Comments on noise - RemStar range

Tonight I put three RemStars alongside each other to compare the noise coming from each. I was prompted to look at this after a recent thread where one of our 'hoseheads' believed his new machine had become much louder 'like a vaccume cleaner' after a couple of weeks use.

I understand that another among us pointed out that it was not uncommon to fail to put the h/h back in tightly after removing it for its periodic cleaning.

The 3 RemStars compared were ..

1) An AUTO (with Cflex) that has had approx 5 months use
2) A BiPap Pro2 with Biflex that has had approx 6 months use (+ new fan motor bearings)
3) A RemStar Plus


Without the H/H fitted the AUTO was by far the quieter machine but interestingly, the motor sound whilst being quieter fluctuates much more that either of the other 2 due to the fact that the fan output goes directly to the air outlet whereas both the BiPap & Plus have longer paths for the air to flow before exiting.

The BiPap & Plus models sounded pretty even in noise level - both these models run the fan at a more or less constant speed that is largely sustained.

The Plus changes the speed of the fan to change the cms pressure being delivered but this is set by the therapist & theoretically the user doesn't get to change it.

The RemStar plus is of course a CPAP & will try to sustain the pressure it is set to

The BiPap does change pressure but doesn't use the fan motor to achieve this but uses an 'air control solenoid' that can adjust its position between 4 cms of air & 25 cms of air. When it drops the machine to a lower pressure (EPAP setting) the solenoid redirects the excess air back into the fan input chamber which does cause the fan to speed up a tiny bit.

The AUTO model has the most sound proofing built into it. The fan module is encased in rubber foam & a cap sits on top of it whereas the Plus & BiPap have no foam baffling inside other than in the air chamber in the base.

The BiPap does have its fan assembly mounted in a gel like rubbery material that absorbs some of the noise it will make.

The Plus doesn't even have that.

Adding the H/H changes to noise quite a bit (lowers it markedly) and of course adding a hose & mask makes the biggest change to sound levels.

The type of mask also will affect how loud the machine sounds.

Each type of mask has 'leak holes' designed to allow exhaled air (co2) to exit. Some leak this air at a far greater rate than others.

Each mask comes with a manual that includes a graph showing the leak rate that occurs at a given cms pressure.

In Summary.

The AUTO is by far the quietest of these three machines & the Plus & BiPap being pretty even.

DSM

Thanks for the report.

My Remstar Pro II is quieter with the integrated HH because it whistles without it? Anyway, I started a topic about HH on this forum. Why do we need a HH when we've been breathing at night without a humidifier all our lives? (One reason is mine whistles without the humidifier connected, even though I haven't been putting any water in it. No heat, either, of course.

Anyway, it appears that XPAP's have a personality, too.

Jerry

My REMStar Auto CFLEX w/HH was a surprise. I went in bracing for a air compressor next to the bed, and find the machine whisper quiet. This machine makes less noise than any of the mask's I use produce from their interface exhaust ports.

I've been happy with this machine and hope it stays alive for a few years.

dsm,

Thanks for conducting the "experiment". I just received my new RemStar Auto and was wondering if it would be louder than my RemStar Plus. It sounds like I'll be looking forward to a "quiet" machine. I wonder if the HH would change things much???

smyles

DSM, I recently had my Remstar Pro returned for repair and ii came back from Respironics running quieter than it ever had. Can't tell it is running except for the air rushing out of it. I noticed that the parts used to repair it were listed as being for an Auto machine(they basically pulled the cover off and replaced everything inside). They also installed a part listed as a "whisper cap", I assume that it also had something to do with the drop in noise. The first few nights on the rejuvenated machine I awoke to the sound of traffic, something I never did before the repair as I couldn't hear anything besides the up and down whirring of the machine.

Just some FYI,
Bob