JP2012093525A - Effector with speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effector with a speaker which is resistive to disturbance noise, achieves reduction in size, and has high-portability.SOLUTION: An electronic board 210 mounted with a signal processing circuit 1 and a speaker 70 fixed on the top face of a stage 220 erected on this electronic substrate 210 in such a manner that a circular sound emission face turns upward are incorporated in a case. A PWM section of the signal processing circuit 1 drives the speaker 70 by a pulse width modulation signal. Thus, an effect can be added without a D/A converter, and thus, a circuit system can be reduced in size, and even if this signal processing circuit is incorporated in the case, an effector with a speaker rich in portability can be realized.

Description

  The present invention relates to an improvement of an effector for adding an effect to a musical tone signal of a musical instrument such as a guitar signal.

  There is a device for converting a musical tone signal of a guitar inputted from the outside into an analog-to-digital format, adding various effects, and converting this to a digital-to-analog format and outputting it from a speaker. As one of the effects, there has been proposed an apparatus that adds a nonlinear effect, that is, a distortion effect by signal processing using a digital signal (see, for example, Patent Document 1). Generally, since the distortion effect does not satisfy the sampling theorem, a special signal processing has been devised. Then, this distortion effect is added to the guitar musical tone signal inputted from the outside, amplified and outputted.

US Pat. No. 5,789,689

  However, in the conventional apparatus, the digital signal is output from the speaker via the D / A converter after analog-digital conversion is once performed on the external musical sound signal and predetermined processing is executed. . That is, the digital signal that has been analog-to-digital converted by the A / D converter is always output after being converted from digital to analog by the D / A converter. For this reason, there is always a period in which the signal exists as an analog signal, and therefore, it is easily affected by external noise within this period. In addition, since an analog power amplifier is present after the D / A converter, heat is generated by this operation, so there is a limit to downsizing the apparatus. In addition, there are few speakers or the like that have a separate body or a large circuit system, and the effector is highly portable.

  The present invention has been made to solve such a conventional problem, and it is an object of the present invention to provide an effector with a speaker for a musical sound signal that is resistant to disturbance noise, can be reduced in size, and is portable.

In order to achieve the above object, the present invention is an apparatus having a substantially rectangular parallelepiped outer appearance that adds an effect to an externally input musical sound signal,
An electronic board (210) on which a signal processing circuit (1) is mounted, and a speaker (70) fixed to the upper surface of a stage (220) in the case so that a circular sound emitting surface faces upward. Built in,
The signal processing circuit (1)
An A / D converter (20) for analog-to-digital conversion of the musical sound signal, an effect adding unit (30) for adding a selected effect to the analog-digital converted signal, and an effect added signal are set. An EQ section (40) that is passed with frequency characteristics, a PWM section (50) that performs pulse width modulation according to a signal from the EQ section (40), and a first switch when the pulse width modulation signal is at a high level And a switching unit (60) for supplying a forward current to the speaker while closing a second switch and closing a second switch when the level is low. It was made to feature.

  According to the present invention, since the speaker is driven by the pulse width modulation signal, an effect can be added without the need for the D / A converter, and the circuit system can be reduced in size and this signal processing circuit can be used as a case. Even if it is built in, it is possible to realize an effector with a speaker that is highly portable.

According to the invention of claim 2, the position of the circular sound emitting surface of the speaker (70) built in the case is set to be the release of the case upper surface plate (200) which is a plate-like member on the upper surface of the case. Since it is built in so as to correspond to the sound hole portion (100), it is possible to make the sound from the speaker sufficiently heard. The invention according to claim 3 is fixed to the case lower surface plate (201) between the case upper surface plate (200) and the case lower surface plate (201) which is a plate-like member on the lower surface of the case. The vertically long rectangular parallelepiped columnar member (230) is erected and an elastic member (240) is provided between the upper portion of the columnar member (230) and the case upper surface plate (200). Therefore, it is possible to prevent resonance with the case when the speaker is sounded. Further, the invention according to claim 4 is preferable because the input analog signal is stabilized because the buffer unit (10) is provided in the signal processing circuit (1) before the A / D conversion unit (20). Further, as in the invention according to claim 5, instead of the PWM unit (50) and the switching unit (60), a delta sigma modulation unit that performs delta sigma modulation on the output from the EQ unit (40) The signal processing can also be realized by providing delta sigma modulation.

