It sounds like a pipe has broken under the car. It is very loud.
By the description you have provided, my first guess would be that you have an exhaust leak. The most common failure is the exhaust flange gasket. You can visually inspect your exhaust pipe and look for obvious leaks from broken pipe or missing (stolen) catalytic converters. If you need help with the repair, a certified mechanic from YourMechanic can come visit your home or office to locate the leaks and have them properly taken care of.
Have a car question? Get free advice from our top-rated mechanics.