One thought about the whistling and I don't know if it will explain away your problem with the whistling even when the machine wasn't hooked up.
I have had the whistling with various nasal pillow masks over the years (not just the P10) but it has been extremely rare and the cause was always improper fit or the inner cone of the pillow got inverted.
Improper fit was usually the pillow was squished a bit and couldn't inflate completely or properly.
With the P10 I found it also occurred when I tried to use my usual XS size and it's simply a bit too small and would try to crawl up inside my nose a bit which then of course will squish the pillow. Doesn't take much squishing to cause a whistle.
The inner cone thing. Most people don't even realize there are actually 2 cones involved in the pillow construction and that the inner cone sometimes inverts and almost disappears. That inner cone isn't easy to see at all. You have to look really close down inside the top of the outside cone that goes a little bit inside the nostril (but it doesn't/shouldn't ever touch the inside of the nostril) and then see the teeny tiny top of the inner cone. If you can't see it.....it got inverted and all that we need to do to fix it is take our pinky finger and insert the end up into the inside of the pillow and push the cone back into position.
I have tried dozens and dozens of masks over the years....nasal pillow mainly but sometimes some over the nose cushions or the under the nose cushion and the P10 still ranks as the most silent of all those masks.
It really spoiled me in terms of vent noise and the darth vader noise.
P10 vent noise is non existent because the vented air is so diffuse.
Most of the time vent noise is caused by the vented air bouncing off something and lets face it...kinda hard to keep stuff away from the vent holes. We either get the bed covers too close to the vent holes or our arm or our bed pillow.
With the P10 I have to put my hand about an inch from the vent holes to even barely feel it.
The Darth Vader breathing noise is a conducted noise thing and caused by other issues that have to be addressed separately. It can happen with any mask though.
The Bleep mask, which is my usual go to mask, does have a vent noise problem without the diffuse but with the diffuser it is just as silent as the P10. I have been using the P10 the past couple of months because of wrist surgery causing me to not be able to attach the ports.
The P10 shouldn't whistle at all. If it does then something is wrong somewhere but since I can't be a fly on your wall...I can't say what is causing it in your case.
All this is of course academic discussion if you have already returned it but I mention this in case others come along and read your thread because they also have a P10 and it is making unwanted noises. Properly fitted....it is the most silent of any mask I have ever tried. The Bleep does match it but only with the added vent diffuser.
That said, not everyone will be in love with it. That's the life of all masks....always going to be lovers and haters of all masks for any number of very valid reasons.
I do wish you luck in your mask search because I know that people just have different wants and needs and preferences when it comes to masks and we just have to try a mask to see how it fulfills those wants, needs and preferences.
Sometimes we just have to kiss a lot of frogs before we find our prince and in the process we learn more about our own preferences as well.
The one new mask I haven't had a chance to try is the ResMed N30 cradle cushion under the nose mask. It supposedly has the same diffused venting system as the P10 so should be silent. You might take a look at it if you haven't already.
https://www.resmed.com/en-us/healthcare ... irfit-n30/
It's fairly new to the market but I have been so happy with the Bleep that I haven't wanted to spend money on an experiment and when I had the hand surgery that meant I had to find an easier mask to put on, I already had the P10 so I just used it.
Maybe it is time for a new experiment. Just for education and to say I tried it.
I prefer as little on my face and head as possible which means zero headgear...so I am not looking to replace the Bleep but sometimes experiments can be fun and break the boredom.
I may have to RISE but I refuse to SHINE.
? Just thought I'd ask.
. I do think the pillows sealing at my nostrils though may have been part of the whistling problem. I even heard the whistling noise just breathing into it with my machine off and the hose unplugged.
. He couldn’t tolerate the nasal pillows he got with his machine, so I bought him a large mask cushion for my mask (I had an old frame still) and he uses that for now. But he can’t stand having anything on him when he sleeps, so maybe I should buy him your bleep mask.