【 Weak current College 】 buildings in the public broadcasting system design issues---Power By 【 China power house network 】

Buildings in the public broadcasting system design issues
As China's national economic development, living standards and continuously improve the material and cultural needs are growing, the public broadcasting system as the building of a high level of electrical design has gradually increased. However, since the public broadcasting system involves building acoustics, electrical, fire, and other disciplines, some designers at design often cannot reasonably sure, sometimes even in the design of an error. Author for design in some problems, propose solutions, just for reference, see criticism and corrected.
1 public broadcast system design's fundamental problem is the acoustic issues public broadcasting system belongs to the category of applied acoustics, sound reinforcement, the people inside through the acoustical, electro-acoustic design to control and improve the sound quality of the room. Public broadcasting system sound amplifying equipment mainly by the audio source device, mixer, power-on time, the floor selector, speakers, and several parts. Over a longer period of time, many people put the microphone a mixer with a loudspeaker so that a set of sound reinforcement system equipment that confuse the amplification system, matching the equipment deemed sound reinforcement system design, this is far from comprehensive. Public broadcasting sound reinforcement system includes: the sound source to the microphone of the acoustic environment, microphone and speakers that sound amplifying equipment, as well as the speakers and the audience area of the acoustic environment (acoustic), this three-part. The basic point is the sound source and the last sound reinforcement with speakers and a sound field. In the public broadcasting system, some people tend to ignore this, there will be some problems. In response to these, the author according to own actual in engineering design, debugging work in practice, several design issues.
2 public broadcast system design issues
2.1 speakers in the room of layout design of sound reinforcement speakers system, the first consideration should be given to the reinforcement of sound field, that is, on the reinforcement of room acoustics to fully grasp, and what performance should be used, how to lay out the speakers for the best results. Because the situation is different, sometimes only according to the speaker's performance and layout method, it is difficult to obtain good acoustics. For example, in the absence of acoustical treatment of the stadium, the sound was enlarged, due to the reverberation serious without clear sound and echo, ECHO, and other special reflex quiver, sound amplifying equipment alone is very difficult to eliminate. Therefore, the room's acoustic properties, they are not good acoustics. 　　The acoustic performance is good, but the layout is not good, also the good acoustics. 　　Speaker layout design should adapt to the room shape, size, the reverberation time, as well as the use purpose, you can press the following points to consider: ① strewn sound pressure distribution should be evenly; ② do not produce a deterioration in the definition of special reflections; ③ not caused by a microphone and a loudspeaker amplifier speakers feedback loop formed by feedback oscillation, i.e., Whistler. For the public broadcasting system, hanging on the side wall speaker box of high quality of the sound field. 　　But based on ease of installation and ease of concealment and other reasons, in the ceiling speakers installed on the ceiling of the programmes has been accepted, and widely used in Hotel corridors, malls suspended ceiling is not very high. Speakers covering area of the physical significance, as shown in Figure l. Figure a represents the coverage angle, h for ceiling height (m), h represents the average height of ear plane (m), r is the radius of the bottom round cylinder (m). According to a certain place of the area and related data, to estimate the required number of ceiling speakers. 　　In principle, the ceiling speakers of distribution to the end of the sound pressure level compared to the uniform.　　Ceiling speakers choose to consider rated power, sensitivity and frequency response range, dimensions, and other major technical indicators, including speaker size on coverage angle. Have important significance. Typically, the wavelength of the acoustic speaker size hours, radiation is directed, Sonic has become around the axis of a bunch of speakers, the deviation from the axis of the audience will hear the sound of the frequency of direct. Then override width. Much? has been used Center to 4000Hz with octaves pink noise to measure the speakers, the axis with the speaker into a corner when measured in the direction of the sound pressure level. In the sound pressure level than the sound pressure level decreases 6dB axes of the resulting angle is the angle of a coverage. If the speakers are deemed to be in an infinite baffle of plane rigid piston, Sonic wavelength and rigid piston size comparable, acoustic irradiation appears higher the directivity, frequency, the shorter the wavelength of sound waves directed sharp. Calculation according to deviate from the main drop 6dB sound beam axis angle, available data covers the angle a. 　　Many works about using 16cm cone speakers (a = 48 °) for units of the ceiling speakers, rating: 3-5W, sensitivity in 90dB/m · W above, frequency response in about 100-8000Hz, practical application of the effect is pretty good. In ceiling-mounted higher or reverberation time longer Auditorium use ceiling speakers, for clarity. Effective approach is to improve the speaker directivity factor or reduce the distance between the speakers and the audience to increase the direct-to-noise ratio of the mixed sound. 　　There is a speaker can be suspended from the ceiling and suspension allows the speakers as close as possible to the human ear, improving clarity. Ceiling speakers number, location, and model choice, must and interior decoration design closely, sometimes had to yield to the decoration of the electro-acoustic design needs and budget constraints. But the electro-acoustic design must place the sound level balance as the key, the speaker arrangements must also be taken into account this factor.
