Very High Pitch Sound - please evaluate
Hi all. I am sure that in the realm of things, this isn't too important. But I'm hoping you OSCAR/data gurus can give me some insight into this.
My family woke up to a very painful and extremely high pitch noise last night. Apparently it was coming from my mask. So I took a look at the timeframe they mentioned (12:45am-ish). I see that something happened (flow limit). But I wonder why it would have caused my mask to make such a high pitch noise. Do you have any idea? My husband says the noise was due to the Bernoulli effect. But what would have caused that?
Of note, I've recently modified my P10 by poking some holes in the mesh so it will vent better. I wonder if condensation built up and caused noise while air tried to squeeze out. I plan to poke more holes in the mesh, to give a few more areas of venting.
[attachment removed per OP]
09-27-2020, 08:21 PM
(This post was last modified: 09-27-2020, 08:22 PM by srlevine1.)
RE: Very High Pitch Sound - please evaluate
Just saying, it is a stunningly bad idea to modify mask venting as it can alter the designed dynamics of therapy delivery and certain reporting parameters.
The last time I encountered a high-pitched noise was when my mask appeared to be whistling through an unintentional leak apparently caused by a sharp object. And, one of the most common causes of whistles is a partial blocakage of the exhalation ports, possibly caused by water vapor or dust. You should also check the fittings and hose connection.
Best of luck.
"The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." -- Marcus Aurelius
RE: Very High Pitch Sound - please evaluate
One or more of your holes in the mask you modified is likely creating a high-pitched whistle from the vent. I don't know which hole that might be but air passing through a confined opening creates acoustic noises. The higher the velocity and the sharper the whistling noise. You have created an opening that increases the velocity of air exiting the mask, and it is whistling. You are really on your own. to determine which of the holes you made is creating this problem, and enlarge it or create additional holes to reduce the velocity at the one that is driving your family nuts. Otherwise, toss that mask frame and get back to the original that is quiet.
It's really tempting to combine this with your previous thread about modifying the mask
http://www.apneaboard.com/forums/Thread-...-VENT-more
RE: Very High Pitch Sound - please evaluate
My mask (F30 AirFit) will squeal at times. It's not so loud that it bothers my wife, but loud enough to bother me. I'll try a couple of times to readjust the mask, but if not successful, the mask comes off, and that's it for my SA Therapy for the night.
It is an air leak for sure. Some nights go very well, and some don't. I'm still struggling trying to figure out why.
RE: Very High Pitch Sound - please evaluate
Thanks for the feedback.
I think it's logical to conclude the sound came from the holes I made in the mesh of my mask. I think my exhales are too humid for the mesh, and cause the mesh to not vent well. (It is well-known that the P10 does not vent well when the mesh is damp.) So I think my exhaled humidity was too much for even my pinholes, and perhaps I need more pinholes and/or larger holes.
[Moderator note: thread closed at the request of OP]
