Static sound at the start of each event

My Video Doorbell 2nd gen arrived this morning and after setting it up and having a play (haven’t installed yet) I noticed that each event has a static noise at the start. Example here (1 second mark) https://ring.com/share/c8e5cea5-0ec0-4d85-a276-d60491b31bf9

It seems to be as the microphone fires up as doesn’t happen when audio is disabled. Is this normal?