Patent Application
20210233503
The present invention relates to a method for controlling an effect applying device for applying an acoustic effect to a sound signal, and an effect applying device.
As an example of a speaker capable of modulating an input sound signal and applying a special acoustic effect, a rotary speaker disclosed in Patent Literature 1 is given. The rotary speaker has a speaker horn rotationally driven by an electric motor or the like in a speaker box. For example, when the speaker horn approaches an audience through rotational driving, the frequency of sound emitted from the speaker horn gradually increases due to the Doppler effect, and the volume of the sound gradually increases. Conversely, when the speaker horn moves away from the audience, the frequency of the sound emitted from the speaker horn gradually decreases due to the Doppler effect, and the volume of the sound gradually decreases. In addition to this, a complex acoustic effect corresponding to the shape of the speaker or the horn is applied to the sound. Hereinafter, both the acoustic effect applied to the sound by the rotary speaker and the acoustic effect obtained by simulating the rotary speaker through signal processing are referred to as a “rotary speaker effect”.
In general, in a rotary speaker, the rotation speed of a speaker horn can be switched between two levels, high speed and low speed, according to a user operation performed on a switch or the like. A rotary speaker is often used to apply an acoustic effect to a sound played by an electric organ, a guitar, or the like, and a user of the rotary speaker, such as a performer of an electric organ, performs while switching the rotation speed of a speaker horn through a switch operation.
Patent Literature 1: Specification of U.S. Pat. No. 2,489,653
In recent years, various techniques for simulating the rotary speaker effect through signal processing have been proposed. Ina rotary speaker, there is a delay from when speed switching is instructed until when the rotation speed of the speaker increases, and it is desirable to also reproduce this delay from the viewpoint of reality. In the simulation of the rotary speaker effect, when the rotation speed value (the parameter corresponding to the rotation speed) is changed after being delayed due to the switch operation, no change occurs in the sound immediately after the switch operation, and thus it has been found that there is a problem in that it is difficult for the user to realize that the rotation speed has been switched. In a physical rotary speaker, immediately after performing a switch operation, the user can feel the speed switch from a change in the driving noise of an electric motor, a subtle variation of the performance sound caused by a change in the driving power of the electric motor, and the like. However, such a change and variation have not been taken into consideration in the mode of simulation realized by conventional signal processing.
The present invention has been made in view of the above-described circumstances, and provides an effect applying device for a rotary speaker effect, which enables a user to immediately feel switching of a rotation speed value when a switching operation of the rotation speed value is performed.
In order to solve the above issues, the present invention provides a control method of an effect applying device for applying a rotary speaker effect corresponding to a rotation speed value to a sound signal and controlling a tone color of the sound signal, the control method including: in response to a speed change command, gradually changing the rotation speed value from a first speed at that point in time to a second speed higher than the first speed, and changing control of the tone color from a first characteristic to a second characteristic that is different in tone color from the first characteristic, prior to the change in the rotation speed value.
In a control method according to a more preferable aspect, the second characteristic is more pronounced in the high frequency range than the first characteristic.
In the control method according to the preferable aspect, in response to the speed change command, the rotation speed value is gradually changed from the first speed to the second speed in accordance with a first change curve having a predetermined first delay.
In a control method according to a further preferable aspect, in response to the speed change command, the control of the tone color is gradually changed from the first characteristic to the second characteristic in accordance with a second change curve having a second delay shorter than the first delay.
In the control method according to the further preferable aspect, the change in the control of the tone color is synchronized with the change in the rotation speed value.
In the control method according to the further preferable aspect, the control of the tone color is performed by at least one of: (1) a filter that increases or decreases a high frequency component of a sound signal; (2) nonlinear conversion of a sound signal; (3) addition of a noise component; and (4) selection of a different sound signal.
In order to solve the above issues, the present invention provides an effect applying device including: a signal processing unit configured to apply a rotary speaker effect corresponding to a rotation speed value to a sound signal and control a tone color of the sound signal; and a control unit configured to, in response to a change command of the rotation speed value, gradually change the rotation speed value from a first speed to a second speed higher than the first speed with a first change curve having a first delay, and gradually change control of the tone color from a first characteristic to a second characteristic that is different in tone color from the first characteristic with a second change curve having a second delay shorter than the first delay.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A: Embodiment
As shown in
The control unit 10 is a program execution unit such as a CPU or a microcomputer. The control unit 10 functions as a control center of the device 1 by executing a control program 62 stored in the nonvolatile storage unit 60. Hereinafter, the control unit 10 operating according to the control program 62 is referred to as “control unit 10′”. As shown in the functional block diagram of
The external device I/F unit 20 is an aggregate of interface circuits for connecting external devices such as a sound source circuit and a speaker. Although specific illustrations are omitted in
The user I/F unit 30 includes an operation element operated by the user of the device 1, and the operation content of the user with respect to the operation element is transmitted from the user I/F unit 30 to the control unit 10. The user of the device 1 refers to a performer who plays the device 1. Specific examples of the operation elements included in the user I/F unit 30 include a performance operation element 31 for the user to perform a performance operation, and a speed changeover switch 32 for the user to give an instruction to change the rotation speed value. In
The signal processing unit 40 is, for example, an SPU (Signal Processing Unit). As shown in
The second effector 44 performs, on the sound signal X2, signal processing for controlling the tone color, and outputs a sound signal X3 resulting from the processing to the D/A converter of the external device I/F unit 20. The second effector 44 of the present embodiment uses one high shelving filter in which the control band is set to a high frequency band (several k to around a dozen kHz), adjusts the signal components of that band of the sound signal X2 in accordance with the gain G instructed by the control unit 10, and executes processing for outputting the adjusted sound signal X3.
