Right now, it's got flexible tubing (tin, aluminum?) that bends once (90 degrees) at the base of the dryer, travels up the wall about six feet, and then makes another 90 degree bend to the outside. The outlet on the outside of the building has a simple hood and flap.
Question #1: Could this setup really produce a fairly loud, high- pitched noise that can't be heard from inside (just the other side of a drywalled, non-insulated garage wall)? Question #2: Since I can't hear it from the inside, can I rule out the exhaust fan and conclude it's a whistle from rushing air moving through the vent hose? Question #3: Would moving to a rigid vent pipe or a different outlet cover help with air/whistle noises?
Thanks for any input. Much appreciated.