After tracking a subject, my two SD4A425DB-HNY cameras make a very audible sound when returning to the default position. It is loud enough to draw the subjects attention.
That's normal with most ptz when they move back to the deafult position at high speed. The SD5A825GA-HNR ptz I have doesn't make any audible sound while auto tracking, but the ptz motor would make this Woooooozzzz sound that's loud enough to hear even inside the house with the windows close if you stand near the area. It's even more noticeable at night when it's quiet around the area with no other distracting sound.