Gotcha, you're right.
Go to your car, and drag your fingernail down the rotor, and see if you can feel any imperfections in the rotor itself.
On another note, have you ever replaced your rotors, or had them resurfaced?
EDIT: Reason I ask is because perhaps the rotor is damaged, or needs to be replaced. On another note, I heard EBC's aren't as good for the rotors as other pads.