JP4149453B2 - Howling prevention method, wireless microphone loudspeaker, karaoke equipment - Google Patents

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.
JP-A-8-13079 Japanese Patent No. 2773656

  In any conventional howling prevention technology, if the microphone is brought extremely close to the 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 using an electromagnetic wave such as a microwave band or an infrared ray as a carrier wave. In the former type, the microwave antenna is a radio signal receiving means, and in the latter type, the infrared sensor is a radio signal receiving means. In any type, the closer the wireless microphone that emits the transmission signal is to the wireless signal receiving means (which is an antenna or an infrared sensor, but representatively an antenna), the greater the reception intensity 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 installing the antenna on the speaker side. This idea was developed to create the present invention.

The wireless microphone loudspeaker according to the present invention is specified by the following items ( 1 ) to ( 13 ).
( 1 ) A wireless microphone loudspeaker including a radio signal receiving unit, a reception demodulation amplification unit, a speaker, a reception intensity detection unit, a reception control unit, a control unit, a howling detection unit, a memory, and an initialization switch ( 2 ) The radio signal receiving means is disposed close to the speaker and can receive a radio signal from the wireless microphone. ( 3 ) The reception demodulation amplifying means receives the signal received by the radio signal receiving means. ( 4 ) The speaker outputs the audio signal of the reception demodulation amplifying means acoustically. ( 5 ) The reception intensity detection means detects the reception intensity by the radio signal reception means ( 6 ). reception control means suppresses or prevents that it (7) control means the operation of receiving and demodulating amplifying means under the control of the control means, receiving strong reception intensity detection means detects When becomes excessive, suppression or to prohibit the operation of receiving and demodulating amplifying means by the reception control means
(8) The howling detection circuit detects the occurrence of howling by analyzing the audio signal of the reception demodulation amplifying means.
(9) The memory stores received intensity data
(10) The initialization switch can be used to specify the initialization mode.
(11) The control means performs the initialization mode when specifying the initialization mode, and otherwise performs the normal mode.
(12) In the initialization mode, when the howling detection means detects the occurrence of howling, the reception intensity data detected by the reception intensity detection means is written to the memory.
(13) In the normal mode, the reception intensity detected by the reception intensity detection means is compared with the reception intensity data stored in the memory to determine whether it is excessive or not.

The wireless microphone loudspeaker according to the present invention is specified by the following items (21) to (27).
(21) A wireless microphone loudspeaker comprising radio signal reception means, reception demodulation amplification means, speakers, reception intensity detection means, reception control means, and control means.
( 2 2) Radio signal receiving means should be placed close to the speaker and receive radio signals from the wireless microphone.
(23) The reception demodulation amplification means includes a gain adjustment means for demodulating the reception signal by the radio signal reception means and outputting an audio signal, and variably setting the audio signal amplification gain.
(24) The speaker outputs sound signals of the reception demodulation amplifying means acoustically.
(25) The reception strength detection means detects the reception strength by the wireless signal reception means.
(26) The reception control means suppresses or prohibits the operation of the reception demodulation amplifying means under the control of the control means.
(27) The control means suppresses or prohibits the operation of the reception demodulation amplifying means by the reception control means when the reception intensity detected by the reception intensity detection means becomes excessive, and receives according to the set gain of the gain adjustment means. Changing criteria for determining whether strength is excessive
The karaoke apparatus according to the present invention includes a wireless microphone, a microphone tidy device, a radio signal receiving unit, a reception demodulation amplification unit, a speaker, a reception intensity detection unit, a reception control unit, and a control unit. A karaoke apparatus that mixes and amplifies karaoke accompaniment music and singing voice and outputs the sound, and is specified by the following items (31) to (38).
(31) A wireless microphone must be held by a singer and capable of singing voice input.
(32) The microphone tidy device should be placed close to the speaker and keep the wireless microphone tidy.
(33) The wireless signal receiving means is disposed close to the speaker and can receive a wireless signal from the wireless microphone.
(34) The reception demodulation amplification means includes a gain adjustment means for demodulating the reception signal by the radio signal reception means and outputting an audio signal and variably setting the audio signal amplification gain.
(35) The speaker acoustically outputs a mixed signal of the audio signal of the reception demodulation amplifying means and the audio signal of karaoke accompaniment music.
(36) The reception strength detection means detects the reception strength by the wireless signal reception means.
(37) The reception control means suppresses or prohibits the operation of the reception demodulation amplifying means under the control of the control means.
(38) The control means suppresses or prohibits the operation of the reception demodulation amplifying means by the output control means when the reception intensity detected by the reception intensity detection means becomes excessive, and receives according to the set gain of the gain adjustment means. Changing criteria for determining whether strength is excessive

