Sound Comparison - Respironics System One Vs. ResMed S9

System One sound levels compared to the ResMed S9. Found on Youtube! The Winner is System One!

Yeah, that's "dynamic noise level", though, and vid is from Philips. What they're saying is that the volume changes less with the PR1. That's probably because their exhalation relief doesn't back off as much. The actual decibel level of the S9 is lower. Both machines are pretty quiet, but the vid is trying to spin the fact that the PR1 makes a little more noise than the S9. It's sort of like bragging that your sports car stops form its top speed faster than your competitor's without mentioning that the other car goes 40 mph faster than yours.

A number of people here seem to have problems with PRS1 machines becoming noisier after a while or being noiser than other. Mine seems to be noiser on some nights for reasons I haven't figured out yet.

My new PRS1 auto is virtually silent in operation. That said, looking at the video, the difference between the PRS1 and the S9 is less than one dB. Most people cannot tell the difference at that level. It takes 3dB's to make a sound appear to be twice as loud. I think both manufacturers have made it a priority to get the noise level as low as possible since noise is one factor leading to non or partial compliance.

In my circumstance, the loudest noise is the wind noise of the air moving through the mask. I'm not sure what the mask designers can do to make that even quieter.

---just enough white noise that I'm not aware of the tinnitis.
Totally silent would be unbearable.

At last, soeomne comes up with the "right" answer!