JP4826295B2 - Speaker system - Google Patents

Description

  The present invention relates to a speaker system having a structure in which a low frequency region and a high frequency region are controlled at the same directivity angle.

  The directivity of a speaker used in a speaker system (including a cabinet, a speaker unit, etc.) has different characteristics between a low frequency and a high frequency.

  For example, in a low-frequency sound (speaker diameter 77 mm, 1.25 kHz), circular directivity spreading over the whole can be obtained as shown in FIG.

  On the other hand, the directivity is narrowed as shown in FIG. 7 for high-frequency sound (speaker diameter 77 mm, 8 kHz).

  On the other hand, in a theater, a movie theater, a gymnasium, etc., as shown in FIG. 8, it is desirable to concentrate sound in an area (solid line) where spectators are present.

However, since the directivity is wide in the low frequency range, it extends to the dotted line area in FIG. For this reason, when the sound is concentrated in the area where the audience is present, a horn such as JP-A-6-133385 (Patent Document 1) is attached in front of the speaker unit, and the low-frequency sound, It controlled the directivity of the high range.
JP-A-6-133385

  However, since the lower the frequency range, the larger the horn must be attached, there is a problem that an appropriate large room and installation place are required and the cabinet itself becomes large.

  In addition, since the directivity shape does not change at high frequencies, there has been a problem that if a high frequency sound is collected in a target area, a horn having a different angle must be created.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a directional speaker system that can cover both a low range and a high range with respect to a predetermined area without using a horn.

  The present invention provides first and second frequency characteristics including a first reproduction frequency region having a first directivity angle and a second reproduction frequency region having a second directivity angle narrower than the first directivity angle. In a speaker system including a second speaker unit and a cabinet in which the first and second speaker units are attached to the front side,
  The cabinet is
  The first speaker unit and the second speaker unit are intersected with a central axis passing through the acoustic center of each speaker unit having an intersection on the back side of the cabinet, and symmetrical with respect to one plane including the intersection. Arranged to be
  The distance between the respective acoustic centers of the first and second speaker units in the first reproduction frequency range of the speaker system when at least each of the first and second speaker units is a point sound source. Determined by the directivity angle, the number of speaker units, and the wave number of sound,
  The second reproduction frequency of the speaker system when the first and second speaker units are used at the same angle formed by the plane and the central axes of the first and second speaker units. The directivity angle in the frequency range is determined to be substantially the same as the directivity angle in the first reproduction frequency range of the speaker system.
This is the gist.

  As described above, according to the present invention, both the low frequency region and the high frequency region can be controlled at the same directivity angle with respect to a desired area without attaching a horn to the front surface. Moreover, since a horn is not required, a cabinet can be reduced in size.

  In general, the directivity is wide in the low frequency range, so that it radiates to areas other than this area, for example, only in the audience area. Originally, even in the low and high ranges, it is very efficient to use only this area. For this reason, this invention made it possible to cover both a low region and a high region with two speakers.

  The speaker system of the present embodiment is preferably used as two stereo systems, an R side (right sound) speaker system and an L side (left sound) speaker system.

  In the present embodiment, the configuration on the R side will be described as an example.

  The speaker system of the present embodiment incorporates two speaker units and can control both low and high frequencies with the same directivity angle.

  For this reason, since it is not necessary to attach a horn to the front part of a speaker unit, a cabinet structure can be reduced in size and can be installed regardless of a place.

  Here, the directivity angle is defined. The directivity angle of the present embodiment refers to the directivity angle up to an angle where the sound pressure level is 6 dB lower than the value on the front axis.

  In addition, the low frequency region in the present embodiment refers to a frequency region where the directivity angle is 360 degrees, and the high frequency region is a frequency where the directivity angle is 120 degrees or less.

  FIG. 1 is a schematic configuration diagram of a speaker system according to the present embodiment. However, FIG. 1 excludes the upper cabinet.

  As shown in FIG. 1, the front side of the lower cabinet 1a of the speaker system 1 has a substantially isosceles triangle shape with a long bottom. In the lower cabinet 1a, the baffle face plate 2 integrated with the bottom plate 14 is provided vertically. The baffle face plate 2 has a right baffle face plate 2a and a left baffle face 2b with respect to the center (front shaft 18), and the center is formed at an included angle of about 120 degrees. The baffle face plates 2a and 2b constitute L-shaped wall faces 3a and 3b on the bottom side.

  Further, a bass reflex port plate 4 is provided so as to surround the L-shaped wall surface 3a of the baffle face plate 2a and the L-shaped wall surface 3b of the baffle face plate 2b. ing.

