JPS631594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional sound electronic musical instrument in which a sound image of an electronic musical instrument is controlled to be localized or continuously moved in any direction within a horizontal plane.

The configuration of electronic musical instruments currently on the market is to create musical sound signals such as flute or piano using an electric circuit and reproduce them through one or more speakers. There are some things shown below.

This means that after inputting the musical tone signal to input terminal ₁ ,
Branched into 3 channels, time delay elements 1, 2, 3
(for example, BBD) and amplifier 4 to reproduce the signals from three speakers SP1, SP2, and SP3, respectively.The delay time of time delay elements 1, 2, and 3 ranges from 1ms to 7ms with a cycle of 0.5 seconds. By moving the time delay elements 1, 2, and 3 and setting the delay time phase difference between each of them to 120 degrees, the musical sound emitted from the musical instrument 5 has a sense of expansion within the horizontal plane shown by area A in FIG. You can have it. However, since the localization direction of the musical sound image is completely uncertain and the center of the sound image is ambiguous, the listener 6 is placed in a very unstable psychological state. In other words, it is possible to reproduce the sense of spaciousness of the sound, but it is not possible to reproduce the expansion of the localization range of the sound image.

On the other hand, the localization range of the sound image is limited to only one direction (direction 0) as shown in FIG. 3 because currently available electronic musical instruments reproduce one channel even when a plurality of reproduction speakers are used.

Above are examples of commercially available electronic musical instruments.
FIG. 4 shows a method of applying two-channel stereo to an electronic musical instrument to localize a sound image using an instrument signal between two reproduction speakers, and FIG. 5 shows the localization direction range.

The musical instrument signals input to the five input terminals ₁ to ₅ have the voltage level ratio between the two channels varied by the two-channel panpot 7, and are reproduced by the two speakers SP1 and SP2 via the amplifier 4. .
Sound images ' ₁ to ' ₅ are 2 channel pan pots 7
According to the voltage level between the two channels, the listener 6 can be freely positioned between the direction l of the left speaker SP1 and the direction r of the right speaker SP2.

However, with this method, it is not possible to localize to the side or behind the listener.

The present invention has been made to eliminate the above-mentioned drawbacks, and is a three-dimensional system that freely localizes the sound images of the direct sound and indirect sound of the musical instrument signal in each direction in the horizontal plane by reproducing two speakers of an electronic musical instrument. The present invention provides an acoustic electronic musical instrument. Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 6 shows an embodiment of the present invention in which a sound image is localized in a 360° direction around the listener 6. The signal output from the scale sound source 8 is sent to a keyboard switch circuit means 9 for selecting an arbitrary pitch, a timbre conversion circuit means 10a for converting the timbre of an arbitrary musical tone, and a time delay device and a reverberation adding device for creating indirect sounds, for example. indirect sound generating circuit means 10
b, the signal is inputted to a plurality of electric circuit means 11 (for example, a 6-channel panpot) that can freely control the voltage level ratio between the 6-channel outputs. Among the six channel outputs, the first output O ₁ , the second
The output O ₂ is directly input to the mixer 16 and the third output
O ₃ and fourth output O ₄ are electrical circuit means 1 that localizes the sound image in the left and right directions at 90 degrees with the front of the listener 6 as 0 degrees.
8, and the fifth output O ₅ and the sixth output O ₆ are
The signals are respectively input to the mixer 16 via electric circuit means 19 for localizing in two arbitrary directions behind the listener 6. The electric circuit means 18 and 19 are composed of front and back determining circuits 12 and 14 and binaural difference creating circuits 13 and 15, respectively. mixer 16
After being mixed, the signals input to the 1 and 2 are output as 2-channel signals, and are reproduced from two reproduction speakers SP1 and SP2 via an amplifier 4.

Regarding the fore/aft judgment circuit and the binaural difference creation circuit, see, for example, Masatoshi Shinbo et al.'s "Direction Localization in Stereo Playback" Electro-acoustic Research Committee material.
It is described in detail in EA76-61 (1976), and will be summarized here.

As shown in FIG. 10, in the case of two-speaker reproduction, there are four transfer functions between the two speakers and both ears. In normal stereo listening,
As shown in FIG. 11, symmetrical transfer functions are equal.

As shown in Figure 9, if a sound source is located at the position of the sound image that should be localized at an arbitrary distance and direction, the sound pressure generated in the auditory canals of the left and right ears is P _L ,
Let P _R be the transfer functions from the sound source to the left and right auditory canals as H ₀₁ and H ₀₂ . On the other hand, playback speaker SP.1
Assume that the signal applied to the speaker SP.2 is E _L , the signal applied to the speaker SP.2 is E _R , and the transfer function of the speaker is 1.
Also, at this time, the sound pressures reproduced in the auditory canals of the left ear and right ear are assumed to be P _L ′ and P _R ′. Furthermore, the transfer function from speaker SP.1 to the left ear is H ₁₁ , and the transfer function to the right ear is H 11 .
H ₁₂ and the transfer functions for speaker SP.2 are defined as H ₂₁ and H ₂₂ in the same way.