  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.

=== Basic configuration and functions of karaoke equipment ===
FIG. 1 shows an external view of a karaoke apparatus as a wireless microphone loudspeaker to which the present invention is applied, and FIG. 2 shows an outline of its electrical system configuration.

  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 performance processing unit 8 performs accompaniment music based on the karaoke data under the control of the main computer 1 and emits the sound through the speaker 10 via the mixing amplifier 9. A wireless signal (singer's singing voice) from the wireless microphone 15 is input to the wireless microphone receiving device 11 via the antenna (wireless signal receiving means) 12, an audio signal is taken out, and input to the mixing amplifier 9. Two antennas 12 of the wireless microphone receiver 11 are installed in proximity to the two speakers 10 arranged on the left and right of the display device 6 (in the vicinity of the front of the cone paper of the speaker 10). A storage holder (microphone organizer) 16 for a wireless microphone 15 that is not in use is disposed beside each speaker 10.

  Various video information related to the karaoke performance is provided to the user by the video memory 4, the display processing unit 5, and the display device 6 under the control of the main computer 1. For example, during a karaoke performance, a karaoke video accompanied by a lyrics telop is displayed, and a scoring process and results are also displayed. During the performance pause, various information such as information indicating the performance reservation status, music-related advertising information, karaoke-related information such as this week's best ten are displayed.

=== Wireless Microphone Receiver 11 ===
FIG. 3 illustrates a schematic configuration of the wireless microphone receiver 11. The wireless microphone receiver 11 includes two antennas 12 that receive radio signals from the wireless microphone 15, and a diversity reception circuit (reception demodulation amplification means) 111 that demodulates and amplifies reception signals from the antennas 12 and outputs audio signals. An output switch circuit (reception control means) 112 interposed in a system for outputting the audio signal demodulated by the diversity reception circuit 111 to the mixing amplifier 9, and a signal level detection circuit (reception intensity detection means) for detecting the reception intensity by the antenna 12. ) 113 and a microcomputer (control means) 114 for overall control of these circuit systems.

  As is well known, the diversity receiving circuit 111 selects and demodulates and amplifies the received signal of the two antennas 10 having the better reception state (the reception intensity is higher).

  When a user approaches the speaker 10 while holding the wireless microphone 15 while singing, or returns to the microphone tidy device 16 with the wireless microphone 15 switched on, the wireless microphone 15 approaches the speaker 10. The intensity of the carrier wave of the wireless microphone 15 received by the antenna 12 increases. When the reception intensity detected by the signal level detection circuit 113 becomes equal to or higher than a predetermined reference value (described later) stored in an appropriate memory, the microcomputer 114 determines that the reception intensity is excessive and switches the output switch circuit 112 off. Stop audio output. In this case, the output from the wireless microphone receiver 11 is not supplied to the mixing amplifier 9. Therefore, occurrence of howling can be reliably prevented.

  Thereafter, when the reception intensity falls below the reference value, the output switch circuit 112 is turned on again and output to the mixing amplifier 9.

The reception control means is not limited to the output switch circuit 112. When the reception intensity is determined to be excessive, the audio output from the diversity reception circuit 111 may be suppressed by being attenuated greatly so as not to cause howling without stopping the audio output. 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 circuit 113 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.

