Mask air vents noisy

[pazza46]

Hi
I have posted about this before about the vents on my mask being noisey. It starts aftr about 10-15 mins wearing the mask. I can hear myself breathing,after that the vents make a load hissing noise. Also it feels like the air is swirling inside the mask. I have had some good nights with it. But also a lot of noisey nights. My hose has a cover on it to prevent rain out,
Mask is a Quattro FX full .

Thanks