Several methods to eliminate the noise of dancing bluetooth speaker system (2)

If the dancing bluetooth speaker system is poorly grounded, noise will be sent to the next level of equipment, and sometimes the sound of the radio broadcast will be induced. Therefore, grounding has a major impact on noise elimination. There are also certain technical requirements for this:

(1) The grounding point of the dancing bluetooth speaker system should not be connected to the same point as the ground wire of the power supply, so as to prevent the noise of the power grid from entering the dancing bluetooth speaker system.

(2) It is better to use multi-strand textile wire for the grounding wire, and the area of ​​the welding point should be large enough, and good welding is required to avoid false welding, false welding, and desoldering. Do not use welding oil when welding, use alcohol rosin. If soldering oil is used, alcohol should be used to clean the solder joints and nearby circuits after soldering to prevent corrosion of components and circuit boards.

(3) The dancing bluetooth speaker device should not be grounded at the input and output at the same time, forming a ground loop, which is prone to inductive self-excitation.

(4) Grounding requires a single-point grounding at the input end, because the signal level at this point is small and the noise level is also the smallest. Grounding at this point will short-circuit the noise to the ground and clear it. If the output point is grounded, the signal level is relatively high and the noise level is relatively high at this time, so it is not easy to eliminate the noise completely.

Two eliminate the inherent noise of the equipment itself

The dancing bluetooth speaker system is composed of multiple devices, such as microphones, DVD decks, mixers, effects, equalizers, compressors, exciters, electronic crossovers, power amplifiers, speakers, etc., each Equipment can be the source of noise. In order to find and judge which unit the noise is generated from, it is necessary to detect the inherent noise of each unit. The specific inspection procedures are described as follows.

1. Turn on the dancing bluetooth speaker system

The power-on sequence is started step by step according to the sequence of the signal flow. After turning on, there is noise from the speaker. First of all, you can turn off the power of the wireless microphone receiver to determine whether there is noise. If the noise disappears, it proves that the noise is generated by the wireless microphone receiver: if there is still noise, it proves that the noise is not generated by the wireless microphone receiver. Other units can be tested.

2. You can turn off the sound gain knobs of other microphones in turn

If the noise disappears when the knob of a microphone channel is turned off, it can be judged that the noise is caused by this channel. If the noise is still the same, check other units.

3. Turn off the power of the DVD player and observe whether the noise disappears

If the noise disappears, the noise source is caused by this: if there is noise, the noise is not caused by this, and you can continue to detect other units.

4. Turn off the power switch of the mixer to identify whether the noise disappears

If the noise disappears, it proves that the noise is produced by the mixer: if the noise still exists, it proves that the noise is produced by other units.

5. It can turn off and listen to the peripheral equipment in turn

Continue to shut down and listen to peripheral devices such as effect processors, exciters, compressors, equalizers, electronic crossovers, power amplifiers, and acoustic feedback suppressors, and observe whether the noise disappears. If the noise disappears when a unit is turned off, it proves that the noise is generated by the unit.

6. Specific inspection

After discovering the noise-producing unit, you can open the case and perform a specific inspection of the structure in the body to check whether the circuit board jumpers, sockets, interfaces, and connectors are in good contact. Perform uncharged and charged detection on components, and those with repair capabilities can detect faulty or damaged parts. If there is no repair capability, a new unit must be replaced.

Three eliminate the interference noise of the power supply

1. Noise interference of light thyristor

On the stage, the most disturbed by power noise is the noise from the lighting thyristor, because the brightness and intensity changes of the lights in theaters and dance halls are not achieved by changing the voltage of 0 ~ 220V, but can be controlled by electronic circuits. The conduction angle of the thyristor changes the conduction area of ​​the sine wave of the alternating current to realize the change of the control power transmission. Therefore, the sine wave in the power supply is changed into a sawtooth wave-like form, which produces obvious 50Hz ripples in the power supply. In the dancing bluetooth speaker system, obvious noise appears. In order to eliminate the interference noise of the thyristor, the most effective way is to provide two phases of the three-phase power supply for light use, and use the other phase as a dedicated dancing bluetooth speaker system. In this way, the interference of the light SCR can be avoided.

2. Clutter interference from power grid

In the public power grid, electric drills, impact drills, electric welders, elevators and other equipment from nearby construction sites are often connected in parallel to the public grid, and household appliances of residents in nearby communities, such as washing machines, refrigerators, and range hoods, are often connected to the public grid. Produce a certain amount of pollution. If you use a dual trace oscilloscope to test it. It can be clearly seen that there are often many high-frequency burrs on the sine wave. In order to eliminate the noise interference of these external power supplies, the following methods can be adopted:

(1) If the grid voltage is often low, use a voltage regulator together with a voltmeter to adjust the low or high voltage, that is, adjust the voltage to be used within the 220V range through the voltage regulator. Due to the electromagnetic circuit of the voltage regulator, the noise in the power supply can be eliminated to a certain extent.

(2) Use a regulated power supply. The automatic stabilized power supply is to identify the low or high voltage in the power grid through the comparison circuit in the electronic circuit, and then control the voltage regulator to automatically start through the servo circuit to adjust the power supply voltage within the range of 220V. Electronic circuits and voltage regulators have a certain effect on eliminating power supply noise.

(3) Use an isolation transformer. The isolation transformer is a high-power power transformer, the grid voltage is the primary, and the operating voltage is the secondary coil. In this way, the primary voltage and the secondary user power supply are not directly connected, the noise in the power supply is filtered relatively clean, and the used electricity is purified.

(4) Use a small clean power source. Made with electronic circuits, it can be made small and exquisite, and can be installed in a larger power plug box to provide power for wireless microphone receivers and mixers, as well as for effect processors, exciters, compressors, and equalizers. , The electronic frequency divider provides power, which has a good purification effect on the power supply, which can improve the tone quality of the dancing bluetooth speaker system.