Sounds like a scalloped tire

We have a early 90’s grand marquis that i just put 4 tires on, and there is a slight flapping noise coming from the drive line, checked tires and a cartalk reader said it might be a internal tire problem, in which we also had checked to no sucess. i was wondering could it be a drive shaft, rear end, bearing or ? it’s a slight noise and goes faster when you do and slows down when you do, when i was younger i just turn up the stereo. i’m open for suggestions.

How did you have the tires checked for possible internal fault? On a road force balancing machine?

the tech. took each wheel off and inspected internally then balance them on the car.