So I had new brakes & rotors put on the wifes car about a month ago. I do not drive it much, but drove it today and noticed what I would call a whisper in the brakes when I get down to lower speeds while braking. SO I cannot hear it when I first start braking, but as I slow toward a stop it I hear a whisper. No vibrations or shimmy just this whisper. Any thoughts, and should I be concerned? Thanks.