As a system, public broadcasting must comprehensively consider the harm of various elements to the system in the design scheme. Therefore, on the basis of selecting high-quality electroacoustic equipment, according to the careful system design scheme, careful system adjustment and excellent sound construction standard, we can achieve the beautiful and natural sound quality of the dial-up sound. Next, I have sorted out some tips on the design and installation of public broadcasting and emergency broadcasting system, and share with you:
Tips for public broadcasting design:
(1) Transmission technology: the power feed method of the system is cable television broadcasting transmission method.
(2) Provision for line attenuation: In the public address system, the line attenuation from the output of the amplifier machine equipment to the customer speakers farther on the line shall meet the following requirements:
Business process broadcast shall not exceed 2 dB (at 1 kHz)
Service broadcasting shall not exceed one decibel (at 1 kHz)
The explosion-proof switch line with uniform output shall be selected, and the output voltage shall be 70V or 100V.
Volume calculation method of power amplifier:
Calculation method of business broadcast system and business broadcast system: P=K1 × K2 ×Σ Po
Where: P - total rated output power of power amplifier (W);
Po--Ki × Pi, larger rated power (W) for each separate broadcast;
Pi -- short-circuit capacity of the customer's machinery and equipment separated by the ith;
Ki -- additional demand coefficient of the ith separation;
For service broadcasting, the Ki of each variety show in the hotel room is 0.2-0.4;
Ki of music background variety show is 0.7-0.8
K1 -- compensation index of line attenuation: 1.26 when the line attenuation is 1dB; 1.58 when the line attenuation is 2dB;
K2 - embrittlement index, generally 1.2-1.4;
Calculation method of safety accident broadcasting system: the system has the following two methods:
The volume of power amplifier is 1.3 times of the number of speakers in the system. The volume of power amplifier shall be determined by 1.5 times of the number of larger 3-layer speakers in the system.
Reservation of power amplifier
The power amplifier of public address shall be set with backup data power amplifier, and the power amplifier shall be delivered automatically or manually in case of common failure of power amplifier in operation. The reserved power amplifier of the power amplifier used for critical broadcasting (such as the power amplifier for safety accident broadcasting) should be able to be fully automatically delivered for use immediately in case of common failure of the amplifier in operation. The total number of reserved power amplifiers shall be determined according to the volume of key broadcast loads.
Speaker setting
3W speaker boxes are set in offices, daily living rooms, changing rooms, etc.
Ceiling mounted loudspeakers are generally used in building corridors, and the spacing of loudspeakers is considered as 2.5 times of the building height (ceiling height). Use 3-5W ceiling speaker.
3-6W speaker box should be installed in the lobby, general meeting hall, hotel, shopping mall, leisure and entertainment club, etc.
The control box of the bedroom bed in the hotel adopts 1W-2W speaker.
Under the condition that the Japanese tatami floor in the architectural decoration design is high enough, the sound column or composition sound should be selected for the large capacity site.
When setting speakers in noisy, wet and cold places, horn speakers should be selected. The noise coefficient of the horn speaker used in the noisy site should be 10-15dB higher than the noise.
