Early model 2015 sneaking up on 25,000 miles and our belt has loosened some over the summer where we are being reminded of it since the seasonal temps have been getting cooler where the belt will squeal under acceleration when first starting out and cold, (currently in the mid-20s low 30s), but after a few miles the belt warms and tightens up to where it quiets down. The angle drive any more just has a slight mechanical whine, and like Edward Neal summarizes, it would not even be discernible if the vehicle was enclosed and insulated.
Bill