  Furthermore, speaker units 6 and 7 having a diameter of, for example, about 77 mm are attached to the baffle face plates 2a and 2b. The speaker units 6 and 7 are composed of center caps 8 and 9, cone vibration papers 10 and 11, magnets 12 and 13, and the like. Center axes 15 and 16 of the center caps 8 and 9 are front shafts 18 of the baffle face plate 2. Are attached to each other at an angle of about 30 degrees (for example, error ± 0.5 degrees).

  Further, screws 20 and 21 for connecting to the upper cabinet are provided at the connecting portion between the baffle face plate 2a and the L-shaped wall surface 3a, and at the connecting portion between the baffle face plate 2b and the L-shaped wall surface 3b. Further, the baffle face plate 2 is covered with a hatching net 23 having a vertex angle of about 120 degrees. Further, an input terminal 25 is provided.

  Here, the included angle (120 degrees) of the baffle face plate 2, the angle 30 degrees of the central axis 15 of the speaker unit 6 with respect to the front axis 18, the angle 30 degrees of the central axis 16 of the speaker unit 7, the speaker unit 6, 7 and the distance d between the acoustic centers will be described.

  In general, the acoustic center position of a speaker varies depending on the shape of the enclosure to which the speaker is attached, and the position also varies depending on the frequency. However, when the speaker aperture is sufficiently small compared to the wavelength, The center is good. The low frequency region in the present embodiment is a frequency at which the directivity angle is 360 degrees, and corresponds to the case where the size of the speaker is sufficiently small compared to the wavelength. Therefore, the distance d is between the centers of the opening surfaces of the speaker units 6 and 7. Distance.

  The aforementioned d is derived by calculating the following equation (1).

[Equation 1]
This formula is established theoretically. Reference: “Speaker System (above)” edited by Takeo Yamamoto, Radio Technology Co., Ltd. D = | sin ((nκd / 2) sinγ) / nsin ((κd / 2) sinγ) |
D: Directivity of point sound source In this case, 0.5 is substituted n: Number of speaker units In this case, 2 is substituted κ: Wave number γ: Angle from front axis of speaker unit In this case, 60 ° is substituted In the form, d was 110 mm when both the low frequency range and the high frequency range had a directivity angle of 120 degrees.

  After deriving d, the speaker units 6 and 7 are arranged at an interval of 110 mm, and then the speaker units 6 and 7 are arranged until the high frequency of the sound from the speaker units 6 and 7 reaches a desired directivity angle (120 degrees). The angle determined by inclining 7 is 30 degrees from the front axis 18.

  At this time, as shown in FIG. 2, it was possible to obtain directivity characteristics having a directivity angle of 112 degrees at a position of −6 dB from the speaker surface at a frequency of 1.25 kHz.

  Further, at a frequency of 8 kHz, as shown in FIG. 3, a wide directivity characteristic having a directivity angle of 128 degrees in the front direction was obtained.

  Based on this result, the included angle of the baffle face plate 2 shown in FIG. 1 is 120 degrees, the angle formed by the central axes 15 and 16 of the speaker units 6 and 7 and the front axis 18 is 30 degrees, and d is 110 mm. A speaker unit was constructed.

  Since the angles of the central axes 15 and 16 of the speaker unit 6 and the speaker unit 7 and the front axis 18 are 30 degrees, respectively, the angle is a quarter of the directivity angle of 120 degrees.

  That is, by incorporating two speaker units and tilting these speaker units by 30 degrees with respect to the front axis, the directivity angles of the low frequency range and the high frequency range can be controlled at substantially the same angle.

(1) Control of the low frequency region In a low frequency region where the directivity angle is 360 degrees with one speaker, two speakers are arranged at a distance d (110 mm in this case) derived from Equation 1. The directivity angle (about 120 to 128 degrees) could be controlled.

(2) High frequency range control With a single speaker, the directivity angle is very narrow (120 degrees or less in this case), so the sound axes of the two speakers face each other outward in the high frequency range. It was possible to expand the orientation angle (112 degrees).

  The speaker unit that sets the directivity angle in the low frequency region and the high frequency region to 120 degrees as the same angle by setting the angle of the speaker unit to 30 degrees with respect to the distance d between the two speakers and the front axis in (1) above. An arrangement structure could be obtained.

  Therefore, since a relatively wide directivity angle of 120 degrees can be obtained in the low frequency range and the high frequency range, there is no need for a horn for the low frequency range as in the prior art, and it is necessary to make a horn for the high frequency range. Absent. In addition, since the baffle face plate 2 has an angle of 120 ° and a directivity angle that can cover the low and high frequencies with two speaker units, it is not necessary to provide a low-frequency speaker, so the overall size is reduced. it can. Further, in the present embodiment, when the diameter of the speaker units 6 and 7 is 77 mm, the low frequency range is 1 KHz or less, and the high frequency range is 4 KHz or more.