  According to the present invention, it is possible to achieve an effect of having a speaker for a musical sound signal that is strong against disturbance noise, can be reduced in size, and is highly portable.

1 is a configuration diagram of a signal processing circuit 1. FIG. It is a top view of an effector main body with a speaker. It is an AA arrow line view in FIG. It is explanatory drawing of the operation example of the EQ part 40. It is explanatory drawing of the signal of the PWM part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the signal processing circuit 1 mounted on the electronic substrate 210 will be described.

  The signal processing circuit 1 includes a buffer unit 10 that stabilizes an external input signal input from the outside at an amplification factor “1”, and an A / D conversion unit 20 that performs analog-to-digital conversion on an analog signal output from the buffer unit 10. An effect adding unit 30 for adding the selected effect, an EQ unit 40 for passing a digital signal with a set desired frequency characteristic, a PWM unit 50 for performing pulse width modulation, a switching unit 60, and a sound. And a speaker 70 for emitting sound.

  FIG. 4 is an explanatory diagram of an example of a change in frequency characteristics due to passage through the EQ unit 40. Before passing through the EQ section 40, a dotted line is shown, and with the set frequency characteristics, the level with respect to the frequency of the signal passing through the EQ section 40 is shown by a solid line. In this manner, the EQ unit 40 can perform signal processing such as high frequency band enhancement with a desired frequency characteristic.

  Now, the analog signal output from the buffer unit 10 is digitized by the A / D conversion unit 20, but the effect adding unit 30 produces effects (distortion, vibrato, tremolo, echo, etc.) selected by a foot switch described later. For example, it is configured to change the degree of effect addition by detecting the depression amount of the operation pedal described later. The signal to which the effect is added passes through the EQ unit 40 and is input to the PWM unit 50.

  For example, the PWM unit 50 looks at the digital signal sequence composed of “1” and “0” sequentially input from the EQ unit 40 at predetermined intervals, and sets the magnitude of the value indicated by the digital signal sequence in the predetermined cycle. Pulse width modulation for outputting a pulse with a corresponding duty ratio is performed. FIG. 5 is an explanatory diagram of pulse width modulation, and is configured to output a pulse train that rises from a low level, maintains a high level, and then goes to a low level from a signal having a wide pulse width PW1 to a signal having a narrow pulse width PW2. Has been.

In the switching unit 60, the pulse width modulation signal is supplied to the switch 61, while the signal obtained by inverting the pulse width modulation signal by the inverter 63 is supplied to the switch 62. When the pulse width modulation signal is at a high level, only the switch 61 is closed and a positive constant voltage (+ Vcc) is applied to supply a forward current to the speaker 70, whereas when the pulse width modulation signal is at a low level, the switch 62 is closed. A negative constant voltage (−Vcc) is applied to supply reverse current to the speaker 70. For the sake of explanation, a circuit using a negative voltage is shown, but in the case of a single power supply, an H bridge circuit may be used. Thus, the effect-added sound is amplified and emitted from the speaker 70. According to this, a D / A converter is not required and an effect-added sound can be generated, and the circuit system can be reduced in size and cost can be reduced as much as the D / A converter is unnecessary. In addition, an analog power amplifier is not required and the amount of heat generated is reduced, so that the circuit system can be further miniaturized. Instead of the PWM unit 50, a signal processing can also be realized by providing a delta-sigma modulation unit that performs delta-sigma modulation on the output from the EQ unit 40 and performing delta-sigma modulation. In this case, a sparse / dense signal corresponding to the magnitude of the value of the input digital signal sequence is generated.

  FIG. 2 is a plan view of the effector with a speaker. The planar view is a horizontally long rectangular shape and the appearance is a rectangular parallelepiped shape. Foot switches 81, 82, 83, and 84 are provided on the case top plate of the case of the effector with speaker, and four different effects are assigned to the foot switches 81, 82, 83, and 84, respectively. . Therefore, when any foot switch is depressed, a desired effect is added. Further, an input terminal 95 is provided, and a plug provided at the tip of a connection line with an instrument such as a guitar is inserted. Further, when the operation pedal 110 is depressed, the degree of effect addition changes. Further, although not shown, an effect operator 90 for adjusting various effect effects is provided. Two sound emitting holes 100 each having a large number of small holes are formed at positions corresponding to the two left and right speakers incorporated therein.

