i just got my backing plate and pads from Detailers Paradise and attached the backing plate and the yellow pad to my PC. I turned it on and i was just wondering if what i heard is normal. i hear a high-pitched noise along with a little bit of a grinding noise. i did switch out the counter weight. this was at the lowest speed. what am i supposed to be hearing during normal operation of my PC? i could post a .wav file if need be.