JP2007006322A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker of which a configuration is simplified comparatively and which can obtain excellent acoustic characteristics by efficiently propagating vibration to a diaphragm and sufficiently vibrating the entire diaphragm. <P>SOLUTION: The present invention relates to a speaker 1 which discharges musical sound corresponding to a musical sound signal S and the speaker 1 comprises: a diaphragm 2; an attachment 4 provided on the diaphragm 2; and a vibrator 3 which is attached through the attachment onto the diaphragm 2 in the state of keeping a gap G1 with between the vibrator and the diaphragm 2, vibrates in response to the inputted musical sound signal S, radiates a sonic wave W generated by the vibration through the gap G1 onto the diaphragm 2 and discharges musical sound from the diaphragm 2 by vibrating the diaphragm 2. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a speaker that is used in an independent speaker unit, an electronic musical instrument, and the like and emits a musical sound.

  The present applicant has already proposed this type of speaker in, for example, Japanese Patent Application No. 2004-163668 (published publication is not issued). This speaker includes a diaphragm made of a single wood plate and two electromagnetic actuators (hereinafter referred to as “actuators”) directly attached to the diaphragm. This actuator is driven when a musical sound signal generated by an electronic musical instrument or the like is input, and vibrates the diaphragm. Thereby, a musical sound corresponding to the musical sound signal is emitted from the diaphragm.

  However, the above speaker has room for improvement in terms of efficiently vibrating the entire diaphragm and obtaining good acoustic characteristics. That is, in this speaker, the diaphragm is vibrated by two actuators directly attached to the diaphragm. As described above, since the vibration generated in a point shape by the actuator is propagated to the entire diaphragm, the vibration is not easily propagated to a position far from the actuator, and the entire diaphragm can be sufficiently vibrated. Therefore, good acoustic characteristics cannot be obtained. In particular, when the diaphragm is made of plywood or when the mass of the diaphragm is large, the acceleration vibration is difficult to propagate and tends to be insufficient, so the above problem becomes significant. In addition, since the actuator is directly attached to the diaphragm, in order to make the vibration of the actuator easy to propagate to the diaphragm as much as possible, the actuator is attached to the diaphragm with its contact surface pressed against the diaphragm appropriately. It is necessary to attach firmly, and the installation and adjustment of the actuator becomes complicated. For the same reason, there is a possibility that the acoustic characteristics may be adversely affected by noise components being mixed during the operation of the actuator.

  The present invention has been made to solve such problems, has a relatively simple configuration, and efficiently propagates vibrations to the diaphragm, and sufficiently vibrates the entire diaphragm. An object is to provide a speaker capable of obtaining characteristics.

  In order to achieve this object, the invention according to claim 1 is a speaker that emits a musical sound according to a musical sound signal, and includes a diaphragm, a mounting portion provided on the diaphragm, and a diaphragm. In the state where there is a gap, it is attached to the diaphragm via the attachment portion, and vibrates according to the input musical sound signal, and the sound wave generated by the vibration is radiated to the diaphragm via the gap. And a vibrator that emits a musical sound from the diaphragm by being vibrated.

  According to this speaker, the vibrator is attached to the attachment portion provided on the diaphragm, and a gap, that is, an air layer is formed between the vibrator and the diaphragm. The vibrator vibrates according to the input musical sound signal, and radiates sound waves generated thereby to the diaphragm via the air layer, thereby vibrating the diaphragm. Thereby, a musical sound corresponding to the musical sound signal is emitted from the diaphragm. As described above, since the sound wave according to the musical sound signal is propagated from the vibrator to the diaphragm with a planar spread through the air layer formed between the vibrator and the diaphragm, the vibration is efficiently transmitted to the diaphragm. And is efficiently and sufficiently propagated throughout the diaphragm. As a result, the entire diaphragm can be sufficiently vibrated, and excellent acoustic characteristics can be obtained. For this reason, it is possible to use a relatively inexpensive vibrator such as an electromagnetic actuator used in a loudspeaker, for example.

