JPH09230859A - Electronic musical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the trouble that a timbre changes unnaturally owing to variation in frequency characteristics of auditory sensation when sound volume is varied. SOLUTION: This electronic musical instrument is provided with a plurality of filters F1-Fn which have frequency characteristics corresponding to a plurality of loudness curve groups based upon the sound volume as a parameter and an output channel determining means 5 which generates filter selection information on the basis of sound volume setting information set with variable resistors of the electronic musical instrument and controls a selector 3. Then the musical sound signal generated by adding the outputs of simultaneous sound generating channels of a musical sound signal generation part 1 by an adder 2 is outputted through one of the filters F1-Fn, selected by a selector 3, to give the musical sound signal having optimum frequency characteristics based upon an equal- loudness curve corresponding to the sound volume, thereby reducing the influence of auditory characteristics of the ear when the sound volume is varied.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electronic musical instrument having a loudness function.

[0002]

BACKGROUND OF THE INVENTION Electronic musical instruments usually have knobs or switches for setting the volume. By operating these knobs and switches, the overall volume of the electronic musical instrument can be adjusted. The volume referred to here is not the change in volume caused by playing, such as a loud sound when you play strongly on the keyboard, and a soft sound when you play softly on the keyboard. It is a so-called "volume" for setting. As a result, when using the electronic musical instrument, it is possible to perform at an appropriate volume according to the time and place.

In recent years, electronic musical instruments for digitally controlling the volume have been realized. For analog,
The signal output from the tone signal generator and input to the amplifier is controlled by the variable resistor, but in the case of digital,
A volume control signal is sent to the tone signal generator to control the amplitude of the generated tone.

[0004]

By the way, it is known that the human ear has different audible frequency characteristics depending on the loudness of the sound. The human ear has the highest sensitivity in the vicinity of 3 KHz to 4 KHz, and the lower or higher frequencies have lower sensitivity. Especially, a low frequency of 100 Hz or less has a considerably low sensitivity, so that a low frequency component is hardly heard at a low volume. This property is commonly known as the Fletcher isoloudness curve.

For this reason, for example, in the tone signal which was optimal at a certain volume setting, the bass component and the treble component become hard to be heard by reducing the volume, and 3 KHz to 4K.
The middle frequency component around Hz is noticeable. That is,
When the volume is changed, there is a problem that the timbre changes unnaturally and is heard due to the change in the frequency characteristic in the sense of hearing, although the electric frequency characteristic does not change.

The present invention has been made in order to solve such a problem, and when the volume is changed, there is a disadvantage that the audible frequency characteristic changes and the timbre changes unnaturally. The purpose is to prevent.

[0007]

In order to solve the above-mentioned problems, an electronic musical instrument of the present invention has a plurality of tone signal generating means for generating pronunciation information corresponding to performance information and a plurality of frequency characteristics corresponding to volume. One filter, one of the plurality of filters is selected in accordance with the volume setting information generating means for generating information for setting the volume of the musical instrument, and the volume setting information generated by the volume setting information generating means. , Selecting means for supplying the output of the tone signal generating means.

Since the present invention comprises such technical means, one of a plurality of filters is selected so as to generate a musical tone signal in accordance with the frequency characteristic corresponding to the volume when the volume of the musical instrument is changed. The timbre change and the band deterioration on the auditory sense at the time of volume are corrected. Since the filter is selected according to the volume, the control is simple and a high operation speed can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of the main part of the present invention. In FIG. 1, each of a plurality of simultaneous tone generation channels ch1, ch2, ... The output of the tone signal generator 1 of each channel is added and synthesized by the adder 2 and supplied to the selector 3. The tone generator circuit does not necessarily have to have a plurality of sound generation channels.

The selector 3 is switched and controlled by the output channel determining means 5 which generates selection information based on the volume setting information of the musical instrument, and is selected from a plurality of parallel filter circuits F1 to Fn constituting the filter 4. Two adders
Supply the output of. The filter circuits F1 to Fn are provided with frequency characteristics corresponding to each of a plurality of equal loudness curve groups having a volume as a parameter.

The output channel determining means 5 is, for example, as shown in FIG.
As shown in (3), selection information for selecting one of the seven filter circuits is generated corresponding to the volume setting information set by the volume of the electronic musical instrument or the like. Each filter circuit F
Although each of 1 to Fn is composed of a digital filter, if a D / A converter is inserted in the subsequent stage of the adder 2, each filter circuit can be composed of an analog filter.

