Indesit WIXE127 w.machine drum making a loud noise on spin?

My Indesit WIXE127 washing machine has started making a loud banging noise on the spin cycle, but it doesnt make this noise on a slow or very fast spin, just the middle spin before it really gets going. It also doesnt make a noise if the washing machine is empty (I tried to see if it was anything to do with the weight?) No bra wires or anything appear to be trapped. The machine is approx 3/4 yrs old. Never had a problem with it before, what do you think is causing the noise? and how do I fix it? Help please