JPS61219295A - Acoustic field simulator - Google Patents

Abstract

PURPOSE:To make it possible to adjust the direction of virtual sound source at a special point in an acoustic field that is provided by an acoustic simulator by locating plural balance control circuits with a branch structure at an acoustic signal generating circuit and connecting a speaker to each terminal. CONSTITUTION:By adjusting the output ratio of speakers S1 and S2 with the ratio control means RC1 of a balance control circuit BC1, the direction of the virtual sound source in the acoustic field by the speakers S1 and S2 is set approximately as that of an OP1. On the other hand, the output ratio of speakers S3 and S4 is adjusted with the ratio control means RC2 of the second balance control circuit BC2 and the direction of the virtual sound source in the acoustic field by speakers S3 and S4 is set approximately as that of an OP2. Furthermore, by adjusting the ratio of the input of the balance control circuit BC1 to that of the second balance control circuit BC2 with the ratio control means RC3 of the third balance control circuit BC3, a virtual sound P can be set at a prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an acoustic field simulator that simulates an acoustic field by adjusting the relative intensities of the outputs of a plurality of speakers.

b. Prior Art FIG. 4 is a block diagram of a conventional acoustic field simulator and a conceptual arrangement of speakers.

In this case, four speakers are arranged in a two-dimensional plane,
Each speaker S −, S b + S c, S a is connected to a preamplifier A *, A respectively from a single signal source SGa.
b, A c, A a and amplitude controllable amplifier circuit C-
, Cb, CC+ The signal sent via Ca is emitted as an acoustic signal.

When simulating that the sound source is at point P in Figure 4, the distance r between each speaker s, sb, sc, s and point P is
Calculate a+ rb+ rc+ r4 from the coordinates of each point,
Utilizing the fact that acoustic energy density is proportional to the inverse square of distance, the acoustic field created by a single sound source located at point P is simulated by adjusting the output of each speaker using the amplitude controllable amplifier circuit.

The output intensity of each speaker is adjusted by the amplitude controllable amplifier circuits c, cb, ce, C, which are controlled by the control means CNT, and the control procedure is performed in the form of software for each speaker arrangement. are input and exchanged.

C1 Problems to be Solved by the Invention In the case of conventional acoustic field simulators, even if the speaker arrangement slightly changes, it is not possible to use software for other arrangements, and the output intensity of each speaker must be calculated anew. Therefore, it has been difficult to deal with cases where the speaker arrangement is not symmetrical. It is an object of the present invention to propose an acoustic field simulator that can easily accommodate such a speaker arrangement, and can also quickly respond to when the speakers are moved.

Means for Solving the d0 Problem The above object has been solved by an acoustic field simulator that emphasizes the direction rather than the distance between the virtual sound source and each speaker.

That is, it consists of an acoustic signal generation circuit SC that generates an acoustic signal, and a pair of amplifier circuits having a common input terminal connected to the output terminal of the acoustic signal generation circuit SG or the output terminal of another balance control circuit, a plurality of balance control circuits BC having gain control means for controlling the gains while keeping the ratio of gains of both amplifier circuits constant; and ratio control means for changing the ratio of gains of both amplifier circuits; and an input terminal. consists of a power amplifier circuit connected to the output terminal of the balance control circuit BC, and a speaker connected to the rear stage of each of the power amplifier circuits, the acoustic signal generation circuit is connected to the first stage, and the plurality of balance control circuits The problem was solved by an acoustic field simulator characterized in that the circuit BC is arranged in a branch structure, and the loudspeaker is connected to each end of the branch structure.

00 Effect The speaker S disposed at the final stage of the acoustic field simulator according to the present invention is paired with another speaker St sharing one balance control circuit BC through a power amplification circuit, and the balance By manually or electronically controlling the ratio control means of the control circuit BCt, the virtual sound source P1 of the acoustic field created by the speakers s and St observed at a specific point 0 in the acoustic field created by the acoustic simulator is controlled. The direction can be adjusted.

