1. Sound source output machine equipment:
First of all, let's start with the sound source output machinery and equipment. In fact, for this part of machinery and equipment, public broadcasting and general speaker systems are the same. The only area that must be paid attention to is the role of full-screen play (AUTOPLAY). Since the actual operation of most public broadcasting systems is not undertaken by full-time personnel, a "main power switch" will be set in the system, In order to facilitate the actual operation of the staff, and most of the system will also have the equipment to execute the starting at a fixed time. Today, after a user turns off the "main power switch", he cannot notice that when the switch power of the audio source output device must be turned off independently, the next time the starter position is executed manually or at a fixed time, it will cause some redundant sound output, causing confusion on the spot.
Sound source input machine equipment has always been a relatively difficult problem in the public address system. Because the general sound source input machine equipment will add the role of voice adjustment, it should not only integrate all the sound source input signals, but also undertake the output signals after decoration and integration, and the public address should be able to lengthen the transmission interval of sound signals and cope with the huge number of broadcast program speaker systems, Therefore, it is impossible to select the low characteristic impedance output of 0, 4 Ω, 8 Ω and 16 Ω applied by the general speaker, so the high characteristic impedance output of 0, 70 V and 100 V with carrier communication is adopted instead. Because the voice signal is very easy to lose frame after being charged by the transformer, so we must pay attention to whether there are input channel columns with various signal sources when selecting the application device In addition to whether the total number of channel columns is sufficient, we should also pay special attention to the role of voice adjustment, whether there are types of channel columns with adjustable voice color, and how many categories of channel columns can be decorated and keyed in voice/signal, etc
2. Power amplification circuit machinery and equipment:
Power amplification circuit machines and equipment are the most important torsion in all public address server cabinets, and also the most important torsion in the sound transmission system. They assume that the audio signal output after the audio source is input into the machines and equipment and the audio signal is enlarged in many ways, and after the carrier communication is added, it becomes the sound signal output with the carrier communication, Therefore, special attention should be paid to the selection of application devices: whether the heat removal performance of the power amplifier circuit itself is excellent. Due to the high temperature caused when the signal becomes large in many aspects and the carrier communication is added, it is impossible to apply it for a long time if its own heat removal standard is not good enough; Secondly, it is necessary to consider that the horn output terminal should have high characteristic impedance output of 0, 70V and 100V in addition to the low characteristic impedance output of 0, 4 Ω, 8 Ω and 16 Ω. The more types the horn output terminal has, the better. Finally, it is necessary to pay attention to the electric flow (load) protection equipment. Ordinary people often choose resettable commercial fuse breakers for better convenience, but the principle of this type of protection equipment is based on the temperature required by the current. When the temperature reaches a certain level, the internal resistance band will be bent, and the actual effect of maintenance will be achieved. However, for the equipment itself, it is impossible to show proper and accurate maintenance, Therefore, it is still proposed to use the conventional tubular safety tube, which can achieve real maintenance effect only with fast response.
3. Sound output machine equipment (horn system):
The key to the use of horn speakers is to consider the location. Speaker horn of different materials and forms will have different sound characteristics. How to match them to produce the necessary tone and sound on the spot will hone the designer's work experience and wisdom. In addition, because public broadcasting is the sound signal of additional carrier communication, it is necessary to refit a positive and intermediate transformer for each speaker. In order to better save costs or facilitate the construction of the project, we cannot choose the method of sharing resources with multiple speakers and a positive and intermediate transformer.
