Wow ... I was at my medical equipment providers shop today sampling some other cpap machines to see if they might be quieter than my new pr system one 450p.

She had set up an m series for me to try with my pressure .. which is 13. It was louder ... but the one she had didn't have the available M series whisper cap which supposedly lowers the noise 3 decibels.

Anyway we tried another machine ...one of the older rectangular units that has a muffler on the back ... That is the type I had used before the pr system one and that unit died after 9 years faithful service ... That 9 year old unit was in fact quieter than the new pr system one ...

The one she had for me to test hadn't been set to my pressure ...it was set at 20 .... WOW ... I can't image getting a leak free seal at that pressure ... it must be very difficult ... I could hardly hold my full face mask on at that velocity ... I have new found respect and sympathy for those whose pressure is that high ... from now on when they say they have mask leak problems I'll just nod my head ...