JPH023360B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electronic musical instrument, and is particularly capable of creating a sense of spaciousness and spatiality in a sound field when an electric signal (instrument sound signal) without sound field spatial information is reproduced through a speaker. The object of the present invention is to provide a sound field spatiality creation device for an electronic musical instrument.

Generally, in an electronic musical instrument, the output signal of one or more oscillators is controlled by a keyboard or the like, and the musical instrument signal is obtained through a timbre conversion circuit, and when reproduced through a speaker, the reproduced sound field has no spatial characteristics. For this purpose, the space creation device (usually called Celeste) shown in FIG. 1 is equipped. In FIG. 1, an electrical signal input to an input terminal 21 is branched into two, and signals S ₁ and S ₂ are obtained through time delay devices 22 and 23 (for example, Matsushita Electronics Industries MN3004), respectively.
Amplified by amplifiers 24 and 25, the electronic musical instrument body 26
It is reproduced by the speakers 27 and 28 installed in the. The time delay devices 22 and 23 set the frequency of the two-phase low frequency oscillator 29 to about 0.5 Hz, and the two
Signals f ₁ , f 2 converted into frequencies by applying the outputs V ₁ and V ₂ via voltage controlled oscillators 30 and ₃₁
The delay time is controlled by In this case, the player M feels that the musical instrument sound spreads in the area L between the two speakers SP27 and SP28.

This principle will be explained with reference to FIGS. 2 to 4. FIG. 2 shows that when the impulse D is input to the input terminal 21, _FIG .
Shows S ₂ signal. That is, the S ₁ or S ₂ signal changes during the delay time t ₁ to t ₂ from the time T when the impulse D is input, that is, the time (t ₂ −t ₁ ). In reality, t ₁ is about 2ms, t ₂ is about 6ms,
The change time is about 0.5s. Figure 3 describes the contents of Figure 2 in more detail, and shows the S ₁ signal and
It can be seen that the S ₂ signal changes in the completely opposite direction from time t ₂ to _{t 1} . Figure 4 shows the changes in the S ₁ and S ₂ signals in Figure 3 and the sound image direction α perceived by the performer M.
Conditions 1, 2, and 3 in FIGS. 3 and 4 correspond to each other. As shown in Figure 4, the reason why the sound field spreads in area L is that the sound image direction α periodically changes between the angle θ from the center line O to the speaker.
The main reason is that it changes every 0.5 seconds.

However, the sense of expansion of the sound field due to the spatiality creation circuit used in the above-mentioned electronic musical instruments is fixed between the two speakers 27 and 28, as shown in area L in FIGS. 1 and 4. In addition, since a time delay device such as a BBD is used, there is a problem in that the S/N ratio deteriorates due to beats caused by the clock frequency.

The present invention solves these conventional drawbacks, and provides voltage-controlled amplification means to which an input signal branched into two channels is applied by the output of a two-phase triangular wave generation means that outputs signals having an opposite phase relationship. The output of the voltage-controlled amplification means is passed through the virtual sound source creation means, applied to the speaker, and reproduced. According to this configuration, the performer can:
You can enjoy high-quality sound that extends to areas outside the speakers that cannot be reproduced with conventional methods.

The present invention will be described below with reference to drawings of embodiments. FIG. 5 shows an embodiment of the present invention,
In the figure, 1 is an input terminal, 2 and 3 are voltage control amplification means, 4 is a two-phase triangular wave generation means, 5 is a timing control means for generating clock pulses, and 6 and 7 are analog switches with 4 circuits per contact. The switching means is composed of, for example, a 2-bit control multiplexer μpD40669 manufactured by NEC Corporation. 8, 9 are virtual sound source generating means, 10, 11 are amplifiers, 12, 1
3 is a speaker.

The signal input to the input terminal 1 is branched into two, and the signals S ₁ and S ₂ are obtained via the voltage control amplification means 2 and 3.
After obtaining outputs O 1 to O ₄ and outputs O ₅ to O ₈ by analog switches 6 and 7 with ₄ circuits per contact, outputs O ₁ and O ₅ , outputs O ₂ and O ₆ , and outputs O ₃ and O ₇ , out
By adding O ₄ and O ₈ respectively, the output ₁ ,
Generates O ₂ , ₃ , ₄ . Next, outputs ₁ and ₂ are added directly without any intervention, and outputs ₃ and ₄ are added via virtual sound source generating means 8 and 9, which will be described later, to obtain outputs _{5 and 6} , which are added via amplifiers 10 and 11. It is reproduced by the speakers 12 and 13. The voltage control amplification means 2 and 3 are controlled by the triangular wave generation means 4, and the triangular wave generation means 4 and the switching means 6 and 7 are controlled by the output P of the timing control means 5.

