Solution:
Two Xiaomi Karaoke Microphones can be paired together for two people. When the Bluetooth pairing is successful, double click the on both microphones to enter the dual-microphone pairing state, with a beep. When the pairing is successful, a beep will sound. The microphone that is successfully paired with the mobile device is the primary microphone and the other is the secondary microphone. When both microphones are not paired, the primary microphone is randomly configured. When neither microphone is Bluetooth paired, the primary microphone is randomly configured. When the two microphones are paired, a background tone will be emitted at the same time, but the user's voice will only come out of the current microphone.
Double click on the dual microphone button of either microphone to exit the dual microphone pairing mode.