  FIG. 4 is an external view of the speaker system of the present invention. FIG. 4A is a top view of the upper cabinet. FIG. 4B is a front view of the speaker system. FIG. 4C is a side view of the speaker system. FIG. 4D is a rear view of the speaker system. FIG. 4E is a top view on the lower cabinet side.

  As shown in FIG. 4, the upper cabinet 1b is provided with screws 28 (28a, 28b,...) With nuts for connecting to the lower cabinet 1a or for connecting to a mounting jig on the ceiling. In addition, speaker units with a diameter of 77 mm are provided on the left and right (one is not shown) on the front side of the speaker unit. Furthermore, as shown in the side view, a screw 26 with a nut for connecting the upper cabinet is provided. Furthermore, an input terminal is provided on the back surface.

  The speaker system of the present embodiment shown in FIG. 4 is very small because the height of the speaker units 6 and 7 is 77 mm, the height is 100 mm, the width is 366 mm, and the depth is 200 mm.

  That is, even in a small speaker system, a wide directivity angle can be obtained over a low range and a high range.

  FIG. 5 is an electric circuit diagram of the speaker system of the present embodiment. As shown in FIG. 5, hot lines 29a and 29b and return lines 30a and 30b are connected to the speaker units 6 and 7 of the baffle face plates 2a and 2b, respectively. The hot lines 29 a and 29 b are branched at the connection point 31 b and connected to the speaker units 6 and 7.

  The return lines 30a and 30b are branched at a connection point 31a and connected to the speaker units 6 and 7. Each of these lines has the same length. A protective circuit element 33 is provided between the connection point 31a and the input terminal 32a. The protection circuit 33 has a function of shutting off and returning again when an overcurrent flows.

  Sound signals (low frequency or high frequency) input from the input terminals 32a and 32b of the input terminal unit 25 are output to the speaker units 6 and 7 via the hot line. The speaker units 6 and 7 convert this sound signal into sound.

  At this time, since the central axes 15 and 16 of the speaker units 6 and 7 are at an angle of 30 degrees with respect to the front axis 18, they have a wide directivity of 120 degrees when the sound pressure level is reduced by 6 dB. . That is, both a low range and a high range are covered with a small speaker system.

  In the above embodiment, two speaker units are provided. However, two or more speaker units may be provided if necessary.

  Moreover, although the said embodiment demonstrated using the speaker unit whose aperture is 77 mm, an aperture may be 77 mm or more. However, when a speaker unit of 77 mm or more is used, the dimension of d is also increased.

It is explanatory drawing explaining the structure of the lower cabinet of this Embodiment, and arrangement | positioning of a speaker. It is explanatory drawing explaining the directivity characteristic of the low frequency area (1.2 kHz) in the speaker system of this Embodiment. It is explanatory drawing explaining the directional characteristic of the high frequency range (8 kHz) in the speaker system of this Embodiment. It is an external view of the speaker system of the present invention. It is an electric circuit diagram of the speaker system of the present embodiment. It is explanatory drawing explaining the directional characteristic of the low frequency range (1.2 kHz) of the speaker system of the conventional one speaker unit. It is explanatory drawing explaining the directional characteristic of the high frequency range (8 kHz) of the speaker system of the conventional one speaker unit. It is explanatory drawing explaining the acoustic area with respect to a spectator.

Explanation of symbols

1 Speaker system 1a Lower cabinet 1b Upper cabnet 2 Baffle face plate 2a Right baffle face plate 2b Left baffle face plate 4 Bass reflex port plate

Claims (1)

  First and second speakers having frequency characteristics including a first reproduction frequency region having a first directivity angle and a second reproduction frequency region having a second directivity angle narrower than the first directivity angle In a speaker system including a unit and a cabinet in which the first and second speaker units are attached to the front side,
  The cabinet is
  The first speaker unit and the second speaker unit are intersected with a central axis passing through the acoustic center of each speaker unit having an intersection on the back side of the cabinet, and symmetrical with respect to one plane including the intersection. Arranged to be
  The distance between the respective acoustic centers of the first and second speaker units in the first reproduction frequency range of the speaker system when at least each of the first and second speaker units is a point sound source. Determined by the directivity angle, the number of speaker units, and the wave number of sound,
  The second reproduction frequency of the speaker system when the first and second speaker units are used at the same angle formed by the plane and the central axes of the first and second speaker units. The loudspeaker system is characterized in that the directivity angle in the frequency range is determined to be substantially the same as the directivity angle in the first reproduction frequency range of the loudspeaker system.

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