In recent years, in large-scale shopping malls or activities, we always see the figure of "LED fan". Its appearance is similar to the fan, but it can display various patterns when rotating, and some can display dynamic 3D patterns, which is very cool. Every time we see it, we can always make people stop and watch it, which plays a very good role in publicity and promotion. So how do LED fans display patterns?
Strictly speaking, this so-called "fan" is just a vivid way to call it. In fact, it is a kind of "rotating LED light bar", and its professional name is holographic 3D smart glare screen. After power on, the "fan blade" starts to rotate, which can present a 3D image at the same time, cool and lifelike. At the same time, according to the size and color of the pattern, the LED fan can well hide its leaves, because there is no frame and no fixed screen, so the dynamic picture is like floating in the air, very realistic.
The 3D smart screen not only uses the hardware of rotating LED, but also uses the visual persistence of human eyes. For the hardware equipment of rotating LED, simply speaking, it is to calculate the change frequency of LED light according to the rotation speed of "fan blade". When different LED lights are lit at different times, different patterns will appear. The so-called visual persistence refers to that when the human eye is observing the scene, the light signal is transmitted to the brain nerve, which takes a short period of time. After the end of the role of light, the visual image does not disappear immediately, and the human eye can still maintain its image for about 0.1-0.4 seconds. This kind of residual vision is called "afterimage". The visual phenomenon is called "visual persistence", and the single product can be unique. Vertical display effect can also display the overall effect in combination.
3D holographic fan screen application: shopping malls, brand stores, stores, airports, etc. A good choice to reflect brand effect and brand grade
Principle of 3D holographic screen: Generally speaking, one or more strings of LED lights are arranged on the fan blades. Here, it is assumed that there are 20 LED lights, which are numbered 1-20 at a time from the axis to the edge of the fan blades. In order to explain the principle briefly, we assume that when the fan speed is 60 laps per minute (in reality, the speed is much higher), the human eye will have visual persistence. Let's assume that the LED light is 0 degrees above the fan in 0 seconds. If you want to display the effect of 6:00 on the fan, the minute hand needs to point to the top and the hour hand needs to point to the bottom. It is necessary to turn on the number 1-20 to display minute hand in 0 second, turn on the number 1-10 to display hour hand in 0.5 second, turn on the number 1-20 to display minute hand in 1 second, turn on the number 1-10 to display hour hand in 1.5 second, and so on, so that the human eye will receive a complete picture of the clock at 6:00. For complex patterns, LED fans will have more complex structure and programming equipment. Through the combination of LED light bar rotation and visual persistence, people will see a dynamic 3D picture of the rotating LED fan.
3D holographic fan screen structure: the screen body mainly has light bars and, according to different ones, some have two. Add rotary motor, built-in 3D holographic system and information receiving system.
At present, the main application of 3D smart screen is advertising. Because of its editability and realistic display effect, it is believed that in the near future, it will be applied in more fields.
3D Holographic Advertising LED Fan Display Advertising Led Display,3D Holographic Advertising Led Fan Display,Indoor Advertising Led Display,3D Holographic Led Fan Display Shenzhen Vision Display Technology Co,.LTD , https://www.ledvdi.com I believe that everyone will generally say several programs. Some people say that the power of the amplifier should be 1.2-1.5 times larger than that of the speaker. Some people say that the power of the amplifier is twice as large as that of the speaker. Some people say that 1:1 is also OK. What is the doorway in the end?
First, the speaker, according to the AES standard, the general speaker can withstand the instantaneous peak input power 4 times (6 dB) higher than its rated input power in a short time, that is, if a nominal 300W speaker can withstand for a short time 1200W input power.
In addition, the power amplifier, according to the standards of the US FTC laboratory, in the case of sufficient power supply capacity, the power amplifier can instantaneously output a peak output power higher than its rated output power of 3 decibels, that is, a rated output power of 300 watts. The power amplifier can provide twice the peak output power of the rated output power in a short time, that is, provide 600W of output power in a short time. Then, if you want a power amplifier that can provide 1200W peak output power, the power amplifier's rated output power needs to reach 600W. Home theater network shopping guide network welcomes you!
