Loud roaring type noise accelerating between 40 and 50mph?

Ford Focus recently serviced but after a week began making a roaring type of loud engine (?) noise accelerating between around 45-50mph. Plus some window vibration. After 55 and cruising at 70 no more noise. Yet it returns when the speed goes back down to 50 and then disappears in the low gears and low speeds.

Exhaust? Bearings? Seals? Wheels?

I recommend taking your Focus to a Ford Dealer to be properly diagnosed. Ask to speak with the service manager. He'll be in the best position to look into your concern and advise of the next steps.

In the meantime, locate a dealer near you and set up an appointment with the link below:

http://owner.ford.com/...ateADealer

Enjoy the rest of your day!