(1) Use shielded cables to reduce interference from surrounding electromagnetic fields.

Microphones typically have an impedance of only a few hundred ohms and a weak output signal. Therefore, it is recommended to use shielded cables for signal transmission to reduce interference from surrounding electromagnetic fields.

Note: One end of the shield of the shielded cable must be well connected to the microphone housing, and the other end must be well connected to the housing of the audio equipment to be effective.

(2) Use balanced lines to transmit signals, reducing external interference.

Microphone cables should not only use the special shielded cables mentioned above, but should also be connected as balanced lines using twin-core microphone cables. Using balanced lines to transmit signals, using the principle of interference cancellation, can reduce external interference to a certain extent.

Note: The balance of the line must be ensured by the signal source, transmission line, and load. As long as one of the parties does not guarantee the aforementioned balance conditions, the balance of the entire system will be destroyed. Therefore, it is recommended that recording workers frequently check the balance of each link in the system to ensure their normal operation.

(3) Avoid large vibrations.

All microphones should be protected from vibrations. Strong vibrations will not only cause severe overload of the microphone signal, but also easily damage its components. Strong vibrations can demagnetize the magnet of a dynamic microphone, thereby reducing its sensitivity. Excessive vibrations can also move the magnetic circuit position, causing the magnetic circuit to jam the voice coil or vibrate the voice coil and diaphragm, completely destroying the microphone. If a condenser microphone is subjected to strong vibration while energized, the distance between the diaphragm and the fixed plate may suddenly decrease, and the polarization voltage may break down the diaphragm. Therefore, it is recommended to avoid vibration as much as possible when using the microphone, and be extra careful when moving the microphone. It is best to turn off the power of the condenser microphone before moving it. In addition, when working outdoors in windy environments, a windscreen or wind cone needs to be added to the microphone.

Note: Never try to listen to the sound of the microphone by tapping or blowing.

(4) Ensure that the polarity phase of the microphones in use is the same.

In stereo sound pickup, the polarity of the microphone is directly related to the sound image direction. Usually, in professional sound pickup, people often need to use multiple microphones at the same time. If the polarity phase of the two microphones used at the same time is different, the microphone signals will cancel each other out in the circuit. In order to avoid this, we must ensure that the polarity phase of all microphones in use is the same. It is recommended to check the polarity of each microphone in advance when using multiple microphones for sound pickup.

What if you forget to check the polarity of the microphone in advance and urgently need to use multiple microphones for sound pickup? In this situation, we use three emergency processing methods:

① Increase the distance between the microphones. The distance between microphones facing back-to-back is as close as possible.

② When recording outdoors, try to use or have several dynamic microphones. Because the reverse phase situation mainly occurs when using condenser microphones, while dynamic microphones, due to their low sensitivity, generally do not have a reverse phase situation.

③ Check whether the mixer has a microphone polarity reversal switch. To simplify the calibration of microphone polarity, some mixer products have this setting.

(5) Pay attention to the proximity effect.

In general, directional microphones will exhibit a proximity effect, so low-frequency enhancement will occur during close-range sound pickup. In order to prevent linear distortion from affecting sound quality, it is recommended to appropriately attenuate the low-frequency components during use, or move the microphone away from the mouth "corner pickup".