Follow up... So, when last I wrote, I had just started using a Remstar M AFlex. Initially this machine was extremely quiet, but within a month it made more noise (but tolerable). That developed into a "moan" on exhale, not too loud but still audible. 1 Year later, it developed a very loud whine/whir...

Well, that's the reason for my Q. All my machines (expect my most recent) were supplied by DME and setup correctly. I've changed the filters, and cleaned etc, as per instruction. My pressure is low (5 cm), maybe that blower speed is just too slow for it! I will say, my first straight CPAP never deve...

I've been on CPAP etc now for 8 years. But, I'm also on my 4th Respironics Remstar. About every 2 years, it sounds like the bearings wear out, and the machine starts making a whining noise heard mostly through the hose (not so much at the machine itself). Soon thereafter the machine dies completely ...