JPH04225699A - Sound field controller - Google Patents

Abstract

PURPOSE:To facilitate sound field control by increasing a howling margin. CONSTITUTION:An A/D converter 9 receiving a signal from a microphone is connected to a howling detection means 21, which detects howling between the microphone collecting sound of a reproduction field and each reproduction speaker. A sound field control means 22 for which the howling detection means 21 is connected measures a howling limit level by a howling signal from the howling detection means 21 and stores a sound field data in the state of no occurrence of howling to a sound field data memory, and a signal processing means 10 sets a sound field data so as to increase a large howling margin by using the sound field data relating to the state of no occurrence of howling and the signal processing means 10 processes the input signal by using the sound field data to control the sound field.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention mainly relates to a sound field control device for creating an arbitrary sound field to be reproduced by signal processing and correcting the acoustic characteristics of a reproduction location. .

0002

[Background Art] In recent years, realistic sound field reproduction has become important, and sound field variable devices that can simulate the sound field of a hall, etc., and reflected sounds and reverberations that collect the sound in the hall with a microphone have been developed. Sound field control devices have been developed that extend the reverberation time and increase the sense of spaciousness in the hall.

FIG. 4 is a block diagram showing the configuration of a conventional sound field control system. In FIG. 4, a microphone 1 is connected to a microphone amplifier 2 and a subsequent sound field control device 3, and the sound field control device 3 performs signal processing on the sound picked up by the microphone 1 to create a target sound field. Further, the sound field control device 3 is connected to speakers 5a to 5h via amplifiers 4a to 4h for each channel, respectively, and reproduces and outputs sound field-controlled from each channel of the speakers 5a to 5h.

FIG. 5 is a block diagram showing the configuration of the sound field control device 3 in FIG. 4. In FIG. 5, a sound field menu selection means 6 for selecting a desired sound field is connected to a sound field data control means 7, and the sound field data control means 7 is connected to a sound field data memory 8. Sound field data is read out from the sound field data memory 8 according to the sound field menu selected by the selection means 6. Further, the A/D converter 9 to which the input terminal is connected and the sound field data control means 7 are connected to the signal processing means 10, and the signal from the microphone amplifier 2 is inputted to the A/D converter 9. After being D-converted, it is input to the signal processing means 10. At this time, the sound field data control means 7 sets the sound field data in the signal processing means 10 so that the sound field is inputted by the sound field menu selection means 6. Perform signal processing to match the scene. The signal processing means 10 is connected to D/A converters 11a to 11h for each channel,
The D/A converters 11a to 11h are connected to respective output terminals, and each channel is subjected to D/A conversion and then outputted from each output terminal.

The operation of the above configuration will be explained below. First, a signal picked up by the microphone 1 is amplified by the microphone amplifier 2 and then input to the A/D converter 9 of the sound field control device 3.The signal is converted into a digital signal by the A/D converter 9 and then converted into a signal. It is input to the processing means 10. On the other hand, the sound field data control means 7 calls out the sound field data matching the menu selected by the sound field menu selection means 6 from the sound field data memory 8 and transfers it to the signal processing means 10, thereby forming the selected sound field. Using the sound field data from the sound field data control means 7, the digital signal input to the signal processing means 10 is processed to control the sound field. The processed signals are converted into analog signals for each channel by D/A converters 11a to 11h, amplified by amplifiers 4a to 4h, and reproduced and output from speakers 5a to 5h for each channel. Ru. As a result, a sound field intended by the input user that matches the menu selected by the sound field menu selection means 6 is realized.

[0006]

[Problems to be Solved by the Invention] However, in the conventional configuration described above, the microphone 1 for collecting sound is often located far from the sound source, and in order to increase the sound collection level, it is necessary to use the microphone amplifier 2, amplifiers 4a to 4h, or signal processing. The gain of the means 10 must be increased and used. Then, howling occurs between microphone 1 and each speaker 5a to 5h,
The problem was that the sound field could not be controlled as desired.

