Welcome christophe..
Firstly, a week is not enough to get a machine sorted to know if it is what you are happy with.
If you are lucky the doctor might hit on settings close to what you need, but for most it takes up to a month to get it near something that works.
My trial was for a month with a Dreamstation set on auto with the maximum and minimum the specialist thought would encompass the range I'd be in.
Once the data was in he then recommended a fixed pressure machine set to the pressure worked out on the auto machine.
I chose to buy a Dreamstation Auto and have it set to fixed pressure mode at the setting the specialist recommended [saves me renting a machine for retesting that I plan to do every 18 months or so..]
Today [May 25th] is actually the first anniversary of me starting on CPAP.. over that period I have tweaked the humidity and heated hose temperatures, and recently increased my fixed pressure from 7 to 8 to reduce my blocked nose that has come back now that we are heading in to winter here, and also because I felt a little deprived of air when I first start using the machine each night [though that feeling disappeared when I drifted off to sleep because my breathing rate and volume dropped]
The Dreamstation is a great machine, you can occasionally hear the fan react to the back pressure as you breathe out, but it is only a very slight increase in noise, and usually only if you are exhaling/inhaling harder than usual.... under normal load it is very quiet, and you quickly become used to it and won't notice it [just like the old fashioned wind up clocks that used to tick away on the bedside table, the noise become 'invisible' to the mind]
It also takes time to get used to wearing the mask and using the machine, for many people it can take weeks or months... but others are in to the routine within a few days, or a week or two.
Hang in there, the people here on this forum have a wealth of knowledge stored away in their collective brain.. you will find the information you need to work it all out in the end.
Ock.