JP3433483B2 - Effect device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a filter including a delay (delay circuit) such as a comb filter to change the frequency spectrum of a musical tone signal, and flanges the musical tone signal. The present invention relates to an effect device for providing an effect such as a ling effect. 2. Description of the Related Art Various types of effect devices for giving an effect to a musical tone signal have been put into practical use, and among them, there is an effect device called a flanger.
The flanger is an effect device using a comb filter including a delay, and is a device that changes the timbre of a musical tone by changing the delay time of the comb filter every moment. By passing a tone signal through this comb filter, a tone effect such as a rising and falling sound of a jet can be created. FIG. 8 shows a block diagram of a conventional flanger. This flanger is of the digital type, and the read address of the RAM constituting the delay is set to LFO.
(Low-frequency oscillator) moves periodically to produce a flanging effect. [0003] However, such a conventional flanger cannot reflect the player's intention in real time and has a low frequency output by the LFO irrespective of the input tone signal. Only the flanging effect of a fixed period by the signal could be obtained, and it was monotonous. An object of the present invention is to provide an effect device that can arbitrarily control a change in delay time of a filter including a delay. According to the present invention, as shown in FIG. 1, a filter B including a delay A for filtering an inputted musical tone signal, and the delay B according to the level of the inputted musical tone signal are provided. Delay time control means C for controlling the delay time of A
It is characterized by having. In FIG. 1, an input tone signal is input to a filter B including a delay A. The tone signal is selectively emphasized / attenuated by the filter B by the filter B, and the frequency spectrum is changed (the tone is changed).
Is output. The delay time control means C controls the delay time of the delay A according to the level of the tone signal. Delay A
When the delay time changes, the filtering characteristic of the filter B changes, so that the degree of change of the frequency spectrum also changes, and the timbre of the output tone signal also changes. As described above, since the filtering characteristics of the filter B change in accordance with the level change of the input tone signal, the change of the tone becomes easy to hear in conjunction with the level change of the tone signal. Also, the player can control the magnitude of the timbre change by manipulating his own sounding level. FIG. 2 is a block diagram of an effect device according to an embodiment of the present invention. This effect device is an effect device called a flanger. The delay 3 corresponds to the delay A in FIG. 1, and the adder 2, the delay 3 and the coefficient multiplier 4 correspond to the filter B in FIG. Further, the level detection circuit 5 and the coefficient multiplier 6 correspond to the delay time control means C. A digital tone signal (original tone signal) input from the outside is applied to an amplifier 1, a level detection circuit 5 and a coefficient multiplier 9. The signal amplified by the amplifier 1 is provided to the delay 3 via the adder 2. Delay 3
Is composed of a RAM, which writes the data of the musical tone signal to a write address to be sequentially added in accordance with a sampling clock, and reads the data from a read address delayed by a predetermined number from the write address. The read data is input to the coefficient multiplier 4 and the coefficient multiplier 7. The coefficient multiplier 4 multiplies the input signal by a coefficient Feedback for setting a feedback amount, and returns the multiplied signal to the adder 2. The coefficient multiplier 7 has a coefficient Effect Level for determining the strength of the flanging effect.
Is multiplied by the signal and output to the adder 8. On the other hand, the original sound signal is also input to the adder 8 via the coefficient multiplier 9. The coefficient multiplier 9 multiplies the original sound signal by a coefficient Direct Level for controlling the level of the original sound signal, and outputs the result to the adder 8. The adder 8 adds the input original sound signal and the signal on the delay 3 side and outputs the result to the outside. On the other hand, in the delay 3, the amount of delay between the read address and the write address is corrected according to the input level of the original sound signal. The level detection circuit 5 detects the input level of the input original sound signal. The detected level data is input to the coefficient multiplier 6. The coefficient multiplier 6 multiplies the level data by a sensitivity coefficient Sensitivity, and inputs the result to the delay 3 as a correction value of the read address. The delay 3 has a read address calculation circuit, combines this correction value with a reference delay amount, and generates a read address based on the combined value and the write address at that time. The delay 3 outputs data read from the read address to the coefficient multipliers 4 and 7.
