It's not the pads/rotors or any combination of the same. It's not the material the pads are made of. It's vibration. More vibes, at the right frequency and you have more sound. Change the frequency and you change the sound. You have to dampen it, isolate what is vibrating (the pads)from the object it is striking (the calipers). Take off the front pads and look for any shiny spots where the pads contact the calipers. Eliminate the contact by your choice of anti squeal grease (I bought some at NAPA, its red, looks like it won't dissapate as easily as the light stuff) on all the shiny spots. Reassemble. The rears use the usual grease/shims on the pads. I fill the 4 holes on the back of the pads level with grease, kind of a spring resevoir if you will. Don't for get the pins that hold the pads on. Grease both ends and where the hold down spring contacts the pins. My 2 cents.