Valve hissing very recently started hissing loudly

[tlstew64]

I have been using the ResMed F-20 Full Face mask for a while. About a week ago the elbow (or valve) on the headgear started making a lot more noise. I mean noise to the point that after around a minute I pull the thing off and turn off my machine. It has always had a lot of air blowing from it, but it was more an ability to feel the air than so much noise. Any ideas/hints to fix? I will be able to order new mask per insurance in a few days. What types do you feel are (at this point) MOST quiet, and of course most comfortable? I have searched and searched about the hissing issue to no avail-glad I found this group. Real people may be able to guide/help finally. Thank you in advance. Tammy