JPH04306100A - Compact disk for sound field reproduction and sound field controller - Google Patents

Abstract

PURPOSE:To realize a CD from which a sound field intended by a CD manufacturer and to reproduce a more excellent sound field from the CD with respect to the sound field reproduction CD and the sound field controller. CONSTITUTION:The Compact Disk is a Compact Disk for a sound field controller generating an effect sound signal from an acoustic signal and reproducing a sound field by outputting the signal from a relevant speaker and into which music information, control information and sound field information relating to generate the effect sound signal are recorded. The sound field controller is a sound field controller to reproduce the signal of the Compact Disk comprising a reproduction means 2 for the Compact disk 1, an effect sound signal generating means 4 and a speaker system 5 is provided with an effect sound control means 6 to control the effect sound generating means 4 based on the sound field information.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a sound field control device and a compact disc for sound field reproduction, and more particularly to a compact disc which also records information regarding a sound field suitable for reproducing music recorded on the compact disc. The present invention relates to a disc and a sound field control device for playing the compact disc.

0002

[Prior Art] When listening to a performance in a concert hall, etc.
In addition to the sound generated by musical instruments, we also hear the reflected sound reflected from the surrounding environment, and this reflected sound determines the characteristics of the sound at the performance venue. FIG. 14 is a diagram showing temporal changes in sound detected at a certain listening point when sound is generated on a stage in a concert hall. As shown in Figure 14, the sound detected at the listening point is divided into direct sound that comes directly from the stage and reflected sound that is reflected from the surroundings. It can be divided into early reflected sound, which is the reflected sound of the sound, and reverberant sound, which is reflected many times and comes from all directions and gradually attenuates. The sound state formed by such direct sound and reflected sound is called a sound field.

[0003] A device called a sound field control device is in practical use, which reproduces sound equivalent to that heard in a concert hall using an audio system and reproduces a realistic sound field. The basic configuration of the sound field control device is shown in FIG. 15, and an acoustic signal corresponding to a direct sound is recorded in the acoustic signal source 12h. Sound corresponding to this acoustic signal is output from direct sound speakers 51h and 52h. At the same time, the sound effect generator 4h generates signals corresponding to early reflected sounds and reverberant sounds from the acoustic signal, and the corresponding speakers 5
Output from 7h, 58h and 59h. The initial reflected sound and reverberant sound generated by the sound field control device are collectively referred to as sound effects.

Sound field control devices are used in famous concert halls, churches, chamber music rooms, jazz clubs, etc.
Sound effect patterns such as those shown in , and artificially determined patterns are stored, and sound effect signals are generated according to the sound effect patterns selected by the user to match the music to reproduce a desired sound field. That's what I do. The acoustic signal that is the basis for reproducing the sound field is recorded on a record or compact disc (hereinafter referred to as C
It is called D. ) and is played back as an audio signal on a record player or CD player. In recent years, digital recording type CDs have come to be mainly used. Acoustic signals recorded on CDs and records are either recorded in a predetermined performance room or recorded as a performance in an actual concert hall or the like for the sole purpose of recording on these.

[0005]

[Problem to be solved by the invention] Therefore, it is difficult to record only direct sound, especially when recording at a concert venue.
The acoustic signal will also include reflected sound from the performance venue, that is, sound effects. As mentioned above, current sound field control devices create a sound field according to sound effect generation patterns stored in advance on the device side, on the premise that acoustic signals include only signals corresponding to direct sound. , the sound effect pattern is independent of the acoustic signal. Therefore, if a sound field is created according to a sound effect generation pattern from an acoustic signal that also includes sound effects, there is a problem in that the sound effect components included in the acoustic signal are doubled, making it difficult to hear and difficult to adjust. In addition, current CDs and records are not only intended for sound field control devices, but are also intended to be played on stereo audio systems, so recording only direct sound is insufficient. Sound effects are actively added so that you can hear the realistic sound even when played in stereo.