  In addition, since the diaphragm is vibrated through the air layer formed between the vibrator and the diaphragm, it is easy to attach and adjust the vibrator to the diaphragm, and the configuration of the speaker can be simplified. For the same reason, the diaphragm is vibrated through sound waves, so that the above-described mixing of noise components can be prevented.

  The invention according to claim 2 is characterized in that the speaker according to claim 1 further includes a differentiating circuit for differentiating the musical tone signal and then outputting it to the vibrator side.

  According to this configuration, the musical sound signal is differentiated by the differentiation circuit and then sent to the vibrator side. Since a musical tone signal is generally composed of amplitude information, the musical tone signal is converted into velocity information by differentiating the musical tone signal. The acoustic impedance of the vibrator can be expressed by an incomplete differentiation according to the thickness of the air layer between the vibrator and the diaphragm and the velocity of the sound wave. For this reason, by outputting a musical tone signal representing velocity information output from the differentiating circuit to the vibrator, a sound wave representing acceleration information obtained by differentiating the musical tone signal twice is emitted from the vibrator to the diaphragm. Then, when such a sound wave is propagated to the diaphragm, vibration including an acceleration component is propagated to the entire diaphragm. In this way, the sound signal is differentiated by the differentiation circuit and further differentiated by the sound wave emission from the vibrator, so that the acceleration vibration can be efficiently and sufficiently applied to the entire diaphragm, so that more excellent acoustic characteristics can be obtained. Obtainable.

  The invention according to claim 3 is a speaker that emits a musical sound according to a musical sound signal, the diaphragm, a metal plate attached to the diaphragm so as to extend along the diaphragm, the metal plate, and the input. And a vibrator that emits a musical sound from the diaphragm by vibrating according to the generated musical sound signal and transmitting the vibration to the diaphragm through a metal plate.

  According to this speaker, the metal plate is attached to the diaphragm, and extends along the diaphragm, and the vibrator is attached to the metal plate. The vibrator vibrates according to the input musical sound signal, the vibration propagates along the metal plate, spreads over the entire metal plate, and is further transmitted to the diaphragm via the metal plate. Thereby, the diaphragm vibrates, and a musical sound corresponding to the musical sound signal is emitted from the diaphragm. In this way, the vibration of the vibrator is propagated from the metal plate to the diaphragm with a linear spread, so that the vibration is efficiently given to the diaphragm and is efficiently and sufficiently propagated throughout the diaphragm. As a result, the entire diaphragm can be sufficiently vibrated, and excellent acoustic characteristics can be obtained. In addition, since a metal plate only needs to be added between the vibrator and the diaphragm, a speaker can be realized with a relatively simple configuration.

  According to a fourth aspect of the present invention, in the speaker according to the third aspect, the metal plate includes a main body portion attached to the diaphragm in a surface contact state, and a rising portion that rises from the main body portion and has the vibrator attached thereto. It is characterized by having.

  According to this configuration, since the vibrator is attached to the rising portion of the metal plate that rises in a non-contact state with the diaphragm from the main body, the rising portion is likely to vibrate due to the vibration of the vibrator. Further, since the main body portion of the metal plate is attached to the diaphragm in a surface contact state, vibration propagated from the rising portion can be efficiently transmitted from the contact surface with the main body portion to the diaphragm. As a result, vibration can be more efficiently propagated through the entire diaphragm, and the entire diaphragm can be further sufficiently vibrated, so that more excellent acoustic characteristics can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show a speaker 1 according to a first embodiment of the present invention. The speaker 1 is assembled as a speaker unit (not shown), and the speaker unit is built in an electronic musical instrument, an audio device, or the like, or is connected to these and used independently.

