.

  Further, the rear speaker unit 4Bnrr and the rear speaker unit 4Bnrl are arranged at positions corresponding to the front speaker unit 4Bnfr and the front speaker unit 4Bnfl on the straight line X2 parallel to the straight line X1 and separated by the distance d in the backward direction. Arrange the orientation as the backward direction.

  The front speaker units 4Bnfr and 4Bnfl and the rear speaker units 4Bnrr and 4Bnrl are speaker units having the same characteristics with the same diameter and the same frequency characteristics, and are used in a state where the sound from the back is cut off by attaching to the enclosure. To do.

  A shielding plate 41 is provided between the front speaker units 4Bnfr and 4Bnfl and the rear speaker units 4Bnrr and 4Bnrl. A structure that doubles as the shielding plate 41 and the enclosure may be used.

  FIG. 5 is a block configuration diagram of the speaker device 4. As shown in FIG. 5, the input unit 50 sends the input acoustic signal to the band dividing unit 51. The band dividing unit 51 includes n sets of BPFs (Band Pass Filters) 51n including capacitors and coils. The BPF 51n divides the frequency band of the input acoustic signal and outputs the band-divided acoustic signal to each speaker set 4Bn. Further, the left-right distance wn between the front speaker unit and the rear speaker unit in each speaker set is set to approximately ½ of the wavelength of the center frequency of the acoustic signal divided for each speaker set by the band dividing unit 51.

  The speaker device 4 includes a first band speaker set 4B1, a second band speaker set 4B2, a third band speaker set 4B3, a fourth band speaker set 4B4, a fifth band speaker set 4B5, and a sixth band speaker. Six speaker sets 4Bn of the set 4B6 are provided.

  The input unit 50 sends the input acoustic signal to the band dividing unit 51. The dividing unit 51 includes six sets of BPFs 511 to 516, and divides the input acoustic signal into six frequency bands having different center frequencies by ½ octave.

  The BPF 511 outputs an acoustic signal in a frequency band with a center frequency of 500 Hz to the supply unit 521 of the first band speaker set 4B1. The supply unit 521 supplies the acoustic signals divided in band to the front speaker units 4B1fr and 4B1fl as they are, and supplies the acoustic signals divided in band to the rear speaker units 4B1rr and 4B1rl by inverting them. Also, the left-right distance w1 between the front speaker units 4B1fr and 4B1fl and the rear speaker units 4B1rr and 4B1rl is set to 0.34 m, which is a half wavelength of an acoustic signal having a center frequency of 500 Hz.

  The BPF 512 outputs an acoustic signal in a frequency band centered on a frequency 707 Hz that is 1/2 octave higher than the center frequency 500 Hz of the BPF 511 to the supply unit 522 of the second band speaker set 4B2. The supply unit 522 supplies the acoustic signals divided into bands to the front speaker units 4B2fr and 4B2fl as they are, and supplies the rear speaker units 4B2rr and 4B2rl with the phase of the acoustic signals divided into bands reversed. Further, the left-right distance w2 between the front speaker units 4B2fr and 4B2fl and the rear speaker units 4B2rr and 4B2rl is set to 0.24 m which is a half wavelength of the acoustic signal having the center frequency of 707 Hz.

  The BPF 513 outputs an acoustic signal in a frequency band centered at a frequency 1 kHz that is 1/2 octave higher than the center frequency 707 Hz of the BPF 512 to the supply unit 523 of the third band speaker set 4B3. The supply unit 523 supplies the acoustic signals divided into bands to the front speaker units 4B3fr and 4B3fl as they are, and supplies the acoustic signals divided into bands to the rear speaker units 4B3rr and 4B3rl by inverting them. Further, the left-right distance w3 between the front speaker units 4B3fr, 4B3fl and the rear speaker units 4B3rr, 4B3rl is set to 0.17 m which is a half wavelength of the 1 kHz acoustic signal.

