The screeching sound during the live broadcast is generally caused by the wireless microphone picking up sound repeatedly. The Lark M2's built-in microphone is an omnidirectional condenser mic with high sensitivity. When there are people in the live room playing the live streaming sound externally, the wireless microphone will pick up the sound coming from the phone, resulting in a feedback loop that can cause screeching. To avoid screeching, you can wear headphones while watching the live streaming, or monitor the live streaming from outside the live room.