JP2006311071A - Howling prevention method, wireless microphone loudspeaker, karaoke equipment - Google Patents

Abstract

[PROBLEMS] To prevent howling when a wireless microphone is brought close to a speaker.
In a wireless microphone loudspeaker, a radio signal from a wireless microphone is received by a signal supplementer, an audio signal extracted from the received signal is amplified, and sound is output from a plurality of speakers installed separately from each other. A signal supplement is placed in close proximity to each of them, and the reception strength by each signal supplement is detected separately. When the reception strength by a certain signal supplement is excessive, it is placed close to the signal supplement. For the speaker, the acoustic output of the extracted audio signal is prohibited or suppressed.
[Selection] Figure 3

Description

  The present invention relates to a howling prevention technique in a loudspeaker using a wireless microphone such as a karaoke apparatus, and more particularly to a novel technique focusing on the distance between a wireless microphone and a speaker.

Various techniques for preventing howling in a loudspeaker are known. For example, Japanese Patent Laid-Open No. 8-130792 discloses a technique for predicting and suppressing a frequency band in which howling occurs by measuring a frequency characteristic of sound. Japanese Patent No. 2773656 discloses a technique for detecting howling by using a notch filter that detects a frequency band in which howling occurs and attenuates only the gain of the band.
Japanese Patent Laid-Open No. 8-130792 Japanese Patent No. 2773656

  With any conventional howling prevention technology, when a microphone is brought extremely close to a speaker, acoustic vibrations from the speaker are largely input to the microphone, and thus it is difficult to prevent howling.

A typical wireless microphone transmits a signal having an electromagnetic wave such as a microwave or infrared rays as a carrier wave. In the former type, the microwave antenna is a signal capturing device, and in the latter type, the infrared sensor is a signal capturing device. In any type, the closer the wireless microphone that emits the transmission signal is to the signal capturing device (antenna or infrared sensor, but representatively an antenna), the greater the reception strength by the antenna. That is, the smaller the distance between the antenna and the wireless microphone, the higher the reception strength by the antenna.
The inventor of this application pays attention to the above fact and thought that the reception strength by the antenna increases as the distance between the speaker and the wireless microphone decreases by setting the antenna on the speaker side. This idea was developed to create the present invention.

The howling prevention method according to the first invention is specified by the following items (1) to (4).
(1) A method for preventing howling in a wireless microphone loudspeaker that receives a radio signal from a wireless microphone with a signal capturing device, amplifies a microphone sound signal extracted from the received signal, and outputs sound from a plurality of speakers installed apart from each other (2) A signal capturing device is placed close to each speaker. (3) The reception strength by each signal capturing device is detected separately. (4) The reception strength by a certain signal capturing device is excessive. The sound output of the microphone audio signal should be prohibited or suppressed for the speakers located in the immediate vicinity of the signal trap.

  A wireless microphone loudspeaker according to a second aspect of the present invention includes a plurality of loudspeakers that are spaced apart from each other, a wireless microphone, and a plurality of signal captures that are arranged in close proximity to each speaker and that can receive a wireless microphone radio signal. , Detection means for detecting the reception intensity of each signal capturer separately, reception means for extracting the microphone sound signal from the reception signal of the signal capturer, and amplification for amplifying the microphone sound signal and outputting sound from each speaker And a control means for discriminating that the reception intensity by the signal capturing device has become excessive and prohibiting or suppressing the sound output of the microphone sound signal from the speaker disposed close to the signal capturing device. And

In the second invention, the following items (31) to (32) may be provided.
(31) The amplification means is one amplification circuit common to each speaker. (32) The control means includes a plurality of switches interposed in an output system that connects one amplification circuit and each speaker.

In the second invention, the following items (41) to (42) may be provided.
(41) The amplification means includes a plurality of amplification circuits for each speaker,
(42) The control means includes a plurality of switches interposed in an input path connecting the receiving means and each amplifier circuit.

  At this time, each amplifier circuit may mix and amplify an audio signal input from another system and a microphone audio signal.

In the second invention, it is desirable to include the following items (51) to (57).
(51) It is provided with a howling detection means, a memory, an initialization switch, and an operation mode control means. (52) The howling detection means analyzes the audio signal of the reception means to detect the occurrence of howling,
(53) The memory stores the received intensity data. (54) The initialization switch can be designated to input the initialization mode. (55) The operation mode control means is initialized when the initialization mode is designated. Mode, otherwise normal mode is performed (56) Initialization mode is that when the howling detection means detects howling occurrence, the received intensity data detected by the detection means is written to the memory (57) normal mode Compares the received intensity detected by the detection means with the received intensity data stored in the memory to determine whether it is excessive or not.

  In this case, the memory can store the reception intensity data for each of the plurality of detection means, and the initialization mode preferably writes the reception intensity data at the time of occurrence of howling to the memory for each detection means.