  The BPF 514 outputs an acoustic signal in a frequency band centered at a frequency of 1.4 kHz that is 1/2 octave higher than the center frequency of 1 kHz of the BPF 513 to the supply unit 524 of the fourth band speaker set 4B4. The supplying unit 524 supplies the front-speaker units 4B4fr and 4B4fl with the band-divided acoustic signals as they are, and supplies the rear speaker units 4B4rr and 4B4rl with the phase of the band-divided acoustic signals inverted. Also, the left-right distance w4 between the front speaker units 4B4fr, 4B4fl and the rear speaker units 4B4rr, 4B4rl is set to 0.12 m, which is a half wavelength of the acoustic signal having a center frequency of 1.4 kHz.

  The BPF 515 outputs an acoustic signal in a frequency band centered at a frequency 2 kHz that is 1/2 octave higher than the center frequency 1.4 kHz of the BPF 514 to the supply unit 525 of the fifth band speaker set 4B5. The supply unit 525 supplies the acoustic signals divided into bands to the front speaker units 4B5fr and 4B5fl as they are, and supplies the acoustic signals divided into bands to the rear speaker units 4B5rr and 4B5rl by inverting them. Also, the left-right distance w5 between the front speaker units 4B5fr and 4B5fl and the rear speaker units 4B5rr and 4B5rl is set to 0.085 m which is a half wavelength of the acoustic signal having the center frequency of 2 kHz.

  The BPF 516 outputs to the supply unit 526 of the sixth band speaker set 4B6 a sound signal in a frequency band centered on a frequency 2.82 kHz that is 1/2 octave higher than the center frequency 2 kHz of the BPF 515. The supplying unit 526 supplies the front-speaker units 4B6fr and 4B6fl with the band-divided acoustic signal as it is, and supplies the rear speaker units 4B6rr and 4B6rl with the phase of the band-divided acoustic signal inverted. Further, the left-right distance w6 between the front speaker units 4B6fr and 4B6fl and the rear speaker units 4B6rr and 4B6rl is set to 0.06 m which is a half wavelength of the acoustic signal having the center frequency of 2.82 kHz.

Even if the interval wn between the speaker units is not exactly λn / 2, it is effective if 0.3λn ≦ wn <0.8λn as in the first embodiment. More preferably, if 0.45λn ≦ wn <0.75λn, a greater effect is achieved. Furthermore, even if the distance between the front and rear and the distance between the left and right of each speaker unit are not necessarily the same, it is effective as long as each is within the above-mentioned range.
In addition, even if the divided sound signals of all frequency bands are not output by the speaker set as described above, the structure of outputting the sound signals of the frequency band for which high directivity is desired by the speaker set as described above is also effective. Play.

    In the n speaker sets 4Bn of the speaker device 4 of the present embodiment, the front speaker unit 4Bnfr and the front speaker unit 4Bnfl, and the rear speaker units 4Bnrr and 4Bnrl respectively constitute a tone Zoise type speaker.

  Further, the front speaker unit 4Bnfr and the rear speaker unit 4Bnrr, and the front speaker unit 4Bnfl and the rear speaker unit 4Bnrl each constitute a dipole speaker. Thus, as in the first embodiment, the side lobes of the front speaker units 4Bnfr and 4Bnfl, which are tone Zoise type speakers, are also the same as the Zoning type speakers and are driven in the opposite phase. By canceling out lobes, directivity can be increased in a certain wide frequency band.

  Thereby, since the frequency band which one speaker set can handle can be expanded, the number of speaker sets can be reduced and the apparatus can be miniaturized.

  In addition, the speaker set in the speaker device 4 of the present embodiment exhibits high directivity using four speaker units as in the first embodiment, and the two speaker units are arranged in the horizontal direction by approximately ½ wavelength. Therefore, it is possible to reduce the size as compared with the conventional speaker device.

  In addition, each speaker set bears the output of an appropriate frequency band, so it has a high directivity. Furthermore, since n speaker sets having different left and right intervals are used for each appropriate frequency band, the speaker apparatus as a whole is a speaker apparatus having high directivity over a wide frequency band. Therefore, even when it is desired to output a sound source of a wider frequency band such as BGM (Back Ground Music), a sufficient directivity can be obtained.

