There was a jingle in the hotel room.

If you only have this sound point when you close the door, another important thing may be the sound made by the door lock. The power of the electronic door lock is the battery, and the battery power is not enough. The smaller the battery charge, the smaller the battery sound and keep ringing. As for sound and frequency, it is different. It takes 5- 10 minutes to find a hotel to change rooms or batteries.