Audio broadcasting system involves a wide range, from the factories, schools, hotels, railway stations, docks, square to the venue, theatre, gymnasium, residential quarters, such as, without exception, have close relationship.

In civil engineering design, the broadcasting system can be divided into the following categories:

Public broadcasting system for the public area (square, station, wharf, shopping mall, restaurant, corridor, classroom, etc.) and parking lot. This system is mainly used for voice broadcast, so the definition is the most important. Moreover, the system often carries on the background music broadcast, in the case of disaster or emergency, and can be converted to an emergency radio.

Radio and sound system for hotel guest room. This system includes room audio broadcasting and emergency broadcast, often by rooms in the bedside table in broadcasting, room broadcast containing a plurality of available band. In the emergency broadcast, room broadcast automatically stop automatically switch to the emergency broadcast.

In the auditorium, theater auditorium sound reinforcement system, as the representative of the stadium. This is a professional sound system is strong, it should not only consider the electro acoustic technology problem, is also involved in architectural acoustics. Both overall can not be neglected, the broadcasting system tend to have comprehensive multi-purpose requirements, not only for the use of assembly language sound reinforcement, are often used in theatrical performances, for large-scale live performance of the sound system, electric power ranging from tens of thousands, many of hundreds of thousands of watts. Therefore, to high power loudspeaker and power amplifier, on system configuration and equipment selection has certain requirements, should pay attention to the problem of power line load at the same time.

Broadcast sound system for meeting room, report hall, etc.. Such systems are generally provided with the background music and emergency broadcasting system, but because of its particularity, it is also often set up in the conference room and the report hall of the conference broadcast system. For higher requirements or the international conference hall, it is necessary to design a special audio and video system, such as simultaneous interpretation system, conference voting system and large screen projection television.

From the above introduction shows that for all building, hotels and other buildings for civilian use in audio broadcasting system, basically can be summarized into three types: A, public broadcasting system, the agency cable broadcasting system. It includes background music and emergency broadcast function, usually combine together, usually playing background music or other programs, fire and other emergency, converted to alarm broadcasting. Direct transmission rate of transmission and broadcast in this system with the microphone to the public broadcasting speakers are generally not the same room, so silent feedback problems, and the constant pressure for the typical system; second, the auditorium sound reinforcement system, this system uses professional audio equipment, and require high power speaker system and power amplifier, due to the microphone and sound reinforcement speakers in a hall, so there exists sound feedback and howling, and because of its distance is short, so the system is generally used in low resistivity; third, special meeting system, although it is sound reinforcement system, but has its special requirements, like voice translation system.

Composition of broadcast sound system

No matter what kind of radio sound system, it can basically be divided into four parts: program equipment, signal amplification and processing equipment, transmission lines and speaker system. Program source equipment: source programs are usually broadcast radio, CD player and recording booth and so on equipment to provide, in addition to the microphone, electronic musical instruments.

Signal amplification and processing equipment: including mixer, pre amplifier, power amplifier and a variety of controllers and audio processing equipment, etc.. This part of the equipment is the most important task for the signal amplification, followed by the choice of the signal, mixer and preamplifier role and status of similar (of course, function and performance index of mixer higher) and their basic functions are complete signal selection and pre amplifier. In addition, it is also responsible for volume and sound effects of adjustment and control. Sometimes in order to better carry out the balance of the frequency and the sound quality, but also a separate input graphic equalizer. This part is the control center of the whole broadcast sound system ".

The power amplifier sends the signal from the preamplifier or mixer to power amplifier, and then through the transmission line to promote the speaker to sound. Transmission line, although simple, but with different system and transmission mode and different requirements, to the auditorium, theater,, due to the distance from the power amplifier and speakers. In general, the direct feeding way of low resistance and large current and transmission line requirements with a special horn line, and on the public broadcasting system, due to the wide area service, long distance, in order to reduce the transmission lines caused by the loss, often using high pressure transmission, due to the small current transmission, so on the transmission line requirements is not high.

Speaker system: the speaker system requires the entire system to match, and the location of the choice to be realistic. Auditorium, theater, song and dance halls, sound quality requirements are high, while the speaker is generally used in large power speakers, and the public broadcasting system, because it is not so high on the requirements of the sound, the general use of 3W-6W ceiling speakers that are good;

The characteristics of broadcasting system:

Background music referred to as BCM is abbreviation of back groud music, its main role is hidden in the noise and create a relaxed and harmonious atmosphere, listen to the people if not listening to, cannot tell the difference between the position of the sound source, with less volume is to create a relaxed and pleasant atmosphere of music. Therefore, the effect of the background music has two, one is to cover up the psychological environment noise, two is to create an atmosphere of adaptation with the indoor environment, it is in hotels, hotels, restaurants, shopping malls, hospitals,