2.2 public broadcasting system should and fire emergency broadcasting system combination.
In the building has been designed with fire emergency broadcasting system, such as the further design independent public broadcasting system, could cause the speakers in the repeat settings inside the building, not only causing economic waste, but also the building of internal decoration effect.
At the same time, due to a fire emergency broadcasting system usage is low, but important, once used, must be guaranteed to work, but as managers often ignore the usual unused fire emergency broadcasting system maintenance. While the public broadcasting system in the usual usage is high, the management and operations staff on publicTotal broadcast system equipment situation, on the usual problems will be solved. Therefore, the public broadcasting system and fire emergency broadcast system in combination, will make the fire emergency broadcasting system in a good state of maintenance.
In addition, in the design of fire emergency broadcast system, some design often set alarm at the same time. The disadvantage of this design is in the fire, often too loud alarm, evacuating personnel couldn't hear fire radio emergency notification. But if you do not set the alarm, may occur in some places need to evacuate personnel did not hear the fire signals. To resolve this issue, install the reverberation device before a fire alarm controller, the device configuration a invectives microphone (handheld). In case of emergency, may issue a fire alarm signal, press the speakerphone key, you can stop the call alarm signal, such as language notice issued evacuation, release the call key, fire alarm signal recovery.
2.3 public broadcasting system line laying due to public broadcasting system of transmission of the signal to the audio signal, we usually mean pressure 100V voltage is audio, with ordinary multimeter measuring voltage inaccurate it is for this reason. In accordance with the electrical specification, different voltages, different currents of lines do not allow laying in the same wire or tube. In construction, sometimes not aware of this, the public broadcasting system link and other weak lines laid in the same Groove. If other flea power line voltage is not above 50V, does not interfere with the radio signals; audio signals are always contiguous, do not interfere with other electronic circuits. However, once the signal is not continuous, or the signal is adjusted by the SCR, it will interfere with other electronic signals, so the design time should strictly to public broadcasting channels and other weak lines apart.
Trunk route, you can add the trunkings, metal separators in public broadcasting channels separate laying in the side. In the automatic fire alarm system design code (GB50116-98), there is no detailed provisions for the laying of the emergency broadcast line, but the section 10.2.2: fire control, communications, alarm lines to adoption of laying, the use of metal pipe or flame retardant treatment of hard plastic pipe protection and laying in the not burning body layer of protection, and protection should not be shorter than 3 mm thickness. When using Express installation, you should adopt the metal pipe or trunkings protection and should be a metal pipe or trunkings with fire protection measures. As a result of broadcasting channels in fire and rescue, its role and alert line similar to the design should strictly follow the alert line laying laying design requirements.
2.4 public broadcasting system volume faded by section usually design, public broadcasting system volume control in the mixer, amplifier fore, power amplifier and other settings in the control room equipment, this will result in the following two issues: ① as audio signal online will result in losses, in particular the transmission distance of long lines, signal in line with the first end-to-end sound pressure level difference is large, the system is very difficult to balance when debugging. 　　② inconvenient to manage, different places of the sound pressure level sometimes have different requirements, it is difficult to meet. In each layer wiring box additional tuning switch can solve this problem, as shown in Figure 2. System debugging, adjustable tuning switch balanced sound pressure level. Normally, managers or the floor where the audience can freely adjust the volume as needed. In case of emergency, control room operators can cut through the relay strong, volume switch to maximum, thus ensuring that the needs of the emergency broadcast.
2.5 Hotel bedside Cabinet speaker layout in design hotel bedside Cabinet speaker, usually design speaker power 1W, placed in the lower bedside table set control panel, General construction installation into small cone speakers, speaker directivity is very poor, music sound great. Design uses coaxial speakers (3-5W), guaranteeing the sound pressure level, at the same time without affecting your bedside use of premise, the bedside Cabinet into a speaker, an instance of the project, and achieved good results.
2.6 strong plug switch used in some places inside the building, such as Museum and medium Hall, hotel restaurant, small meeting rooms, these places are not regularly with live sound reinforcement, amplification devices can be designed to move type, speakers use public broadcasting system's speakers. This will not only reach the sound reinforcement needs, but also reduces equipment room, while also saving money. Specific practices are in place for site amplification of insert Panel set a strong, strong in the Panel set up for relay, fire emergency broadcast of strong cut. In the field you want, as long as the sound reinforcement through plug into the Panel, the amplifier and the public broadcasting system's speakers are connected, you can achieve on-site sound reinforcement.