[Third embodiment]
<Configuration>
In the first embodiment, when the center frequency of the frequency band for driving the speaker unit is f and the wavelength is λ, it is high when the interval w between the left and right speaker units is set to approximately λ / 2 as described above. Directivity can be obtained. However, even for an acoustic signal having an odd multiple of the frequency, the sound pressure in the direction of 90 degrees is canceled out from the directivity direction, and the acoustic signal in the front-rear direction is increased, so that high directivity is also obtained.

FIG. 6 shows an example of directivity when an acoustic signal having even and odd multiples of the frequency f is input to the speaker device 1 of the first embodiment in which the distance between the front and rear speaker units is λ / 2. FIG. 6 a) is an example of the directivity when an acoustic signal having a frequency twice as high as the frequency f is input to the speaker device 1. FIG. 6B) shows an example of directivity when an acoustic signal having a frequency three times the frequency f is input to the speaker device 1. FIG. 6 c) is an example of directivity when an acoustic signal having a frequency four times the frequency f is input to the speaker device 1. FIG. 6D) shows an example of directivity when an acoustic signal having a frequency five times the frequency f is input to the speaker device 1.
As can be seen from FIGS. 6b) and d), the speaker device 1 of the first embodiment has a high directivity with respect to an acoustic signal having a frequency three to five times the frequency f, but from FIGS. 6a) and c). As can be seen, the directivity is low for frequencies twice and four times the frequency f.

  On the other hand, it is generally known that the directivity of the speaker unit itself is increased for an acoustic signal having a relatively high frequency because the diameter and wavelength of the speaker unit are close to each other. FIG. 7 shows an example of directional characteristics when acoustic signals having different frequencies are input to the speaker unit. FIG. 7a) is an example of directional characteristics when an acoustic signal having a frequency of 2 kHz is input, and there is no portion where the sound pressure of the output is ½ of the maximum sound pressure in front of the speaker unit. There is no half-value angle. FIG. 7b) shows an example of directivity when an acoustic signal having a frequency of 2.83 kHz is input, and the half-value angle is about 57 °. FIG. 7c) shows an example of directivity when an acoustic signal having a frequency of 4 kHz is input, and the half-value angle is about 36 °. FIG. 7d) shows an example of directivity when an acoustic signal having a frequency of 5.66 kHz is input, and the half-value angle is about 25 °. FIG. 7e) shows an example of directivity when an acoustic signal having a frequency of 8 kHz is input, and the half-value angle is about 17 °. FIG. 7 shows that the directivity increases as the frequency of the input acoustic signal increases. Moreover, if the half-value angle is smaller than 60 °, the directivity of the speaker unit is felt to be high in terms of audibility. Therefore, the speaker unit in the example of FIG. 7 exhibits high directivity when an acoustic signal having a frequency of 2.83 kHz or more is input.

  The total directivity when many sound sources with the same directivity are arranged is given by the product of the directivity of each sound source and the directivity of the placement when these sound sources are replaced with point sound sources. It is known. Accordingly, in the third embodiment, when the half-value angle of the directivity of the speaker unit is 60 ° or less (where m is an integer of 2 or more) with respect to the frequency 2 mf of the acoustic signal in the speaker device of the second embodiment, It is assumed that an acoustic signal having a frequency of (2m-1) f or higher is also output from the dividing unit.

  As a result, a high directivity is obtained for the acoustic signal having the frequency (2m-1) f by the arrangement of the dipole method, and the directivity of the speaker unit itself is enhanced for the acoustic signal having the frequency of 2 mf or more. Therefore, high directivity can be obtained for all acoustic signals having a frequency of (2m-1) f or higher.

  A specific configuration of the speaker device according to the third embodiment will be described. In the third embodiment, for the n sets of speakers of the second embodiment, in addition to the sound signal of the frequency band obtained by frequency division from the band dividing unit with the center frequency as the center, (2m− 1) This is an example of a speaker device that also outputs an acoustic signal having a frequency more than doubled. The configuration other than the band dividing unit is the same as that of the second embodiment, and a description thereof is omitted.

