SPCR

Sweet! These don't come often enough. Now off to finish reading. =P
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The Noiseblockers certainly seem the most well-rounded? for the silent enthusiast, though they're prob too expensive for me. One of the reasons I buy mostly Scythe is because of their prices, cheapest of the bunch always for me. Lastly, perhaps there could be a push towards testing more PWM fans, to go along with said great motherboard controllers. It may not be necessary seeing as voltage control works just as well, but as more motherboards offer greater control, and more PWM fan headers, it's definitely enticing to switch to a full PWM fan setup. This is something I may do on my next build. I like the idea of fans powering off even (not sure if this is currently possible) when not needed. Currently my fans are undervolted, but it's enough airflow for my computer even at load. So this means whenever I'm at idle, I'm getting too much airflow haha. The biggest driving factor? Dust! While I am content that I'm not restricted by high TDP components or too loud of fans, dust is now the thing I'm trying to avoid if I can haha.

It's a shame the TrueQuiet Pro 120 isn't more impressive. It would've been nice to have seen such a genuinely unusual design make a real performance difference.

If you're correct about the less turbulent airflow being responsible for reducing its cooling efficacy, maybe it'd work better as a case fan than it does mounted on a CPU cooler?

Just nitpicking a little bit : the Kanomax 6803 Anemometer was due for calibration almost 3 years ago(06-06-09)

Thanks for the great review. Here's the data in graphical form. It could be fine tuned to help show the overlapped data points, but this picture really helps to focus the results. Hopefully, there weren't any transcription errors

Sorry, but I couldn't let this lie...

you know exactly what noise level (within a decible or so) will obtain.

Regardless of whether there should be a "you" before "will obtain", I have one question: what's a decible?

Thanks for the article!
Spod

(Long time lurker, long time poster, more of a lurker these days but still around!)

Yay! Fans were well tested and it was a thorough review! When will more fans be tested!?

There is one fan that i would really like to see tested because of its special purpose as intake fan and that is the Silverstone Air Penetrator. Its focused flow fan should be great for pushing air specifically across hdd bays or pushing out hot air from GPU into the PCI brackets.

I have this fan at home and will be testing it but alas i have no professional equipment.

MikeC wrote:http://www.silentpcreview.com/Fan_Roundup_6_Scythe_Noiseblocker_Antec_Nexus_Thermalright
...

• Interestingly, the Nexus 120 doesn't get a single win or runner up in this roundup.

...

And what about at the 18dBA and 14dBA levels, MikeC? Formally it looks like to be the "leader".

Only two fans in that roundup are "PWM". Starting from this, assuming that M12-PS has the same acoustics characteristics as M12-P in each speed level, and knowing that SPCR already had tested the Slip Stream 120 PWM, which is the best "PWM" fan for a heatsink like Venomous X or Megahalems (both relatively have a considerable gap between fins)?

Although the choice will probably be between Noiseblocker M12-PS and Scythe Slip Stream PWM (TY-170 cannot be because its size), if someone believes that another fan is better, feel free to say.

Nice to see the Noiseblocker fans and the Gentle Typhoons get reviewed.

There's the Donate for Reviews FAQ for those reviews you just can't wait to see. For example a fan, like the Silverstone Air Penetrator mentioned earlier, would require a total donation of 50 USD, with a minimum donation of $10 per head. You could get 5 people together, each donating $10 (USD, or 8 EUR, which is about two pints of beer in Finland), and you'd have your review article. Get another $50 or more and we could get a roundup going (Mike did mention fans would only be done in roundups!).

Or we can wait a year or two and see if the maker or a store might sponsor the review. As the FAQ linked above says, "time is money", and reviews done to the SPCR standard no doubt take up a lot of time.

If you want a sample of a successful review donation drive, see "Samsung EcoGreen F3 2000GB". My offer to pitch in for a fan roundup still stands, although it might be best to move the discussion here, "Donate: 120 & 140mm fan round-up". I'd be interested in a more thorough test of the Define Mini's fans as well as the AC PWM fans, both 120 mm.

Edit 1 typo, edit 2 roundup note.

lb_felipe wrote:which is the best "PWM" fan for a heatsink like Venomous X or Megahalems (both relatively have a considerable gap between fins)?

After a while, I ended up swapping a pair of Scythe Slipstream 120 PWM with a pair of Scythe Slipstream 140 PWM on a Prolimatech Armageddon (I have to get rid of the Armaclips), as it was a better trade off for me.

But (as someone told probably for the wrong reasons) there are several different thresholds to what is (acceptably) quiet.

Very nice review. It's good to see that fans are still being reviewed. I was starting to wonder if they would ever be reviewed here again.

CA_Steve wrote:Thanks for the great review. Here's the data in graphical form. It could be fine tuned to help show the overlapped data points, but this picture really helps to focus the results. Hopefully, there weren't any transcription errors

I think the graph really helps, assuming linearity between data-points. If I understand correctly, if you are trying to

• Minimize sound at fixed cooling, you want the left-most curve.
• Minimize temp rise at fixed sound volume, you want the bottom-most curve.