FIG. 2 shows a schematic structure of an electronic musical instrument to which the present invention is applied, and FIG. 3 shows an operation panel of the electronic musical instrument. The electronic musical instrument of this embodiment is basically a microcomputer system, and has a CPU 11 connected by a bus 10.
A ROM 12 and a RAM 13 are provided, and a panel switch group 14, a pedal switch 15, and an I / O terminal of the CPU 11 are provided.
The MIDI interface 16 is coupled.

The panel switch group 14 includes volume switches 14a and 14b (up / down buttons) also shown in FIG.
As shown in FIG. 3, on the panel surface, transpose switches 14c and 14d, a tone color selection switch 14e,
14f ... 14i etc. are provided. ROM12
Is a memory area 12a, 12b, 1 for storing a program for processing data input / output and internal operation of the electronic musical instrument, tone color data, and filter coefficients for realizing an equal loudness curve.
Including 2c.

A keyboard 22 attached to an electronic musical instrument is further connected to the bus 10 via a touch sensor circuit 23, and a sound source including a multi-channel tone signal generator 1 and a channel adder 2 shown in FIG. A circuit 17 is connected, and tone generation data is formed based on the performance data transferred from the CPU 11 and the waveform data supplied from the waveform memory 18.

The tone data added and synthesized by the tone generator circuit 17 is passed through any one of the seven filter circuits F1 to F7 constituting the loudness filter 4 selected by the selector 3 and the amplitude controller 19 And is led to a sound system 21 including an amplifier and a speaker via the D / A converter 20.

The amplitude control section 19 includes a panel switch group 1
Volume information set by the volume switches 14a and 14b in 4 is given from the CPU 11 via the bus 10,
Here, the amplitude of the sound generation data is controlled to increase or decrease the sound volume. Further, the volume information is converted into the selection information of FIG. 7 by the CPU 11 (including the output channel determining means 5 of FIG. 1) and supplied to the selector 3 through the bus 10.

FIGS. 4 to 6 are flowcharts showing the control flow of the microcomputer system shown in FIG. 2. FIG. 4 is a main process, FIG. 5 is a panel event process, and FIG.
FIG. 6 shows each routine of keyboard event processing.

In FIG. 4, first, in step S1, the CPU
11, the RAM 13, the sound source circuit 17 (sound source LSI), etc. are initialized, and subsequently, the plurality of filter coefficients stored in the filter coefficient memory area 12c of the ROM 12 are loaded into the respective filter circuits F1 to F7. . In addition,
The filter coefficient may be set in advance in each of the filter circuits F1 to F7 without providing the filter coefficient memory area 12c. After that, panel event processing R1, pedal event processing R2, keyboard event processing R3, and other processing R
4 are sequentially executed, and these routines are repeated.

In the panel event process R1, as shown in FIG. 5, in steps S10, S11 and S12, the volume switches 14a and 14b and the tone color selection switches 14e to 14 are selected.
It is checked whether i, or any other switch has been operated.

When the volume switches 14a and 14b are operated, volume information is loaded into the amplitude controller 19 via the CPU 11 of FIG. 2 in step S13. As a result, the volume produced by the sound system 21 changes as specified by the volume switches 14a and 14b.

Next, in step S14, selection information for selecting one of the filter circuits F1 to Fn is generated according to the set value of the volume based on the volume information, which is step S14.
It is loaded into the selector 3 at 15. As a result, the filter circuit having the optimum frequency characteristic along the equal loudness curve corresponding to the volume setting value is selected. The flow then returns to the main routine.

When it is detected in step S11 or step S12 of FIG. 5 that the tone color selection switch or other switch is operated, the corresponding tone color selection process R5 or other process R6 routine is performed. And then return to the main routine. If neither switch is operated, no processing is performed and the process returns to the main routine.

Routine R for keyboard event processing shown in FIG.
3, the ON event, OF in steps S20 and S21
The determination of the F event is performed. Here, if it is an ON event, the tone parameter calculation processing routine R7 is executed, the tone parameters obtained thereby are loaded into the tone generator circuit 17 (tone generator LSI) of FIG. 2 in the next step S23, and in step S24. Pronunciation processing is performed.

In the calculation of the tone parameters in the routine R7, necessary tone color data is read from the tone color data memory area 12b of the ROM 12, and the tone information of the keyboard 22 shown in FIG. This is a process of calculating a parameter necessary for generating a musical sound in the generation unit 1.

