Can someone help me with my new telly please ?

I brought a 19" lcd tv from tesco the other day it has built in freeview, dvd and ipod dock everything is workin fine and i brought an ipod of my friend today and i plugged it in the ipod dock and went to play my music and it plays but the sound is horrible like its a radio with a bad ariel has anyone else who has a telly/ipod dock had this problem? please need to know if its the ipod dock faulty, if so then i can take it back and get a new telly =/