Further, one speaker S3 other than the speakers s and St is paired with another speaker S4 that shares one balance control circuit BC2 via a power amplification circuit, and the ratio control means of the balance control circuit BCz By controlling , it is possible to adjust the direction of the virtual sound ill P t observed at the specific point 0 of the acoustic field produced by the speaker S3 Sa.

The input terminals of both the balance control circuits BCt and Bct are connected to a common third balance control circuit BC3, and
By controlling the ratio control means of the balance control circuit BC3, or by controlling the ratio control means of the balance control circuit BC3, or both balance control circuits BCzBC
By adjusting the gain control means of z, or by using both in combination, the position of the virtual sound source P can be changed.

Furthermore, the gain control means of each balance control circuit is controlled by utilizing the fact that the energy density of the acoustic field decreases according to the distance between the sound source and the observation point, and the gain control means of each balance control circuit is controlled from the above specific point 0 to the virtual sound source position. Change the distance to P.

The ratio control means and the gain control means of the balance control circuit can be controlled manually or electronically, or can be switched between manual adjustment and electronic control.

Embodiment FIG. 1 is a conceptual diagram of the acoustic field formed by the block diadam and speaker group of a preferred embodiment of the acoustic field simulator according to the present invention, and FIG. 2 (A) and (B)
are the four speakers S In S t, S 3 in Fig. 1.
゜Explanatory diagram conceptually showing the arrangement of a virtual sound source P in the acoustic field by S4, observation point 0, and speakers Sr and St, Fig. 2 (
C) has four speakers sl, St, 33. S4, observation point 0, speaker Sl, 3! , S3. FIG. 3 is an explanatory diagram conceptually showing the arrangement of virtual sound source positions P in the acoustic field according to S4.

Four speakers S in FIG. 1 1. S z, S 3.
S a is the power amplifier circuit PA1. P.A.W.
PA2 is connected to the output terminal of PA4, and the power amplifier circuits PA, PA2 are connected to the output terminal of the first balance control circuit BC, and the power amplifier circuits PAz, PA are connected to the output terminal of the first balance control circuit BC.
a is connected to the output terminal of the second balance control circuit BC, and the input terminal of the balance control circuit BC+, 8Cz is connected to the output terminal of the third balance control circuit BC3,
The input terminal of the third balance control circuit BC3 is connected to the output terminal of the acoustic signal generation circuit SG.

The first balance control circuit 8C, the second balance control circuit BC, and the third balance control circuit BCI each include gain control means GC+, GCt, and GCz and ratio control means RC+ and RCI RC3. By adjusting , the position of the sound source P of the acoustic field observed at a specific point 0 in the acoustic field can be changed.

There are many degrees of freedom in adjusting the gain control means and ratio control means, and there are various methods. Examples of these adjustment methods are shown below.

1. When driving only 2 out of 4 speakers Observation point 0 and 4 speakers S +, S z, S s
, S a, by a virtual straight line, the acoustic field is divided into four quadrants 1, n, III, and IV. For example, as shown in FIG. 2, the speaker S, centering on point 0,
When setting the virtual sound source P in the first quadrant, which is the area between SZ and SZ, for example, the gain of the second balance control circuit BC2 is set to zero by the gain control means GC2 of the second balance control circuit BC2. , Speaker S+.

Only S2 is driven. Note that this can also be achieved by setting the input of the second balance control circuit BC to zero by the ratio control means RC of the third balance control circuit BC3.

In this state, by adjusting the ratio control means RC of the first balance control circuit BC, the relative intensity of the outputs of the speakers S1 and S2 is changed, and the direction of the virtual sound source observed at the observation point O is changed.

When the speaker arrangement, the position of observation point 0, and the virtual sound source position P are specifically determined at the site, the ratio set by the ratio control means RC can be approximately determined by one of the following methods. can be determined.

