Don't know if this has been posted anywhere before.

Has anybody else seen this fan review site? Looks pretty new.

http://atreview.net/en/casefan.html

Each fan has a Youtube video "review" with noise / cfm measurements and quality audio recordings!

Hope you SPCR readers find this interesting!

Cheers

1. Very interesting. I compiled a buch of posts on the subject here:
viewtopic.php?p=537752#p537752

2. The link you posted finally confirmed what I thought, but couldn't confirm. The Scythe Gentle Typhoons are one of the top fans in handling high static pressure.

3. The Enermax batwing style fans do static pressure extremely well too. I didn't really expect that.

Indeed: but do you know which methodology do they use? Some results (1.71dB!) seem just unreliable (AFAIK there's no way to record such a level).

On the DB level, it looks like must have just set their instrument for 0 dB at whatever ambient sound level hey had. They will not soon replace SPCR as a source of sound level data.

But on static pressure and cfm, you can observe their technique. It appears to be reliably self consistent. You can't ask for more.

And already they have the best static pressure database around.

I think this site is a find.

Are you referring to their youtube videos? If in case, sorry, but I can't rely upon some fancy images.
Some explanatory documents are what I need.

Why?
The video shows you all you need to know.
You see the devices they use to measure the different things and you see how they use them.

1.71 dB is the sound pressure rise over ambient noise.

Really? I don't "see" the ambient, I don't know the noise floor, I don't know the equipment specs, I don't know if and how they are calibrated, and so on: I'm accustomed to CFM and pressure values measured in wind tunnels, not by hand and/or in a computer-manipulated brief videos.

To be more clear: I haven't said they are wrong, at all, I say they lack to supply some (lots of) basical information needed to evaluate their alleged findings (starting from who they are).

That is what I figured. As far as I am concerned, SPCR is still the gold standard when it comes to dB. But this new site is a good site with goos information that complements SPCR's testing.

Did you notice any surprise results perusing their testing? I looked most for the static pressure info. I need to go back and look around a bit more.

Really? What a stupid boy I am, I haven't found the words "rise" or "over" and misinterpreted those data...

...so, in the case of the Antec TrueQuiet, if the ambient noise were around 10dB (a semi-anechoic chamber) the actual sound pressure would be around 12dB, if it's 20dB it would be 22dB, if it were 40dB it would be 42dB... how many dB? Uh, the ambient noise would look like undeclared...

And what about the margin of tenths of dB, apparently with a small, handy instrument? I would want one, it's really impressive (MikeC contents himself with 1dB)...

...or what about the renowned Scythe Slipstream M? It should give 50% more CFM than the Slipstream L, but it would be 40 (forty) times louder than the latter, and about 100 (one hundred) times louder than the above mentioned Antec True Quiet.

Hey ces, look: we have a noise champ!

Not to mention the Gentle Typhoon AP13: at equal CFMs the Slipstream M would be almost 8-10 (eight-to-ten) times louder than it...
Have you ever heard a Slipstream spinning at 1200rpm? And the GT? Not to mention that a 20dB rise over an ambient - say - of 20dB will give 40dB... Have you ever heard a true 21dB level? And a 13dB one? And a 40dB?

...please, I really don't say a word about their proficiency, just there are a lot of things apparently undocumented, and this is rough for logic if you're not a genius (are you a genius?).

(RE-EDITED the message)

mdrumt, I didn't notice any Scythe Slipstreams there. Did you?

I have my moments

Can anyone discern whether the fans being tested are pushing air through the filter or are pulling air through the filter?
http://atreview.net/en/casefan.html

Yeah, I guess so: maybe seldom.

There you go. No reason to take all this so seriously. It's just electrons floating in the air.

Hi didn't look into the sites methodology before posting. I mainly found the sound recordings of each fan very handy!

I didn't look into all the fans listed, this one looks like a Slipstream however doesn't it?

http://atreview.net/en/casefan/sy1225sl12l.html

Update: It is, same model as listed here: http://www.scythe-usa.com/product/acc/0 ... etail.html

800rpm version

Have emailed the site to see if they can provide some methodology details

EDIT: I would also like to see a SPCR review of these apparently amazing Antec Truequiet fans!

Great

Say so here:
viewtopic.php?f=9&t=58350&start=30

Got a reply from the site:

"The noise level of the site is a value to which the back ground noise is pulled from the FAN operation sound.

True Quiet 120 Low
FAN operation sound 36.25dB
back ground noise 34.54dB

True Quiet 120 High
FAN operation sound 45.42dB
back ground noise 34.48dB"

He apologises for his English.

All I know is that you can't compare dB levels from one situation to those of another. The background noise seems high. Does anyone have an opinion on how that effects the relative readings of the fans.

It must reduce the accuracy of the relative readings, but if he reviewed a Nexus would it help us assess fans he has reviewed but which SPCR has not?

What are your opinions?

I just went here: http://atreview.net/en/contact.html
And sent him this message:
=============================

1. Did you know what you have become very popular here
viewtopic.php?f=9&t=61922

2. silentpcreview.com is one of the top sites of people in the USA who are interested in quiet fans. We are all excited about what you are doing.