  3 is an AA arrow view of the plan view of FIG. That is, it is a schematic explanatory view of a cross-sectional view cut along a line AA. A space is provided between the case upper surface plate 200 that is the surface of the case of the apparatus main body that has a substantially rectangular parallelepiped appearance and the case lower surface plate 201 that is the back surface (bottom surface) of the case of the apparatus main body. The upper surfaces of the U-shaped fastening members 250 and 251 are fixed to the case upper surface plate 200 with screws 260 and 261, respectively. The electronic board 210 on which the signal processing circuit 1 is mounted is fixed to the lower surface of the U-shaped fastening members 250 and 251 with screws 263 and 262.

  Then, a stage 220 that is a rectangular parallelepiped externally in the depth direction of the drawing from the signal processing circuit 1 is erected from the electronic substrate 210, and a circular sound emitting surface is located above the planar upper surface. Thus, the speaker 70 is placed and fixed by adhesion. Since the circular sound emitting surface of the speaker 70 is incorporated so as to correspond to the position of the sound emitting hole 100 of the case upper surface plate 200, the sound from the speaker can be heard sufficiently well. .

  Further, between the case upper surface plate 200 and the case lower surface plate 201, a vertically long rectangular columnar member 230 which is bonded and fixed to the case lower surface plate 201 is erected, and the upper portion of the columnar member 230 and the case upper Since the sponge as the elastic member 240 is provided between the face plate 200, it is possible to secure the strength of the case against the stepping and to prevent the resonance with the case during speaker sounding.

  According to the embodiment described above, the circular sound emitting surface is fixed to the upper surface of the electronic substrate 210 on which the signal processing circuit 1 is mounted and the stage 220 erected on the electronic substrate 210 so as to face upward. The speaker 50 is built in the case. Since the speaker is driven by the pulse width modulation signal, an effect can be added without using the D / A converter, and the circuit system can be reduced in size and this signal processing circuit is built in the case. However, it is possible to realize an effector with a speaker that is highly portable.

  As described above, the present invention can be used in an apparatus that adds an effect to a musical sound signal.

DESCRIPTION OF SYMBOLS 10 Buffer part 20 A / D conversion part 30 Effect addition part 40 EQ part 50 PWM part 60 Switching part 70 Speaker 100 Sound emission hole 200 Case upper surface board 201 Case lower surface board 210 Electronic substrate 220 Stage 230 Columnar member 240 Elastic member 250 Fastening member 251 Fastening member

Claims (5)

A device that adds an effect to a musical sound signal input from the outside and has a substantially rectangular parallelepiped case,
An electronic board on which a signal processing circuit is mounted, and a speaker fixed to the upper surface of a stage in the case so that a circular sound emitting surface faces the upper part are incorporated in the case,
The signal processing circuit includes:
An A / D converter for analog-to-digital conversion of the musical sound signal, an effect adding unit for adding a selected effect to the analog-digital converted signal, and an EQ for passing the effect-added signal with a set frequency characteristic And a PWM unit that performs pulse width modulation according to the signal from the EQ unit, and when the pulse width modulation signal is at a high level, the first switch is closed to supply a forward current to the speaker. And a switching unit for closing the second switch and supplying a reverse current to the speaker when the level is reached. The effector with a speaker according to claim 1,
The position of the circular sound emitting surface of the speaker incorporated in the case is incorporated so as to correspond to the sound emitting hole portion of the case upper surface plate which is a plate-like member on the upper surface of the case. An effector with a speaker. In the effector with a speaker as described in any one of Claim 1 and 2,
Between the case upper surface plate and the case lower surface plate which is a plate-like member on the lower surface of the case, a vertically long rectangular parallelepiped columnar member fixed to the case lower surface plate is erected and an upper portion of the columnar member And an effector with a speaker, wherein an elastic member is provided between the case upper plate and the case upper plate. In the effector with a speaker as described in any one of Claims 1, 2, and 3,
In the signal processing circuit, an effector with a speaker, wherein a buffer unit is provided in front of the A / D conversion unit. The effector with a speaker according to any one of claims 1, 2, 3, and 4,
An effector with a speaker, characterized in that, in the signal processing circuit, a delta sigma modulation unit that performs delta sigma modulation on an output from the EQ unit is provided instead of the PWM unit.

Images