Posts Tagged ‘Servo’

Welcome to my round 11 fan testing.  This is a fairly small round of fans from the kits I previously tested.  Rather than do my normal written form, I’m trying to do this more video based.

Before I do that, I would first like to thank my parts sponsors, without their support this test wouldn’t have happened:

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Kit Fans Intro

This video does some physical comparisons of the fans and gives you a good close up look of the fan, sleeving, build quality, etc compared with my previous best performing fan the Gentle Typhoon.

Fan Test Rig Description

This video is just a quick overview of the flow bench and meters used in the fan testing to follow.

Individual Fan Tests

The following videos are of the actual test run on each fan recorded with audio and stepping through 50FPM air flow results.  You can now easily adjust two or more fan videos to like air flow numbers and pause them both, then switch back and fort for a direct apples to apples air flow comparison.

Larkooler Kit Fan

Corsair H100i SP120 Kit Fan

Swiftech H220 Kit Fan

XSPC 750 Kit Fan

Servo Nidec Gentle Typhoon AP-15

Extracted Results

These were pulled from the video, by isolating a looped region where air flow was close to the 50FPM increment.  This provides the resulting detail read on the meters and a calculated RPM.  On the right are some subjective noise quality comments I added as I reviewed and extracted the results.

R11-FanTesting-Detail

Summary Radiator Noise Level vs Radiator Air Flow

This is the “Meat & Potatoes” result.  While I wish I could measure noise quality in a good quantitative way, that’s really not possible.  The next best thing is to compare noise levels when mounted to a radiator at like air flows through that radiator.  It takes into account the fans pressure capabilities and puts it in a more real world condition.  It’s not perfect, but the best thing I’ve been able to come up with to simplify radiator noise performance.  Fans that extend further right are capable of higher air flow maximum results at 12V.  Fans with lines lower on the Y axis are producing more air flow per noise level.

R11-FanTesting-Summaryl

No real surprise, but the kit fans all tested relatively the same (most within 3dbA or less differences which fall within the “barely perceptible” level).  The Helix fan did for some reason have a bit higher than expected harmonics on the radiator bench which didn’t seem to be as noticeable when actually testing in a case, but it is something I heard a little when trying push only.  In push+pull I noticed most of that helix harmonic disappeared.

I would consider the kit results to be relatively similar, they are like most fans and all perform roughly the same.  The Gentle Typhoon however does seem to retain that unique ability on a radiator and tested upwards to 8-9dBA lower in noise level at 12V than other fans producing the same flow.  The H100i fans and their 2700RPM capability did produce the highest maximum air flow, but it comes at the prices of having a fairly gritty noise quality.  Noise quality isn’t captured well in the graph and really only something you can listen for in the videos.

The other aspect I’m now noticing that is missing from this single fan test bench is harmonics between the two same fans.  In the thermal testing using the kits and earlier noise testing, I had significant RPM harmonics issues with the H100i fans, but a single fans test scenario completely misses that.  This is something I seriously want to consider in fan flow bench future upgrades.  I think it is important to capture the “paired fan” harmonics effects as it can be fairly significant.  The helix H220 fans did really well paired together in the kit testing, but you just can’t see that in a single fan test.

Also as noted some of the pressure harmonics issues can also be mitigated for by going push + pull.  The helix fans don’t show real well in this single push test, but I found when testing four fans in push/pull on a radiator the fans worked very well together.  They are not up to Gentle Typhoon silence or build quality standards, but in use I would say they fair better than what the above chart or single fan test result demonstrates.

I also think the Larkooler fan subjectively sounds quieter than the produced dBA.  I’m not sure how to describe it, but the sound type is more lower in frequency and seem to contain less motor noise and gritty noise that is more prevalent in the other fans.  It has a noise quality that reminds me of the noise blocker series which I’ve always liked.  Noise level doesn’t measure anything special, but I think this fan does have pretty good noise quality particularly at slower speeds.  This is another one where my own ear and the meters don’t really agree all that well..:)

This at least gives you one more perspective on the sound.  I would suggest listening to the fans at like air flow levels and make a decision not based on noise level, but what you perceive as being less irritating.  That is likely a combination of frequency, noise quality, and noise level.  Don’t put too much weight on the noise level, it is important, but it’s not the entire picture and each person and each setup will be slightly different.

So there is another round and the Gentle Typhoon retains it’s low noise/rad air flow ratio crown.  Nothing comes close…

As part of my radiator testing, I did purchase several sets of fans to experiment with.  Since the Gentle Typhoon AP-15 did so well in a noise/cfm ratio in previous testing I had been curious how the higher speed GTs work in comparison.  The AP-29 differs from the AP-15 in that it only has 7 blades as opposed to 9 and it also has a special and unique stiffening ring.  I tried to make contact with Scythe about possibly sponsoring fans but my request was ignored and I could never make any sort of actual contact.  The Titans are just something I found perusing SVC one day and had to have a set and also picked them for my radiator testing since they were cheap, in stock, and had a good RPM range.

