Air Mini Hose noise solution

[Frequenttraveler]

As a frequent traveler, I got tired of hauling my Airsense 10 around and sprung for the Airmini. Took it on its inagural trip to Germany (without testing it first) and couldn't sleep at all with it due to EXCESSIVE noise around the venting humidifer chamber (How was this not noted in trials???). As I laid out this huge chunk of change and wanted to make it work, I had an idea on how to possibly reduce this "darth vader hose noise) and wanted to see if anyone else had any ideas. My idea was to take the extra Resmed Slimeline tubing (unheated version) that came with my Airsense 10. The unheated slimeline tubing has rubber boots on both ends. I then removed the humidix chamber from the Airmini and pushed that end of the hose into the rubber boot on one end of the slimeline tube. On the other end of tehe slimeline tube I took my REGULAR P10 mask (which has the venting function in the bottom of the mask) and hooked that to the other end of the slimeline. It now doubles the tube length by adding this slimeline tube into the mix and eliminates most of the noise caused by the humidix/venting chamber sitting right below my chin. Still not a perfect solution and definitely more noisy than my Airsense 10, but a bit more tolerable. This allows me to pack this smaller unit (although now have the extra tubing to contend with), and get use out of this really expensive airmini wth a much smaller travel issue than dealing with the large case for the Airsense 10. I assume I am getting enough of an exhale through the P10 venting so as not to be sucking CO2 and I wanted to see if anyone had any other "ideas".

[ateeluck]

Thanks to another post on this forum (http://www.apneaboard.com/forums/Thread-...-EZEX-CPAP), I put together a little muffler.  I don't have a travel CPAP, but my main machine is quite loud without the humidifier attached.  I opted for the Dreamstation instead of the Airsense 10 because the humidifier is detachable and can be left at home when travelling.

If you have some spare parts (a short hose and some hose joiners and couplers, maybe from an old mask) you can easily put one together with any small container.  Here are some pictures of mine.  The original post had the entrance and exit on opposite sides of the container, but I based mine on the humidifier chambers of both my past and present machines: air comes out an adjacent side.  It cut the machine noise by about 80%, and the sound of sucking air on inhale maybe 20%.

I hot-glued the parts together and then took it and my machine to the DME to pressure test it.  No drop in pressure.

[Frequenttraveler]

The muffler idea is a good one. Wasn't sure how they actually constructed it from the posts. Any insight you'd like to share?
The other issue I had was that on the airmini, the humidix chamber was also the relief chamber for exhale as they use the moisture in the exhale to humidify. I can do without that on travel and needed to ensure there is a vent to exhale, thus the use of the regular P10 mask which has a vent in it. I think making a "muffler" would be the final piece I need so anything you can share on constructing the muffler will be greatly appreciated.

[ateeluck]

I used a 7/8" forstner bit to drill the holes, and a hot glue gun to paste in the parts (they have a ridge that prevent them from going right through the holes).  The container is a prescription cream/gel container I happened to have.

I didn't take the coupler apart, just put the assembly right in the container, but it'll likely work the same without that extra length inside. The coupler came with the hose that you see in the first two pictures, they were a lead hose from a past mask that provided the free rotation. The other piece I cut out of last year's mask.



Good luck!

Andrew

[Frequenttraveler]

So there's nothing in the "muffler", no baffles or anything. How does that reduce noise?

[pholynyk]

I think the sudden change in diameter of the airway into the surrounding chamber is what does it. The pressure pulses get diffused, and the outlet off to the side probably helps, too.

More baffles would diffuse the noise more, but also increase the flow resistance, and therefore decrease the pressure available at the mask.

[ateeluck]

I don't know the physics of it very well, but from what I read in the other thread, the machine noise travels with the air from the machine through the tube to the mask.  The muffler disrupts the air path causing the machine noise to be knocked out.  The air then is forced through the only opening available, so it continues, but with much of the noise removed.  That's why it's so much quieter for me if I have my humidifier attached.  The muffler acts like my humidifier chamber, but much smaller.

I also used a makeup remover pad to cushion the air slamming to the bottom of the jar and help absorb the machine noise, but I didn't see much of a difference than without.  If you do this, make sure your humidex is between the muffler and the mask, as the makeup remover pad might absorb moisture.  After a night of using the muffler, I found my mouth drier than usual.

[Frequenttraveler]

thanks

[trish6hundred]

Hi Frequenttraveler,
WELCOME! to the forum.!
Good luck to you with CPAP therapy and also with getting your AirMini to be less noisy.
Hang in there for more responses to your post.

[Frequenttraveler]

I find that most of the noise is created by the humidix chamber. Thats the reason I went back to my old P10 mask with the vent in it to allow the exhalation but got rid of the humidix chamber by rigging the slimeline cables. Might still add the muffler idea. Resmed needs to find a way to minimize the sound in the humidix area or the setup is a BUST!