  Hereinafter, an example in which n = 5 will be described. FIG. 8 is a perspective view showing the speaker device 8 of the third embodiment of the speaker device of the present invention, and the configuration and arrangement of the speaker unit are the same as those of the speaker device 4 of the second embodiment shown in FIG. Description is omitted. The speaker unit of the present embodiment is assumed to have the directivity shown in FIG.

  FIG. 9 is a block diagram of the speaker device 8. As shown in FIG. 9, the speaker device 8 includes a first band speaker set 8B1, a second band speaker set 8B2, a third band speaker set 8B3, a fourth band speaker set 8B4, and a fifth band speaker set. Five speaker sets 8Bn of 8B5 are provided.

  The input unit 90 sends the input acoustic signal to the band dividing unit 91. The band dividing unit 91 includes five sets of BPFs 911 to 915.

  FIG. 10a) shows the frequency characteristics of the acoustic signal output by the BPF 911. The BPF 911 outputs an acoustic signal 1001 in a frequency band centered on a frequency of 500 Hz to the supply unit 921 of the first band speaker set 8B1.

  Now, the frequency of an even multiple (2 m, where m is an integer of 2 or more) of the center frequency of 500 Hz of the acoustic signal supplied to the speaker set 8B1 is 2 kHz when m = 2. As can be seen from FIG. 7 a), in the speaker unit of this example, there is no half-value angle in front of the 2 kHz acoustic signal. On the other hand, when m = 3, the frequency 2m times 500 Hz is 3 kHz. As can be seen from FIG. 7 b), the speaker unit of this example has a half-value angle of directivity with respect to an acoustic signal having a frequency of 2.83 kHz of about 57 °. Since the half-value angle of the directivity for an acoustic signal having a frequency of 3 kHz is smaller than this, the half-value angle of the directivity for an acoustic signal having a frequency 2 m times 500 Hz is smaller than 60 ° when m = 3 or more. I understand that.

  Thus, for the speaker set 8B1, it is assumed that m = 3, and an acoustic signal having a frequency of 2.5 kHz or more, which is (2m−1) times 500 Hz, that is, 5 times, is output.

  Therefore, the BPF 911 supplies not only the acoustic signal 1001 in the frequency band centered on the frequency of 500 Hz but also the acoustic signal 1002 in the frequency band of 2.5 kHz or higher, which is five times the center frequency of 500 Hz, to the first band speaker set 8B1. Output to the unit 921.

  The supply unit 921 supplies the output acoustic signal as it is to the front speaker unit 8B1fr and the front speaker unit 8B1fl, and reverses the phase of the output acoustic signal to the rear speaker unit 8B1rr and the rear speaker unit 8B1fl. Supply. Further, the interval w1 between the front speaker unit 8B1fr and the front speaker unit 8B1fl and the rear speaker unit 8B1rr and the rear speaker unit 8B1rl is set to 0.34 m which is a half wavelength of the acoustic signal having the center frequency of 500 Hz.

  FIG. 10b) shows the frequency characteristics of the acoustic signal output by the BPF 912. The BPF 912 outputs an acoustic signal 1003 in a frequency band centered on a frequency 707 Hz that is 1/2 octave higher than the center frequency 500 Hz of the BPF 911 to the supply unit 922 of the second band speaker set 8B2.

  Now, the frequency of an even multiple (2 m, where m is an integer of 2 or more) of the center frequency 707 Hz of the acoustic signal supplied to the speaker set 8B2 is 2.8 kHz when m = 2. As described above, the speaker unit of this embodiment has a half-value angle of directivity with respect to an acoustic signal having a frequency of 2.8 kHz is about 57 ° and is smaller than 60 °. It can be seen that the half-value angle of the directivity is smaller than 60 ° when m = 2 or more.

  Therefore, it is assumed that m = 2 and an acoustic signal having a frequency of 2.1 kHz or higher, which is (2m-1) times 707 Hz, that is, 3 times, is output to the speaker set 8B2.

