Sounds like something is off balance

Does it make the sound when you are sitting still, at the same rpm, in park? If so, it's probably in the engine, trans. If not, try swapping the tires front to back. if the sound changes, it's probably the wheels/tires. or, try putting up the rear on jackstands, if the sound is there, it's not the front suspension, and you should try listening to each side to see where the sound is coming from. Rotate the driveshaft 180*, and re install. If the sound changes, it's probably there. Remember, you are looking for changes in sound, or vibration, it doesn't have to be better, just different. A cheap auto parts store automotive stethoscope will help narrow it down.