Multifunctional audio equipment sound reinforcement system, the main consideration is that the sound reinforcement system conveys clear, easy-to-understand, clear and warm music without noise interference. At the same time, it is necessary to ensure that it has an excellent frequency response width and a small distortion response under the condition of a uniform sound field. So the choice of speaker system is very important.

All signals except the target signal in the multifunctional audio equipment system are noise, but the signal and the noise exist at the same time and complement each other. When the signal is in different places, it definitely creates noise, but the noise doesn't have to be caused by the different places. To remove noise in an acoustic amplification system, let's first look at the relationship between ground and signal:

Grounding and signaling are often referred to as references and topics. The signal ground is the reference of the signal, and the ground usually refers to the connection with the ground, but in the sound reinforcement system, it has nothing to do with the ground. is the reference set in the system, and grounding is essential. It looks simple, but it's actually quite complicated. According to its different functions, it can be divided into functional grounding and protective grounding. Functional ground includes the following four types.

(1) Working grounding, also known as system grounding, is to ensure the normal operation of the system, prevent system oscillation, and ensure the reliability of equipment in the system. Grounding is usually required at the appropriate location where the multifunction audio equipment unit operates. As a common 220V power supply, the ground wire is the neutral point of the transformer. sound reinforcement system

(2) To obtain a stable reference potential, set the logic ground, also known as DC neutral.

(3) The shield ground is a ground installed to prevent the influence of electromagnetic induction on the system. It is the complex grounding of all grounding systems because it prevents others from interfering with each other at the same time. The higher the interference frequency, the denser the metal mesh used for shielding, otherwise the effect will not be achieved.

(4) Install the signal grounding to ensure that the reference potential is stable, that is, the above reference object.

In the sound reinforcement system of audio equipment, the logic grounding, signal grounding and shielding grounding are organically combined through the grounding end of the signal line, so that the system equipment works at a unified potential. It should be emphasized that the signal input terminal and the signal output terminal of the same device should not be connected together. The pre-i level output should only be connected to the post-I level input, otherwise the signal may float through the ground feedback. Of course, it is very difficult to completely eliminate noise. We can only control or reduce the voltage of the noise as much as possible to improve the signal-to-noise ratio of the system so that the noise does not interfere.