Well, now everyone can know through the above instructions, in order to let the amplifier and speakers fully express the performance of various music peak signals, then the rated output power of the amplifier is equal to twice the input power of the speaker.
However, in this configuration, you are not required to fully add the rated power of the amplifier to the speaker. If it is fully added, the speaker actually receives an input power that exceeds its rated input power by 1 times, that is, the speaker is always overloaded. Working status, this is a very dangerous state for the speakers.
Therefore, according to the power amplifier output power and speaker input power ratio of 2:1, the purpose is only to allow the speaker to express its peak output capability. However, the control of the input level of the power amplifier is stricter at this time. Under normal circumstances, for example, the rated input level of the power amplifier is 0 dB, then the power amplifier input level setting is 3 dB lower than the rated power input level, that is, the 600W power amplifier is only operated at 300W. When a signal with a peak characteristic of 4 times (6 dB) enters the power amplifier, the actual input level of the power amplifier reaches 6+(-3)=+3 decibels, and at this time, the instantaneous output power of the power amplifier reaches the rated output. The power is doubled to match the peak input power of the speaker. What would happen if you didn't control the level like this? For example, the same rated 600W power amplifier pushes 300W speaker, the power amplifier still according to its rated input level, then the power amplifier normally inputs 600W power, the speaker is equal to eating 1 times the power comes in, when a +6 decibel (4 times) peak signal enters At the time, it is said that the peak output power of the power amplifier should reach 2400W. However, the peak output capability of the power amplifier is only 2 times. It can't emit 4 times of undistorted power. What happens when it can't be sent out? Clipping, what about clipping? The audio signal that was originally a sine wave turned into a square wave. Well, the horn is easily hanged because of this square wave.
Therefore, using a power amplifier with 2 times the input power of the speaker to push the speaker has a theoretical basis, but the system level setting is very high. If it is aimed at a master who can correctly control the level, this method can be used to achieve perfection. Music performance. However, if the operator is not very familiar with this, it is very dangerous.
How to set this level? There are two ways. The first one sets the normal working level of the system to 0 dB. When the output level of the device in the preamplifier stage is 0 dB, the volume potentiometer of the amplifier is reduced by 3 dB. Second, set the system's normal operating level to 0 dB, and then reduce the mixer's output level by 3 dB under normal conditions. I personally prefer the former method, so the signal-to-noise ratio of the front end of the system can be increased by 3 decibels.
Having said that, a friend said: How do I control this level? This requires a limiter to help you control. If the previous method is used, if the amplifier input sensitivity is 0.775v (0dB), then the limiter is set to +6dB. If you follow the latter method, the limiter is set to +3 decibels. In this way, the front signal is increased, and the peak signal level applied to the power amplifier will not exceed 6 decibels, and the system is safe.
Let's say that the power of the speaker and the amplifier is 1:1. <br> The power of the amplifier and the speaker is 1:1. The same is the speaker with 300W. The peak receiving capacity is 1200W. The power of 300W is 600W. According to the above description, that is, when the amplifier enters the peak state, the speaker can only obtain the peak input power of half of its peak withstand capability from the power amplifier. What is the problem with this? Friends can see that the speaker is only a little discount on the peak performance. So what are the benefits? The advantage of this is that the speaker will not be overloaded when the working level is normal. But some friends will also ask, how can I control the input signal not overloaded? And the project has been handed over, and it is not my operation. To avoid this, it is also necessary to use the limiter. In other words, an input sensitivity of 0.775v (0dB), output 300W power amplifier, as long as you set the front limiter limiter level to 0 decibels, do not let more than 0 decibel continuous audio signal into the amplifier, then The output of the amplifier will not exceed 300W, so it will not overload the speaker. 