  Further, in the second invention, the receiving means may be a diversity receiving circuit that extracts a microphone sound signal by selecting a reception signal having a high reception intensity among the reception signals from the plurality of signal capturing devices. The amplification means may include gain adjustment means for variably setting the audio signal amplification gain, and the control means may set a criterion for determining whether or not reception is excessive according to the set gain of the gain adjustment means. .

  When the wireless microphone is brought close to the speaker, the reception intensity detected by the reception intensity detection means becomes excessive, the operation of the reception demodulation amplification means is suppressed or prohibited, and howling can be effectively prevented. In particular, when there are a plurality of speakers, only the output from a speaker that is likely to cause howling is suppressed or prohibited, so that the output from other speakers is continued, and the occurrence of howling can be prevented without a sense of incongruity for the audience.

=== Basic configuration and functions of karaoke equipment ===
An external view of a karaoke apparatus as a wireless microphone loudspeaker to which the present invention is applied is shown in FIG. 1, and an outline of an electrical system configuration is shown in FIG.

  The main computer 1 controls the entire karaoke apparatus. The hard disk device 2 stores various information such as a program of the main computer 1, a karaoke database, a video database, an operation record database, and a store visitor information table. The operation / display panel unit 3 can input various types of information by the user, and can display various types of information for the user. The communication control unit 7 communicates with an external karaoke server or a member information server via a communication line. In addition, communication with the portable computer 14 is possible via the wireless port 13. The portable computer 14 can exchange various information in an interactive manner with users participating in a karaoke gathering.

  The antenna 12 of the wireless microphone receiver 11 is close to each of the two speakers (10a, 10b) disposed on the left and right sides of the display device 6 (near the front of the cone paper of the speakers (10a, 10b)), Two units are installed. In the vicinity of the side of each speaker (10a, 10b), a holder (microphone organizer) 16 for storing or charging the unused wireless microphone 15 is disposed.

  The performance processing unit 8 performs stereo accompaniment music based on karaoke data under the control of the main computer 1, amplifies the right channel music signal by the right channel mixing amplifier 9a, and emits the sound from the right speaker 10a, The channel music signal is amplified by the left channel mixing amplifier 9b and emitted from the left speaker 10b. A radio signal (singer's singing voice) from the wireless microphone 15 is input to the wireless microphone receiving device 11 via the antennas (12a, 12b) and an audio signal is taken out, and left and right output switches (FIG. 3) described in detail below. 112a, 112b) and distributed input to the left and right mixing amplifiers (9a, 9b).

=== Wireless Microphone Receiver 11 ===
FIG. 3 illustrates a schematic configuration of the wireless microphone receiver 11. The wireless microphone reception device 11 includes two antennas 12 that receive radio signals from the wireless microphone 15, a diversity reception circuit 111 that demodulates and amplifies reception signals from the antennas 12 and outputs audio signals, and a diversity circuit 111. Receiving intensity is individually detected by the output switch circuits (112a, 112b) and the left and right antennas (12a, 12b) respectively interposed in the two systems that output the demodulated audio signals to the left and right mixing amplifiers (9a, 9b). A signal level detection circuit (113a, 113b) and a microcomputer 114 for overall control of these circuit systems are provided.

  As is well known, the diversity reception circuit 111 selects and demodulates a received signal having a better reception state (higher reception strength) from the two left and right antennas (12a, 12b). The signal level detection circuit (113a, 113b) is provided for each antenna (12a, 12b), and individually detects the reception intensity at the left and right antennas (12a, 12b). Then, the signal level detection circuit outputs a control signal for the right output switch 112a based on the reception strength by the right antenna 12a, and outputs a control signal for the left output switch 112b based on the reception strength by the left antenna 12b.

  The output switch circuits (112a, 112b) are configured to correspond to the left and right amplifiers (9a, 9b), respectively, and can individually turn on / off the output of audio signals to the left and right amplifiers (9a, 9b). ing.

  While the user is singing, the user approaches the speaker (10a, 10b) while holding the wireless microphone 15 in the hand, or returns to the microphone tidy device 16 with the wireless microphone 15 switched on. 10a and 10b), the strength of the carrier wave of the wireless microphone 15 received by the antennas (12a and 12b) increases. For example, when the wireless microphone 15 approaches the right speaker 10a and the reception intensity detected by the right signal level detection circuit 113a is equal to or higher than a predetermined reference value (described later) stored in an appropriate memory, the microcomputer 114 receives the signal. It is determined that the intensity is excessive, and the sound output from the speaker 10a adjacent to the right antenna 12a is stopped. That is, the right output switch 112a is switched off.

