hard to say without hearing it, if the rotors are worn, it may just be the new pads "seating"...real bad noise could mean the pads are in wrong, not safe.
ok do3 im going to check and see if thats the case now the pad with the line should be on the outside of the caliberThe side that goes toward the rotor has a slot across the entire pad area to indicate wear ??? I don't know a better way to tell you, but I was thinking the same thing. I had a set of EBC HH rear pads years ago that made noise until I wore them out and replaced them. Brakes are important
Against the rotorok do3 im going to check and see if thats the case now the pad with the line should be on the outside of the caliber
Break pistons should be cleaned when pads are changed.
Also, I put copper slip on the REAR of the pads to stop brake squeal
If you are worried, buy a good set of brand name pads for your application from one of the board sponsors.