When the OFF event is detected in step S21, it is further checked in step S25 whether the damper pedal is on or off. If the damper pedal is on, the sound is continuously produced. If it is off, the release speed is changed. The sound is attenuated by being set in the sound source circuit 17.

FIG. 7 is an example of a conversion table for obtaining the selection information of the filter circuits F1 to F7 according to the volume setting value. The volume setting value on the horizontal axis is used as the address and the filter selection number on the vertical axis is read out. Be done. Therefore, this conversion table selects a filter circuit which gives the tone signal a frequency characteristic along the optimum equal loudness curve corresponding to the volume setting value set by the volume switches 14a and 14b.

In the above embodiments, the volume using the up / down switch is used, but a slide type or knob type analog variable resistor is used, and the signal obtained by this is A / D converted and the volume is changed. You can also get configuration information. Further, although the conversion table (FIG. 7) is used to obtain the filter selection information for the volume setting value, the filter selection information may be directly calculated by a functional expression.

As described above, according to this embodiment, when the volume of the musical instrument is changed, the optimum one is selected from the plurality of filters so that the musical tone signal along the equal loudness curve of the volume is generated. The timbre change and band deterioration on the audibility at low volume are corrected.

In the above embodiment, in order to realize the frequency characteristic along the equal loudness curve according to the set volume, an FIR digital filter is used, but in consideration of cost, A second-order IIR filter, which is smaller in scale than the FIR filter, may be used.

As described above, when the second-order IIR filter is used, it is difficult to accurately realize the frequency characteristic corresponding to the equal loudness curve, but it is possible to obtain the frequency characteristic according to it. Therefore, the auditory characteristic of the ear at a low volume can be corrected to the extent not causing a problem although it is not perfect.

It is to be noted that, by reversely utilizing such an auditory characteristic of the ear, a second-order IIR filter is used to intentionally set a frequency characteristic such that the bass range is slightly increased when the volume is increased. By increasing the power of the sound,
It is also possible to increase the sense of volume.

[0032]

According to the present invention, a plurality of filters having a frequency characteristic corresponding to a volume, for example, a frequency characteristic corresponding to each of a plurality of equal loudness curve groups having the volume as a parameter are used to set the volume. By selecting the filter of the corresponding frequency characteristic and giving the frequency characteristic along the equal loudness curve to the musical tone signal, the auditory characteristic of the ear when the volume is changed is corrected, the timbre change in the auditory sense and band deterioration Can be reduced. As a result, even if the volume is changed, the tone color does not change unnaturally, and it is possible to always generate a well-balanced tone signal. Also, since you only have to select the filter according to the volume,
The control is simple and a high operating speed is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an electronic musical instrument to which the present invention has been applied.

FIG. 3 is a schematic view of an operation panel of the electronic musical instrument.

FIG. 4 is a flowchart showing a main routine of a control flow of the electronic musical instrument.

FIG. 5 is a flowchart showing a panel event processing routine.

FIG. 6 is a flowchart showing a keyboard event processing routine.

FIG. 7 is a diagram showing an example of a conversion table for selecting an optimum filter circuit according to a volume setting value.

[Explanation of symbols]

 1 Musical sound signal generating section 2 Adder 3 Selector 4 Filter 10 Bus 11 CPU 12 ROM 13 RAM 14 Panel switch group 15 Pedal switch 16 MIDI interface 17 Sound source circuit 18 Waveform memory 19 Amplitude control section 20 D / A converter 21 Sound system 22 Keyboard 23 Touch sensor

Claims (3)

[Claims] 1. A tone signal generating means for generating pronunciation information corresponding to performance information, a plurality of filters each having a frequency characteristic corresponding to the volume, and volume setting information generation for generating information for setting the volume of a musical instrument. Means and a selecting means for selecting one of the plurality of filters according to the volume setting information generated by the volume setting information generating means and supplying the output of the tone signal generating means. . 2. The electronic musical instrument according to claim 1, wherein the plurality of filters have a frequency characteristic corresponding to each of a plurality of equal loudness curve groups having volume as a parameter. 3. The tone signal generating means has a plurality of tone generation channels, and includes adding means for adding outputs of the plurality of tone generation channels, and the selecting means supplies the output of the adding means to a selected filter. The electronic musical instrument according to claim 1, wherein