! , as shown in FIG. 2(A), the speakers S1. The angle α formed by the position P of the virtual sound source at observation point O2, and the angle β formed by the position P of the virtual sound source, observation point O, and speaker S2 are measured, and the ratio of the outputs A, , A, of the speakers SI and St is determined. Adjustment is made by the ratio control means RC of the first balance control circuit BC so that the following equation is satisfied.

A: Az = sin α: sin β
(1)ii, as shown in Figure 2 CB), from the point P where the line segment connecting the speakers S1 and S2 intersects with the straight line connecting the observation point 0 and the position P of the virtual sound source, to the speaker S+,
Distances Ll and L2 to Sz are measured, respectively, and the ratio control means RC of the first balance control circuit BC+ is adjusted so that the ratio of the outputs A+ and Az of the speakers S, , SZ satisfies the following equation.

A+: Am =L+: Lx
(In both cases 21i and 21i, the ratio calculation and the control of the ratio control means RC can be performed using a microcomputer or using the scale of a potentiometer.

Note that the gain control means GC of the third balance control circuit BC3, depending on the distance from the observation point O to the position P of the virtual sound source,
By adjusting the distance, a sense of distance can be obtained.

When setting the virtual sound source position P in the second quadrant, which is an area centered on the point O and sandwiched between the speakers Sz and Ss, the first balance control circuit BC is used.

The power amplifier circuits PA'+, PA are controlled by the ratio control means RI of
The human power of a is set to zero and only the speakers SZ and 33 are driven.

The relative outputs of the speakers St and S are adjusted using the gain control means R of the first balance control circuit BC and the gain control means R2 of the second balance control circuit BC, and the output ratio is calculated using the gain control means R2 of the second balance control circuit BC. An expression similar to the previous expression (11, +21) can be used.Adjust the gain control means GC3 of the third balance control circuit BC3 according to the distance from the observation point 0 to the position P of the virtual sound source. This gives a sense of distance.

It is also possible to similarly set the position of the virtual quantity sp in the first quadrant and the second quadrant.

2. When driving four speakers For example, when setting the virtual sound source P in the first quadrant of FIG. 2(C), proceed as follows.

For example, when setting the virtual sound source P in the quadrant (2) of FIG. 2(C), the procedure is as follows.

Pl is the point where the straight line connecting speaker S1 and speaker S2 intersects with the straight line connecting observation point 0 and virtual sound source P, and speaker S3 is
P2, speaker S+, speaker S
2 and point P, respectively, L2, speaker Ss
, Sa and the point P2 are L:+ and L-, respectively.

Speaker S+, Sz.

The ratio of the outputs of (11 or 2) is adjusted by the ratio control means RC of the first balance control circuit flc, and the direction of the virtual sound source of the acoustic field by the speakers sl, s2. The output ratio of the other speakers Ss and Sa is (1)2 or (2).
), the ratio control means RCz of the second balance control circuit BC2 can adjust the direction of the virtual sound source of the acoustic field by the speaker 53S4 approximately to the direction of OPt.

Further, when the distances between the points P, , P and the virtual sound source P are respectively LS and Lm, the first balance control circuit BC
, to the input of the second balance control circuit BCt, by adjusting the ratio R of the input of the third balance control circuit BC3 so as to satisfy equation (3). It can be set in a predetermined position.

R= La / (Ls + Lm) 3. When driving 6 speakers Figure 3 shows a preferred embodiment of the acoustic field simulator according to the present invention when simulating an acoustic field using 6 speakers. FIG. 2 is a block diagram of the system and a conceptual diagram of an acoustic field formed by a group of speakers.

In the acoustic field simulator shown in Fig. 3, balance control circuits BC++, BC+□ are connected in place of the power amplifier circuits PA+, PAz in the block diagram of Fig. 1, and power is supplied to the output terminals of the balance control circuits BCz, BC+□, respectively. Amplifier circuit P8II+ PAI2 and PAz+, P
Connect Azz to the power amplifier circuit PA++, PA+□
, pAzt, pA, , speaker S Ia+ S
15. S 2□ szb are respectively driven.

