S9 users please come in,strange noise with the machine

[beylow]

Hi everyone.

I'm currently using S9 AutoSet. It does more quite than S8 series. But I noticed that the machine generates strange noise when I'm exhaling. The noise sounds like whistle. It's kind of annoying and affacts me from falling into sleep.
When the pressure is low(under 8 cmH2O), I don't hear this whistle. When the pressure is increasing, the whistle becomes more and more obvious.

I'm pretty sure that there is no problem with my mask and hose. Because when I use the same mask and hose with S8 Elite II, I don't hear this whistle. When I'm using the machine without humidifier, the whistle remains. That's why I can make sure the noise comes from the machine.
I contacted resmed and told them this problem. They ask me to send the machine to them. Finally, they changed a new S9 AutoSet for me, because my machine was bought 2 weeks ago.
With the new machine, I still can hear the fxxxing whistle. It's driving me crazy......

I recorded the noise here. Since the volume of whistle is so low, it's more easier to hear it by turning your speaker volume to high.
Tallenne_11_.wav - 0.44MB

I don't know if this is common with S9 AutoSet machines. Please, S9 users, let me know if your machine has the same noise. Or, how do you deal with it.
Thanks a lot in advance.

[Big S]

My S9 also whistled when I exhaled. If I slowed my exhalation, the whistle went away. Since this really wasn't an option to lessen the noise, I added a regular filter to the stack of filters I use since I suspected this as the source. I tried several configurations and they all worked for me. Right now, I have a HEPA type filter sandwiched between regular filters and the whistle is gone. I also tried doubling the regular filter behind the HEPA filter and made sure the inlet to the machine was covered with the material before installing the cover. I don't have an autoset though and my pressure is 11 cm H2O. Good luck!

[leonardlake]

Thanks for the suggestion BigS.

I too have the exhale whistle even though I have had my S9 Autoset replaced once. I will try your filter configuration fix. My whistle is rather loud; my wife has commented on it even though I have the machine placed down low on a small stepstool on my side of the bed.

[beylow]

My S9 also whistled when I exhaled. If I slowed my exhalation, the whistle went away. Since this really wasn't an option to lessen the noise, I added a regular filter to the stack of filters I use since I suspected this as the source. I tried several configurations and they all worked for me. Right now, I have a HEPA type filter sandwiched between regular filters and the whistle is gone. I also tried doubling the regular filter behind the HEPA filter and made sure the inlet to the machine was covered with the material before installing the cover. I don't have an autoset though and my pressure is 11 cm H2O. Good luck!

Thank you Big S.
I'm wondering what kind of filter do youmean by HEPA filter? Is it bacterial filter like https://www.cpap.com/productpage/In-lin ... bipap.html , or HypoAllergenic like https://www.cpap.com/productpage/resmed ... neric.html ?

[DreamDiver]

Check out my S9 vs. M-Series Pro Audio Smackdown on this very same issue.
viewtopic/t49987/S9-Autoset-vs-MSeries- ... KDOWN.html
This has been an issue with the S9 since the beginning. Most people don't even notice it until they are made aware. I find it a lot less objectionable than the hoover vacuum/batmobile jet-engine sound of the M-Series Pro.

If you place the machine well below the level of the bed and not directly on the top of the nightstand at eye level, the whistling is drastically reduced.

[chunkyfrog]

We both have hearing aids--which are not worn at night.
Neither of us has a clue if there is any whistling.

[sol]

I hear that whistling sound on exhaling and it is annoying and if try to hold my breath it will stop .

[Big S]

Beylow, it is the hypoallergenic filter and not the inline filter. However, I think with my machine it is more a matter of filling up the filter area volume under the plastic cover with more filter material. If you don't need the hypoallergenic filter, try two regular filters since stack would be thicker and may muffle the sounds better. I also keep my S9 lower than the mattress top as leonardlake and DreamDiver have mentioned. I hope this works for you, good luck!

[Bobby269]

I read on the Resmed web site. If you are using the Climate control hose you should not use the hypoallergenic filter.
My unit doesn't whistle.

[BanjoPaterson]

Bit of a history here that may or may not help...

First, I noticed the whistle sound on exhale with my first S8 II in 2008, which was so loud compared to the rented machine that I returned it. I then sat with my DME, who brought out 4 machines, and tried each one until I found the least worst, if that makes any sense. Asked if I could have the rental machine, but he said there was warranty issues (I suspect they keep the quietest machines for the trial rental ). The machine still had a slight whistle, but after 10 minutes it would abate (or my breathing would change), and the sound wasn't so bad. Placed it under the bed and happily used the machine.

Then, late November 2010, decided to trial the S9. Rented a trial machine from my DME and it was fantastic. Decided to fork out and buy an S9. Sat with the DME and tried 3 of them, again went with the least worst, but wasn't happy with it (but decided after the palava from the S8 to just go with it). The machine was intolerable as I was getting echoes up the tube and after the first night. Went straight back to DME and said that, rather than return it, to get it repaired. DME listned to it and agreed, so sent to Resmed who concurred, replaced fan and sent it back. All the while I used my S8 II which, surprisingly, had stopped producing the whistling sound.

