JPH0113517Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a public address system that mixes a sound source signal such as a tape or record with a microphone signal to amplify the sound.

Conventional configuration and problems In recent years, with the popularity of karaoke, cassette tapes, 8-track cartridge tapes, etc. are used as accompaniment sound sources for home and business use, and microphone output is mixed with this for playback. Various devices are used.

However, when singing using such a loudspeaker system, amateurs in particular tend to lose the pitch and tempo midway through the song, and may have vague memories of the melody. , it is necessary to make it easy to sing without mistakes. However, if you enable the singer to hear the accompaniment clearly, since the accompaniment and the singing voice signal received by the microphone are mixed, it is inevitable that the singer's own singing voice received by the microphone will also be heard louder, and this will go back into the microphone, and eventually This will cause howling. Of course, this howling can be alleviated to some extent by arranging the speakers, using a unidirectional microphone, and adjusting the direction, but if the equipment is prepared and the singer is an amateur, then such consideration is required. is difficult.

First, a conventional example will be explained using FIG. 1 is a microphone, the output of which is applied to a variable resistor 4 via a preamplifier 2 and a mixing resistor 3.
On the other hand, the output of the tape playback head 11 is applied to a variable resistor 4 through a preamplifier 12 and a mixing resistor 13, where it is mixed with the signal from the microphone 1, the level is adjusted by the variable resistor 4, and the output amplifier 5 and is amplified by speaker 6
The sound will be louder. At this time, when trying to make the accompaniment sound louder as described above, the singing voice from the microphone 1 is also amplified, and this amplified sound enters the microphone 1, resulting in a drawback that howling is likely to occur.

Purpose of the invention The present invention solves the above-mentioned conventional drawbacks, and aims to realize a public address system that allows singers to hear the accompaniment loud enough to make it easier to sing, and that is less likely to cause howling.

Structure of the invention The present invention includes a microphone signal preamplifier that amplifies a signal from a microphone, an accompaniment signal preamplifier that amplifies an accompaniment sound source signal, and a mixing circuit that mixes the outputs of the two preamplifiers. , a first amplifying signal from the first mixing point of this mixing circuit.
a power amplifier, a first speaker operated by the output of the first power amplifier, and an output of the microphone signal preamplifier by appropriately adjusting the constant of the mixing circuit at a point other than the first mixing point. A second mixing point that amplifies the signal from the second mixing point where the output of the accompaniment signal preamplifier is mixed at a sufficiently large ratio compared to the accompaniment signal preamplifier.
a power amplifier, and a second speaker operated by the output of the second power amplifier, a mixed output sound of a microphone signal and an accompaniment signal is obtained from the first speaker; It is configured so that the main output sound is the accompaniment signal from the speaker.In particular, if the singer listens to the output sound of the second speaker, the accompaniment sound will be louder and it will be very easy to sing, and the output sound will be It is possible to realize a public address system in which howling is less likely to occur even when input to a microphone occurs.

DESCRIPTION OF THE EMBODIMENT FIG. 2 is a circuit diagram of an embodiment of the present invention. In FIG. 2, the output of microphone 1 is the same as in FIG. are the same, but the output of the preamplifier 12 is adjusted by a newly provided variable resistor 14, amplified by an accompaniment output amplifier 15, and amplified by an accompaniment speaker 16. At this time, the output of the microphone 1 tries to flow into the variable resistor 14 through the resistor 13, but the preamplifier 12
The output impedance of the mixing resistor 13 and the combined impedance of the variable resistor 14
If the value of is very large, the backflow will be very small and will not be a problem in practice. By appropriately changing this impedance ratio, it is possible to control the leakage of the output of the microphone 1 to the accompaniment output amplifier.Furthermore, if you want to completely shut out the output component of the microphone 1 from the speaker 16, the third
As shown in the figure, a buffer amplifier 17 for preventing signal backflow may be provided between the preamplifier 12 and the mixing resistor 13.

Now, if the loudspeaker 6, which outputs the mixed output of the audio to the microphone 1 and the accompaniment, is directed toward the audience seats so that the singer can hear the sound of the accompaniment speaker 16, the singer can clearly hear the accompaniment sound. It becomes easier to sing accurately in pitch and tempo. Furthermore, since the output sound of the accompaniment speaker 16 contains little or no microphone signal, howling is unlikely to occur even if this output sound is input to the microphone.

Note that in the case where a small amount of microphone signal is output from the accompaniment speaker 16 as shown in FIG.
The singer can hear a little of his own voice, creating a good atmosphere and making it easier to sing. On the other hand, in the case where only the accompaniment sound is output from the accompaniment speaker 16 as shown in FIG. 3, the possibility of howling is extremely reduced.

In the embodiment described here, a tape was used as the accompaniment sound source, but it is obvious that if a pick-up cartridge is used in place of the tape playback head 11, a disk record can be used as the sound source.
Furthermore, a tuner or line input may be used as the sound source.

Furthermore, the variable resistors 4 and 14 may be linked together, or one of them may be fixed. Furthermore, the accompaniment speaker 16 is the mixing output speaker 6.
The accompaniment speaker may be made smaller, and the accompaniment speaker may have a special sound quality by devising the speaker and circuit so that the accompaniment can be heard best.

Effects of the invention The present invention includes a first speaker that mixes and outputs a microphone signal and an accompaniment signal, and a second speaker that mainly outputs an accompaniment signal. By making the sound audible to the singer, the singer can sing at the correct pitch and tempo without making any mistakes based on the clear accompaniment, and furthermore, it is possible to provide an excellent public address system with very little risk of howling. .

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, FIG. 2 is a circuit diagram showing one embodiment of the present invention, and FIG. 3 is a circuit diagram of another embodiment. 1...Microphone, 2...Preamplifier, 6,
16...Speaker, 11...Playback head, 12...
...Preamplifier, 13...Mixing resistor.

Claims (1)

[Scope of utility model registration request] a microphone signal preamplifier for amplifying a signal from a microphone; an accompaniment signal preamplifier for amplifying an accompaniment sound source signal; a mixing circuit for mixing the outputs of the two preamplifiers; and a first mixing circuit for mixing the outputs of the two preamplifiers. a first power amplifier that amplifies the signal from the mixing point, a first speaker operated by the output of the first power amplifier, and a constant of the mixing circuit at a point other than the first mixing point as appropriate. a second power amplifier that amplifies a signal from a second mixing point where the output of the accompaniment signal preamplifier is mixed at a sufficiently larger ratio than the output of the microphone signal preamplifier; a second speaker operated by the output of the power amplifier, a mixed output sound of a microphone signal and an accompaniment signal is obtained from the first speaker, and a sound mainly consisting of an accompaniment signal is obtained from the second speaker. A public address system characterized by being configured to obtain output sound.