In either case, it looks like the Scythe's are the way to go.

Have you checked to see how well the fans with multiple data points fit a power law or a exponential fit?

Great review. I was surprised to see the configuration of the Antec TQ120. I tried to do something similar way back in 2003, but the strip of aluminum was too unbalanced to test the hypothesis.

This feature is related to the forward sweep of the blades on most fans. To take best advantage of the outer ring on the TQ120, Antec should use blades that are swept back. Swept blades in either direction helps quiet the fan, because it lessens the angle of attack. (It also makes the "crossing" angle between the blades and the support struts quieter.) The downside of sweeping the blades forward (as most fans do) is that the air then "slips" inward toward the hub, where the velocity and the blade area is lower. Swept back blades on the other hand, would let the air "slip" outward toward the tips of the blades where the velocity and the blade area is greater.

On a typical fan, if the blades are swept backward, the air would "slip" off the end of the blade; thereby lowering the CFM. That is the purpose of the outer ring -- to stop the air from "slipping" off the end of the blades. So, to take full advantage of the design, the blades should be swept backward if you have an outer ring.

Question for you Mike: was the velocity of the air coming off of the TQ120 in a different "pattern" than say the Gentle Typhoon fans; with their extremely swept forward blades? Or was there no detectable difference?

fantastic article. thanks mike!!

Nice work. It really opened my eyes regarding the Noise Blocker fans which I was curious about. I look forward to the next fan roundup which I hope will involve 120mm and up PWM fans (Scythe, Noise Blockers, Be Quiet!, etc.) with Fan Xpert2.

Yeah, they was too much loud...

NeilBlanchard wrote:To take best advantage of the outer ring on the TQ120, Antec should use blades that are swept back.

Why would it make any difference if it is swept forward or swept backward?

ces wrote:

NeilBlanchard wrote:To take best advantage of the outer ring on the TQ120, Antec should use blades that are swept back.

Why would it make any difference if it is swept forward or swept backward?

Besides this (in the same post)?

NeilBlanchard wrote:Swept back blades on the other hand, would let the air "slip" outward toward the tips of the blades where the velocity and the blade area is greater. [...] On a typical fan, if the blades are swept backward, the air would "slip" off the end of the blade; thereby lowering the CFM. That is the purpose of the outer ring -- to stop the air from "slipping" off the end of the blades. So, to take full advantage of the design, the blades should be swept backward if you have an outer ring.

PS. I think I remember Neil's experiment. It was something else back then.

What is wrong with letting the air slip off the hub. See:
http://www.bing.com/images/search?q=rev ... 9F&first=1

ces wrote:What is wrong with letting the air slip off the hub. See:
http://www.bing.com/images/search?q=rev ... 9F&first=1

I'm sure we'll have Neil explain it in more detail, but I took it to mean that directing air to the less powerful part of the fan (hub with narrow blade, obstructed motor area and relatively slower rotation) is less than ideal. If that air was directed to the outer edges of the fan, it would gain greater "push" behind it from the faster, wider sweep of the blade: the reason why we use longer-bladed fans in the first place, more air throughput with less RPM.

Nicias wrote:I think the graph really helps, assuming linearity between data-points.

It may not be linear between data points - but it'll be monotonic and the piece-wise linear approximation is good enough to see what's going on. Here's a zoomed in view with data line color mapped to the mfgr:

Das_Saunamies wrote:Nice to see the Noiseblocker fans and the Gentle Typhoons get reviewed.

There's the Donate for Reviews FAQ for those reviews you just can't wait to see. For example a fan, like the Silverstone Air Penetrator mentioned earlier, would require a total donation of 50 USD, with a minimum donation of $10 per head. You could get 5 people together, each donating $10 (USD, or 8 EUR, which is about two pints of beer in Finland), and you'd have your review article. Get another $50 or more and we could get a roundup going (Mike did mention fans would only be done in roundups!).

Or we can wait a year or two and see if the maker or a store might sponsor the review. As the FAQ linked above says, "time is money", and reviews done to the SPCR standard no doubt take up a lot of time.

If you want a sample of a successful review donation drive, see "Samsung EcoGreen F3 2000GB". My offer to pitch in for a fan roundup still stands, although it might be best to move the discussion here, "Donate: 120 & 140mm fan round-up". I'd be interested in a more thorough test of the Define Mini's fans as well as the AC PWM fans, both 120 mm.

Edit 1 typo, edit 2 roundup note.

I missed this post earlier... and this post & so many others here are examples of the ways SPCR forum members always manage to surprise & entertain me... in many different ways and for different reasons. lol!

