Doesn't sound like a rotor problem to me. First off, rotors don't actually warp in the way people picture. What happens is that they start to wear unevenly, and that wear pattern gets worse with more use -- in other words, you start with a spot that's a little thinner than the rest of the rotor, and that gets larger and thinner as it goes.

You will feel that as a pulsating pedal, and poor braking. The pads are forced off the rotor by the uneven thickness. It only takes a couple thousandths to severely degrade braking performance, an amount that can usually be turned out safely.

I've never heard it make noise.