My money is on CV joints or possibly a wheel bearing. Jack the car up, lock the steering, and see if you can wobble the wheel by hand (make sure the whole steering knuckle isn't moving. That's more about the tie rods.). If so, the bearing is shot. If it tends to click when you turn, it's more likely a cv joint. Warped rotors usually are only noticeable when you apply the brake. The fact that it changes frequency as you accelerate, means its most likely near the wheel. If it was engine related, it would change tempo or pitch with every shift of the transmission.
You could also have broken belts in your tire if they're severely worn, which can cause noise and wobbling.