Your microphone is wireless. It may be that the interference is relatively large, affecting the stability of the transmitter and receiver. Unscrew the microphone, which has the band address, or it may be a mismatch of bands. Ask the manufacturer who purchased the speaker, what is the microphone that should use the specific band, let them give a switch. Stability of square dance speakers general northern manufacturers are better, solid materials. Recommended Thunder brand, many parks can be seen, listening to the sound effect is not bad.
Also, do you have a wireless headset. If so, try to see if it is stable. If it is stable, it is basically a microphone problem.