FIG. 6 shows a timing diagram of the P, S ₁ S ₂ , 01 to 08 signals. The pulse of P ₁ is the timing control means 5
The triangular wave generating means 4 and the switching means 67 are triggered by the output from the triangular wave generating means 4 and the switching means 67. For example, when pulse P ₁ is input, the output of voltage control amplification means 2
The level of S ₁ becomes smaller, and the output S ₂ of the voltage control amplification means 3 becomes larger, so that the level difference between the two channels changes. And analog switch 6,
7 turns on only the outputs O ₁ and O ₆ , the sound image moves from the speaker 12 to the speaker 13 in the region L of FIG. Next, when P ₂ is input, only the outputs O ₂ and O ₇ are turned on, and the sound image moves from the speaker 13 to the speaker 14 in the area. That is, by controlling the embodiment shown in FIG. 5 as shown in FIG. 6, the sound image can be moved including the horizontal direction, and by controlling the embodiment shown in FIG. It can be expanded.

Methods for controlling the sound image direction localization include a method of changing the level difference between two channels and a method of changing the time difference between two channels. In this embodiment, the method is based on the former method of changing the level difference. In FIG. 7, a signal input to input terminal 1 is branched into two and passed through voltage control amplification means 2 and 3, respectively, to obtain output signals S ₁ and S ₂ , which are output from amplifiers 10 and 11 and speakers 12 and 13. will be played. The voltage control amplification means 2 and 3 receive triangular wave signals l ₁ ,
It is controlled by a two-phase triangular wave generating means 4 which generates _l2 . That is, the sound image direction α perceived by the performer M in FIG. 7 is in the direction from the speaker 12 to the speaker 13, that is, to the right, because the _S1 signal becomes small and the _S2 signal becomes large in the case of area 1 in FIG. Continuously move to the left. In other words, it is the same as the change from condition 1 to condition 3 shown in FIG. This method does not use a time delay device, so a high S/N ratio can be achieved.

In addition, as a method of expanding the region L of the sense of sound field expansion as described above to the side of the performer M when reproduced by the speakers 12 and 13, a virtual sound source speaker is created at 90 degrees to the side of the performer M. , actual sound source speaker 12,1
This can be achieved by changing the level difference not only between the three but also between the real sound source and the virtual sound source speakers or between the virtual sound source speakers.

Next, the above-mentioned virtual sound source generating means 8 and 9 will be explained based on FIG. 9. In the figure, 17 is a binaural common circuit, and 18 is a binaural difference generating circuit.
is formed. And in this figure,
H ₁₁ and H ₁₂ are transfer functions between the speakers SP ₁ and SP ₂ and the left and right ears of the listener M, and Hφ ₁ and Hφ ₂ are the transfer functions of the speaker SP ₃ placed 90° to the left of the listener M. is the transfer function between the left ear and the right ear of the listener. Now, the sound pressure given to the left and right ears of listener M by applying signals to speakers SP ₁ and SP ₂ is the same as that of speaker SP ₃ , which is placed 90 degrees to the left of the listener.
If the sound pressure is the same as that given by , listener M feels as if only speaker SP ₃ is placed. In order to create such a phenomenon, a binaural common circuit 17 and a binaural difference generating circuit 18 are connected in front of the left and right speakers SP ₁ and SP ₂ , and the characteristic of the binaural common circuit 17 is Hφ ₁ /H. ₁₁ , and the characteristics of the binaural difference generating circuit 18 are (H ₁₁ Hφ ₂ −
H ₁₂ Hφ ₁ )/(H ₁₁ Hφ ₁ −H ₁₂ Hφ ₂ ).

When such a virtual sound source creation means is used, while listener M is listening to the sound radiated from speakers SP ₁ and SP ₂ , it is as if speaker SP ₃ is located 90 degrees to the left of listener M.
is placed, and it feels like you are listening to the sound being radiated. In other words, a virtual sound source speaker SP ₃ is created 90° to the left of the listener.

As described in detail above, according to the present invention, the performer can enjoy high-quality sound extending to areas outside the speaker, which is the actual sound source. Furthermore, since the sound image direction localization is controlled based on the level difference variation method between the two channels, there is no need for a time delay device such as a BBD, and there is an advantage that a high S/N ratio can be achieved.

[Brief explanation of drawings]

Figure 1 is a block diagram of a spatiality creating device used in a conventional electronic musical instrument, Figures 2, 3 and 4.
5 is a block diagram showing an embodiment of the electronic musical instrument of the present invention, FIG. 6 is a timing diagram of the same instrument, and FIG. 7 is a sound image direction localization control circuit of the same instrument. FIG. 8 is a block diagram of the output waveform of the two-phase triangular wave generating means used in the same circuit, and FIG. 9 is a block diagram of the virtual sound source generating means of the same musical instrument. 2, 3... Voltage control amplification means, 4... Two-phase triangular wave generation means, 5... Timing control means, 6, 7
...Switching means, 8, 9...Imaginary sound source creation means, 1
0,11...Amplifier, 12,13...Speaker.

Claims (1)

[Claims] 1 branching means for branching an input signal into two channels; two-phase triangular wave generating means for outputting a signal of opposite phase; and outputting the input signal branched into two channels by the branching means from the two-phase triangular wave generating means. a switching means for switching the output of the voltage controlled amplifying means to a plurality of outputs; and an imaginary sound source generating means for creating a part of the output of the switching means into an imaginary sound source; A sound field spatiality creating device comprising a phase triangular wave generating means and a timing control means for controlling the output timing of the switching means.