ZERFUN UHF Dynamic Cardioid Wireless Microphones ZERFUN Wireless Microphones are well-made cardioid wireless mics which means they pick up noise unidirectionally(Only when we speak towards the top of the microphone will there be a sound, while there will be no sound when speaking on the side). With this pickup pattern, the directional vocals are easy to isolate from background noise. How to check whether the microphone and the receiver have quality problems? First Check the normal working status of microphone and receiver: 1. Receiver power Indicator is on and the antennas are correctly installed; 2. microphone power Indicator is on; 3. Receiver RF Signal Indicator A, B, C, D is on(Means microphone A, B, C, D have connect with receiver rightly. NOTE: The Microphone Volume Control of Receiver is also Microphone RF Signal Indicator). If all yes, it means microphone and receiver device have no quality problem, can work normally. How to adjust the microphone channel and frequency? Press the "Channel/Frequency Adjustment Button" of microphone to change the microphone working channel/frequency, to avoid interference. Most of the time, the microphone and receiver have no quality problem, very likely that the current microphone frequency is being disturbed, so we need to switch microphone frequency to avoid interference. If you encounter a microphone, there are noise, interference, and signal cut in/out, etc, you can try to adjust the microphone frequency, find the frequency that is suitable for your surrounding environment, and let the product can work normally. How to reset the microphone and the receiver connection(Repairing)? Turn on the receiver and turn off mic first. Make sure both mic and receiver within 20"distance. Hold down the channel-adjust button of mic first, and then press power button of mic. When screen shows "----", release both buttons and wait for seconds. If"----" disappears, it means pairing/reset is successful. If you encounter that both microphone and the receiver can power on, but "the microphone cannot connect to the receiver" or "the microphone has no sound", you can try to reset the connection between the microphone and the receiver and let the product can work normally.