Hissing / Buzzing during use.

So I am new to the cpap and I have a REMStar Plus with a heated humidifier. I am using a full face mask (Mirage Quattro - Medium). When using the mask I am getting this hissing/buzzing noise (not like a mask leak). Almost sounds like its the flap in the mask vibrating or something in the machine. Has anyone else had this issue or figure out a way to get this machine/mask more quiet?

Is it normal to have some noise from the machine (when taking deep breaths I almost sound like darth vader) as well as this hissing/buzzing?

EDIT: Let me add that I start at 4, ramp to 8.

TIA,
Andy