I also had an air dryer installed on ours this past June at our Freightliner Shop. It does quiet down the compressor banging sound, though not completely. But the bigger reason is to prevent water getting into the brake system and rusting components. I have a 2016 so I have air brakes.
__________________
Perry and Bernadette
2016 Seneca 36FK
2017 Colorado ZR2
2012 Rans Seavo Tandem Bicycle