Note that the configurations of the speakers Si, the second balance circuit BC for driving the speakers S4, etc. are the same as those of the acoustic field simulator shown in FIG.

Balance control circuits BC1+ and BC+z are ratio control circuits RCz and RC+, respectively, like other balance control circuits.
□ and gain control circuits GC,,,cc, , by adjusting the ratio of the outputs of the speakers S and 1°So, the position of the virtual sound source in the acoustic field due to the output of the speakers SIa+Sob can be changed from the speaker 5Ill+sob. It can be changed on the connecting straight line. For example, speaker S1□ 31k
When the outputs of are equal, the virtual sound source pHllb of the acoustic field generated by both speakers is located at the center of both speakers. Speaker S. Similarly for +Szb, the virtual sound source Ptmz
b can be provided. As a result, 4 speakers P1□
,.

This is equivalent to a simulator using P2□b, S3, and S4, and the output of each speaker can be adjusted using the method described above.

In order to ensure stable operation, it is preferable to use a dual type amplifier circuit in which two amplifier circuits are incorporated in one RC as the balance control circuit of the acoustic field simulator according to the present invention.

Furthermore, it is preferable that the amplifier circuit of the balance control circuit is provided with offset adjustment means in addition to ratio control means and gain control means. In this case, virtual i) Even when the symmetry of the speaker arrangement is low, it is possible to approximately simulate the acoustic field due to a single sound source based on the geometric arrangement of the speakers.

ii) A desired acoustic field can be simulated on-site in response to the placement of speakers or in response to changes in speaker placement.

iii) Although it is somewhat easy to determine the gain of each speaker from the distance between the virtual sound source and each speaker, it is very difficult to adjust the level between each speaker to give a sense of direction. Since the sound field simulator according to the present invention sets the position of the sound source with emphasis on the sense of direction, level adjustment can be easily and smoothly performed, and can therefore be achieved without causing any discomfort.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a preferred embodiment of the acoustic field simulator according to the present invention and a conceptual diagram of an acoustic field formed by a group of speakers, and FIG. 2 (^). (B) is an explanatory diagram conceptually showing a virtual sound source P of the acoustic field caused by the speakers S,,S,, and FIG. 2(C) is the speaker S,,S,. FIG. 2 is an explanatory diagram conceptually showing the position P of a virtual sound source in an acoustic field caused by S,,S. FIG. 3 is a block diagram of another preferred embodiment of the acoustic field simulator according to the present invention and a conceptual diagram of an acoustic field formed by a group of speakers, and FIG. 4 is a block diagram of a conventional acoustic field simulator and a conceptual diagram of the speakers. This is a layout diagram. SG...Acoustic signal generation circuit BCI BC2BC3...Balance control circuit RC, B
CI RCff...Ratio control means GCt GCz G
C2...gain control means PA, PAt PA,...
Power amplifier circuit St St S3 S4...Speaker 0
...Specific point P in the acoustic field...Virtual sound source of the acoustic field

Claims (4)

[Claims] (1) Consisting of an acoustic signal generating circuit SG that generates an acoustic signal, and a pair of amplifier circuits having a common input terminal connected to the output terminal of the acoustic signal generating circuit SG or the output terminal of another balance control circuit. , a plurality of balance control circuits BC having gain control means for controlling the gains while keeping the ratio of gains of both amplifier circuits constant and ratio control means for changing the ratio of gains of both amplifier circuits; It consists of a power amplifier circuit whose terminal is connected to the output terminal of the balance control circuit BC, and a speaker connected to the rear stage of each of the power amplifier circuits, the acoustic signal generation circuit is connected to the first stage, and the plurality of balance control circuits An acoustic field simulator characterized in that the control circuit BC is arranged in a branch structure, and the speaker is connected to each end of the branch structure. (2) The acoustic field simulator according to claim 1, wherein the balance control circuit is a dual type amplifier circuit. (3) The acoustic field simulator according to claim 1, wherein the balance control circuit includes offset adjustment means. (4) The acoustic field simulator according to claim 1, wherein the number of speakers is four.