FYI, I actually had 16 fans being tested for the last couple of weeks, and towards the end, struggling with data overload as the flight time to Taipei and Computex loomed, I reluctantly shelved the rest to deal with it more cogently in a followup article, so don't worry, another one will be coming soon -- do I dare say within 2-3 weeks? This will deal with most of the fan samples we have on hand, and by then we will probably have another carton of samples from various fan brands who want to be in on the next roundup.

Also, tho this is in the wrong place, I did meet up with the Noctua follks, and though it was way too loud to hear the demo of their early prototype ANC fan, I had a long & fruitful discussion with key players at both Noctua and RotoSub. This is a fascinating technology & promising, details of which I will post as soon as I have time to take better pics and process more of the technical info while still trying to take in the rest of what's here at Computex. Now, back into the teaming fray of Taipei. (It was ~11C when I boarded the plane in Vancouver at 2am, and 36 hrs later, 29C at 80% humidity at 8am in Taipei. Sweat wanting to splash my keyboard... Should have had an ice coffee. )

As I wrote in my post, the inner part of the blades are moving more slowly, and they are often narrower at the base, and the inner part of the swept area is smaller than the outer part; by definition.

If you can prevent the air from "slipping off" the ends of the blades with the enclosing ring, like on the Antec TQ120, then in theory it is better to have the blades swept back. Again, because the ends are moving faster, they are often larger.

NeilBlanchard wrote:If you can prevent the air from "slipping off" the ends of the blades with the enclosing ring, like on the Antec TQ120, then in theory it is better to have the blades swept back. Again, because the ends are moving faster, they are often larger.

I thought the fan blades worked sort of like airplane wings and that that as a result, the air had little axial momentum. See:
http://www.bing.com/images/search?q=air ... 74&first=0
When I have seen pictures of smokey airflow from fans, it sure seems like that is so.

MikeC wrote:FYI, I actually had 16 fans being tested for the last couple of weeks, and towards the end, struggling with data overload as the flight time to Taipei and Computex loomed, I reluctantly shelved the rest to deal with it more cogently in a followup article, so don't worry, another one will be coming soon -- do I dare say within 2-3 weeks? This will deal with most of the fan samples we have on hand, and by then we will probably have another carton of samples from various fan brands who want to be in on the next roundup.

Excellent news! Thanks for the heads-up, and enjoy the trip.

quest_for_silence wrote:

lb_felipe wrote:which is the best "PWM" fan for a heatsink like Venomous X or Megahalems (both relatively have a considerable gap between fins)?

After a while, I ended up swapping a pair of Scythe Slipstream 120 PWM with a pair of Scythe Slipstream 140 PWM on a Prolimatech Armageddon (I have to get rid of the Armaclips), as it was a better trade off for me.

But (as someone told probably for the wrong reasons) there are several different thresholds to what is (acceptably) quiet.

Thank you. In your situation, 140mm fan makes more sense because the area of ​​Armageddon. This is like what Mike suspected that occurs with Archon when using a TY-170.

I'm looking for a 120mm fan and heatsink because something else may prevent the use of the first PCIe slot.

That said which is the best 120mm PWM fan for heatsink for SPCR standards?

Despite the specified 1000~2000 RPM range, Fan Xpert 2 had no trouble starting and running this fan at 700 RPM.

Can this be applied to the VenomousX SB-E's fan and ASRock Z77 Professional's fan controller?

What I wonder is if the motherboard will reduce the fan speed to about 700 RPM even though its specified minimum speed is 1000 RPM.

VenomousX SB-E: http://www.thermalright.com/products/in ... =27&id=194

120mm PWM fan specs:

Dimension: L120*W120*H25mm
Rated Speed: 1000~1500RPM±15%
Noise Level: 19.6~37.4 dBA
Air Flow: 35~66.5CFM
Connector: 4Pin PWM

Interesting to hear confirmation of the tonal noise of the higher RPM Gentle Typhoons. I currently have two of these sitting idle in my box o' fans for this very reason. One of these is the 1850 RPM mentioned in the article, but the other is an 1150, which unfortunately exhibits the ringing tone when the voltage is turned down.

Another problem with these fans (in my experience) is sample variation. I've owned five GTs (3 AP-15s, 2 AP-13) and three of these exhibited distinctive and unpleasant bearing chatter at all speeds.

After this review, however, I'd love to get my hands on a few of the 800 RPM ones.

lb_felipe wrote:That said which is the best 120mm PWM fan for heatsink for SPCR standards?

It is hard to say what is the "best", but the Scythe 120mm PWM fan (viewtopic.php?f=13&t=64339&start=30) works very well with Asus Fan Xpert2 allowing a start up speed south of 400 rpm (30%) which is essentially inaudible in a case and provides more than adequate cooling in combination with the Venomous X on my CPU. However, given the limited fan control utility provided by ASRock, unless you can use Speedfan with that board, I would be hesitant to extrapolate anything from my experience or this article in relation to your setup.