I use another brand (Resmed) and pulled my old one apart to see what’s inside. They are well engineered - and they need to be, as they run 7-8 hours, every night. They also have quite a bit of soundproofing surounding the pump. Mine had spray expanding foam and the spongy seat padding type, but this is all outside the airflow. I suppose they could use foam inside the air tubes for further sound damping, but it seems a bit dumb as if any breaks off it will go straight up your nose.