High-efficiency speaker circuit for rural stage

The high-efficiency loudspeaker circuit for rural stages is suitable for use in large-scale theatrical performances such as Spring Festival and gatherings, in order to allow more audiences to hear clearly.
    (1) Working principle of the circuit The speaker circuit is shown in Figure 8-24. The input stage is the microphone Y, which receives the voice of the actor on the stage. It
is converted into an electrical signal through the voice coil of the microphone, sent to the primary of the transformer Tl for impedance matching, and then sent from the secondary output to the next stage for audio amplification
. Before amplification, a "passive" audio compensation network composed of RP1 and C, and RP2 and C2 is inserted. Its function is to reduce noise interference
and improve high and low frequencies. The post-amplifier is composed of IC1 and forms a BTL power amplifier circuit . The output audio The signal is low impedance, and the input transformer Gan T2 performs
impedance transformation, and the secondary output is high impedance, which can be matched with the microphone input end of the amplifier device. When working, just insert the "JK" plug into
the "microphone jack".
    After the high-efficiency loudspeaker is successfully assembled, it should be equipped with a suitable plastic casing. Its working power supply is 6-9V, which needs to be connected externally or
taken out from the loudspeaker equipment. Special metal wires can be purchased from speaker stores to connect microphones and speakers. The shielding layer should be grounded.
The "JK" head-catching wire connected to the "microphone input" at the output end should be matched with the amplifier. The two correction potentials of the "passive" network in the movement are RP1 and RP2.
Adjust it to the appropriate position, and seal it with paint once the adjustment is made until the speaker volume is satisfactory.
    Note: Do not place the microphone and the speakers of the speaker equipment in the same position to prevent the audio signal from being "retransmitted" and causing howling. If
the stage area is not enough for one speaker , you can add another one.