My wife and I tried an "A/B" comparison, running the M series with and without the Whisper Cap attached. We otherwise silenced the room. We both agreed that the Whisper Cap does, in fact, reduce the noise from the M series machine. However, the reduction is very, very small. So small that it would ...

Cpap.com is now selling a "whisper cap" for M series respironics machines. https://www.cpap.com/productpage/respironics-m-series-cpap-whisper-cap.html I got one of these a week or so ago. It makes a huge difference in the sound level, at least for me. I wasn't so terribly upset with the noise befor...