The volatile storage unit 50 is a RAM, for example. The volatile storage unit 50 is used by the control unit 10 as a work area when the control program 62 is executed. The nonvolatile storage unit 60 is a flash ROM or a hard disk, for example. The control program 62 is stored in advance in the nonvolatile storage unit 60. The control unit 10 reads the control program 62 from the nonvolatile storage unit 60 to the volatile storage unit 50, in response to power-on or the like of the device 1, and starts execution of the control program 62.
The control unit 10′ executes a control method that remarkably shows the characteristics of the present invention. More specifically, the control unit 10′ executes the periodic processing shown in
In step SA110 subsequent to step SA100, the control unit 10′ determines the value of the variable SS. When it is determined that the value of the variable SS is “0” and the first speed VL is selected by the speed SW32, the control unit 10′ decreases the value of the index t indicating the degree of change in the rotation speed value by Δt0 toward the minimum “0” (step SA120). The decrease in the index t stops when the value becomes “0”. Conversely, when it is determined that the value of the variable SS is “1” and the second speed VH is selected, the control unit 10′ increases the value of the index t toward the maximum value “1” by Δt1 (Δt0 and Δt1 are sufficiently smaller values than 1, and Δt0>Δt1) (step SA130). The increase in the index t stops when the value becomes “1”. That is, the index t is a value that changes in the range of 0 to 1. For example, as shown in
In step SA120 or step SA140 subsequent to step SA130, the control unit 10′ calculates the rotation speed value SV of the virtual rotary speaker and the gain G for controlling the high frequency component of the sound signal according to the value of the index t calculated in step SA120 or step SA130, and further calculates the virtual speaker position SP as the integrated value of the past the rotation speed values SV. Then, in step SA150 subsequent to step SA140, the control unit 10′ provides the rotation speed value SV and the speaker position SP generated in step SA140 to the first effector 42, and provides the gain G generated in step SA140 to the second effector 44.
As shown in the functional block diagram of
For example, when the rotation speed value is increased in response to the LH change command, the generation unit 12 calculates the rotation speed value SV that gradually changes from the first speed VL to the second speed VH, in accordance with a first change curve GP1 (see
In parallel with this, the generation unit 12 calculates the gain G of the high frequency component according to the index t and the second change curve GP2 (see
Because the curve GP2 has the delay D2, the high frequency component of the sound signal starts to increase with a delay corresponding to the delay D2 from the point in time when the LH change command is provided. Here, because the delay D2 is smaller than the delay D1, in the present embodiment, after the LH change command is provided, the tone color of the sound changes before the rotation speed value of the rotary speaker effect applied to the sound changes. The user of the device 1 can perceive that a slight change in the tone color of the sound from the speaker provides an instruction to switch the rotation speed value and the rotation speed value changes. Because the rotation speed value is switched from the low speed to the high speed mainly when invigorating a performance, it is preferable to increase the high frequency component of the sound to make the tone color splendid. It can also be said that the second delay D2 is defined by the second change curve GP2.
It is important that there is a difference in delay time between the curve GP1 and the curve GP2. The shape of the curve GP1 is preferably the shape of a change curve measured in the physical rotary speaker or a shape imitating the change curve. The shape of the curve GP2 is not so crucial, and may be the same as or different from the curve GP1. If it is desired that the switching can be clearly perceived by the user, the maximum inclination of the curve GP2 may be increased. On the other hand, if it is desired to make the switching less noticeable to the user, the maximum inclination may be reduced.
