Vibration when applying brake

Good day, please i am using a 2003 toyota Camry le v6,i purchased it around January 2020. When i apply the brake the car vibrate and i can feel on the Steering wheel. I was told to change the rotor, brake pads and did wheel balancing as well, still the same result i had to change the rotor, brake pads and wheel balancing again, when i apply the brake at 60 m/h i feel the vibration but any thing above or below 60 i don’t feel the vibration and i have been to 2 good mechanics but it not fixed. Please what can be wrong