JPH09230869A - Electronic musical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent inconvenience of hearing unnaturally varied tone due to a change in frequency characteristic of hearing sense when sound volume is varied. SOLUTION: Based on the volume setting information set by volume, etc., of an electronic musical instrument, a filter coefficient information is generated to achieve a most optimal filter characteristic for the volume, and a filter coefficient information generation means 4 is provided to set in filter 2. The output of a plural simultaneous tone generation channels of a tone signal generation part 1 are added by an adder 3 and a digital tone signal as an addition output is outputted through a filter 2 of which the characteristic is changed in response to setting a volume. Thus, an influence due to a hearing sensation characteristic of ears is reduced when tone is change in volume, by enabling a tone signal to be provided with an optimal frequency characteristic according to an equal loudness curve corresponding to volume.

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 generation channels and a tone signal generator for generating tone information corresponding to performance information; Adder means for adding outputs of a plurality of sound generation channels of the signal generator, a filter connected to the latter stage of the adder means, volume setting information generating means for generating information for setting the volume of the musical instrument, and the volume setting information. Filter coefficient information generating means for setting the frequency characteristic according to the set volume in the filter according to the volume setting information generated by the generating means.

Since the present invention comprises such technical means, when the volume of the musical instrument is changed, the filter characteristic is optimally set so that a musical tone signal corresponding to the frequency characteristic corresponding to the volume is generated, and when the volume is low, The timbre change and band deterioration on the auditory sense can be corrected. Moreover, in the present invention, since the outputs of a plurality of tone generation channels of the tone signal generator are added and synthesized and then the filter processing is performed, the loudness can be corrected with a single filter for a plurality of tone generation channels.

[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, the digital tone signal output from the tone signal generator 1 is output to an amplifier and a speaker via a digital filter 2 that gives a frequency characteristic according to an equal loudness curve.

In the case of an electronic musical instrument having a plurality of simultaneous tone generation channels, a plurality of tone generation channels ch1, ch2 ... Each comprising a tone signal generation section 1 are prepared, and those channel outputs are combined into one by an adder 3. After being added, it is output to the digital filter 2.

Information such as the multiplication coefficient of the filter 2 is supplied from the filter coefficient information generating means 4. The filter coefficient information generating means 4 is based on the volume setting information set by the volume of the electronic musical instrument, etc., and is a filter coefficient for realizing an optimum filter characteristic for the volume (frequency characteristic along the equal loudness curve of each volume). Generate information.

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 3 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 the loudness filter 2 and the amplitude controller 1 is operated.
9 and further through the D / A converter 20 an amplifier,
It is led to a sound system 21 including a speaker and the like. To the amplitude control unit 19, volume information set by the volume switches 14a and 14b in the panel switch group 14 is given from the CPU 11 via the bus 10, and the amplitude of the sound generation data is controlled to increase or decrease the sound volume. To be done.

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 tone generator circuit 17 (tone generator LSI), etc. are initialized. After that, the panel event processing R1,
Each routine of the pedal event process R2, the keyboard event process R3, and the other process R4 is 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, the 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, the ROM 12 of FIG.
The filter coefficient is read out from the internal filter coefficient memory area 12c to the CPU 11 (including the filter coefficient information generating means 4 of FIG. 1), and the read filter coefficient corresponds to the volume setting value in the next step S15. Is converted to This conversion is performed in order to set the frequency characteristic of the filter 2 along the equal loudness curve corresponding to the volume setting value.

For example, in this conversion process, a conversion table for reading a predetermined correction coefficient using the volume setting value as a key is prepared, and the correction coefficient is read based on the volume setting value.
This is performed by multiplying the standard filter coefficient read from the filter coefficient memory area 12c of the ROM 12 by the correction coefficient and converting it to the optimum filter coefficient corresponding to the volume. As the loudness filter 2, for example, 10
If a FIR filter with multiple stages is used, 10
Conversion tables are required.

The filter coefficient converted in step S15 is loaded as a multiplication coefficient in the loudness filter 2 in step S16. The flow then returns to the main routine.

When it is detected in step S11 or step S12 in 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.

To calculate the tone parameters in the routine R7, necessary tone color data is read out from the tone color data memory area 12b of the ROM 12 and the touch information of the keyboard 22 is added to the tone signal of 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 shows an example of a conversion table for obtaining the optimum filter coefficient according to the volume setting value. FIG.
In the example of step S15, the correction coefficient is read out based on the volume setting value. However, in the example of FIG. 7, the horizontal axis indicates the volume setting value as an address and the vertical axis indicates the filter coefficient value in FIG. It is read from the area 12c. In this case, the volume switch 1
The optimum filter coefficient value corresponding to the volume setting value set in 4a and 14b is obtained.

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 (for example, FIG. 7) is used to obtain the filter coefficient for the volume setting value,
The filter coefficient value or the correction coefficient of the filter coefficient may be directly calculated by calculation using a functional expression.

Further, in the above embodiment, in order to realize the frequency characteristic according to the set volume, the FIR digital filter is used to provide the frequency characteristic corresponding to the equal loudness curve. In consideration of the above, a second-order IIR filter having a smaller 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, the frequency characteristic of the filter is changed in response to the setting of the volume, and the frequency characteristic along the equal loudness curve is given to the musical tone signal. It is possible to correct the auditory sensation characteristics of the ears and reduce the timbre change and band deterioration in the auditory sense. 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. Moreover, in the present invention, since the filter processing is performed after adding the outputs of a plurality of simultaneously sounding channels of the tone signal generator, only one filter is required, and the loudness correction can be performed with a simple configuration.

[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 obtaining an optimum filter coefficient according to a volume setting value.

[Explanation of symbols]

 1 tone signal generator 2 filter 3 adder 4 filter coefficient information generator 10 bus 11 CPU 12 ROM 13 RAM 14 panel switch group 15 pedal switch 16 MIDI interface 17 tone generator circuit 18 waveform memory 19 amplitude controller 20 D / A converter 21 sound system 22 keyboard 23 touch sensor

Claims (2)

[Claims] 1. A tone signal generator having a plurality of tone generation channels for generating tone generation information corresponding to performance information, an addition means for adding outputs of a plurality of tone generation channels of the tone signal generator, and the addition. A frequency corresponding to the set volume by the filter connected to the latter stage of the means, 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. An electronic musical instrument comprising: filter coefficient information generating means for setting a characteristic in the filter. 2. The electronic musical instrument according to claim 1, wherein the filter coefficient information generating means sets a frequency characteristic corresponding to an equal loudness curve in the filter according to the volume setting information.