You can disable the speed limit chime or replace it with a visual warning in Autopilot settings in the control panel. Try that to at least rule it out. However it's a single chime, not 4, so it's probably not what you're hearing.
Test out the alert sounds for (1) getting into the car and pressing the brake before buckling the seatbelt, (2) shifting into D while the trunk is not fully closed, (3) opening a door while in D rather than P, (4) parking proximity sensors.
It would help new owners if the Owners Manual included audio samples of the alert sounds.