The present invention solves the above-mentioned conventional problems, and aims to provide a sound field control device that can increase the howling margin and perform good sound field control. .

[0008]

[Means for Solving the Problems] In order to solve the above problems, the sound field control device of the present invention includes a howling detection means for detecting howling between a microphone that picks up sound in a reproduction field and each reproduction speaker; a sound field data memory for storing data for creating an arbitrary sound field; a signal processing means for signal processing an input signal to control the sound field using the set sound field data; and a howling signal from the howling detection means. The sound field data of a state in which howling does not occur is stored in the sound field data memory, and the sound field data in a state in which howling does not occur is stored in the sound field data memory during sound field data control. and sound field data control means that can set sound field data to the signal processing means so as to increase the howling margin using the field data.

Further, the sound field data control means in the sound field control device of the present invention automatically measures the howling margin for each sound field data and sets the level of the sound field data of the channel having the small howling margin in advance to be lowered. The configuration is such that the sound field data is set in the signal processing means.

Furthermore, the sound field data control means in the sound field control device of the present invention automatically measures the howling margin for each sound field data, and changes the frequency characteristics of the sound field data of the channel having a small howling margin in advance. The configuration is such that the signal processing means is set in the signal processing means.

Furthermore, the howling detection means in the sound field control device of the present invention detects howling in real time during a performance, and the sound field data control means reproduces the howling channel of the sound field data set in the signal processing means. The sound level is lowered, and the reproduced sound level of the sound field data of other channels is increased by the amount that the reproduced sound level is lowered, so that the overall reproduced sound level is kept constant.

0012

[Operation] With the above configuration, the channel of the speaker that causes howling is detected from among multiple speakers, the howling limit level is measured, the sound field data in a state where no howling occurs is stored in the sound field data memory, and the sound field data is During control, this measurement result is used to change the level and data structure of the collected sound and the sound field data used for signal processing to increase the howling margin, so that howling is less likely to occur without significantly changing the sound quality. It is possible to control the sound field using the collected sound as the sound source, for example to extend the reverberation time at the playback location or increase the sense of spaciousness.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the same reference numerals are given to those having the same functions and effects as those of the conventional example, and the explanation thereof will be omitted.

FIG. 1 is a block diagram showing the configuration of a sound field control device according to a first embodiment of the present invention. In FIG. 1, an A/D converter 9 into which a signal from a microphone 1 is input is connected to a howling detection means 21, and the howling detection means 21 connects a microphone 1 that picks up sound from a reproduction field and each reproduction speaker 5.
Howling between a and 5h is detected. The howling detection means 21 is connected to the sound field control means 22, and the sound field control means 2
A howling signal is output to 2. The sound field control means 22 is
In accordance with the sound field menu selected by the sound field menu selection means 6, sound field data is selected from the sound field data memory 8 which stores data for creating an arbitrary sound field and set in the signal processing means 10, or The howling limit level is measured by the howling signal from the howling detection means 21, the sound field data in a state where no howling occurs is stored in the sound field data memory, and the howling occurrence state stored in the sound field data memory at the time of sound field data control is measured. The sound field data is set in the signal processing means 10 so that a large howling margin is obtained by using sound field data in a state where there is no noise.

The operation of the above configuration will be explained below. First, the sound of a performance, lecture, etc. is inputted from the microphone 1, amplified to an appropriate level by the microphone amplifier 2, and then inputted to the sound field control device 3. The signal input into the sound field control device 3 is converted into a digital signal by the A/D converter 9 and input to the signal processing means 10. On the other hand, when the desired sound field is inputted by the sound field menu selection means 6, the sound field data control means 22 selects a sound field in which realizable sound field data is stored in advance by performing appropriate calculations in the signal processing means 10. The intended sound field is retrieved from the data memory 8, and the signal processing means 10 performs appropriate calculations to set the sound field data in the signal processing means 10. The signal processing means 10 processes the digital signal from the A/D converter 9 using the sound field data from the sound field data control means 22, and this signal processed signal is outputted for each of a plurality of channels and sent to the D/D converter 9. The signals are converted into analog signals by A converters 11a to 11h. The analog signals converted by the D/A converters 11a to 11h are amplified by amplifiers 4a to 4h for each channel, and then reproduced and outputted from the speakers 5a to 5h, respectively. The signal processing means 10 is equipped with eight channel outputs into which sound field data can be independently convolved.

