This is a touring/wagon model, manual transmission. At about 30,000 miles it began to intermittently roar inside the car, drowning out the radio. Sounds like you are driving down the road next to a running train or that a running semi truck is just inches away. However no vibration felt. Took it to a dealer and though they could not make it demonstrate the noise they found a loose mounting rod on aftermarket cruise control and tightened it up. Sound went away for about 10 months but is now back and the mount is still very tight. This noise randomly comes and then goes within a few minutes, happens on different roads, temperatures, times of day, engine warmth, tires have been rotated. Car has been inspected and serviced according to factory recommendations. Last visit at 46,500 they replaced the pins which the calipers slide on. They also adjusted the parking brake cable, but it still rolls backward on slight grades with parking brake full on. This noise is very disconcerting to passengers who think the car is about to blow apart and I cannot blame them.
On one of these many repair forums a guy told me the parking brake levers are rusted, which causes the parking brake shoes to drag which heats them up and causes the noise. Googling around give me a lot of hits about Hyundai parking brake issues. Is that the most likely cause of the noise or is there something else which jumps out?