Does it change sound when you lightly apply the brakes? Some brake pads have metal wires embedded in them to make a noise when the pads wear down. Did you check your pad thickness? Sometimes a stuck caliper can wear the pads unevenly (ie one side not the other so you'd need to remove the wheel to inspect). I'd also check to make sure the dust shield is not damaged as well at that time. If the noise happens when turning, then I'd suspect you have tire noise, which can be an alignment or worn steering or suspension component.

 

 

sure, debris can get caught between the rotor and splash guard, or the guard (that thin metal shield behind the brakes) can be bent. Brake pads also can pick up a glazing or squeal due to insufficient grease on the back of the pads - or if somebody didn't install the shims. I'd pull the tires off and have a look see for anything obvious.