Had a problem with a '93 Bonneville that sounds similar. Not sure if the same as yours or not. Barely audible, right front, and could hear better when it reflected back off a curb. New pads and having the rotors turned did not stop it. Later, when the rotor warped and couldn't be turned again - new rotors and pads stopped the noise. Why the new rotors and not the turned ones, I don't know.
DANG..the pads are new...wonder if it is the rotor then?