  Similarly, when the wireless microphone 15 approaches the left speaker 10b and the reception intensity detected by the left signal level detection circuit 113b becomes equal to or higher than the reference value, the microcomputer 114 determines that the reception intensity is excessive and sets the left output switch 112b. The sound output from the speaker 10b close to the left antenna 12b is stopped by switching off.

  As described above, since the sound output from the speakers (10a, 10b) where the howling is likely to occur is stopped, the occurrence of howling can be surely prevented. Moreover, since the sound output from the other speaker (10b, 10a) is continued, the sound output is not interrupted. In addition, since the output of the sound input from the wireless microphone 15 is also stopped at the speakers (10a, 10b) that are likely to generate howling, the sound output is continued without affecting the output of the karaoke accompaniment music. .

  After that, if the reception intensity of the antenna (12a, 12b) is lower than the reference value, the output switches (112a, 112b) that have been turned off are turned on again to the corresponding mixing amplifiers (9a, 9b). Resumes output.

The control means is not limited to the output switch circuit 112. When it is determined that the reception intensity is excessive, the sound output from the corresponding speakers (10a, 10b) may be suppressed to be attenuated so as not to generate howling without being stopped. Various circuit systems are possible for the suppression, and any circuit may be adopted.
In order to inhibit the output, the output switch circuit 112 is provided in the above-described embodiment, but various circuits for stopping the output of the audio signal can be configured.

=== How to set judgment criteria ===
There are various methods for setting a reference value for determining that the reception intensity is excessive. The determined reference value is stored in an appropriate memory.
In this embodiment, an initialization switch 115 for instructing the wireless microphone receiver 11 in the initialization mode is provided. When the initialization mode is designated and inputted by the administrator of the karaoke apparatus, the microcomputer 114 determines the reference value by the following initialization mode processing and sets it in the memory.

  In the initialization mode, the howling detection circuit 116 sequentially analyzes the frequency of the audio signal and monitors the presence or absence of howling. The administrator who has designated and input the initialization switch 115 gradually brings the wireless microphone 15 closer to the speaker. When the howling detection circuit 116 detects howling, the reception intensity detected by the signal level detection circuits (113a, 113b) at that time is stored in the memory. The above operation is repeated until a specified input for ending the predetermined initialization mode is made. When howling occurs multiple times, the minimum received intensity is stored in the memory. That is, when the detected reception intensity is smaller than the value stored in the memory, it is updated and stored.

  The reference value determined in this way may be a value common to the left and right speakers (10a, 10b), or may be set to each of the left and right speakers (10a, 10b). When the reference value is set individually, it is determined whether or not the reception intensity is excessive based on a different reference value for each speaker (10a, 10b) even in the normal mode.

If a value slightly smaller than the reception intensity at the time of howling is stored in the memory, howling can be prevented more reliably.
When the initialization mode is activated, a predetermined default value is stored in the memory in advance. A reference value that can prevent howling in a general environment is set (so as not to be too small). The default value may be rewritten only when the memory value set / updated when the initialization mode is activated last time is smaller than the default value.

  As a method for specifying the end of the initialization mode, for example, the initialization switch 115 may be pressed again. Alternatively, the automatic return type initialization switch 115 may be disposed in the wireless microphone 15 so that when it is pressed with a finger, it is regarded as an instruction input for the initialization mode, and when it is released, it is regarded as an instruction input for ending the initialization mode.

  As another method for determining the reference value, the reference value may be variably set in conjunction with the set value (audio signal amplification gain) of the volume adjustment (gain adjustment means) of the wireless microphone 15. That is, when the user can adjust the volume of the wireless microphone 15 and the microphone volume is set to be large, howling is likely to occur near the speakers (10a, 10b). The reference value to be set is set to a small value. On the other hand, when the volume is set low, howling does not easily occur even when approaching the speakers (10a, 10b), so that the reference value can be set to be inversely large.

  Note that the present invention can be applied in an overlapping manner with conventional howling prevention methods. Further, it can be applied to both a radio wave type wireless microphone and an infrared type wireless microphone.

=== Other Embodiments ===
When a wireless microphone loudspeaker according to the present invention is installed in a conference room or the like, as illustrated in FIG. 4, a large number of speakers (10a, 10b, 10c...) Are arranged widely scattered in the room. Is done. In this case, only the audio signal via the wireless microphone 15 is output from each speaker (10a, 10b, 10c...). The audio signal from the wireless microphone 15 is input to a single amplifier 9, distributed to each speaker (10a, 10b, 10c...) And emitted. In this case, the audio distributed from the amplifier 9 through the output switch circuit (112a, 112b, 112c...) In the output path from the amplifier 9 to each speaker (10a, 10b, 10c...). The output is turned on / off for each speaker (10a, 10b, 10c...). When a speaker or the like walks around with the wireless microphone 15 and approaches the speaker 10a, for example, and howling occurs, the switch 112a for the speaker 10a is turned off. Therefore, the audio output from the speaker 10a is completely stopped.

