I'll try to keep this to "just the facts":
1) Machine is a Transcend Auto w/ EZEX.
2) Masks tested were Respironics Dreamwear and a Fisher/Paykel Opus.
3) Tried both masks with and without the Qtube muffler
4) Dreamwear mask was far too loud both with and without the muffler. Muffler didn't seem to make any difference at all. Could not even get to sleep with ramp pressure set way low.
5) Opus mask WITHOUT muffler was far more quiet than Dreamwear WITH the muffler.
6) Opus mask WITH the muffler was far more quite than without it, maybe half as loud. This seems to be the "quiet enough" answer for me.
Conclusion (for me anyway) - The Transcend is a good light weight option for those who travel and the right combination of mask and muffler makes a HUGE difference in noise levels!!
The Transend/Qtube/Opus mask combination is almost as quite as my "home" CPAP and I look forward to using it many times as I travel.