Furthermore, when considering the propagation of sound in an actual performance venue, the number of sound sources is not limited to one point, but is multiple. Particularly in the case of a large band such as an orchestra, many sound sources exist over a wide range, so current sound field control devices can only reproduce the direct sound of all sound sources from an acoustic signal. However, the current situation is that it is not possible to reproduce the desired sound field.

[0007] For the above-mentioned reasons, once recorded audio signals are used by people involved in the production of CDs and records, including people called mixers, with the assumption that they will be played back on a stereo audio system or sound field control device. By editing, it becomes an audio signal that is finally recorded on a CD or the like. However, current sound field control devices form a sound field by creating sound effects according to a predetermined sound effect generation pattern, regardless of the intention of producing a CD or record as described above. This poses a problem in that even if the sound effect generation pattern imitates the reverberation pattern of a famous concert hall, the sound effect will be far different from the sound actually heard at a concert venue.

[0008] Sound field control devices attempt to provide the sound and sense of presence as if you were at an actual concert venue, but they cannot reflect the intentions of the producers of CDs and records. At present, it cannot be said that a desired sound field can be obtained. Furthermore, if sound effects are inappropriately generated, sounds that are inferior to those of a normal stereo audio system may be reproduced. Of course, the sound effect generation pattern can be changed by the user's operation, and adjustments can be made to obtain the desired sound field.
In addition to being cumbersome to operate, there is a problem in that the intention of the producer of the CD or the like cannot be conveyed in any case.

The present invention has been made in view of the above problems, and although it is limited to CDs, it aims to realize a CD and a sound field control device that can reflect the intentions of the CD producer in the sound field control device. do.

0010

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention focuses on the fact that compact discs can record digital information. Sound field information related to sound effect generation to reproduce a sound field that is considered preferable,
Recorded as digital information on a compact disc. The sound field control device generates sound effects based on this sound field information to create a sound field. FIG. 1 is a diagram showing the basic configuration of a compact disc for sound field reproduction and a sound field control device according to the present invention. In the drawings, parts having the same functions are designated by the same numbers, and each block diagram other than that shown in FIG.

That is, the compact disc for sound field reproduction of the present invention uses a speaker system 5 composed of a plurality of speakers to generate a sound effect signal corresponding to reflected light in a predetermined space from an acoustic signal. A compact disc for use in a sound field control device that reproduces a sound field similar to a sound field in a predetermined space by outputting from a corresponding speaker, and reads and reproduces music information recorded with sound signals and the sound signals. Control information necessary for this and sound field information related to sound effect signal generation for reproducing a sound field suitable for music information are recorded.

Further, the sound field control device of the present invention is a sound field control device for reproducing the above-mentioned compact disc 1 for sound field reproduction, and includes a reproducing means 2 for reproducing information recorded on the compact disc 1; , a sound effect signal generating means 4 that generates a sound effect signal from the reproduced acoustic signal, and a speaker that is composed of a plurality of speakers and outputs a sound based on the reproduced acoustic signal and the generated sound effect signal from the corresponding speaker. The sound field control device comprising the system 5 is characterized in that it includes a sound effect control means 6 that controls the sound effect signal generation means 4 based on the reproduced sound field information.

[0013]

[Operation] Digital information can be recorded on a CD, including information regarding audio signals and control information necessary for the CD reproducing means 2 to read and reproduce the audio signals. Therefore, in addition to this information, the CD producer records sound field information on the CD to reproduce the preferred sound field intended at the time of CD production, and the sound field control device adjusts the effect based on the read sound field information. Generating sound makes it possible to reproduce a sound field that reflects the CD producer's intentions.

[0014]

[Embodiment] First, an embodiment of how to record sound field information on a CD will be described. Basically, the sound field information may be in any format as long as it is recorded according to predetermined rules so that it can be read and deciphered during playback. For example, it is possible to record the audio signal in the recorded lead-in information, but it is not easy to use this part due to the standards that have already been established.
An example of using a sub-coating block (hereinafter referred to as sub-code) will be described.

