Noise level comparison - Old Remstar Auto vs. New M series

Justin_Case wrote:I think some are imposing your own unilateral views, beliefs, and opinions on others. We have to take into account the "majority" or the fact that most people have not grown up or live in a noisy environment. If most people grew up or live next to a firehall with sirens going on and off all night or if you liven in an area where gun shots and sirens were common then CPAP will be quiet as a whipser.

For most of us, noise is not a common element during sleep. The fact that most us are not accustomed to noise while sleeping deserves acknowledgement and not your selfishness. There is NOTHING natural about xPAP. No wonder compliance is so low.

For those that are not bothered by it or noise in general, that's your opinion but you don't represent the majority of the population.

I took the previous posts as supporting your view rather than disregarding it. I took them to imply that comments such as Snoredogs and GuestRTs are inaccurate at best and uncalled for at worst. I also took them to reinforce the comment I made on the first page about 5 posts down...

Anonymous wrote:I think this proves that much like masks, everyone is going to be completely different! One persons quiet is going to be another persons racket.

Thanks Guest,

There is absolutely nothing constructive or helpful in some of the posts here about noise. Basically, my inferences from those posts is that if you can't get use to the noise, your an idiot or worse.

This is a forum to help others, not for trolls or to post inflammatory comments.

Wulfman wrote:After reading the comments about the different generations of machines, I thought it was an interesting test.....and I thank Snoredog for posting it.

I also want to thank Snoredog for taking the initiative to perform the tests and share the results. It's nice to have something concrete to look at. I am always impressed with how dedicated the people are here and their willingness to go the extra mile to answer questions. Thank you.

OK I'm new here but here's my 2 bob worth....

Thanks Snoredog for the tests. But below I'd like to suggest some different ways of doing the tests to make them more effective.

Now I have tried the Auto Cflex, the M series Auto Cflex and the ResMed Autosprit in Australia. I rented them all for 1 week and decided not to buy the M Series.

The M series is the LOUDEST of all units. When sitting idle (ie on 6) its OK and nice a quiet, but when you breath it makes a high pitch squeel with each breath. Maybe some of you out there can't hear it but my ears are as good as new (I'm 32) and it was very annoying. In fact if I woke at night I could not stop concentrating on the sound. Plus I could "feel" a mechanical motor sound coming through my pillows. And if used on CPAP mode at setting of 10 or more it was REALLY LOUD.

Also want to let Snoredog know that 1dB difference is not insignificant. 3dB of difference means DOUBLING the sound... its all expotential you know.

So snoredog can you try the tests again but on fixed pressure of 10 or so?then I reckon the difference will be greater.

In the end I was dissapointed not to buy the M series. I really wanted that unit cause a) its the latest technology b) size for travel and c) the display features are great. I was bummed when I found it so loud.

in the end i bought the respironics Auto with Cflex (i think you call it Pro2 in USA). Whilst its bigger and the small display is crap its by far the quietest of the 3. (oh and I didn't pick the resmed either because it was the most expensive and also quite loud).

anyway I hope this helps someone before they buy it, especially if they have sensitive ears like me.

[quote="swifty"]...
Also want to let Snoredog know that 1dB difference is not insignificant. 3dB of difference means DOUBLING the sound... its all expotential you know.
...

Swifty, I know this is perhaps immaterial to the point of the thread, ie, I think the consensus is that the "M" sounds louder. However, what you must be referring to is that you must double the POWER (as in an amplifier) to get a 3db increase. It takes 10x to double the perceived loudness...

JM

[quote="JM"][quote="swifty"]...
Also want to let Snoredog know that 1dB difference is not insignificant. 3dB of difference means DOUBLING the sound... its all expotential you know.
...

Swifty, I know this is perhaps immaterial to the point of the thread, ie, I think the consensus is that the "M" sounds louder. However, what you must be referring to is that you must double the POWER (as in an amplifier) to get a 3db increase. It takes 10x to double the perceived loudness...

JM

swifty wrote:1dB difference is not insignificant. 3dB of difference means DOUBLING the sound... its all expotential you know.

JM wrote:you must double the POWER (as in an amplifier) to get a 3db increase. It takes 10x to double the perceived loudness.

JM

Thanks JM! That explains the issue very clearly and succinctly.