  As shown in FIG. 1, the speaker 1 includes a diaphragm 2, two electromagnetic actuators (hereinafter referred to as “actuators”) 3 and 3 (vibrators) that vibrate the diaphragm 2, and each actuator 3 on the diaphragm 2. Are composed of two mounting bolts 4 and 4 (mounting portions), two power amplifiers 5 and 5, two differential circuits 6 and 6, and the like.

  The diaphragm 2 is made of, for example, a single plate of natural wood such as Sitka spruce or spruce, or a wooden plate such as plywood, and is formed in a rectangular shape. The diaphragm 2 is formed with two front and rear bolt holes 7 (see FIG. 2) at two positions separated by a predetermined distance from both ends in the length direction.

  The actuator 3 is composed of, for example, an electromagnetic actuator used for a loudspeaker. As shown in FIG. 2, as shown in FIG. 2, a support plate 8, a ferrite magnet 9 attached to and supported by the lower surface of the support plate 8, and a ferrite magnet 9, a plurality of electromagnetic coils 10 (only two are shown) provided so as to oppose the left and right, a diaphragm 11 connected to these electromagnetic coils 10 and covering the ferrite magnet 9 from below, the ferrite magnet 9 and the diaphragm 11, a plurality of dampers 12 (only two are shown) provided between the two. The electromagnetic coil 10 is driven by being excited according to a musical sound signal S output from a musical sound reproducing device 16 such as an electronic musical instrument or an audio device, and the vibration of the electromagnetic coil 10 is transmitted to the diaphragm 11. The diaphragm 11 vibrates. Two bolt holes 8 a and 8 a are formed at the end of the support plate 8.

  The mounting bolt 4 is passed through the bolt hole 7 of the diaphragm 2 from below, and is fixed to the diaphragm 2 by tightening a nut 14 screwed into the mounting bolt 4 against the upper surface of the diaphragm 2. . A vibration isolator 13 made of hard rubber or the like is interposed between the head of the mounting bolt 4 and the lower surface of the diaphragm 2 and between the nut 14 and the upper surface of the diaphragm 2. Further, the upper end portion of the mounting bolt 4 is passed through the bolt hole 8a of the support plate 8, and the support plate 8 is sandwiched between two upper and lower nuts 15 and 15 which are screwed into the bolt hole 8a. As a result, the actuator 3 is attached to the diaphragm 2 via the attachment bolt 4, and a gap G <b> 1 (air layer) is formed between the diaphragm 2 and the actuator 3.

  The power amplifier 5 amplifies the musical sound signal S representing the amplitude information output from the musical sound reproducing device 16 with a predetermined gain, and then outputs the amplified signal to the differentiating circuit 6. The differentiating circuit 6 differentiates the amplified musical sound signal S to convert the amplitude information of the musical sound signal S into speed information, which is then output to the actuator 3. The actuator 3 vibrates according to the input musical sound signal S, and radiates a sound wave W from the diaphragm 11 to the air layer.

  The sound wave W is radiated from the actuator 3 in a state where the speed information of the musical sound signal S is converted into acceleration information for the following reason. The following equations (1) and (2) represent the sound pressure P and the particle velocity V at the position of the distance r from the actuator 3 when sound waves are emitted from the actuator 3 into the air, respectively.

ここで、ｋは波数、ρは音響インピーダンスのスカラ分、ｃは音速、Ａは体積速度である。したがって、このときの音響インピーダンス（＝Ｐ／Ｖ）Ｚは、次式（３）によって与えられる。また、波数ｋを角周波数ω／音速ｃで表し、角周波数の複素数ｊωをラプラス演算子ｓに置換した後、展開すると、音響インピーダンスＺは、式（４）のように表される。すなわち、音速ｃ／距離ｒに極を有する不完全微分で表すことができる。

Here, k is the wave number, ρ is a scalar component of acoustic impedance, c is the speed of sound, and A is the volume velocity. Therefore, the acoustic impedance (= P / V) Z at this time is given by the following equation (3). Further, when the wave number k is expressed by the angular frequency ω / sound speed c, the complex number jω of the angular frequency is replaced with the Laplace operator s, and then expanded, the acoustic impedance Z is expressed as in Expression (4). That is, it can be expressed by incomplete differentiation having a pole at the speed of sound c / distance r.