Next, the sound field data is adjusted to increase the howling margin. First, sound field menu selection means 6
The sound field data control means 2 realizes the sound field selected in
2 to the signal processing means 10, data in which the sound field data level of the channel of the speaker 5a is gradually increased is transferred. The howling detection means 21 constantly detects howling occurring between the microphone 1 and the speaker 5a, and when howling occurs, the sound field data control means 22 lowers the sound field data level until the howling disappears. Store it in the data memory 8. Next, the next speaker 5
Increase the sound field data level of the channel output from b, and if howling occurs, perform the above operation. Repeat the above operations for all channels, and store the results as the sound field data of the selected data in the sound field data memory 8.
Remember it. This series of operations is performed for the sound field menu and microphone position to be realized.

For example, when giving an actual lecture, sound field data matching the microphone position and sound field data conditions of the lecture is selected from the sound field data memory 8, and the sound field data control means 22 selects the sound field data from the signal processing means 10. Set it to . By performing sound field control in this state, it is possible to realize sound field control with less howling.

As described above, by measuring the howling limit level of each speaker 5a to 5h and storing sound field data in a state where no howling occurs, sound field control can be realized in a state where the howling margin is large. .

[0019] In addition, if there is sufficient playback sound level,
To reduce the sound field data level of a speaker with the smallest howling margin to prevent the overall playback sound balance from being disrupted. Furthermore, if one speaker is extremely prone to howling, the sound field data level of surrounding speakers may be increased to adjust the playback sound balance.

[0020] In the first embodiment, one microphone and eight channel speakers were used, but a greater effect can be obtained by changing the number of microphones and channels depending on the size of the playback area, reverberation time, etc. It will be done.

FIG. 2 shows a flowchart of a sound field control device according to a second embodiment of the present invention, and other constituent elements are the same as those of the first embodiment. In FIG. 2, first, each speaker 5a
5h, start from channel 1 of speaker 5a. In step A1, signal processing is performed to convolute the input signal with sound field data, which is an impulse response of a hall, etc., to control the sound field, and in the next step A2, it is checked whether channel 1 is causing howling. When howling is detected by the howling detection means 21 in the same manner as in the first embodiment, information on the frequency of howling is transferred to the sound field data control means 22, and the process moves to step A3. Sound field data control means 2
In step 2, a filter coefficient for lowering the level of the howling frequency in that channel is calculated and transferred to the signal processing means 10. Here, the filter coefficient constitutes a notch filter for lowering only the howling frequency. The signal processing means 10 simultaneously performs calculations for realizing a notch filter and calculations for realizing a sound field based on the filter coefficients. The above operation is performed for each channel to realize a notch filter independently for each channel. That is, if there is no howling in step A2, step A after step A3
4, it is checked whether all eight channels of speakers 5a to 5h have finished. If not completed, step A5
Move to the next channel 2, Step A1 to Step A4
This is repeated and when all eight channels are completed, the process returns to step A1.

In this way, by setting a notch filter for each channel and playing back, it is possible to control the sound field to a level that does not cause howling without eliminating frequency components that are prone to howling, compared to when playing with only one channel. It can be performed.

