Whistling from mask?

I have been using a Simplus FFM mask for awhile and its been doing well. I recently got new insurance that covers 100%, so I decided to get a DME (previous was all privately purchased) and got a new Airsense 10 machine and an Airfit 10 FFM. I like the Simplus better so I have been using that, but since I got the new machine the Simplus has been whistling at night. I can't figure it out. If I run my fingers over the defuser it'll stop for a second and then start again. It wakes me up. The Airfit doesn't have this problem. Pressures are the same, humidity might be a little higher, was on 5 on the Respironics, on 6 on the Resmed. Not sure how that translates.

Any ideas?

Until someone comes along familiar with your mask I'll reply in general. I'm guessing you've already checked all parts to make sure all parts are securely in place. You mentioned increasing your humidity - is there any apparent moisture in the mask? My exhaust holes whistle when there's even imperceptible moisture around the vent holes. Hopefully someone else can be of more help.

And check that the vent holes have been punched through - there was an issue a couple of yrs ago with another mask where a bunch were sold with many blockages that needed repunching with a needle, etc... Not as likely to be your issue with that mask, but worth a look I guess.

It never did it with the old machine... It may be humidity I guess ill try to turn it down and see what happens.

I doubt if it's caused by the humidity. I use the simplus FFM and have my humidity level set at 8. Mine has never whistled, but I constantly fight leaks with it. I use a pretty high pressure (20-25 cm H2O IPAP). On the rare occasion I clean my mask, I use a soft brush to make sure the holes are clear.

I wonder if the diffuser needs a really, really good cleaning or maybe replaced.
How old is the whistling diffuser?

I bought the mask about a week ago and had the same problem initially. But having played with it a bit I can tell its caused by moisture build up in the upper diffuser area. For some reason this mask accumulates moisture much more readily than the quattro I was using before it and the holes are smaller in the diffuser and it has a tendency to whistle. However I also got a new machine (from S8 to S10) and in the process of getting a combined humidifer with fancy sensors and all that jazz my moisture and humidity issues have been solved and the mask will no longer whistle.

So my advice is turn the humidity down until you eliminate the moisture build up.