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.

I thought it was pronounced Kay Melly-on, so I never tried it because of the silly name.

Pihole will be unaffected.

Gerald Ratner (UK high street jeweller) did a pretty good job, calling his own products “crap” and almost destroying the company. He’s on Wikipedia.