I ran into this issue for the first time today. It really couldn’t have come at a worse time either. I had a notice from the building manager of the apartment I live in stating they were going to be entering apartments with their lenders today. Perfect time for me to really test out the cameras. I set up all three of mine and had them in really good areas to capture anyone that enters and be able to listen in. When they came, could see everywhere they went, perfectly and clearly, but I could not hear a single word that was said. It was muffled from the crackling sound that is constant while the cameras are operating.
I am wondering has this always been the quality of the sound used for these cameras? Or is this an issue with a current firmware update?