Airsense 11 noise

[ThisisXian]

Hi all,

I’ve had my airsense 11 for about a month and it’s been fine. However, it’s started making a “machine” sounding noise that I can hear through the mask. Mask is nasal cushion. The sound is not air or whooshing or air leak or anything like that. I can just hear the sound of the machine working through the mask. The machine doesn’t sound broken or like it’s struggling. Just gently humming along.
I do not hear the noise emanating from the machine, nor does my wife hear it. I hear the noise through the mask.
The day before the noise began I’d removed the hose for cleaning and attempted to remove the valve, but couldn’t and didn’t want to force it, though I did apply pressure. Tonight I’ll put the machine on the carpeted floor to absorb any vibration and make extra sure the humidifier tub is seated properly.
If anyone has any tips or advice it’d be greatly appreciated. I have a feeling if I try to take it back to where I bought it (1hr drive each direction) they’ll find some reason to say they couldn’t recreate the sound, or that it’s within an acceptable level (it’s not), or some kind of hassle. I’d much rather remedy the situation myself.
This board seems to have very experienced members and good advice so I thought I’d give it a try.
Thanks