In the construction of sound reinforcement system, system failures are often caused by improper wires, unreasonable installation methods, irregular welding of interfaces and irregular use of connectors. At the same time, irregular construction will also cause inconvenience in maintenance. Then, the following are the safety precautions for sound engineering construction that I have compiled for you. Welcome to read and browse.
1. Wire:
Microphone wire: 2-core or 4-core shielded wire is used, which is mostly used for surface mounting occasions. The outer skin of the wire is thick, and there is a tensile filler inside, which has good flexibility, beautiful appearance and various color types. Suitable for surface installation of wired microphone.
Audio signal wire for engineering: 2-core or 4-core shielded wire is used, and there is less filling material in the wire, so the outer diameter of the wire is relatively thin, which is convenient for threading in the wire tube. When connecting equipment in the cabinet, it is also convenient to arrange and tie wires, and the wires in the cabinet are very clear, which is also conducive to later maintenance and overhaul.
Speaker wire for engineering: Oxygen-free copper speaker wire with different wire diameters can be selected according to the power of speaker and power amplifier, and the wire diameter is generally 2.0-4.0mm square. In order to facilitate the construction and meet the construction requirements, we should use the special horn wire for this project, and the constant cross section of the wire is round, which is convenient for the laying and threading of trunking and conduit.
2. Accessories and connectors
It mainly includes connectors, wall interface boxes and customized accessories.
Interface box: Interface boxes of different projects need to be configured according to the specific requirements of the project. The interface box can be installed on the ground and wall. In order to cooperate with the decoration, the interface box is mostly installed in a hidden way. The universal type can be used, that is, it is prefabricated by the manufacturer, and the project construction personnel install it in the designated position according to the design requirements, and weld the embedded signal line with the connector of the interface box.
For engineering projects with special needs, it is necessary to customize the interface panel or interface box, and configure the interface according to actual needs. The panel should be designed and manufactured in advance as required, which is more in line with the actual use requirements. The installation of customized interface box can be determined according to the installation location, size and installation method, which is more in line with the actual needs of the project, but special attention is also paid to the standardization of customized equipment, and the interface should conform to the industries of various interfaces in the system.
Connector: There are two main types of audio signals: balanced and unbalanced. The balance connectors are mainly Canon and 3-core 6.35mm straight connector. The connector used for microphone connection is usually based on cannon interface, and the signal transmission part can adopt three-core 6.35mm straight connector and cannon connector. The male part of the gun joint must be the output interface, and the female part must be the input interface. The connectors used for unbalanced audio signal connection mainly include Lotus interface and dual-core 6.35mm straight connector. The connecting plugs between the power amplifier and the loudspeaker mainly include banana head, double-core 6.35mm straight connector, special connector for four-core or multi-core loudspeaker and screw terminal. Generally, the power output end of the power amplifier has a special terminal, and the specifications of the terminal are all international standards. Can you directly use the special terminal for the speaker? Banana head? It is very flexible to adjust the output phase of the speaker and change the wiring.
3. Building technology
Public address system requires higher construction technology, because the actual audio signals are easily interfered by the outside world, such as electromagnetic interference, strong electrical interference and mutual interference between audio signals when they are transmitted between devices. In order to avoid external interference of audio signals, the following anti-interference measures are usually adopted.
First, prevent power signal interference. Because the power supply uses the frequency of 50-60Hz for transmission, and this frequency can be clearly recognized by human ears, low-frequency AC sound is often heard in speakers due to poor grounding of equipment, poor grounding of signals and poor shielding of signal lines, and such noise is easy to identify. This kind of interference signal is mostly due to the power audio, so the system guarantees it? Clean? Power supply is particularly important. At the same time, it is necessary to use the in-phase power supply in the three power supplies to avoid the power supply noise caused by the phase difference of the power supplies.
Second, prevent electromagnetic interference. This kind of interference signal often affects the signal transmission of the system. In order to avoid this interference, we should pay attention to the anti-interference ability of signal lines, and adopt balanced transmission mode and double-core shielded audio lines for audio transmission.
Third, in the same system, there is less mutual interference between signals. However, there will also be serious crosstalk in the system, that is, a channel has been silenced and the system still has sound. At this time, it is necessary to strictly check the connection mode of the line. The serious problem of crosstalk is usually caused by the construction workers mistakenly connecting the signal line to the shielding layer of a certain equipment. This kind of fault usually needs to check whether the equipment connection practice is standardized.
Complete the fourth joint welding with high standard. This requirement can be said to be the basic method for the sound reinforcement system to work stably and avoid all kinds of interference. In fact, the construction of sound system can be considered as the work of connecting various devices from another angle. In this connection process, there are actually only connecting cables and various connecting connectors. As long as the use of cables meets the requirements and the welding process of joints meets the technical requirements, most problems can be avoided.
4. Cable wiring
Wiring should be neat and parallel. Cable ties and special tools are used to tie cables in trunking and lines in cabinet, and detailed line marks are made at all cable joints. The connection mode, interface and line mark of the line should also have corresponding drawings, and records can be inquired. The spacing of cable ties on a straight cable should be the minimum number of ties to keep the cable in the required shape.
5. Equipment installation
Equipment installation is mainly divided into sound reinforcement field equipment installation and equipment installation in the computer room. On-site installation equipment mainly includes the installation of various input interfaces of sound reinforcement system and the installation of sound reinforcement speakers. The installation methods of speakers can be roughly divided into: ceiling installation, hanging installation, wall installation, hidden installation and floor installation. According to the way of cooperation with decoration, it can be divided into: open and concealed. According to the pre-designed speaker installation position, the speaker fixing device is embedded under the decorative surface before decoration and sealing, which is convenient for fine installation and adjustment after decoration.
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