[0015] Each signal is recorded frame by frame on the CD in the format shown in FIG. Here, an 8-bit signal is recorded for each frame as a control signal,
Signals for 98 frames are collected to form one data block. This data block is called a subcode block and has a format as shown in FIG. As shown in FIG. 3, the first two frames of the subcode block are synchronization patterns, and the remaining 96 frames can be used. The 8 bits of data are assigned channel names from P to W in order, the P channel is used as a flag bit to indicate whether it is during a song or between songs, and the Q channel records the song number and time information. Although it cannot be used because it is
The other channels P to W are undefined areas, and sound field information can be recorded in these areas.

When reading subcodes from a CD, the time required to read one block is 1/75 seconds, and as will be described later, the necessary sound field information does not require a large capacity, and only one type of sound field can be read. Since a few blocks are sufficient to represent the data, there is no problem with reading time or the like even if subcodes are used. Next, a reproducing section that reads and reproduces signals from a CD in which sound field information is recorded in subcodes as described above will be explained. Usually, such a part is called a CD player, and a device that generates sound effects based on the audio signals played by the CD player is often called a sound field control device.
Here, the entire system will be referred to as a sound field control device.

FIG. 4 is a diagram showing the configuration of a CD player. Although the details of the CD player are widely known and will not be explained here, the part indicated by the broken line in FIG. After assembling the subcodes as information, it is output to the system controller 30b. Sound field information is recorded in this subcode according to a predetermined rule, and the system controller 30b displays the sound field information on the display operation section 29b to show the user what kind of sound field information has been added. or outputs sound field information to the subsequent sound effect generator.

Next, a section for generating a sound effect signal from the acoustic signal reproduced by the CD player in FIG. 4 and outputting it from the speaker system will be explained. Sound effect signals can be created using analog circuits, but digital signal processors (hereinafter referred to as DSP) are often used because they can handle multiple complex sound effect patterns, and the sound field control device of the present invention also uses this system. A DSP is used, and its configuration is shown in FIG. The DSP 41c is internally equipped with a large number of adders, amplifiers, and delay devices for digital signal processing, and includes a microprocessor 61c, ROM 62c, and RA.
A microcomputer consisting of an M63c configures a digital filter for generating sound effect signals by setting the coefficients of these amplifiers and delay devices.

[0019] The audio signal output from the CD player is L
It is divided into two channels, the channel and the R channel, and in this state it is a digital signal, so the D/A converter 461
c and 462c, the signal is amplified by amplifiers 471c and 472c, and then sent to the direct sound speaker 5.
They are output from 1c and 52c, respectively. This is a normal stereo audio system, but the sound field control device uses DS from the L channel and R channel audio signals.
Sound effect signal with digital filter made by P41c,
In other words, an early reflection sound signal and a reverberation sound signal are generated, and the D/A
Converters 463c to 466c convert into analog signals,
Amplified by amplifiers 473c to 476c and output to speaker 53c
It is output from 56c.

In the conventional sound field control device, coefficients of a digital filter for generating a predetermined sound effect signal are stored in advance in the ROM 62c, and these coefficients are set in the DSP 41c according to the user's selection. . Furthermore, when the user adjusts the sound effect, the amount of adjustment is detected and the set coefficient is changed. This embodiment further includes an I/O port 64c, which receives sound field information recorded on the CD from the system controller of the CD player, and sets coefficients in the DSP according to this sound field information. are doing.

Various types of digital filters are available for generating sound effect signals, and a typical example is shown in FIG.
The signal obtained thereby is shown in FIG. Figure 6(a)
is a digital filter called a finite impulse filter for early reflected sound, and (b) is a digital filter called an infinite impulse filter for reverberant sound. A signal as shown in FIG. 7 is obtained by the digital filter in FIG. 6, and each amplifier 421d in FIG.
to 426d, and 451d and 452d, delay device 411
The signal obtained changes by changing the coefficients from d to 414d and from 441d to 442d.