It is an external view of the karaoke apparatus which concerns on a present Example. It is a functional block diagram of the karaoke apparatus which concerns on a present Example. It is a functional block diagram of the wireless microphone receiver according to the present embodiment. It is a figure for demonstrating another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main computer 9a, 9b Mixing amplifier 10a, 10b Speaker 11 Wireless microphone receiver 111 Diversity receiving circuit 112a, 112b Output switch circuit 113a, 113b Signal level detection circuit 114 Microcomputer 115 Initialization switch 116 Howling detection circuit 12a, 12b Antenna 15 Wireless Microphone 16 Microphone Organizer

Claims (11)

A method for preventing howling in a wireless microphone loudspeaker that receives a radio signal from a wireless microphone with a signal capturing device, amplifies a microphone sound signal extracted from the received signal, and outputs sound from a plurality of speakers installed apart from each other. ,
Place a signal capturing device close to each speaker,
Detect the received strength by each signal capturer separately,
A howling prevention method for prohibiting or suppressing sound output of a microphone audio signal for a speaker arranged in the vicinity of a signal capture device when reception intensity by the signal capture device becomes excessive.   A plurality of speakers installed at a distance, a wireless microphone, a plurality of signal capturing devices that are arranged in close proximity to each speaker and can receive wireless microphone radio signals, and the reception intensity of each signal capturing device Separately detecting means, receiving means for extracting the microphone sound signal from the received signal of the signal capturing device, amplifying means for amplifying the microphone sound signal and outputting sound from each speaker, and reception intensity by the signal capturing device is excessive. A wireless microphone loudspeaker comprising: control means for discriminating the occurrence of the noise and prohibiting or suppressing the microphone sound signal from being acoustically output from a speaker placed close to the signal capturing device. The amplification means is one amplification circuit common to the speakers,
The wireless microphone loudspeaker according to claim 2, wherein the control means includes a plurality of switches interposed in an output system path connecting one amplifier circuit and each speaker. The amplification means includes a plurality of amplification circuits for each speaker,
The wireless microphone loudspeaker according to claim 2, wherein the control means includes a plurality of switches interposed in an input path connecting the receiving means and each amplifier circuit. The wireless microphone loudspeaker according to claim 4, wherein each amplifier circuit mixes and amplifies an audio signal input from another system and a microphone audio signal. The wireless microphone loudspeaker according to any one of claims 2 to 5, wherein the reception means is a diversity reception circuit that extracts a microphone sound signal by selecting a reception signal having a high reception intensity among reception signals from a plurality of signal capturing devices. apparatus. A howling detection means, a memory, an initialization switch, and an operation mode control means;
The howling detection means detects the occurrence of howling by analyzing the audio signal of the receiving means,
The memory stores the received strength data,
The initialization switch can be used to specify the initialization mode.
The operation mode control means performs the initialization mode when the designation of the initialization mode is input, otherwise performs the normal mode,
In the initialization mode, when the howling detection means detects howling, the reception intensity data detected by the detection means is written to the memory.
The wireless microphone loudspeaker according to any one of claims 2 to 6, wherein in the normal mode, the reception intensity detected by the detection means is compared with the reception intensity data stored in the memory to determine whether or not it is excessive. The wireless microphone loudspeaker according to claim 7, wherein the memory can store reception intensity data for each of a plurality of detection means, and the initialization mode writes reception intensity data at the time of occurrence of howling to the memory for each detection means. The amplification means includes gain adjustment means for variably setting the audio signal amplification gain,
The wireless microphone loudspeaker according to any one of claims 2 to 8, wherein the control means sets a criterion for determining whether or not reception is excessive in accordance with a set gain of the gain adjusting means. A plurality of spaced speakers, a wireless microphone, a microphone tidy device that is placed in close proximity to one of the speakers, and a wireless microphone that is placed in close proximity to each speaker. A plurality of signal capturing units capable of receiving signals, a detecting unit for detecting the reception intensity of each signal capturing unit, a receiving unit for extracting a microphone sound signal from the received signal of the signal capturing unit, and a plurality for each speaker An amplifier circuit that mixes and amplifies the microphone audio signal and the audio signal of karaoke accompaniment music input from the synthesizer and outputs the sound from each speaker, and the signal received by discriminating that the reception intensity by the signal trap is excessive. Control means for prohibiting or suppressing the sound output of the microphone sound signal from a speaker placed close to the trap; With a karaoke machine. The amplifier circuit includes a gain adjustment means for variably setting the audio signal amplification gain,
The karaoke apparatus according to claim 10, wherein the control unit sets a criterion for determining whether or not reception is excessive in accordance with a set gain of the gain adjusting unit.

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