3. If you were to review the NEXUS REAL SILENT CASE FAN D12SL-12
http://www.silentpcreview.com/article69 ... html#nexus
it would generate a lot of traffic from the US as well as the EU for your website.

Doing that would permit us to compare your reviews with those of silentpcreview.com. This would make your website very valuable to us.

Thanks for your good work.

PS: When you test your fans against the filter, for static pressure, are they
(a) pushing air into the filter, or
(b) are they they sucking air from the filter?

========================

Hey, anyone have a spare Nexus to send him?

That "We are all" is (to be kind) a true exaggeration.

Being so, IMHO their findings are pretty useless (I'm wondering whether or not the recorded value for the Slipstream has the same background noise: if it were so, those very quiet Scythes should be around the 45-55dB level... no comment).

I guess it's just math: you're not able to resolve differences between products under the noise floor.

But it's not just a matter of noise floor: providing that noise floor is every time similar, some fan (like the Slipstream) should spin above a 50dB level (around the jet planes above MikeC house sound pressure level), and those values would seem to suggest a possible overall unreliability issue, rather than an unaccuracy one.

Nice find!

These videos provide super high-quality audio samples that tell us how each fan sounds subjectively to our human ears. I think that's a hell of a lot more important for choosing quiet fans than any objective data. Forget about comparing numbers, why not just listen to them for yourselves in high-def audio?!

What do you think the problem is? Is it faulty equipment? Is it too high a background noise? Poor measuring technique? Erratic ambient noise levels? Or?

If it is poor technique, where exactly do you see the evidence of poor technique?

If it is too high a background noise, does it not affect all the fans equally? If so, who cares (except those of us who operate their computers in an anechoic chamber)?

Is not a little noise in the background the most realistic test environment? I don't know about you, but it is for me.

According to this site:
http://www.sengpielaudio.com/TableOfSou ... Levels.htm
The jet planes you refer to generate 140 dB
A typical home has ambient sound of 50dB

So most people, when they are operating a slipstream fan, are doing so with 50dB ambient background noise level. If that is so, why not measure the relative sound levels at 50 dB?

With a with 50dB ambient background noise level, would you even hear a 40dB slipstream?

I was just thinking... doing a thought experiment

If you take a 7v Nexus and compare it to a 12v Slipstream
(a) using SPCR methodology, clearly there the Slipstream will be louder than the Neux
(b) using your own ears in your home, you would be able to hear the difference
(c) using the Japanese site's methodology I would expect it would indicate a similar difference.

I would expect that while the Japanese site's methodology would never meassure the same dB as the SPCR methodology, and the SPCR methodology may be more accurate.... that generally the Japanese site's methodology would generate generally the same dB ranking.

Of cource it would still be missing SPCR's qualitative assessments which are very valuable. But in terms of raw dB, I wouldn't expect its relative rankings to be that far from SPCR.

Maybe there is reason to think otherwise. What are your opinions?

Since I was invited to comment on this new site....

Overall, the youtube videos are useful in giving you a chance to hear the fans without buying them. The mic & recording system seem to have a reasonable degree of transparency. That's the main value of the site, imo. If you can make assessments by comparing the videos/sounds, good for you. I found it difficult to compare.

The rest is very far from any accepted measurement standards.

His CFM measurement technique is basically what I tried to do when I first started testing fans... oh, maybe 6-7 yrs ago. It has no bearing on real CFM or what manufacturers measure and cite. I would not rely on those measurements. Besides, how does any average DIY computer builder "use" and understand CFM? It's relationship to cooling is so poorly understood and so specific to the particulars of each cooling challenge, I've said for years that it's virtually irrelevant if you have some way of controlling fan speed/noise.

The SPL measurement is a joke -- the guy has no understanding whatsoever of how the dB works. His noise floor of 34.5 dB makes all of the noise measurements completely wrong. You cannot get any meaningful information when the ambient is that much higher than the real noise of the fan. Of course, he's not measuring the SPL from 1m, but from extremely close up, because that sound level meter cannot read below 30 dB. Why he's not using "A" weighting I don't know... it might help lower the low limit of the SLM. It's quite possible his real ambient SPL is lower than his SLM reads. Anyway, those dB values -- both the raw seen in the SLM screen in the videos and his "extracted" ones -- are useless. You cannot even compare dB for fan A, B and C with his method, all you can conclude is that the higher dB fans may be louder than the lower dB ones. They will not parallel SPCR 1m dBA measurements in any linear way.

Let's make an example (sort of).

Let's assume we're both in your bedroom in a not so noisy night, about 1mt from each other.
Let's assume then I started insulting you in a loud voice: more probably that not, I could not know so many insults in your language, but the ones I know you would be able to hear crystal clear.

Now let's change the ambient: imagine to be very close to a taking off jet-plane.
Imagine the very same scene, that I insult you in a loud voice and you listen to me: more probably that not, you would not be able to perceive anything other than that jet-plane.
And even if I were not 1 mt from you, but shouting directly into your ear, you still wouldn't be able to hear not even the most offending four letter word.

Eventually let's change again the background: we are in a normal home with an ambient sound of 50dB.
Again I insult you, but now not in a loud voice, just whispering like rustling leaves: whatever you think, you would not be able to perceive my insults.

May I insult you, now?