The relationship between the coefficients of each part of the digital filter in FIG. 6 and the shape of the signal shown in FIG. 7 is that if the input signal for early reflected sound is the direct signal shown in FIG. The interval between the first pulses corresponds to z0, and the interval between each pulse of the early reflected sound corresponds to z1 to z4. If at, which adjusts the intensity of the entire early reflected sound, is set to 1, then a0 to a4 correspond to the intensity ratio between each pulse. Reverberation can be considered in the same way.

Sound effect signals are generally generated as described above, but in what format is the sound field information representing the production intention of the CD producer recorded, and based on that sound field information? How to generate sound effect signals will be explained. One recording format is to show the relationship between the acoustic signal and the sound effect signal as shown in FIG. 14 at the listening point. Therefore, the relationship shown in FIG. 14 can be approximated by the signal shown in FIG. 7, and the sound effect signal generation in the sound field control device is shown in FIG.
Focusing on the fact that this is done by the digital filter shown in FIG. 7, the signal format shown in FIG. 7, that is, the value corresponding to the coefficient of the digital filter shown in FIG. 6, is recorded as sound field information. FIG. 8 shows an example of recording in this format in the subcode. It can be seen that if sound field information is recorded in this format, all sound field information can be recorded in one block of subcodes. What is important here is that the data in FIG. 8 is the relationship between generating a sound effect signal from an acoustic signal, and not the relationship between direct sound and reflected sound in the sound field that is formed.

When generating sound effect signals based on the sound field information shown in FIG. 8, it is necessary to consider the placement of each speaker that outputs direct sound and sound effects in the speaker system used for sound field reproduction. be. However, since speakers are often placed approximately equidistant from the listening point,
In the case of a digital filter, there is no problem even if the values in FIG. 8 are used as the coefficients of the digital filter as long as the output intensity is adjusted. If the digital filter installed in the sound field control device is not the one shown in FIG. 6, the values in FIG. 8 indicate the sound effect signal generation pattern. It is necessary to calculate the matched coefficients, but this can be easily done using a microcomputer.

The above is the sound field information when focusing only on the intensity of early reflected sound and reverberant sound as shown in FIG. It is necessary to generate and output a sound effect signal, taking into account the arrangement of the speakers. In order to perform such control, the sound field information to be recorded needs to take into consideration the speaker system. Therefore, it is conceivable to set a speaker system and a generation system for signals outputted from each speaker as a set, define a typical example in advance, and record these coefficients. An example is shown in FIG.

In the example shown in FIG. 9, the speaker system 5e is composed of six speakers, and the positional relationship of each speaker is determined to be within a certain range. The configuration for generating signals output from each speaker is also determined as shown in FIG. The coefficients of this sound effect signal generation section are determined as shown in FIG. 10, and these coefficients are recorded as sound field information. The coefficients of the early reflected sound generation section 44f and the reverberation sound generation section 45f are determined in the same manner as in the above example.

[0027] When the sound field information is determined as described above, it is necessary to determine a number of pieces of sound field information depending on the speaker system, etc., but in reality, the placement of the speakers and the signals output from them are basically the same. There are several types, and others can be considered variations of these. Moreover, in the system shown in FIG. 9, the coefficients that need to be recorded can be recorded in one subcode, so there is no problem in terms of recording capacity.

Recording of sound field information as described above can reproduce a good sound field if the playback system matches the system intended by the CD producer, but sound field information must be created for each target system. There is a problem in that the amount of work required to create sound field information increases. Therefore, we focused on the fact that considering the speaker system only requires considering the direction of the sound, and recorded the relationship between the acoustic signal and sound effect signal as shown in Figure 7 for each direction range as sound field information. , when playing back, a sound effect signal may be generated in accordance with the system used.

The format of the sound field information has been explained above, but
It can be seen that several subcode blocks are sufficient for the amount of data required to record sound field information. Therefore, not only one but multiple types of sound fields are created as intended by the CD producer, and each type is recorded as sound field information. It is desirable that the user be able to select his or her preferred sound field. This example will be explained.

