The firmware is already the latest. The camera is already wired to the doorbell button, moving it around to test takes too much effrot. Besides, even if the noise issue does not happen in other places, I still need this camera to be installed at the current location, where this product is supposed to be positioned.

I just setup my reolink video doorbelk through WiFi connection.
There is high static noise constantly in video recording, recorded video (on micro SD), and RTSP streaming.
I could barely hear the actual sound, and RTSP streaming is worse than recorded videos.
I have to speak very close to the mic (about 1 inch) in oder to the sound to be recognized in recorded videos (to micro SD). From RTSP/Onvif, the record sound was still not clear.