01 saturn vibration issue?

I have an 01 saturn sl. For a few weeks now if I drive mu car between 50 and 60 mph I feel a bad vibration all over the front of the car and it feels lile its the passenger front. If I stay below 50 or over 60 there is no vibration. I had the tires balanced and rotated and it still happens. The mechanic said I had soft brakes but thats it. Any ideas