Both positive and negative values can be set as the sensitivity coefficient Sensitivity. If a positive value is set, as shown in FIG. 3, the read address is moved backward (by increasing the delay amount) to increase the delay time as the input level of the original sound signal increases. Also,
If a negative value is set, as shown in FIG. 3, the read address is moved forward (by reducing the delay amount) to shorten the delay time as the input level of the original sound signal increases. When the delay time increases, the valley (dip point) moves to the lower side as shown in FIG. 4 (the initial dip point Cf0 is Cf0 = １ ／ T (T:
Delay time). ) The frequency of the swell decreases. Further, when the delay time becomes small, the frequency of the valley moves to the high frequency side as shown in the figure, so that the frequency of the undulation becomes high. Therefore, if the input level and the delay time are positively correlated as shown in FIG. 3, the delay time and the frequency have an inverse relationship. Therefore, as shown in FIG. 5B, the envelopes of the input level and the undulation frequency are reversed. Become. On the other hand, when the input level and the delay time are negatively correlated as shown in FIG.
As shown in (C), the input level and the envelope of the undulation frequency match. FIG. 5A shows the envelope of the musical tone of the attenuation system, and FIGS. 5B and 5C show the delay time (Delay) and the undulation when the delay time of the delay 3 is controlled by this envelope. Frequency (F
req. ). As described above, in this embodiment, since the envelope of the input level matches the delay time or the frequency of the undulation, when this effect device (effector) is used for a guitar, flanging is performed according to the picking strength. The effect is controlled, and a jet speed effect can be produced according to the player's intention. The coefficient Feedbac of the coefficient multiplier 4 is
By increasing or decreasing k, the frequency selection characteristic of the comb filter changes. That is, when Feedback is increased, as shown in FIG. 6, the dip point becomes large, the peak becomes sharp, and the undulation frequency is emphasized. It is appropriate that the delay time of the delay 3 is limited to about 2 to 3 ms at the maximum, and is increased or decreased within the range. In the above embodiment, the delay time is changed in correlation with the input level of the original sound signal. However, the delay time is set by the output of the LFO, and the frequency of the LFO is controlled in accordance with the input level of the original sound signal. You may make it. Further, although a RAM is used as the delay 3 in the above embodiment, a shift register may be used. In the above embodiment, a flanger has been described. However, the present invention can be applied not only to a flanger but also to any effect device having a filter using a delay. Other effect devices using a filter using a delay include, for example, a chorus device and a pitch change device. FIG. 7 shows an explanatory diagram of the chorus device. FIG. 2A is a block diagram of the chorus device. This device uses LFO and delay RAM
By modulating the read address of the
The pitch of the tone signal read from the AM (pitch:
Pitch). This is an apparatus that obtains an effect as if a plurality of people are playing by mixing the read tone signal and the original sound signal. By changing the frequency and level of this LFO according to the input level of the original sound signal, a chorus effect with a change can be obtained. Also, as shown in FIG. 3B, the pitch of the tone signal read from the delay RAM changes variously depending on the oscillation waveform of the LFO, but one of a plurality of waveforms is determined based on the input level of the original sound signal. One may be selected. According to the present invention, the delay time can be controlled in accordance with the input tone signal to change the filtering characteristics of the filter. (Level) can be linked, and a pleasant effect can be given to the listener. Also, the player can freely control the degree of the effect by changing the playing intensity by the playing operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of the present invention; FIG. 2 is a block diagram of an effect circuit (flanger) according to an embodiment of the present invention; FIG. 3 is an input time and a delay time of the effect circuit; FIG. 4 is a diagram showing a frequency characteristic of a comb filter of the effect circuit. FIG. 5 is a diagram showing a relationship between an input level of the effect circuit, delay time, and undulation frequency. FIG. 7 is a diagram illustrating a change in frequency characteristics with an increase in the feedback amount of a comb filter. FIG. 7 is a diagram illustrating another embodiment (a chorus device) of the present invention. FIG. 8 is a block diagram of a conventional flanger. 2-adder 4-coefficient (Feedback) multiplier 3-delay circuit 5-level detection circuit 6-coefficient (Sensitivity) multiplier

Claims (1)

(57) [Claim 1] An effect device comprising: a filter including a delay circuit for filtering an input tone signal; and delay time control means for controlling a delay time of the delay circuit. It said delay time control means for the level of the input musical tone signal is a means for controlling the delay time to have a positive or negative correlation effects device.