Here, the sound pressure ratio of both ears P _R /P _L in Figure 9b or less, P _R /P _L = H ₀₂ /H ₀₁ = A ... (1) P _r /P _l = H ₁₂ /H ₁₁ = B ...(2) E _R /E _L = C ...(3) The sound pressure ratio P _R ′/P _L ′ between the listener's ears due to the reproduction speaker is P _R ′/P _L ′=H ₁₁・E _R +H ₁₂・E _R /H ₁₁・E _L +H ₁₂・E _L =B
・1+C/B/1+C・B...(4) Here, to find the reproduction speaker E _R /E _L required to make P _R /P _L and P _R ′/P _L ′ equal, C= A-B/1-A・B=H ₁₁・H ₀₂ −H ₁₂・H ₀₁ /H ₁₁
・H ₀₁ −H ₁₂・H ₀₂ …(5) This becomes the binaural difference generation circuit.

To determine the direction of a sound source in all circumferential directions, in addition to the binaural ratio, a transfer function for front-back determination is required. Assuming that the electrical input signal in FIG. 9b is A _s , the sound pressure P _L obtained at the listener's left ear is given by P _L =H ₀₁ ·A _s (6). On the other hand, the sound pressure P _L ′ obtained at the listener's left ear in Fig. 11 is P _L ′ = (H ₁₁・E _L +H ₁₂・E _R )・A _s ……(7) Here, P _L Find the condition that makes P _L ′ equal to H ₀₁・A _s =H ₁₁・E _L・(1+H ₁₂ /H ₁₁・E _R /E _L )A _s ……(8) E _L =H ₀₁ / H ₁₁ · 1/1 + (H ₁₂ /H ₁₁ ) (E _R /E _L ) ≒H ₀₁ /H ₁₁ ...(9) This becomes the front/back judgment circuit.

Based on the above, the sound image control circuit for localizing the sound image in the circumferential direction of the listener is shown in FIG. 12.

The listener 6, that is, the performer, uses the timbre conversion circuit means 1.
For example, five different musical tone signals ₁ , ₂ ,
₃ , ₄ , _{and 5} , by varying the level ratio between the six-channel outputs of the same number of six-channel panpots 11, the sound image direction of the direct sound of each instrument signal ′ ₁ , ′ ₂ , ′ ₃ , I′ ₄ and ' ₅ can be controlled. Of course, three different instrument _signals2 ,
The indirect sounds created from ₃ and ₄ are set as ₁ and ₅ , the sound image directions of the direct sound are set as ′ ₂ , ′ ₃ , ′ ₄ , and the sound image directions of the indirect sound are set as ′ ₁ and ′ ₅ to reproduce an unprecedented spatial effect. You can also do it. It is also possible to continuously move a sound image based on a specific musical tone signal. By assembling the above circuit as the electronic musical instrument 17, it is possible to manufacture a stereophonic electronic musical instrument that can freely localize and move the musical instrument sound image around the listener 6.

The principle is shown in Fig. 7. The musical instrument signal is input to the input terminal 1, and the electric circuit means 11 can freely control the voltage level ratio between the six channel outputs _O1 to _O6.
(6-channel panpot) and is reproduced by six reproduction speakers SP1 to SP6. For example, when the instrument signal is output only from _O1 , speaker SP1
Played only from the sound image ○

Claims (1)

[Scope of Claims] 1. Keyboard switch circuit means for selecting a musical tone signal from a scale sound source, and timbre conversion circuit means for converting the musical tone signal supplied via the keyboard switch circuit means into a tone of an arbitrary musical instrument; indirect sound generating circuit means for creating an indirect sound of the output signal of the timbre converting circuit means, inputting the output signal of the timbre converting circuit means and the output signal of the indirect sound generating circuit means, and branching the signal into six channels. and a plurality of first electric circuit means for controlling the output level ratio between each channel, and each output of each of the first electric circuit means is summarized for each channel, and among the outputs of the six channels, the first output and the first electric circuit means are combined. 2 outputs directly,
The third and fourth outputs are provided via a second electric circuit means that localizes the sound image in the left and right directions of the listener, and the fifth and sixth outputs are provided through a second electric circuit means that localizes the sound image in two arbitrary directions behind the listener. It has a mixer that inputs signals through three electric circuit means, mixes these signals, and outputs them as a two-channel signal. A three-dimensional sound electronic musical instrument characterized by localizing a sound image of direct sound and indirect sound in a 360° direction around the instrument. 2. A keyboard switch circuit means for selecting a musical tone signal from a scale sound source, a timbre conversion circuit means for converting the musical tone signal supplied via the keyboard switch circuit means into a tone of an arbitrary musical instrument, and a timbre conversion circuit means for indirect sound generation circuit means for creating an indirect sound of an output signal; the output signal of the timbre conversion circuit means and the output signal of the indirect sound generation circuit means are input; the signal is branched into four channels; and the output signal is output between each channel. A plurality of first electric circuit means for controlling the level ratio and each output of each of the first electric circuit means are summarized for each channel, and among these four channel outputs, the first output and the second output are directly connected to each other.
The third output and the fourth output are respectively inputted via a second electric circuit means for localizing the sound image in the left and right directions of the listener, and a mixer that mixes these respective signals and outputs the mixture as a two-channel signal. 1. A three-dimensional sound electronic musical instrument, characterized in that the sound images of direct sound and indirect sound are localized in a direction 180° in front of a listener by a pair of speakers placed in front of the listener on the left and right sides.