JPH0225193B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a sound source device for an electronic musical instrument, and more particularly to an ensemble sound source device capable of producing musical tones with a natural ensemble feel.

Conventional configurations and their problems Generally speaking, the first or second
A tone created by multiple instruments playing the same melody, such as a violin, is called an ensemble effect or ensemble sound source. Traditionally, to create this kind of sound, a bucket bridge gate device (BBD) is used.
Multiple delay time modulators using variable delay elements such as In this way, each modulator outputs a violin sound with a different pitch, and by mixing these output signals, an ensemble effect is created. However, the effect was not necessarily similar to that of an actual violin ensemble. Another conventional example would be to simply create a violin sound based on the square waves and sawtooth waves output from multiple oscillators and mix them together, but this would require a large number of oscillators and would be inconvenient. It's the economy.

OBJECTS OF THE INVENTION The present invention solves these problems and provides an ensemble sound source device that can produce sounds very close to the natural ensemble feel with a simple configuration.

Structure of the Invention The present invention includes a scale information generator that generates information for determining a scale using an operating device such as a keyboard, and a clock signal that is frequency-divided according to the output of the scale information generator to output an address code. It comprises an address counter, a memory that stores sample values of musical tone signal waveforms and from which the sample values are repeatedly read out according to the address code, and a digital-to-analog converter that converts the output of the memory into an analog signal, A plurality of sets of a series of sample values cut from sample values of a signal waveform obtained by mixing multiple musical tone signals having different fundamental frequencies in the memory, with multiple cycles that are several times or more than the cycle determined by the above fundamental frequency. By storing the sample values belonging to these sets, musical tones with a natural ensemble feel can be read from the memory, and each set of sample values is arranged so that the beginning and end of the set are smoothly connected. The sample values are cut out from each other, and the times at the joints for each set are made to be different. With this configuration, the discontinuous portion of one sample value at the joint is mixed with the continuous portion of another sample value.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a block diagram of one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a scale information generator that generates information that determines the pitch of a sound, that is, a musical scale, using an operating device such as a keyboard. Outputs a digital pitch code _DK representing high. 2 is a programmable address counter which divides a clock signal having a clock frequency _c from a clock generator (not shown) and outputs an address code DAR. Reference numeral 3 denotes a memory that stores waveform information of the sound source, and a digital code S representing a sample value of the waveform written at the address specified by the address code ADR is repeatedly read out at a period corresponding to the musical scale. Let this be a waveform sample S. The waveform sample S is converted into an analog waveform signal by a digital-to-analog converter (not shown) and becomes a musical tone signal.

Memory 3 contains 1 word of waveform sample values.
When storing 12 bits and 1024 samples, 12 x 1024 = 12.288 Kbits are required. Also, the address code ADR is
It can be expressed with a 10-bit code.

Conventionally, the number of samples of musical sound waveforms stored in the memory 3 has been set to about 64 to 128, and one period corresponding to the fundamental frequency of the musical sound signal has been allocated to this sample, and this sample has been read out repeatedly. On the other hand, in this embodiment, a plurality of periods are cut out and stored as the period with respect to the fundamental frequency of the musical tone signal. And the sample value is
Instead of a musical sound signal from a single musical instrument, a musical sound signal from a so-called simultaneous performance, in which a plurality of musical instruments are played simultaneously, is used. An example of this waveform is shown in FIG. When playing in unison, multiple instruments play the same melody, but the pitches are not exactly the same, resulting in a beat-like sound. When two musical instruments play in unison, the musical sound waveform repeats at the frequency difference, that is, the cycle of the beat frequency. For example, if the fundamental frequencies of two instruments _{are 1} and ₂ , and the period is
T ₁ and T ₂ , and if the period ratio T ₁ /T ₂ is expressed as the ratio m/n of integers m and n, then a wave with period T ₁ is n waves,
The wave with period T ₂ is m wave, and the phases of both waves match again.
Therefore, if the waveform for the time length nT ₁ (=mT ₂ ) is stored as a sample value, the two-tone beat-shaped musical tone signal will be completely stored.

When actually cutting out the waveform, it is necessary to pay attention to the fine structure of the waveform so that the first part a and the last part b of the cut are smoothly connected, as illustrated in FIG.

Furthermore, in general, when a plurality of tones are slightly different from each other, it is difficult to find a clear repetition period as described above, but in this case, it is possible to successfully connect them by using the following method.

The first method is to record the sounds of each instrument separately.
When playing and mixing these, the playback speed of each individual signal is slightly increased or decreased so that the waveform closely resembles the beginning of the section to be cut out, and the end of the section is defined as the end of the section. This is a method of mixing signals, sampling between the above-mentioned start and end sections, and storing the sample in the memory 3.