In addition, in the device 1 of the present embodiment, the tone color is changed in synchronization with and prior to the change in the rotation speed value in response to the switching operation. Here, because the value of the first change curve GP1 and the value of the second change curve GP2 change in accordance with the common index t, and these two values have a correspondence relationship with each other, accordingly the change in the rotation speed and the change in the tone color are synchronized with each other. In this manner, it is possible to cause the user to perceive a change in the rotation speed value (switching from low speed to high speed) through a change in the tone color (increase in the high frequency component) without much of a delay from the switching operation. The change in tone color (increase in the high frequency component) when the rotation speed value is increased corresponds to the user's intention to enhance the performance. The basic operation is the same when the user turns off the speed SW32 and instructs switching of the rotation speed value from the second speed VH to the first speed VL (the HL change command). That is, as shown in
As described above, according to the device 1 of the present embodiment, it is possible to electrically simulate the rotary speaker effect while maintaining a realistic auditory sense and make the user realize that speed switching has been performed.
B: Other Embodiments
Although one embodiment of the present invention has been described above, the following embodiments are conceivable in addition to the above embodiment.
(1) Although the device 1 of the above-described embodiment is an electronic musical instrument, the device 1 may also be a single effector that includes a first effector, a second effector, and a control unit thereof and applies a rotary speaker effect to an analog sound signal from an external musical instrument such as an electric guitar, an electric organ, or a synthesizer. In this case, the effector 1 analog-to-digital converts an analog sound signal from the external musical instrument using an AD converter inside the effector 1, and obtains the digital signal X1 shown in
(2) In the above embodiment, the change curves (GP1 and GP2) when the rotation speed value is switched from the first speed VL to the second speed VH and the change curves (GP3 and GP4) when the rotation speed value is switched from the second speed VH to the first speed VL have the same curve shape (delay times are different from each other). However, curves having different shapes may be used in the former case and the latter case. Specifically, in order to reduce the rotation speed value, the rotation speed value may be generated in accordance with a change curve GP3′ in which the start of falling from the second speed VH is earlier than that of the first change curve GP1 and the gradual approach to the first speed VL is gentler than that of the first change curve GP1. In a physical rotary speaker, in the deceleration of the rotation speed, the rotation speed starts to decrease without delay from the point in time of the switching operation (compared with the acceleration), and it takes a long time until the rotation speed stabilizes at the speed VL. Note that the same change curve may be used for the delay of gain G, regardless of whether or not the change curve used for the delay of the rotation speed value is different. In short, any mode may be employed as long as the change in the tone color is synchronized with the change in the rotation speed value. In the above embodiment, the rotation speed value changes from the speed VL (or VH) to the speed VH (or VL) in response to the LH change command (or the HL change command). When the HL change command (or the LH change command) is received in the middle of a change, the direction of the change may be reversed at that point in time, and the speed VX at that point in time may be changed to the speed VL (or VH). In this case, the time t is set to “1” (or “0”) at the time of reverse, and the change curve GP3 (or GP1) and the change curve GP4 (or GP2) may be newly prepared according to the rotation speed value and the gain G at that point in time.
(3) In the above embodiment, the control of tone color of the sound signal to which the rotary speaker effect is applied is realized by the filtering process of increasing or decreasing the high frequency component of the sound signal. However, the control of tone color of the sound signal to which the rotary speaker effect is applied may be realized by nonlinear conversion of the sound signal, addition of a noise component, or selection of a different sound signal, or may be realized by any combination of a plurality of these. Here, the nonlinear conversion is signal processing in which a sound signal is nonlinearly converted and an overtone component is added. The amount of the overtone component to be added can be controlled by changing the shape of the conversion curve. In addition of the noise component, it is preferable to generate high frequency noise having characteristics related to the sound signal and add the high frequency noise to the sound signal. In the selection of the sound signal, as the sound signal generated by the sound source 41, a sound signal having different content of a high frequency component is selected from among sound signals of the same type. In this case, because the sound control according to the gain G is performed by the sound source 41, the effector 44 is included in the sound source 41. Further, in the above embodiment, the control of the tone color is changed from the first characteristic to the second characteristic that is more pronounced in the high frequency range than the first characteristic in response to the LH change command. However, the second characteristic is not limited to a more pronounced characteristic in the high frequency range than the first characteristic, and may be a characteristic different in tone color from the first characteristic. If at least the first characteristic and the second characteristic are different in tone color, the user can perceive the difference.
(4) The rotation speed value and gain generation unit 12 and the speaker position generation unit 14 in the above embodiment are pieces of software executed by the control unit 10, but may be a hardware logic circuit or an FPGA. The signal processing unit 40 may be a DSP or an FPGA. Alternatively, the signal processing unit 40 may be configured by the CPU of the control unit 10.
(5) In the above embodiment, the control program 62 for realizing the control method according to the features of the present invention is stored in advance in the nonvolatile storage unit 60. However, the control program 62 may be distributed written in a recording medium such as a CD-ROM, or the control program 62 may be distributed via a line such as the Internet.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-194885 | Oct 2018 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2019/040300 | Oct 2019 | US |
| Child | 17231567 | US |