  As described above, the tone signal S representing the amplitude information is differentiated by the differentiating circuit 6 and then output to the actuator 3, so that the acoustic wave W representing the acceleration information obtained by differentiating the tone signal S twice from the actuator 3 is generated in the gap G 1. Radiated to the diaphragm 2 through the air layer.

  As described above, according to the present embodiment, the sound wave W corresponding to the musical sound signal S is transmitted from the actuator 3 to the diaphragm 2 via the air layer formed between the actuator 3 and the diaphragm 2. Since the propagation is performed with the spread, the vibration is efficiently given to the diaphragm 2 and is efficiently and sufficiently propagated to the entire diaphragm 2. As a result, the entire diaphragm 2 can be sufficiently vibrated, and excellent acoustic characteristics can be obtained.

  Further, by differentiating the musical sound signal S by the differentiating circuit 6 and further differentiating by the emission of the sound wave W from the actuator 3, the acceleration vibration can be efficiently and sufficiently applied to the entire diaphragm 2.

  Further, since the relatively inexpensive electromagnetic actuator used for the loudspeaker is used as the actuator 3, the speaker 1 can be configured at low cost. Further, since the diaphragm 2 is vibrated through the air layer, the attachment and adjustment of the actuator 3 to the diaphragm 2 are facilitated, and the configuration of the speaker 1 can be simplified. For the same reason, mixing of noise components can be prevented.

  3 and 4 show a speaker 21 according to a second embodiment of the present invention. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 3, the speaker 21 includes a diaphragm 2, two metal plates 22 and 22 attached to the diaphragm 2, and a first actuator 3 attached to each metal plate 22 (only one is shown). And a second actuator 23 attached to the diaphragm 2. At each end in the width direction of the diaphragm 2, five bolt holes 24 (only one is shown in FIG. 4) are formed at intervals in the length direction.

  The metal plate 22 is made of a metal (for example, steel) elongated angle member, and extends over the entire length of the diaphragm 2. As shown in FIGS. 3 and 4, the metal plate 22 has an L-shaped cross-sectional shape, and includes a main body portion 22a and a rising portion 22b that rises upward from the main body portion 22a at a right angle. In the main body 22a, five bolt holes 25 (only one is shown in FIG. 4) are formed at positions corresponding to the bolt holes 24 of the diaphragm 2. The metal plate 22 is fixed to the vibration plate 2 by bolts 26 and nuts 14 that are passed through the bolt holes 24 and 25 of the main body portion 22a of the vibration plate 2 and the metal plate 22 from below.

  The first actuator 3 is for providing acceleration information of the musical sound signal S, and is arranged at a position away from one end of each metal plate 22 by a predetermined distance. As shown in FIG. 4, the first actuator 3 is connected to the rising portion 22 b and the main body portion 22 a of the metal plate 22 via the mounting brackets 27 and 27 having an L-shaped cross section at the upper end portion and the lower end portion of the support plate 8. It is fixed. Thereby, a gap G <b> 2 is formed between the diaphragm 11 of the first actuator 3 and the metal plate 22. The first actuator 3 is connected to the musical sound reproducing device 16 via the power amplifier 5 and the differentiation circuit 6.

  The second actuator 23 is for giving amplitude information of the musical sound signal S, is configured in the same manner as the first actuator 3, and is directly attached to the upper surface of the diaphragm 2. As shown in FIG. 3, the second actuator 23 is disposed at a position away from one end of the diaphragm 2 by the same distance as the first actuator 3. The second actuator 23 is connected to the musical sound reproducing device 16 only through the power amplifier 5.

