Excess noise with a ResMed Air Sense 11

[mesmith9]

I have been using a ResMed Air Sense 11 with an AirFit N30i nasal cradle mask for over a year.  I have no problems sleeping, great sustained O2 levels and no recurrence of my Afib.  However, within the past few months, my wife has stated that it is getting noisier.  The sounds are variable from a low drone to an occasional gurgling sound.  When I occasionally spontaneously awake during the night or when she kicks me, I sometimes get a sense of nasal congestion and basically either change position or blow my nose and go back to sleep.  Any other suggestions for other potential tools or actions to get reduce the occasional noise?  I have also tried a chin strap or the BeBetter mouth tape.  So far the tape has not been very effective, only tried once, and I have not used the chinstrap for quite a while.  Are the noises due to congestion or am I opening my mouth, and this is causing the droning noise?  Any thoughts or suggestions would be appreciated.