[Equipment] New unit, new questions

[Benzi]

Hi Fred

Lately I have noticed (actually my wife was the first to notice  ) that i hear the fan of the S9. In the past I didn't notice anything, I don't know whether it's because we're now sleeping with a closed window so there's no  noise from outside, or because something has happened to the machine. We hear the fan when I inhale and when I exhale. Is it normal to hear something, or should the machine be completely silent?
I also added a humidifier lately, changed nasal piece from n30i to p30i, and am using different replacement filters. The new filters that I got are much thinner than the few that I received with the machine, so I'm using 2 of them. Don't know whether this could have something to do with hearing the fan.

TIA!

[jaswilliams]

The two filters could be causing the machine to work harder making it louder, the filters only protect the blower from hair and fluff entering the machine

[Nightynite]

I received a replacement brand new air sense 10 a while back and it made a whine type noise also.
My DME replaced it with another new machine, all’s fine. So it does happen.

[Benzi]

My machine isn't whining. When I inhale or exhale, it sounds like the machine is breathing. Harder I breathe, louder the sound