How to build a wireless microphone system?

How to build a wireless microphone system?

Before building a wireless microphone system, we must first consider the specific situation of the application scenario. The following is an example of one of our clients' projects. This is a large indoor live performance. The performance hall is about 5,000 square meters with about 2,000 spectators. This project required 16 wireless handheld microphones( 10 for the stage performance and 6 for the spare), approximately 10 sets of headphone/lavalier microphones and several in-ear monitors.

In this large-scale event, a lot of equipment is used, and the frequency range between various devices should be staggered as much as possible. Also, consider the signal interference generated by the electronic equipment (such as mobile phones) and the intercom used by insiders.

After solving the above problems, we start to choose the devices for the wireless system.

1. Signal to noise ratio

The event was held indoors. The environment on the scene was relatively quiet. The line array was loudly pressed, and the number of back-sounding speakers on the stage was also a certain amount. What does this mean?

It means that the signal-to-noise ratio of the system is relatively high, and the total noise value of the live sound system must meet certain requirements.

What is the signal-to-noise ratio? The signal-to-noise ratio is the ratio between the output level value and the noise pressure at the same time. That is, the higher the signal-to-noise ratio, the less noise the machine produces.

After the leveling of the overall sound system is completed, the microphone is used as the source of the input signal, and its number is often more, so the high and low signal-to-noise ratio of the wireless microphone will directly affect the total noise value of the whole system.

2. Frequency stability

The site is about 5,000 square meters, which can accommodate more than 2,000 people. The audio console is placed at the end of the auditorium.

It means that the site area is large and the distance is far. There are more than 2,000 mobile phone interference signals, and the frequency stability of the wireless microphone is required to be excellent, so that the mutual interference can be reduced to a low level.

What is frequency stability? An important parameter for measuring the quality of wireless microphone communication. It involves a lot of research and development issues related to wireless technology (the influence of phase noise of the frequency source on the receiver sensitivity and selectivity of the receiver, the impact on the high-speed digital communication system, the impact on the test system test sensitivity, etc.).

We simplify the understanding of the accuracy between the received signal and the transmitted signal.

3. Bandwidth

The number of wireless microphones used is relatively large. To avoid the problem of adjacent channel interference (sideband superposition) when multiple wireless channels are working at the same time, the frequency interval of the wireless microphone is required to be relatively large, that is, what we usually say: bandwidth should be wide enough

4. Automatic frequency selection

The radio interference signals on site are ubiquitous. If there is no corresponding frequency sweeping equipment, it is difficult for the engineers on site to grasp the actual available frequency. Therefore, the wireless microphone is required to have an automatic frequency sweep function, which can automatically eliminate the disturbed frequency points, and provide available frequency points for the engineers to quickly call to ensure the smooth performance.

5. Automatically synchronizes

Engineers often use more time in the PA speaker sound system debugging, and the parameter debugging time for the wireless microphone is often short. Therefore, in order to reduce the waste of the system setup time of the microphone, the wireless microphone is required to have a automatically synchronizes (including frequency, sensitivity, input attenuation, RF power, name, etc.) to save engineers time.

6. Lockout function

In the live show, there is often a situation in which the device is unexpectedly touched, which affects the going of the performance, so the key lock function is necessary

7. Extend performance

Because it is a live performance, the signal stability of the microphone is required to be adequately guaranteed, no accident is allowed.

Therefore, the wireless microphone must be able to connect to an external device, which can enhance the working state of the wireless microphone and improve stability.

External devices: Antenna Distributor, Antenna Combiner, Directional Antennas, etc.

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