The second method is to cut out a desired section from a concert performance, modulate the beginning part so that the volume gradually increases from zero, and modulate the ending part so that the volume gradually decreases. In this method, the sounds of the section are added to form an endless pattern, and the section is cut off near the middle of the section, thereby obtaining sample values with good waveform continuity even when read out repeatedly. FIG. 4 is a conceptual diagram of the second method.
When using the section A to F from the signal played in unison, the volume of the rising part A to B is modulated to gradually increase as shown in Figure 4a, and the volume of the falling part is modulated gradually. Modulate to decrease. Then A
The sections ~B and E~F are overlapped as shown in Fig. 4b, and cut at points C and D, with D being the starting point and C being the ending point. Then, sampling is performed between D and C. In this way, A to B and E to F will be connected smoothly, and points D and C will naturally be connected smoothly since they are originally continuous parts.

FIG. 5 further gives a smooth sense of ensemble performance. FIG. 5b shows one round of continuous signals created as shown in FIG. 4b. On the contrary,
Figure 5c shows the same type of instruments, such as violins, connected at different times in an ensemble, but also smoothly connected as shown in Figure 4b.
The point where the amplitude is modulated and mixed is _T2 .
Figure 5 d and e are also violin ensembles,
Mixed with T ₃ and T ₄ . Based on these four different sound source waveforms, one round of continuous signals mixed at four different times is mixed to create the signal shown in FIG. 5a. This almost always results in amplitude modulation and mixing;
Since it is a different kind of ensemble, you can get an even smoother ensemble sound. It is better that the times T ₁ to _{T 4} are not at constant time intervals. It is also better to change the slope of modulation per time.

It would be better if the tones and pitches of each of the four ensembles were slightly different. It is also possible to combine completely different instruments.

For the rise of a sound, create and memorize the waveform of the rise as shown in Figure 6, and then change the waveform from K→D→C→
It may be read as D→C...

You can also read out D→C→D→C... and add an envelope to the beginning of the sound. This is known as a conventional method of applying envelopes for musical tone generation.

These processes may be performed on the analog signal, or may be performed once the signal is digitized. Of course, A to B in Figure 4 a and b
The processing method for E to F may be performed by amplitude modulation, delay modulation, spectrum conversion, or the like.

The sample values obtained as described above are stored in the memory 3.

The address counter 2 can be constructed by cascading a programmable divider that performs variable frequency division according to the pitch code _DK , and a counter having the bit length of the address.
In this case, by making the read clock of the memory 3 variable, musical tones of a predetermined pitch can be generated. Also, regarding octave switching, 1
This may be realized by interlaced reading of samples, 3 samples, etc., or by reading out pitch codes corresponding to the frequency.
Accumulate D _K and use the accumulated result as an address code.
A method used as ADR may also be used.

The signal stored in the memory 3 may be a natural musical instrument sound such as a violin, an electronic sound such as a music synthesizer, or a human voice.

Effects of the Invention As described above, the present invention stores sample values of a signal waveform obtained by mixing a plurality of musical tone signals having different fundamental frequencies in a memory, and stores sample values of multiple periods, which are several times or more of the period determined by the fundamental frequency. Since it stores a series of sample values and repeatedly reads out the address code corresponding to the musical scale, it is possible to read out a musical tone signal that closely resembles a natural ensemble feeling with a very simple configuration. can.

In particular, in the present invention, a mixture of a plurality of waveforms with different sound joints is used, so that the joint parts of sample values of each signal waveform are mixed with consecutive parts of other sample values. By doing so, the unnaturalness of the musical tones at the joints is almost eliminated, and a smoother ensemble effect can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
5 to 5 are diagrams showing the signal processing method of the above embodiment, and FIG. 6 is a waveform diagram including the rising portion of the sound. 1... Scale information generator, 2... Address counter, 3... Memory.

Claims (1)

[Scope of Claims] 1. A scale information generator that generates information for determining a scale using an operating device such as a keyboard, and a clock signal that is frequency-divided according to the output of the scale information generator to output an address code. a memory that stores sample values of musical tone signal waveforms and from which the sample values are repeatedly read out in accordance with the address code; and a digital-to-analog converter that converts the output of the memory into an analog signal; A plurality of sets of a series of sample values cut out from sample values of a signal waveform obtained by mixing a plurality of musical tone signals having different fundamental frequencies in the memory with multiple cycles of multiples or more of the cycle determined by the fundamental frequency are stored in the memory. By storing sample values that are a mixture of sample values belonging to these groups, musical tones with a natural ensemble feel can be read out from the memory, and the beginning and end of the sample values of each group can be read out from the memory. An ensemble sound source device characterized in that sample values are cut out so that they are smoothly connected, and the times at the joints for each set are different. 2. Claim 1 is characterized in that the starting part and ending part of the sample value are smoothly connected by substantially matching the aspects of the starting part and the ending part of the sample value. Ensemble sound source device.