  Therefore, the BPF 912 supplies not only the acoustic signal 1003 in the frequency band centered on the frequency 707 Hz but also the acoustic signal 1004 in the frequency band of 2.1 kHz or higher, which is three times the center frequency 707 Hz, supplied to the second band speaker set 8B2. Output to the unit 922.

  The supply unit 922 supplies the output acoustic signal as it is to the front speaker unit 8B2fr and the front speaker unit 8B2fl, and reverses the phase of the output acoustic signal to the rear speaker unit 8B2rr and the rear speaker unit 8B2rl. Supply. Further, the interval w2 between the front speaker unit 8B2fr and the front speaker unit 8B2fl and the rear speaker unit 8B2rr and the rear speaker unit 8B2rl is set to 0.24 m which is a half wavelength of the acoustic signal having the center frequency of 707 Hz.

  FIG. 10c) shows the frequency characteristics of the acoustic signal output by the BPF 913. The BPF 913 outputs an acoustic signal 1005 in a frequency band centered on a frequency 1 kHz that is 1/2 octave higher than the center frequency 707 Hz of the BPF 912 to the supply unit 923 of the third-band speaker set 8B3.

  Now, the frequency that is an even multiple (2 m, where m is an integer of 2 or more) of the center frequency 1 kHz of the acoustic signal supplied to the speaker set 8B3 is 4 kHz when m = 2. As can be seen from FIG. 7c), the speaker unit of this example has a half-value angle of directivity of about 36 ° with respect to an acoustic signal having a frequency of 4 kHz, and is smaller than 60 °. It can be seen that the half-value angle of the directivity is smaller than 60 ° when m = 2 or more.

  Therefore, for the speaker set 8B3, it is assumed that m = 2 and an acoustic signal having a frequency of 3 kHz or more, which is (2m−1) times 1 kHz, that is, 3 times, is output.

  Therefore, the BPF 913 also supplies the acoustic signal 1005 in the frequency band of 3 kHz or more, which is three times the center frequency 1 kHz, in addition to the acoustic signal 1005 in the frequency band centered on the frequency 1 kHz, and the supply unit 923 of the third-band speaker set 8B3. Output to.

  The supply unit 923 supplies the output acoustic signal as it is to the front speaker unit 8B3fr and the front speaker unit 8B3fl, and reverses the phase of the output acoustic signal to the rear speaker unit 8B3rr and the rear speaker unit 8B3rl. Supply. Further, the interval w3 between the front speaker unit 8B3fr and the front speaker unit 8B3fl and the rear speaker unit 8B3rr and the rear speaker unit 8B3rl is set to 0.17 m which is a half wavelength of the 1 kHz acoustic signal.

  FIG. 10d) shows the frequency characteristics of the acoustic signal output by the BPF 914. The BPF 914 outputs an acoustic signal 1007 in a frequency band centered at a frequency of 1.4 kHz that is 1/2 octave higher than the center frequency of 1 kHz of the BPF 913 to the supply unit 924 of the fourth band speaker set 8B4.

  Now, the frequency of an even multiple (2 m, where m is an integer of 2 or more) of the center frequency of 1.4 kHz of the acoustic signal supplied to the speaker set 8B4 is 5.6 kHz when m = 2. As can be seen from FIG. 7d), the speaker unit of this example has a half-value angle of directivity with respect to an acoustic signal having a frequency of 5.6 kHz of about 25 °, which is smaller than 60 °. It can be seen that the half-value angle of the directivity with respect to the acoustic signal is smaller than 60 ° when m = 2 or more.

  Thus, for the speaker set 8B4, m = 2 and an acoustic signal having a frequency of 4.2 kHz or more, which is (2m-1) times 1.4 kHz, that is, 3 times, is output.

  Therefore, the BPF 914 also transmits an acoustic signal 1008 in a frequency band of 4.2 kHz or higher, which is three times the center frequency of 1.4 kHz, in addition to an acoustic signal 1007 in a frequency band centered on a frequency of 1.4 kHz. Output to the supply unit 924 of the set 8B4.

