The general sound reinforcement system includes two categories: sound reinforcement system and sound reproduction system:

1. Sound reinforcement system: The loudspeaker and the microphone are in a unified field, and there is howling, distortion and oscillation caused by acoustic feedback and room resonance. In order to ensure that the system is not chaotic and works properly, the maximum available system gain is 6 dB lower than the critical gain at which acoustic feedback self-excitation occurs.

2. Sound playback system: There are only sound sources such as tape players and CD players in the system, there is no microphone, there is no possibility of sound feedback, and the sound feedback coefficient is 0, which is a special case of the sound reinforcement system.

Sound reinforcement systems can be divided into the following categories according to their uses:

1. Outdoor PA system

Outdoor sound reinforcement systems such as sports venues, stations, parks, art squares, music fountains, etc. It is characterized by large service range, wide space, and large background noise; the sound transmission is mainly direct sound; the sound pressure level is required to be high, if there are sound reflecting objects such as high-rise buildings nearby, the sound wave will be reflected multiple times and the sound pressure level will be high. , which will cause difficulty in sound image localization. The acoustics of external systems are also affected by factors such as weather conditions, wind direction, and environmental disturbances.

2) Indoor sound system

Among them, the most widely used is the indoor sound reinforcement system, including various cinemas, gymnasiums, dance halls, etc. Its professionalism is very strong, not only for various theatrical performances

Provides a sound source, and has high requirements for sound quality. System design should not only consider the subject of electro-acoustic technology, but also the subject of architectural acoustics. Factors such as indoor body shape have a greater impact on the sound quality.

3) Event performance system

In addition to the fixed installation system, the PA system also has a movable system. The temporary system for non-theatrical performances temporarily installed in various large venues (such as sports fields (halls), art broadcasting, large banquet halls, etc.) is called an event performance system. The sound for these event performances must be compact, easy to carry, transport and install, with high reliability and adaptability to a variety of harsh environments. Large-scale event systems have a large investment and are generally leased to professional audio companies.

4. Conference system

With the increase of domestic and international exchanges, teleconferencing, video teleconferencing, and digital conference system (DCN) have developed rapidly in recent years. The conference system is widely used in central, hotels, organizations and government departments.

The conference system mainly includes conference discussion system, voting system, simultaneous interpretation system and video conference system. This system requires audio, video (image) system synchronization, and computer control and storage.

The design of the editing and sound reinforcement system generally starts from the sound field, and then proceeds to the amplifier, the sound processing system, the mixing console, and the microphone and other sound sources. This gradual backwards design step is necessary. Because sound field design is the basis for satisfying system functions and sound effects, it involves the selection of speakers, sound supply schemes, signal paths, etc. The speaker system must be determined to calculate the driving power of the power amplifier and determine the driving signal path, and then further determine the signal processing scheme and the selection of the sound effect platform according to the distribution scheme of the driving power.

Sound field design is the foundation of the sound reinforcement system, which involves the final sound effect of the system, but it is often complicated and complicated work. Due to the rapid development of computer technology, it is now possible to use acoustic software tools of EASE 3.0 or above to perform calculations, and finally achieve the desired sound field design speech [1], [2]. In order to meet the requirements, the sound field design process needs to be repeated many times.

Voting or simultaneous interpretation system can be configured according to different meeting requirements.

When voting, delegates only need to press the voting button on the device in front of them, and the voting results will be displayed on the LCD screen of the chairman unit, or displayed on other screen display devices in the conference room through the CCU and DCN software.

Simultaneous interpretation usually uses at least 1+3 languages (one native language and three target languages) languages, and when necessary, additional auditoriums can be added, except for official representatives.

Languages can be assigned using wired or wireless means:

The cable trunk distribution of the DCN system distributes the translation language to the conference participants. The official delegate listens to the translation language by connecting to the headset on the speaking device with the channel selector, and the non-voting delegate listens to the translation language through the headset with the channel selector.

Radio language distribution adopts infrared system to realize wireless transmission

A typical IR system consists of IR transmitters, radiators, and personal IR receivers:

- Infrared transmitter: one carrier for each language channel

-Infrared radiator: used to distribute the infrared signal to the whole venue.

It can be embedded in the wall or ceiling during installation. Precisely adjust the radiator installation position to obtain the best field infrared signal cover.

-Infrared Receiver: Can receive up to 16 language channels, with high-speed channel conversion function, LED display and voice amplification.