For the multifunctional hall sound reinforcement system, the main consideration is to ensure that the language transmitted by the sound reinforcement system is clear and understandable, the music is clear and warm, and is not affected by noise interference. At the same time, it should also ensure excellent frequency response width and minimal distortion response under the condition of uniform and consistent sound field. Therefore, the selection of speaker systems is of utmost importance.
All signals in the audio system, except for the target signal, are noise, but the signal and noise coexist relative to each other and complement each other. When the signal is different from each other, noise will inevitably be generated, but noise may not necessarily be caused by different ground conditions. To eliminate the noise in the sound reinforcement system, let's first take a look at the relationship between ground and signal:
Ground and signal are commonly referred to as reference and target objects. The signal ground is the reference object of the signal, and grounding usually refers to being connected to the ground, but in a sound reinforcement system, it has nothing to do with the ground. It is a reference object set in the system, and grounding is essential. It may seem simple, but it is actually quite complex. According to its different functions, it can be divided into two categories: functional grounding and protective grounding. Functional grounding includes the following four categories.
(1) Working grounding, also known as system grounding, is to ensure the normal operation of the system, prevent system oscillations, and ensure the reliability of equipment in the system. It is usually necessary to install a grounding at an appropriate location, so that the individual equipment can operate on the basis of that grounding. As usual, the grounding wire of a 220V power supply is taken from the neutral point of the transformer.
(2) Logic grounding is a grounding set to obtain a stable reference potential, also known as the DC neutral point.
(3) Shielded grounding is a grounding system installed to prevent the impact of electromagnetic induction on the system. It is the most complex of all grounding systems, as it not only prevents interference from others, but also prevents interference from others. The higher the interference frequency, the denser the metal mesh used for shielding, otherwise the effect will not be achieved.
(4) Signal grounding is installed to ensure a stable reference potential, which is the reference object mentioned earlier.
In a sound reinforcement system, the logic grounding, signal grounding, and shielding grounding are organically combined through the ground terminal of the signal line, so that the system equipment operates at a unified potential. It should be emphasized that the signal input and signal output terminals of the same equipment cannot be connected together, and the output ground of the previous stage can only be connected to the input ground of the subsequent stage, otherwise the signal may float through the ground wire feedback. Of course, it is difficult to completely eliminate noise. We can only try to control or reduce the voltage of noise as much as possible, improve the signal-to-noise ratio of the system, and prevent noise from forming interference.