  The supply unit 924 supplies the output acoustic signal as it is to the front speaker unit 8B4fr and the front speaker unit 8B4fl, and reverses the phase of the output acoustic signal to the rear speaker unit 8B4rr and the rear speaker unit 8B4rl. Supply. Further, the interval w4 between the front speaker unit 8B4fr and the front speaker unit 8B4fl and the rear speaker unit 8B4rr and the rear speaker unit 8B4rl is set to 0.12 m which is a half wavelength of the acoustic signal having a center frequency of 1.4 kHz.

  FIG. 10e) shows the frequency characteristics of the acoustic signal output by the BPF 915. The BPF 915 outputs an acoustic signal 1009 in a frequency band centered on a frequency 2 kHz that is 1/2 octave higher than the center frequency 1.4 kHz of the BPF 914 to the supply unit 925 of the fifth band speaker set 8B5.

  Now, the frequency of an even multiple (2 m, where m is an integer equal to or greater than 2) of the center frequency 2 kHz of the acoustic signal supplied to the speaker set 8B5 is 8 kHz when m = 2. As can be seen from FIG. 7e), the speaker unit of this example has a half-value angle of the directivity with respect to an acoustic signal having a frequency of 8 kHz is about 17 ° and is smaller than 60 °. It can be seen that the half-value angle of the directivity is smaller than 60 ° when m = 2 or more.

  Therefore, for the speaker set 8B5, m = 2, and an acoustic signal having a frequency of 6 kHz or more, which is (2m-1) times 2 kHz, that is, 3 times, is output.

  Therefore, the BPF 915 supplies an acoustic signal 1010 in a frequency band of 6 kHz or more, which is three times the center frequency 2 kHz, in addition to the acoustic signal 1009 in the frequency band centered on the frequency 2 kHz, and the supply unit 925 of the fourth band speaker set 8B5. Output to.

  The supply unit 925 supplies the output acoustic signal as it is to the front speaker unit 8B5fr and the front speaker unit 8B5fl, and reverses the phase of the output acoustic signal to the rear speaker unit 8B5rr and the rear speaker unit 8B5rl. Supply. Further, the interval w5 between the front speaker unit 8B5fr and the front speaker unit 8B5fl and the rear speaker unit 8B5rr and the rear speaker unit 8B5rl is set to 0.085 m which is a half wavelength of the acoustic signal having the center frequency of 2 kHz.

  In the speaker device 8, the first band speaker set 8B1, the second band speaker set 8B2, the third band speaker set 8B3, the fourth band speaker set 8B4, and the fifth band speaker set 8B5 each have a center frequency. For a nearby acoustic signal, the same high directivity as in the second embodiment is exhibited due to the arrangement of the tone Zoire system. Moreover, high directivity is also shown, as shown in FIG. 6, for acoustic signals each having a center frequency of (2m-1) times. Furthermore, the speaker unit itself has high directivity with respect to an acoustic signal having a frequency of (2 m) or more times the center frequency. Therefore, each speaker set exhibits high directivity even when an acoustic signal of (2m-1) times or more of the center frequency is input in addition to the acoustic signal near the center frequency.

  Similarly to the second embodiment, the speaker device 8 of the present embodiment has a sufficiently high directivity because each speaker set bears an output of an appropriate frequency band. Furthermore, since n speaker sets having different left and right intervals are used for each appropriate frequency band, the speaker apparatus as a whole is a speaker apparatus having high directivity over a wide frequency band. Therefore, even when it is desired to output a sound source of a wider frequency band such as BGM (Back Ground Music), a sufficient directivity can be obtained.

  In addition, the speaker set in the speaker device 8 of the present embodiment exhibits high directivity by using four speaker units as in the first and second embodiments, and two speaker units in the horizontal direction. Since it is only necessary to arrange them with a width of approximately ½ wavelength, the size can be reduced as compared with the conventional speaker device.