  With the above configuration, the musical sound signal S representing the amplitude information output from the musical sound reproducing device 16 is amplified to a predetermined gain by the power amplifier 5 and then output to the second actuator 23 and the differentiating circuit 6. The second actuator 23 vibrates according to the input musical sound signal S, and vibrates the diaphragm 2 directly by the vibration. Further, the differentiating circuit 6 differentiates the input musical sound signal S and outputs it to the first actuator 3. Accordingly, the first actuator 3 emits a sound wave W representing acceleration information obtained by differentiating the musical sound signal S twice to the metal plate 22 through the gap G2. The metal plate 22 is vibrated by the radiated sound wave W, and the vibration propagates along the length direction of the metal plate 22 (arrow A) and spreads throughout the metal plate 22. In this way, the vibration that spreads over the entire metal plate 22 is further transmitted to the diaphragm 2 from the main body 22a that is in surface contact with the diaphragm 2 (arrow B).

  If the mechanical impedance of the metal plate 22 is Zm and the mechanical impedance of the diaphragm 2 is Zo, these mechanical impedances Zm and Zo are calculated by dividing the pressure P by the particle velocity V (= P / V), respectively. Is done. Further, since the pressure P and the particle velocity V depend on the elastic moduli of the metal plate 22 and the diaphragm 2, respectively, the mechanical impedance Zm of the metal plate 22 and the mechanical impedance Zo of the diaphragm 2 have different characteristics. Yes. For this reason, at the boundary surface where the main body portion 22a of the metal plate 22 is in surface contact with the vibration plate 2, vibration from the first actuator 3 is transmitted to the vibration plate 2 while causing phenomena such as reflection, transmission, and bending. Thus, the acceleration vibration can be efficiently and sufficiently applied to the diaphragm 2.

  5 to 7 show the measurement results of the frequency characteristics of the diaphragm 2 at positions near the first and second actuators 3 and 23 (hereinafter referred to as “near positions”), and FIGS. 8 to 10 show the first and second actuators. 2 shows the measurement results of the frequency characteristics of the diaphragm 2 at positions far from the actuators 3 and 23 (hereinafter referred to as “far positions”). Of these drawings, FIGS. 5 and 8 show that both of the first and second actuators 3 and 23 are driven, and FIGS. 6 and 9 show FIG. 7 when only the first actuator 3 is driven. FIG. 10 and FIG. 10 respectively show the case where only the second actuator 23 is driven.

  As is clear from these figures, the case where both the first and second actuators 3 and 23 are driven (FIGS. 5 and 8) and the case where only the first actuator 3 is driven (FIGS. 6 and 9) are compared. Then, in a higher frequency band, that is, a band with a lot of acceleration components, an equivalent sound pressure level is obtained at both the near position and the far position. On the other hand, when only the second actuator 23 is driven (FIGS. 7 and 10), the sound pressure level is greatly attenuated in both the near position and the far position in the band having a large acceleration component.

  Further, comparing the frequency characteristics of the near position and the distant position when both the first and second actuators 3 and 23 are driven (FIGS. 5 and 8), the sound pressure level in the band having a large acceleration component at the distant position. Is slightly attenuated. This is the same when only the first actuator 3 is driven (FIGS. 6 and 9). On the other hand, when only the second actuator 23 is driven, the sound pressure level in a band with a lot of acceleration components is greatly attenuated at a distant position (FIGS. 7 and 10).

  From the above results, when the first and second actuators 3 and 23 are used in combination, the diaphragm 2 is not only near the first and second actuators 3 and 23 but also far from the first and second actuators 3 and 23. It was confirmed that can be vibrated sufficiently.

  As described above, according to the present embodiment, the rising portion 22 b easily vibrates due to the vibration of the first actuator 3, and the vibration is propagated along the length direction of the metal plate 22. Further, since the main body portion 22a is attached to the diaphragm 22 in a surface contact state, the vibration propagated from the rising portion 22b is efficiently transmitted to the diaphragm 2 from the contact surface with the main body portion 22a with a linear spread. be able to. As a result, the vibration can be efficiently propagated through the entire diaphragm 2, and the entire diaphragm 2 can be sufficiently vibrated, and excellent acoustic characteristics can be obtained. Further, since the acceleration information is given to the metal plate 22 by the first actuator 3, the acceleration vibration can be given to the diaphragm 2 efficiently and sufficiently.

