@Livingroom23,

This is normally a result of the Microphone on either the Phone or camera, picking up the sound of whatever is going through your microphone. If you have your device too close to the camera, the camera will be able to pick up the signal from your phone speakers, or your phone's microphone will be able to pick up the sound coming from your camera.

When you are viewing the camera feed, try turning down your phone's volume, and muting the two-way audio stream between your phone and camera. It could also be possible that the volume of the camera is set too high for its environment.