Note that howling can be prevented more reliably if a value slightly smaller than the reception intensity at the time of howling is stored in the memory.
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 speaker 10, so that the reference value to be determined as excessive reception intensity Is set to a small value. On the contrary, when the volume is set low, howling does not easily occur even when the speaker 10 is approached, 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, the present invention can be applied to both an infrared wireless microphone and a radio wireless microphone.

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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main computer 10 Speaker 11 Wireless microphone receiver 111 Diversity receiver circuit 112 Output switch circuit 113 Signal level detection circuit 114 Microcomputer 115 Initialization switch 116 Howling detection circuit 12 Antenna 15 Wireless microphone 16 Microphone rectifier

Claims (3)

A wireless microphone loudspeaker comprising a radio signal receiving means, a receiving demodulation amplifying means, a speaker, a receiving intensity detecting means, a receiving control means, a controlling means, a howling detecting means, a memory, and an initialization switch. And
The radio signal receiving means is disposed in the vicinity of the speaker and can receive a radio signal from the wireless microphone.
The reception demodulation amplification means demodulates the reception signal by the wireless signal reception means and outputs an audio signal,
The speaker acoustically outputs the audio signal of the reception demodulation amplification means,
The reception strength detection means detects the reception strength by the wireless signal reception means,
The reception control means suppresses or prohibits the operation of the reception demodulation amplification means under the control of the control means,
The control means suppresses or prohibits the operation of the reception demodulation amplification means by the reception control means when the reception intensity detected by the reception intensity detection means becomes excessive,
The howling detection circuit detects the occurrence of howling by analyzing the audio signal of the reception demodulation amplification means,
The memory stores the received strength data,
The initialization switch can be used to specify the initialization mode.
The 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 reception intensity detection means is written to the memory.
The normal mode is a wireless microphone loudspeaker that compares the reception intensity detected by the reception intensity detection means with the reception intensity data stored in the memory to determine whether it is excessive. A wireless microphone loudspeaker comprising radio signal reception means, reception demodulation amplification means, a speaker, reception intensity detection means, reception control means, and control means,
The radio signal receiving means is disposed in the vicinity of the speaker and can receive a radio signal from the wireless microphone.
The reception demodulation amplification means includes a gain adjustment means for demodulating the reception signal by the radio signal reception means and outputting an audio signal, and variably setting the audio signal amplification gain,
The speaker acoustically outputs the audio signal of the reception demodulation amplification means,
The reception strength detection means detects the reception strength by the wireless signal reception means,
The reception control means suppresses or prohibits the operation of the reception demodulation amplification means under the control of the control means,
The control means suppresses or prohibits the operation of the reception demodulation amplification means by the reception control means when the reception intensity detected by the reception intensity detection means becomes excessive, and the reception intensity is excessive according to the set gain of the gain adjustment means. Wireless microphone loudspeaker that changes the criteria for determining whether or not. A wireless microphone, a microphone trimming device, a radio signal receiving means, a reception demodulation amplification means, a speaker, a reception intensity detection means, a reception control means, and a control means are provided, and karaoke accompaniment music and singing voice are mixed and amplified. Karaoke device that outputs sound,
The wireless microphone can be used by singers to input singing voices.
The microphone tidy device is placed close to the speaker and keeps the wireless microphone tidy,
The radio signal receiving means is disposed in the vicinity of the speaker and can receive a radio signal from the wireless microphone.
The reception demodulation amplification means includes a gain adjustment means for demodulating the reception signal by the radio signal reception means and outputting an audio signal, and variably setting the audio signal amplification gain,
The speaker acoustically outputs a mixed signal of the audio signal of the reception demodulation amplifying means and the audio signal of karaoke accompaniment music,
The reception strength detection means detects the reception strength by the wireless signal reception means,
The reception control means suppresses or prohibits the operation of the reception demodulation amplification means under the control of the control means,
The control means suppresses or prohibits the operation of the reception demodulation amplification means by the output control means when the reception strength detected by the reception strength detection means becomes excessive, and the reception strength is excessive according to the set gain of the gain adjustment means. A karaoke device that changes the criteria for determining whether or not.

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