  Further, since only the metal plate 22 needs to be added between the diaphragm 2 and the first actuator 3, the speaker 21 can be realized with a relatively simple configuration. Further, by using the first and second actuators 3 and 23 together, the diaphragm 2 can be moved not only near the first and second actuators 3 and 23 but also at a position far from the first and second actuators 3 and 23. It can be vibrated sufficiently, and more excellent acoustic characteristics can be obtained.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the differentiating circuit 6 is provided between the power amplifier 5 and the actuator 3, but may be provided between the musical sound reproducing device 16 and the power amplifier 5. In the embodiment, the diaphragm 2 is made of wood, but is not limited thereto, and may be made of, for example, acrylic or another metal having mechanical impedance characteristics different from that of the metal plate 22. Further, in the second embodiment, the first actuator 3 is attached so as to straddle the main body portion 22a and the rising portion 22b of the metal plate 22, but may be attached only to the rising portion 22b. In the second embodiment, the first actuator 3 is attached to each metal plate 22 and the second actuator 23 is attached to the vibration plate 2 one by one. However, the number is not limited to this, and the number is arbitrary. In addition, it is possible to appropriately change details within the scope of the present invention.

1 is a perspective view of a speaker according to a first embodiment of the present invention. It is the elements on larger scale of the speaker of FIG. It is a perspective view of the speaker by 2nd Embodiment of this invention. It is the elements on larger scale of the speaker of FIG. FIG. 4 is a diagram illustrating frequency characteristics of the diaphragm in the vicinity of the actuator when both the metal plate and the actuator provided on the diaphragm are driven in the speaker of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of a diaphragm near the actuator when only the actuator provided on the metal plate is driven in the speaker of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of the diaphragm in the vicinity of the actuator when only the actuator provided on the diaphragm is driven in the speaker of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of the diaphragm at a position far from the actuator when both the metal plate and the actuator provided on the diaphragm are driven in the speaker of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of a diaphragm at a position far from the actuator when only the actuator provided on the metal plate is driven in the speaker of FIG. 3. FIG. 4 is a diagram illustrating frequency characteristics of the diaphragm at a position far from the actuator when only the actuator provided on the diaphragm is driven in the speaker of FIG. 3.

Explanation of symbols

1 Speaker 2 Diaphragm 3 Actuator (vibrator)
4 Mounting bolt (Mounting part)
6 Differentiating circuit 21 Speaker 22 Metal plate 22a Main body 22b Rising part G1 Gap S Music signal W Sound wave

Claims (4)

A speaker that emits a musical sound according to a musical sound signal,
A diaphragm,
A mounting portion provided on the diaphragm;
Attached to the diaphragm via the attachment portion with a gap between the diaphragm and the diaphragm, vibrates according to the input musical sound signal, and generates sound waves generated by the vibration through the gap. A vibrator that emits a musical sound from the diaphragm by radiating the diaphragm through the diaphragm and vibrating the diaphragm;
A speaker comprising:   The speaker according to claim 1, further comprising a differentiating circuit that differentiates the musical sound signal and outputs the differentiated sound signal to the vibrator side. A speaker that emits a musical sound according to a musical sound signal,
A diaphragm,
A metal plate attached to the diaphragm so as to extend along it,
A vibrator that is attached to the metal plate, vibrates according to the input musical sound signal, and transmits the vibration to the vibration plate through the metal plate, thereby emitting a musical sound from the vibration plate;
A speaker comprising:   The said metal plate has a main-body part attached to the said vibration plate in the surface contact state, and the rising part which stood | started from the said main-body part and to which the said vibrator | oscillator was attached is characterized by the above-mentioned. Speaker.

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