Got back the S9. Whistling on exhale, but not too bad and disappeared after 10 mins. After 14 days the fan produced an annoying, high pitched noise at about 12 KHz. Went back to DME who sent the machine back. At this time happily using my S8, which was now quieter than the S9... got the S9 back two days' ago. They concurred and changed the fan again, and this fan is almost silent BUT... whistling sound on exhale, but disappears when my breathing shallows. So my observations are:

1. The dual fan motor spinning down on exhale may probably responsible for the whistling sound;
2. Spoke to Resmed technician about putting on 2-3 filters, but he advised against it saying that the design of the device included the calculations for the expected air flow rate from the exhaust
3.. I susect, based on my S8 II, that the noise of the fans change with usage. In the S8's case it got worse before it got better. Maybe the reason the rental machines are good are because they've been used and their sound has changed like my S8.

So currently using the S9 quite happily... finally got it to the point where I can happily sleep with it -- and the S8II backup is (now) also quiet. Not sure about teh use of many filters, but if you reckon it works then why not?

Hope that helps....

[Big S]

Bobby269 and Banjo make excellent points. We can't have excessive mufflers on one end and hypopneas on the other. It leads to a constipated machine!

[Guest]

It seems like most S9 machines whistle except lucky Bobby269. Maybe I should try to live with it.
I doubt that this whistle could be a intentional designing fault. So that they can develop next generation product and fix this problem, create some problems which S9 doesn't have. People will always buy new product, since old problems have been fixed, new problems are not informed.
Thanks BanjoPaterson for sharing your story. You suffered more than me......
I'm wondering that why your S8 whistle. I have tried S8 AutoSet and EliteII, non of them whistle. Maybe S8 is a bit noisy, I cannot distinc the whistle from the noise.
I tried to use a S8 filter and S9 filter together last night. It's a bit hard to put S8 filter into S9 cause it's thick. S9 remains whistle...... I definately should buy some S9 filters.
Thanks DreamDiver. Your sound record looks so nice. May I ask how did you make it?
Thanks everyone in this post.

[Wrathwielder]

Hey everyone!

I've been following this whole "S9 noise/chirp" issue since I got mine 6 months ago.
I had previously been using an S7 for 5 years, and it started making a harmonic tone/motor noise that was starting to be more noticeable so I thought it was time to upgrade since insurance will cover one every 5 years.
I was very excited when I got the S9 as it's SO COMPACT compared to the clunky S7. I also liked the heated hose and climate control for rainout prevention, not to mention the smaller humidifier tank and the SD card...
What can I say - I thought it was better in EVERY WAY...until I tried actually using it!

Two things bothered me and my wife:
1) It didn't have the constant sound of the S7 - with the S9 you mainly hear the sound of the air when you breath IN - so now I sound like Darth Vader (before the constant sound of the machine covered up the breath intake sounds)
2) The next morning my wife commented that she heard a "chirp" or "squeak" sound every time I breathed out - I heard it too. This was a deal breaker...
I tried EPR/NO EPR/ramp/no ramp/humidifier/no humidifier...the only thing that helped was actually lowering my cpap level from my usual 16 down to like 10 or so - as the level went down the chirp did as well - but I need it at 16 so that's not a solution.

I've compiled a list of at least 15 different posts from around the web regarding this "chirp" sound and I'm going to send it on to Resmed. I really doubt it will do any good based on the responses others have received from them, but I thought I'd at least give it a try.

So, this wonderful $1300+ machine that insurance bought me has been stored in it's wonderfully tiny traveling case for the last 6 months, and I've been back using my S7. I never thought I'd be so happy to go back to the old one after the 3 days I tried sleeping with the S9. I say "sleeping", but it was more like trying to control how hard I exhaled so I could avoid the chirp and my wife could get some sleep...I could eliminate it completely by exhaling very slowly, but once I fell asleep - back it would come.

It's very strange that this problem was never caught while they were testing the units before they were officially released - it certainly seems like I'm not alone.

I know that a few of you have had luck with adding more filters in the air INTAKE, but based on the fact that it's EXHALING that causes the chirp I wonder if you didn't get an improvement because the air intake was restricted thereby lowering your cpap level which we already know will help the problem...? Just a thought...

Anyways, I popped back on here after being absent for a few months in the hopes that Resmed had actually admitted there was an issue and announced a recall - NO JOY!

I've been dieting and lost 28 lbs over the past several months and because of this I've been able to lower my cpap level to 15, so it looks like my 2 options are to keep at it and shed the remaining 75 lbs I need to lose (and hopefully eliminate the cpap or at least get it down to a much lower setting) or to stick the unit in a RubberMaid tub and "lock in the freshness" along with the annoying chirping

Thanks for listening to my ranting!

-Greg