Residential metal roofing is not noisy. The "noisy" metal roof is a misconception started with agricultural buildings. In an ag building with a metal roof, the roof is usually all there is to the roofing system. There is no under-layment, no insulation, no barriers. The metal panels are screwed into the ag building's rafters - it's that simple. And that's why they are noisy. In fact, rain sounds worse in those kinds of ag buildings. It's as if they act like a drum and amplify the sound.
That is NOT true with a residential metal roof. Between the roof and the living space are several layers of material. Each layer deadens the noise and the potential for amplification. Once you're interested in metal roofing, you'll start to notice that many commercial buildings have them. That would not be the case if they were noisy.