Although the second embodiment uses a notch filter to suppress howling, an equalizer may also be used. FIG. 3 shows a flowchart of a sound field control device according to a third embodiment of the present invention, and other constituent elements are the same as those of the first embodiment. In FIG. 3, for example, during a performance, the howling detection means 21 always detects howling, and when howling is detected in step B1, the sound field data control means 22 adjusts the levels of all channels in step B2. In step B3, the sound field data with the level of all channels lowered by 1 dB is transferred to the signal processing means 10, and further, in step B3, it is checked whether the howling has been corrected. Steps B2 to B4 are repeated until the howling subsides. Once the howling has subsided, the process moves to the next step B5 and processing starts from channel 1. Next, in step B6, the sound field data control means 22 increases the level of the sound field data of channel 1 by 1 dB, and in step B7, the sound field data control means 22 increases the level of the sound field data of channel 1 by 1 dB.
The signal processing means 10 transmits the sound field data whose level has been raised by 1 dB.
In the next step B8, it is checked whether howling has occurred on channel 1. If it has not occurred, proceed to the next channel 2 in step B9 and proceed to step B.
Steps 6 to B8 are executed to check the presence or absence of howling on all channels to confirm which channel the howling has occurred on. When the channel in which howling has occurred is confirmed, the level of that channel is set to be lowered by 1 dB in step B10, and the other channels are returned to their original levels, that is, the desired sound field level. Then, in step B11, the sound field data lowered by 1 dB is transferred to the signal processing means 10. This operation is performed every time howling is detected. However, if you repeat this operation many times, the overall level of the playback sound will drop, so if the level is a certain level lower than the initially set level, it is likely that no other feedback is occurring. Slightly raise the channel level to prevent the playback sound level from dropping. This makes it possible to suppress howling with little change in volume.

As described above, the howling detection means 21 detects howling in real time during a performance, lowers the playback sound level of the channel where the howling has occurred, and
By increasing the playback sound level of other channels that do not cause howling by the amount that the playback sound level has decreased, it is possible to keep the overall playback sound level constant and control the sound field with a large howling margin.

[0025] In the third embodiment, when howling occurs, the volume level of that channel is lowered;
Similar effects can be obtained by changing the sound field data set in the signal processing means 10 as in the second embodiment.

[0026]

As described above, according to the present invention, the howling margin between the microphone and the speaker is automatically measured, and the level of the sound field data to be set in the signal processing means is determined based on the measurement result at the playback location. By setting each channel with the volume balanced, sound field control can be performed favorably with a large howling margin.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a sound field control device according to a first embodiment of the present invention.

FIG. 2 is a flowchart of a sound field control device according to a second embodiment of the present invention.

FIG. 3 is a flowchart of a sound field control device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing the configuration of a conventional sound field control system.

FIG. 5 is a block diagram showing the configuration of the sound field control device in FIG. 4.

[Explanation of symbols]

3 Sound field control device 8 Sound field data memory 10 Signal processing means 21 Howling detection means 22 Sound field data control means

Claims (4)

[Claims] Claim 1: Howling detection means for detecting howling between a microphone that picks up sound in a reproduction field and each reproduction speaker; and a sound field data memory that stores data for creating an arbitrary sound field; A signal processing means for signal processing an input signal to control the sound field using sound field data, and a howling signal from the howling detection means are inputted to measure a howling limit level, and sound field data in a state where no howling occurs is obtained. The signal processing means stores the sound field data in the sound field data memory and uses the sound field data stored in the sound field data memory in a state where no howling occurs during sound field data control so as to increase the howling margin. A sound field control device comprising a sound field data control means that can be set to. 2. The sound field data control means automatically measures the howling margin for each sound field data, and processes the sound field data in advance so as to lower the level of the sound field data of the channel with the small howling margin. 2. The sound field control device according to claim 1, wherein the sound field control device is configured to set. 3. The sound field data control means is configured to automatically measure the howling margin for each sound field data, change the frequency characteristic of the sound field data of the channel with the small howling margin in advance, and set it in the signal processing means. The sound field control device according to claim 1. 4. The howling detection means detects howling in real time during a performance, and the sound field data control means lowers the playback sound level of the howling channel of the sound field data set in the signal processing means, so that the playback sound level is lowered. 2. The sound field control device according to claim 1, wherein the reproduced sound level of the sound field data of the other channels is increased by the amount of the lowered sound field data, thereby making the overall reproduced sound level constant.