DSM, I agree, that pitch makes a difference in sound level perception, but I believe this is taken into account with SD's meter "A" weighting capability.

JM

Anonymous wrote:

swifty wrote:1dB difference is not insignificant. 3dB of difference means DOUBLING the sound... its all expotential you know.

JM wrote:you must double the POWER (as in an amplifier) to get a 3db increase. It takes 10x to double the perceived loudness.

JM

Thanks JM! That explains the issue very clearly and succinctly.

dsm wrote:This types of anon post are really very transparent. No id just a self-serving dollop of twaddle.

dsm, please no more petty posts, pretty please

JM wrote:DSM, I agree, that pitch makes a difference in sound level perception, but I believe this is taken into account with SD's meter "A" weighting capability.

JM

JM,

I don't see how A weighting is going to mean anything whan it comes to comparing a cpap that puts out a very precise hi-pitched whine vs an cpap that puts out a distinct low frequency 'hum' (for want of a better word).

Averaging out the frequency to use as the measure of db is only helpful when measuring mixed noises such as in an office or on the street etc:.

Cheers

DSM

Anonymous wrote:

dsm wrote:This types of anon post are really very transparent. No id just a self-serving dollop of twaddle.

dsm, please no more petty posts, pretty please

Touche!

DSM

(who ever you are )

DSM

Only in that both perceived frequenices are measured this way as a matter of convention. Having said this, I agree that a high pitch whine may be more annoying than a lower hum which may be louder. This too will vary, depending on who is doing the listening whether they are trying to sleep, had a rough day, etc, etc.

I guess the only thing left I have to say on this subject is that I have the RemStar Auto (non M) w/C-flex, currently set @ 9-13cm H2O.

I believe it is fairly quiet, kind of like "white noise." When I start breathing through it, It reminds me a little of Darth Vader, but not loud. It does not bother neither me nor my wife.

In all fairness, I have not had any other xPAP machines to compare this to, and based on this discussion I may not want to try any other.

JM

JM,

Agree re the non M Remstar Auto. It is also the quietest machine I have owned.

My observations on the different sounds is that each brand does differ markedly.

The F&P machines put out a lot of 'sound' in db terms but it is low frequency & very static (almost no variation) so becomes easy to listen to. The machines I have trialled (HC201, HC221KE, HC604) are all 'rock-solid' in that the motor doesn't seem to vary no matter how you breathe.

The older Resmed machines tended to vary greatly.
The S6 is very quiet. The VPAP IIs tended to be quiet. (put out low pitched hum)
The S7 Elite is ok but the S7 Spirit & VPAP IIIs, tend to put out a high pitched whine that varies as you breathe.
The S8 models are a very big improvement over the S7 models re motor hum. (low pitched by comparison to the S7).

Of Remstar models.
The BiPaps put out a constant low pitched hum (some defective ones may put out a higher pitched hum but most seem ok) The blower doesn't vary in speed on the Bipap Pro, Pro2 and S/T models. They use an air-valve to change the pressure & they keep the motor speed constant. These machines are easy to get used to.

The Bipap Auto & Auto are in my experience very good re noise.

The M has been discussed here.

Puritan Bennett are another brand of machine that seem very easy to listen to though have seen some people say that a batch of Mexican manufactured models were noisy.

DSM

...though have seen some people say that a batch of Mexican manufactured models were noisy.

The Mexican manufactured 420e model (informally known as the "siesta model") is programmed to facilitate taking a nap every afternoon during the heat of the day---preferably while leaning against a store front in an eerily quiet village. Some people confuse the Spaghetti Western music that it softly plays as if it were unwanted CPAP blower noise. "Regional" design features... Gotta love 'em.

The other point that I'd like to toss up for consideration is that of manufacturing variation. So far most models (not including the very latest "tiny" PAPs from the two big "R" companies) have been reported to contain a surprising amount of sound variation from one production unit to the next.

In my view taking one, two, or even three of the same model from each manufacturer, then generalizing sound characteristics across tens of thousands of same-model machines, is not an ideal way to "sound rate" or even "sound compare" CPAP models. At that point the comparison is much more anecdotal than empirical. Carefully measure those one, two or three units and you have "empirical anecdotes" versus truly empirical data in my opinion.