  Furthermore, since the speaker device 8 of the present embodiment can output high-frequency acoustic signals in parallel by a plurality of speaker sets, it is possible to reduce the number of speaker sets responsible for high frequencies. For example, the speaker device 8 of the present embodiment omits the sixth band speaker set as compared with the speaker device 4 of the second embodiment. However, the sound signal in the frequency band output from the sixth-band speaker set of the second embodiment is output from another speaker set in the present embodiment. FIG. 10f) shows the frequency characteristics of the acoustic signals output from the BPFs 911 to 915 in an overlapping manner. Since the acoustic signals output by the BPFs 911 to 915 cover the entire frequency band, the speaker device 8 of this embodiment can output an acoustic signal in the same frequency band as the speaker device 4 of the second embodiment. it can. Thus, the speaker device 8 of the present embodiment can reduce the number of speaker sets and can be miniaturized.

  In the high frequency band where the speaker set is driven in parallel, the sound pressure rises compared to other bands, so the high frequency characteristics of the speaker should be adjusted in advance, or a high frequency attenuator, etc. Adjustment is preferred. Moreover, since the directivity of the speaker unit becomes sharper as the frequency of the output acoustic signal becomes higher, for example, LPF (Low Pass Filter) having a cutoff frequency of about 4 kHz is inserted in series in all or part of the speaker units. This may be reduced by doing so.

  Further, even if the interval wn between the speaker units is not exactly λn / 2, as in the first and second embodiments, the effect is obtained if 0.3λn ≦ wn <0.8λn. More preferably, if 0.45λn ≦ wn <0.75λn, a greater effect is achieved. In addition, it is effective even if the configuration is such that an acoustic signal in a frequency band that is an odd multiple of the center frequency is output by some speaker sets so that only a high frequency acoustic signal can be obtained without outputting it by all speaker sets. Play.

1, 4, 8 Speaker device 20, 50, 90 Input unit 51, 51n, 91, 91n Band division unit 21, 52n, 92n Supply unit 4Bn, 8Bn Speaker set 101, 102, 4Bnfr, 4Bnfl, 8Bnfr, 8Bnfl
Front speaker units 103, 104, 4Bnrr, 4Bnrr, 8Bnrr, 8Bnrr
Rear speaker unit 105, 41, 81 Shield plate

Claims (4)

A frequency band obtained by frequency-dividing the input acoustic signal and outputting an acoustic signal in a frequency band centered on the frequency f and an acoustic signal in a frequency band of (2m-1) f or more (m is an integer of 2 or more). A dividing section;
A first speaker unit having a diaphragm directed in a predetermined direction;
A speaker unit having a diaphragm directed in the predetermined direction, wherein the wavelength of the acoustic signal having the frequency f is λ, the diaphragm of the diaphragm with the first speaker unit in a direction orthogonal to the predetermined direction A second speaker unit having a center interval separated by a distance w of 0.3λ or more and less than 0.8λ,
A speaker unit having a diaphragm directed in a direction opposite to the predetermined direction, wherein a distance between a center of the diaphragm and the first speaker unit is separated by a predetermined distance d in a direction opposite to the predetermined direction. A third speaker unit,
A speaker unit having a diaphragm directed in a direction opposite to the predetermined direction, wherein the distance between the center of the diaphragm and the second speaker unit in the direction opposite to the predetermined direction is the predetermined distance d. A fourth speaker unit spaced apart;
A shielding plate provided between the first speaker unit and the second speaker unit, and the third speaker unit and the fourth speaker unit;
The first speaker unit and the second speaker unit are supplied with the sound signal divided by the band dividing unit in the same phase, and the first speaker is supplied to the third speaker unit and the fourth speaker unit. A speaker device comprising: a unit and a supply unit that supplies an acoustic signal having a phase opposite to the phase of the acoustic signal output to the second speaker unit. The m is
2. The speaker device according to claim 1, wherein a half-value angle of a frequency characteristic of the first, second, third, and fourth speaker units with respect to an acoustic signal having a frequency of 2 mf is m that is 60 ° or less. The speaker device according to claim 1, wherein the distance w is set to 0.45λ or more and less than 0.75λ. 4. The speaker device according to claim 1, wherein the first, second, third, and fourth speaker units are speaker units having the same characteristics.