JPS6137038Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a volume sound quality control circuit that increases the volume level of a low frequency or high frequency range compared to the volume level of a middle frequency range to make it easier to hear when the volume of an electronic musical instrument is controlled to be low or high.

Generally, in electronic musical instruments, the volume is controlled by an expression pedal, as shown in FIG. In Figure 1, the sound source signal
The SG is first amplified by the preamplifier PRA, and then the expression pedal is connected to the voltage controlled amplifier VCA.
Under the control of EXP, it is amplified by the main amplifier MNA and output from the speaker SP. Therefore, if the output volume from the speaker is plotted on the vertical axis and the sound source frequency is plotted on the horizontal axis, as shown in FIG. 2, the frequency characteristics shift in parallel depending on the magnitude of the volume level. On the other hand, the ratio between the sound pressure level perceived by the human ear and the speaker volume level is not constant with respect to frequency, and the perception becomes particularly dull at low frequencies. Therefore, it is known that a low-frequency sound at a low volume level in FIG. 2 feels smaller than a mid-range sound at the same volume level. That is, the degree of volume control differs between bass and medium sounds, and it seems that bass sounds are strongly controlled to a low volume level. Furthermore, treble sounds at high volume levels tend to have a duller feel than mid-range sounds, although the extent of the sound differs from that of low sounds at low volume levels.

The purpose of the present invention is to improve the above-mentioned drawbacks and to provide a volume/sound quality control circuit for electronic musical instruments that controls the bass or treble range to have a higher level than the middle range when the volume level becomes low or high. It is about providing.

Hereinafter, a drawing showing an embodiment of the present invention shown in FIG. 3 will be explained. Figure 3 shows a case where the configuration of the voltage-controlled amplifier VCA and expression pedal EXP in Figure 1 has been changed, where TR is a transistor for amplifying the sound source signal, and R1 to R4 are low resistors for setting the operation of the transistors. , C1 and C2 are signal coupling capacitors, NFC is a negative feedback circuit, VC is a volume control section thereof, and TC is a sound quality control section within the negative feedback circuit, and VC and TC are connected in cascade. VR
1 is a variable resistor in the volume control section VC, VR2 is a variable resistance in the tone quality control section TC, and VR1 and VR2 are adjusted in conjunction with each other by operating an expression pedal. R5 and R6 are low resistors for adjusting sound quality, L is the same inductance, and C3 is the same capacitor. When variable resistor VR1 is operated in the direction of increasing the volume (in the direction of increasing the resistance value so that the amount of negative feedback is small), the sliding terminal of variable resistor VR2 is operated in the direction of resistor R6, and vice versa. When it is set to be small, the sliding terminal of VR2 is connected so that it moves in the direction of resistor R5. Therefore, when the volume is high, the R6·C circuit that operates as a high-pass filter becomes effective in the sound quality control circuit TC, reducing the amount of high-frequency feedback and increasing the high-frequency sound volume. FIG. 4 shows its characteristic curve. Conversely, when the volume is low, the R5.L circuit that operates as a low-pass filter becomes effective, and the low frequency components are grounded, reducing the amount of feedback in the low frequency range. As shown in FIG. 4, the volume of the low range becomes slightly louder.

In this way, according to the present invention, when the volume gets louder, the treble is emphasized and the sound contains more harmonic components, and when the volume is lowered, the bass is emphasized, making it easier to hear. As a result, electronic musical instruments have become available that can produce musical tones similar to the changes in volume and tone quality of natural instruments.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the volume control circuit of a conventional electronic musical instrument, FIG. 2 is a diagram showing the volume level versus frequency characteristic of FIG. 1, and FIG. 3 is a diagram showing the configuration of an embodiment of the present invention. FIG. 4 is a diagram showing the characteristics of FIG. 3. EXP……Expression pedal, SG……
Sound source signal, VCA...voltage controlled amplifier, SP...
Speaker, NFC...Negative feedback circuit, VC...Volume control section, TC...Sound quality control section, VR1, VR2...Variable resistor, L...Inductance for sound quality adjustment, C
3... Capacitor for sound quality adjustment, R5, R6... Resistor for sound quality adjustment.

Claims (1)

[Scope of utility model registration request] In order to amplify while controlling the volume and tone quality of the sound source signal, the negative feedback circuit provided in the amplifier circuit is connected in cascade with the volume control section and the sound quality control section, and the variable resistor connected in each control section is used as an expression pedal. A volume/sound quality control circuit for an electronic musical instrument characterized by interlocking adjustment based on operation.