FIG. 11 is a diagram showing the configuration of such an embodiment. In addition to the sound field control device described so far, display means 7g shows what kind of sound field information is available, and the user can select from among the display means 7g. 8g selection means for selecting your favorite sound field
It has. The display means 7g may be a currently used display device such as a CRT or an LED display, and the selection switch may also be an ordinary switch. However, in this case, it is necessary that data indicating the type of sound field is recorded, for example, as shown in Figure 12, the name expressed in an 8-bit code or the like is presented to the user. Data in a format that can be read and understood is required.

FIG. 13 is an example of displaying sound fields that can be selected, and is an example where different sound field information is recorded depending on the type of sound field and the size of the room in which the speaker system to be reproduced is placed. It is.

[0032]

According to the present invention, the sound field control device can reproduce the sound field as intended by the CD producer, and a better sound field can be reproduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic configuration of a CD for sound field reproduction and a sound field control device according to the present invention.

FIG. 2 is a diagram showing a signal recording format of a CD.

FIG. 3 is a diagram showing the configuration of a sub-coding block.

FIG. 4 is a diagram showing the configuration of a CD player.

FIG. 5 is a diagram showing the configuration of a sound effect generation section and a sound effect control section using a DSP.

FIG. 6 is a diagram showing a configuration example of a digital filter for generating sound effects.

FIG. 7 is a diagram showing a sound effect signal generated by the digital filter of FIG. 6;

FIG. 8 is a diagram showing an example of subcoding in which the coefficients of the digital filter shown in FIG. 6 are stored as sound field information.

FIG. 9 is a diagram illustrating an example of a configuration in which a configuration for generating a sound effect signal and a configuration of a speaker system are included as sound field information.

10 is a diagram showing coefficients of the sound effect generation section of FIG. 9; FIG.

FIG. 11 is a diagram showing the configuration of a sound field control device provided with functions for displaying and selecting a sound field recorded for a CD on which a plurality of types of sound field information are recorded.

FIG. 12 is a diagram showing an example of a subcode in which multiple types of sound fields are recorded.

FIG. 13 is a diagram showing an example of a display for a user to select from a plurality of types of sound fields recorded on a CD.

FIG. 14 is a diagram showing temporal changes in sound in a sound field formed by sound being reflected by surrounding walls in a space such as a concert hall.

FIG. 15 is a diagram showing the configuration of a sound field control device.

[Explanation of symbols]

1...CD 2...CD playback means 4...Sound effect signal generation means 5...Speaker system 6...Sound effect control means

Claims (3)

[Claims] [Claim 1] Using a speaker system (5) consisting of a plurality of speakers, a sound effect signal corresponding to the reflected sound between predetermined rooms is generated from an acoustic signal and output from the corresponding speaker. A compact disc for use in a sound field control device that reproduces a sound field similar to the sound field of the predetermined space, comprising music information recording an acoustic signal and control information necessary to read and reproduce the acoustic signal. and sound field information related to sound effect signal generation for reproducing a sound field suitable for the music information. 2. A sound field control device for reproducing the compact disc for sound field reproduction (1) according to claim 1, comprising a reproducing means (2) for reproducing information recorded on the compact disc (1). ), sound effect signal generation means (4) for generating a sound effect signal from the reproduced acoustic signal;
A sound field control device comprising: a speaker system (5) comprising a plurality of speakers and outputting sound based on a reproduced acoustic signal and a generated sound effect signal from the corresponding speakers; reproduced sound field information; sound effect control means (6) that controls the sound effect signal generation means (4) based on
) A sound field control device comprising: 3. The sound field control device according to claim 2, wherein the sound field control device plays back a compact disc in which a plurality of types of sound field information are recorded for the same acoustic signal, Display means (7g) for displaying information so that the type can be identified; and selection means (8g) for selecting sound field information to be used for sound effect generation from the plurality of displayed sound field information.
A sound field control device comprising: