JPH0591596A - Multichannel stereo reproduction system - Google Patents

Abstract

PURPOSE:To obtain a faithful reproduction sound over the entire wall of a reproduction sound field. CONSTITUTION:A plurarity of speakers 1 are arranged all over the wall of the reproduction sound field, the parameter of the reflected sound obtained in each position of the wall surface of the virtual space of the same type as the reproduction sound field set in the original sound field is provided for each speaker 1. It is connected with a voice signal processor 2, and the reflection sound on the wall of the original sound field is electrically processed, and the sound signal processor 2 to be controlled is connected. By inputting a signal to this voice signal processor 2, a sound which can be heard when a sound from the sound source is reflected and reached to the virtual space in the original sound field can faithfully be reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-channel stereo reproduction system.

SUMMARY OF THE INVENTION The present invention relates to a multi-channel stereo system, in which a plurality of speakers installed on a wall of a reproduced sound field are driven so that a sound heard in a part of a space of an actual sound field can be heard. It is intended to be realistically reproduced.

[0003]

2. Description of the Related Art Conventionally, the concept of a sound field creation system as a multi-channel stereo reproduction system is M.Camras (1967.1) HF.
Proposed by Olson (1968.10). The sound field creation system proposed by them is a system in which a microphone output installed on a virtual wall of the original sound field is connected to a speaker in a reproduction sound field corresponding to the microphone and reproduced.

Further, in a sound field simulation system of a research institute related to architecture, a reflected sound structure from a sound source of a room to be simulated to a sound receiving point is obtained in advance, and a plurality of sound waves are installed around a reproduced sound field. There is a method in which a time series of reflected sound from a speaker is convoluted into a sound source signal without reverberation and reproduced (for example, Yuji Korenaga, "Sound Field Simulator" sensor technology, Vol.9 (11) PP17-23.1989).

[0005]

[Problems to be Solved by the Invention] However, the conventional M.Ca
The method proposed by mras et al. (1) The sound used for reproduction is limited to that picked up by a microphone installed on the virtual wall in the original sound field, and (2) the conditions for the original sound field and the virtual wall are limited. Therefore, it lacks applicability to other sound fields and expandability. (3) It is difficult to control the directivity of the microphone used in the original sound field and the speaker placed at the corresponding position in the reproduced sound field. 4) The number of channels for transmitting between the original sound field and the reproduced sound field is the same as the number of microphones, and it is extremely difficult to realize.

Further, in a sound field simulation system by a research institute related to architecture, (1) the number of speakers is small, so that the sound connection between the speakers is not continuous, and (2) the reproduced sound is essentially There is a problem that it is a one-point reproduction in the field and cannot be reproduced over a wide listening range.

The present invention has been made in view of the above-mentioned problems of the prior art, and by arranging a large number of small speakers on the wall surface of the reproduced sound field, the spatial continuity and directivity of the reproduced sound can be improved. The original sound field can be faithfully reproduced in the reproduced sound field by using the simulation technology based on the original sound field design drawing, and the speaker placed on the entire wall of the reproduced sound field can be controlled. By controlling the directivity, good sound field reproduction performance can be obtained over a wide range, and the reflected sound can be faithfully reproduced by transmitting only different sound sources in the original sound field. It is an object of the present invention to provide a multi-channel stereo reproduction method that can reduce the number of stereo channels.

[0008]

In the multi-channel stereo reproduction system of the present invention, a large number of speakers are arranged on the wall surface of the reproduction sound field, and the speakers have a virtual sound field of the same type as the reproduction sound field set in the original sound field. A parameter of reflected sound obtained at each position on the wall surface of the space is obtained in advance, and a sound signal processing device in which the parameter is set is connected, and a signal is input to each of the sound signal processing devices.

Further, in the multi-channel stereo reproduction system of the present invention, a large number of speakers are arranged on the wall surface of the reproduction sound field, and the sound signal processing for electronically processing and controlling the reflected sound on the wall surface of the original sound field in the speaker. A device is connected and a signal is input to each of the sound signal processing devices.

[0010]

In the multi-channel stereo reproduction system of the present invention, a large number of speakers are arranged on the wall surface of the reproduction sound field, and for each speaker, each wall surface of the virtual space of the same type as the reproduction sound field set in the original sound field is arranged. Connect the sound signal processing device that obtains the parameter of the reflected sound obtained at the position in advance and sets the parameter, or connect the sound signal processing device that electronically processes and controls the reflected sound on the wall surface of the original sound field. By directly inputting the sound source signal to each of the sound signal processing devices, the sound that can be heard when the sound from the sound source is actually reflected and arrives in the virtual space in the original sound field is faithfully reproduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to claim 1 of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing a detailed internal configuration of a signal processing device.

In the multi-channel stereo reproduction system of this embodiment, as shown in FIGS. 1 and 2, a large number of speaker groups 1 arranged over the front surface of the wall surface W of the reproduction sound field.
1, ... Signal processing device 2, which is connected to each
2, and signal processing device driving devices 3, 3, ..., Which control the operations of the signal processing devices 2, 2 ,. The reproduced signals input and processed by the signal processing devices 2, 2, ... Are given to the respective speaker groups 1, 1 ,.

As shown in FIG. 2, each signal processing device 2 sets a delay time of the reflected sound with respect to the sound source signal S and adjusts the direction of the digital delay circuits 21, 21, ..., Reflected sound and reverberant sound. Gain adjusting circuits 22 and 2 for setting the magnitude of
2, ..., A reverberation adding circuit 23 that outputs a reverberation waveform having a certain reverberation time-frequency characteristic (frequency characteristic of reverberation time) to the input, and a digital that sets the delay time of the input of the reverberation adding circuit 23. It comprises a delay circuit 24.

Next, the operation of the multi-channel stereo reproduction system of the above embodiment will be described.

FIG. 3 shows the stage St of the concert hall B.
The operation of the system in the case where there is one sound source S above and the sound obtained from the sound source S at the position of the wall surface W of the virtual space PS is faithfully reproduced on the wall surface W of the reproduction sound field will be described. .. Even if there are a plurality of sound sources, it can be easily realized by expanding the following description. As the sound used for the sound source signal S shown in FIG. 2, a direct sound having no reverberant sound obtained by a sound collecting method such as on-microphone is used.

Speakers 1 installed on the wall surface W of the reproduction sound field
1, ... Are arranged as shown in FIG. 4, and as a basic configuration thereof, a speaker interval of D, M in the horizontal direction, and N in the vertical direction is adopted.

With such an arrangement, the speaker group 1, which can be used in common, is used.
It is possible to increase the degree of freedom in directivity control of each of the speaker groups 1, ..., And to efficiently use the entire speaker group 1, 1 ,.

The digital delay circuit 21 of the signal processing device 2 shown in FIG. 2 delays an input signal for a predetermined time and outputs the input signal, whereby M × N speaker groups 1, 1 ,.
When the main beam of ... is directed to zenith angle θ0 and azimuth angle φ0,
The combined directivity in the (θ, φ) direction is expressed by the following equation.

[0020]

[Equation 1]

And a _kl represents the gain of the amplifier with respect to the speaker group at the position (kD, 1D).

Therefore, as shown in FIG. 3, the original sound field D is cut in a virtual space PS having the same size and shape as the reproduced sound field, and the sound image localization of the reflected sound passing through the wall surface W of this virtual space is performed.
The delay time, the magnitude, and the direction of the initial reflected sound up to 80 msec after the arrival of the direct sound that is important for the auditory sense such as the spread of the sound image are set by the digital delay circuit 21 and the gain adjustment circuit 2 respectively.
2 to match the reproduced sound field PS speaker group 1,
Reproduce using 1, ...

For the delay time, the magnitude, and the direction of the reflected sound at this time, the result of the sound field simulation calculated based on the design drawing of the concert hall B in advance is used.

As a method of this sound field simulation, basically, a method called a mirror image method is used, and a sound emitted from one point sound source S is reflected by a flat surface such as a wall surface, A virtual sound source (which is called a mirror image sound source) S ′ at a position symmetrical to the point sound source is replaced with a sound emitted from the virtual sound source, and the sound reflected by a plurality of wall surfaces in the concert hall B is located at a position symmetrical to the sound source on each wall surface. Is obtained as the sum of the sounds emitted from the mirror image sound source S '.

Here, paying attention to one reflected sound, first, the position of the mirror image sound source is obtained, and the propagation path from the sound source of the reflected sound is obtained from this position, whereby the arrival time of the reflected sound from the sound source S and the reflection You can know the sound level. Also,
Since the propagation time of the direct sound from the sound source S can be easily obtained, it is possible to easily know how late the reflected sound comes from the direct sound by dividing the difference between the lengths of the paths by the speed of sound. be able to. Further, the direction of the reflected sound can be known from the position of the mirror image sound source.

Therefore, in order to reproduce the reflected sound (which is referred to as the initial reflected sound) up to 80 milliseconds after the direct sound arrives, the virtual space PS obtained by the simulation is used.
For each reflected sound that arrives within 80 milliseconds after the sound directly arrives at the wall surface W of the speaker group 1, the speaker groups 1, 1,
The delay time, the magnitude, and the direction obtained by simulation in advance are set for each speaker, and the original sound source signal S having no reflected sound is simultaneously input to each speaker 1,
It is possible to faithfully reproduce the initial reflected sound in the reproduced sound field PS from the 1, ... group.

Further, the reflected sound after 80 milliseconds (this is called a rear reverberation sound) increases the number of the reflected sounds arriving at the wall surface W of the virtual space PS per unit time in a series, so that It is not only physically difficult to faithfully reproduce, but also it is not possible to distinguish the reflected sounds one by one from the viewpoint of hearing, so it is not necessary to reproduce it exactly, so the digital delay circuit is used to convert the original sound source signal. After a delay of 80 milliseconds, a reverberation time-frequency characteristic that matches the original sound field is added by the reverberation adding circuit 23 and the gain adjusting circuit 22 and reproduced.

In this way, when the virtual space PS having the same space as the reproduced sound field is placed in the original sound field B, the reflection sound received at each position of the wall surface W is obtained by simulation. The delay time, the magnitude, and the direction parameter of the reflected sound are preliminarily provided from the signal processing device driving device 3 to the digital delay circuits 21, 21 ,. The sound source signal S, which is transferred to the circuit 23 and the digital delay circuit 24 in advance and contains almost no reverberant sound or reflected sound, is given to each speaker group 1, 1, ... Through these signal processing devices 2, 2 ,. Each speaker group 1,
1, ... faithfully reproduces the reflected sound obtained on the wall surface W of the virtual space PS of the original sound field B shown in FIG. 3 on the wall surface W of the reproduced sound field, thereby faithfully reproducing the original sound field within the reproduced sound field. You can do it.

The sound field simulation method used in the present invention is not limited to the mirror image method, and various other proposed methods can be arbitrarily used. Further, in the present invention, the time for distinguishing the early reflection sound and the rear reverberation sound is not limited to 80 milliseconds after the direct sound arrives, and any time can be used.

Next, an embodiment according to claim 2 of the present invention will be described. The block diagram showing the configuration block of the multi-channel reproduction system of this embodiment and the internal configuration of the signal processing device are common to the configuration of the embodiment of claim 1, and are shown in FIG. 1 and FIG. ..

Therefore, the operation of the embodiment according to claim 2 will be described.

FIG. 5 shows the stage S of the concert hall B.
The operation of the system in the case where there is one sound source S on t and the sound from this sound source S is reproduced in the reproduction sound field will be described. Even when there are a plurality of sound sources, it can be easily realized by expanding the following description.

The reproduced sound field PS is obtained by reducing the original sound field B by a certain ratio. At this time, the wall surface of the original sound field and the wall surface of the reproduced sound field have a one-to-one correspondence. For example, a region B ₁ of the wall surface of the original sound field corresponds to a region W ₁ of the wall surface of the reproduced sound field. Therefore, the reflected sound at each point on the wall surface of the original sound field is calculated, and the digital delay circuits 21, 21, ..., Gain adjustment are performed so that the sound is faithfully reproduced by the speaker at each point on the wall surface corresponding to the reproduced sound field. The circuits 22, 22, ..., The reverberation adding circuit 23, and the digital delay circuit 24 are set. The signal processing circuits 2, 2, ...
Through the sound source signal S through the speakers 1, 1, ...
To reproduce the original sound field faithfully in the reproduced sound field. The reproduced sound field is not limited to the original sound field reduced, and a similar shape may be used.

[0034]

As described above, according to the present invention, the delay time, the magnitude, and the direction parameter of the reflected sound obtained at each position of the wall surface of the virtual space set in the original sound field are obtained by the sound field simulation. Correspondence of the reproduced sound field by reproducing from each of the loudspeaker groups arranged on the wall surface in the reproduced sound field of the same size as this virtual space or by calculating the reflected sound at each point of the wall surface of the original sound field by calculation. Since this is reproduced by the speaker at each point on the wall surface, it is possible to faithfully reproduce the original sound field, and in particular, it is possible to reproduce the sound field with a large degree of freedom including the direction of the reflected sound. In addition, by arranging a group of speakers that efficiently aggregates a plurality of speaker units on the wall surface of the reproduced sound field, it is possible to reproduce the sound field more efficiently while faithfully reproducing the directivity at each part of the wall surface. Become.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a signal processing device in the above embodiment.

FIG. 3 is an explanatory diagram showing a relationship between a reproduced sound field and an original sound field in the above embodiment.

FIG. 4 is an explanatory diagram showing an arrangement of speakers in a reproduced sound field in the above embodiment.

FIG. 5 is an explanatory diagram showing a relationship between a reproduced sound field and an original sound field according to another embodiment of the present invention.

[Explanation of symbols]

1 speaker group 2 signal processing device 3 signal processing device drive device B original sound field B ₁ area of wall surface of original sound field PS reproduced sound field (and virtual space) W wall surface of reproduced sound field W ₁ wall surface of reproduced sound field Area St Concert hall stage (original sound field) S Sound source 21 Digital delay circuit 22 Gain adjustment circuit 23 Reverberation addition circuit 24 Digital delay circuit

Claims (2)

[Claims] 1. A large number of speakers are arranged on a wall surface of a reproduced sound field, and a parameter of a reflected sound obtained at each position of a wall surface of a virtual space of the same type as the reproduced sound field set in the original sound field is provided to the speaker. A multi-channel stereo reproduction system in which a sound signal processing device, the parameters of which have been determined in advance and whose parameters have been set, is connected and a signal is input to each of the sound signal processing devices. 2. A plurality of speakers are arranged on the wall surface of the reproduced sound field, and a sound signal processing device for electronically processing and controlling reflected sound on the wall surface of the original sound field is connected to the speaker, and the sound signal processing is performed. A multi-channel stereo playback system in which signals are input to each device.