Ask help:Car's noise

My car is Toyota Camry 2003,平时开低于50 迈时 没问题，可是一但到70迈就开始出现很大的嗡嗡地噪音,可是速度一旦过80迈,噪音开始消失,如果保持60-70迈,这噪音就一直存在.开始想是wheel bearing problem, changed right side wheel bearing (the noise from right side). But the noise is there,when I replace the wheel bearing I found the rotor disc one side is little bit not smooth , but there is not any problem about brake the car.

So my question is the noise is because the rotor? Many thanks