Wuxi Xianglongxin ventilation equipment Factory , https://www.xlx-fan.com
Four things to share in the public address system
Speaking of the public broadcasting system, it has a different architecture model than the general audio system, so when choosing the equipment of the broadcasting system, the matters needing attention are also different. Here are some practical experiences in the work.
First, the sound source output device:
First of all, let's start with the audio source output device. In fact, in this part of the equipment, the public address system is the same as the general audio system. The only thing that needs attention is the autoplay function, because most public The operation of the broadcasting system is not the responsibility of a special person, so a "main power switch" will be set in the system for the convenience of personnel operation, and most of the system will also have a timing start device. â€After turning off, I didn't notice that when the power of this sound source output device had to be turned off separately, the next time the device was started manually or at regular time, some unnecessary sound output would be generated, causing trouble on the spot.
The sound source input device has always been the most difficult to handle in the public broadcasting system, because the general sound source input device will come with a sound quality adjustment function. In addition to integrating all sound source input signals, it is also responsible for modifying the integrated output signal. In order to extend the transmission distance of sound signals and cope with a large number of broadcasting speaker systems, public broadcasting systems cannot use low-impedance outputs of 0, 4Ω, 8Ω, and 16Ω that are used by general audio. , 70V, 100V high-impedance output, because the sound signal is easily distorted after the transformer is pressurized, so we must pay special attention to whether there are input channels (Channel) for various signal sources in the selection of equipment 2. In addition to whether the number of channels is sufficient, it is also necessary to pay attention to the function of sound quality adjustment, whether there are types of channels that can adjust the sound quality, and how much the range of input audio signals can be modified by each channel.
Second, power amplification equipment:
Power amplifier equipment is the largest number in the entire public broadcast cabinet and the most important thrust in the sound transmission system. They are responsible for amplifying the audio signal output after the integration of the sound source input device and adding it to the carrier wave, so that it becomes the sound signal output with the carrier wave. The matters needing attention in selecting and using the equipment are: whether the power amplifier itself has good heat dissipation. Because the signal will be high temperature when the signal is amplified and added to the carrier wave, it cannot be used for a long time if the heat dissipation conditions are not good enough; moreover, you must consider the low-impedance output of the speaker output except 0, 4Ω, 8Ω, 16Ω It also needs to have high-impedance output of 0, 70V, 100V. The more types of speaker output end, the better. Finally, you must pay attention to the current (overload) protection device. Most people often choose resettable fuse breakers for convenience. However, the working principle of this type of protection device is based on the temperature generated when the current passes. As a reference, when the temperature reaches a certain level, The effect of protection can only be achieved if the bimetal inside is bent, but it cannot provide proper and accurate protection for the machine itself. Therefore, it is recommended to use a general traditional tubular fuse. The response time can reach the real Protective effects.
3. Sound output equipment (speaker system):
The selection of speakers is mainly based on the location. Different materials and types of speakers will have different sound characteristics. How to match the sound quality and volume required for the scene will test the designer's experience and wisdom. At the same time, since the public broadcasting system uses the sound signal of the additional carrier, each speaker must be equipped with an intermediate transformer. Do not use multiple speakers to share an intermediate transformer in order to save costs or facilitate construction.
Operation and control equipment:
Operation and control equipment is the most complicated part of the entire public broadcasting system, which can basically be divided into two parts: input control and output control. The input control mainly includes system startup and shutdown control and audio source input option control. These two input signals that can be controlled externally are generally voltage-free short-circuit signals. If the external controller output startup signal is a power signal, please switch to There is no voltage short-circuit signal. When you cannot confirm what kind of input and output signals your equipment has, please test with a three-meter before connecting to avoid damage caused by signal conflicts. As for the output control part, the output control in the public broadcast system is mainly to control the turning on and off of the speakers in the required broadcasting area. This part has been completely changed to digital transmission control, so it must be noted that the digital transmission control signal can be loaded. The number of control units (decoding control boxes) and transmission distance, as well as the specifications of the required transmission cable, because the current transmission signals and transmission architectures used by various brands are not the same, so there are a variety of cable specifications on the market , But in general, the line core is 4 core ~ ​​10 core, the diameter of the line is 0.75 ~ 1.25 as the largest case.
Conclusion
The public broadcasting system plays an important role in many application environments. For example: emergency evacuation, anomalous invasion notification, train information notification, tracing for people and objects, reminders of work and rest. Safety command and reminder announcement.
Therefore, in addition to meeting the most basic legal requirements, the basis for its selection is more important to meet the needs of the owner. At the same time, the characteristics of sound transmission affected by the environment must be taken into consideration. Not only the product purchase, but also attention must be paid to Is the playback effect in the background environment clear when the device is installed? In this way, it can really be considered as a public broadcast installation. The above roughly shares the matters needing attention in the public broadcasting system with readers. Of course, when choosing and planning in actuality, there are also many matters needing attention due to different on-site environments and operating habits. It is recommended that purchasers must think carefully and consider them before purchasing. On-site installation conditions, or seek the assistance of professional manufacturers, to create a truly suitable public address system for you!