Originally Posted by macarule
yeah because when i turn of the front fans the sound stops? i have anti vibration frames on the front but that didnt help at all
Then it is most likely either out of balance or not mounted flush. The former can happen due to a defect. If it just started to happen, the bearing may have gone bad. I had that happen to one of my Fractal fans...and they replaced it. It could also be that it is not mounted flush or the frame is being torqued somehow. Are all four clips securely locked over the fan? Is any of the wiring under one corner of the fan? When you mount the front panel, are you sure that all four posts are fully inserted to the chassis?
You might also be encountering some sort of odd wave harmonic by the vibrations from the HDD colliding with the vibrations from the fan. Can you change the speed of the fan...and if so, does the vibration then go away?
You could also try swapping the fan with another in the case to see if it makes a difference.