Being without any sponsor, I’ll give myself a special thanks to MLL.org for sponsoring this test…:)  I ordered the GT AP-29s from an ebay seller as it seemed to be the cheapest price shipped I could find.  I also ordered the Titan’s from SVC myself since they were on sale for $10.99 and I was anxiously crossing my fingers I would find a good alternative to the GTs.

Gentle Typhoon AP-29

First thing to catch my attention is this fan comes only with 4 pin molex connectors, so you will need an adapter or to rewire it on your own if you need 3 pin.  The fan doesn’t come with much more than standard self tapping case screws.  It is built well though and heavy and more industrial in quality than your average 25mm fan.

Gentle Typhoon AP-15

For comparison purposes with the previous 1000-1800RPM winner, here is the AP15.  The king of CFM/RPM from my previous rounds.

Zalman ZM-F3

For comparison with a good but average noise level and more conventional 7 bladed fan, here is the Zalman ZM-F3.  It what I consider a good average noise level fan at a great price.  It also has a pretty good speed range so it’s a good one to compare with as well.

Titan Kukri

These are the fans I’m using for the radiator testing that were attempting to be low cost GTs.  They look nice and actually do better than the Zalman at slower speeds, but things fall apart quickly at the higher speed range.  The sample tested seemed to have some debris in the motor causing a bit of rubbing type noises from 1400-1800 and then a harmonic developed from 1800 up to 2300RPM.  The debris would probably work itself over time and the harmonic may or may not be specific to the radiator test rig, but that’s what I got in this run.

Charted results

The charts above include looking at a few variables independently.

Of primary value is the air flow vs noise level chart which is the most representative of radiator performance.  It’s not perfect nor as good as actual thermal based testing, but I find it good “quick” simulation that allows looking at the full spectrum of possible undervolting conditions very quickly.  It does however only represent noise “Level” and not “Quality”.

Chart 2 is just comparing RPM to noise and plots a similar response.  The GTs are very good about keeping noise “Level” down to a minimum when mounted to a radiator and much the same using RPM between the 15 and 29.

Chart 3 is taking a closer look at how much air they push per RPM.  This is where the GT 15s doing very well having a higher blade count without stiffening ring allows them to produce more air per RPM.  General most fans produce the same amount withing about a 200-400RPM window though.  Somewhat surprising though, the Titan despite it’s similar appearance doesn’t have the same flow/rpm advantage as the GT 15s.  There is quite a bit more gap between fan blade and frame and slightly different blade pitch as well as how the back of the blade curves more than the GTs.  The AP-29s do a bit better than average at slower speeds, but seem to loose all of that advantage from about 2000RPM on upwards which I suspect is mostly due to the stiffening ring causing turbulence.

Conclusion

The higher speed AP-29 does seem to follow in a similar trend (CFM per RPM) as the exceptionally low AP-15 did although I would say subjectively when listening to the videos side by side, the 15 is producing less motor noise and smoother in sound.  The stiffening ring does seem to eliminate the resonance spikes that are present as specific RPM levels of the AP-15, so that’s a good thing although the CFM per RPM level is not quite as good as the 15 which is also probably due to this same ring.  The range is a bit more limited on the lower end were 5V is basically starting at 1200RPM, but it makes up for that in it’s near 3000RPM maximum at 12V.

While it’s hard to find fault in the AP-29, I personally find noise levels beyond 2000RPM still to high for my taste despite the noise levels being significantly lower than your average fan and also find the noise quality of the GT15 better than the 29 at slower speeds so it is a bit of a compromise.  I think more people would be better off with the slower speed 15, but the AP-29 does extend the fan power range for those needing similar GT quality in a higher speed flavor.  As with pretty much all fans, you can’t have it all and extremely high speed fans generally struggle at slower speeds and the AP family is much the same there.  The AP-29s are exceptionally good at 1800-3000RPM, but  the AP-15s are still king of 1000-1800RPM levels.

The Titan Kukri’s do pretty well at slower speeds and they do have a more desirable white blade color, but they are not even in the same league regarding build quality as the gentle typhoons.   On my particular test rig with radiator, I also had high speed harmonics and other not so smooth motor type noises as RPMs increase beyond about 1400RPM and particularly beyond 1800RPM.  Not quite sure why but I suspect it’s the blades flexing since the plastic used is softer than that of the GTs and not as reinforced at the hub either.  Overall a great fan for the price when operated at slower speeds, but the Titans are not at all outperforming or coming close in performance to the GT-15 in terms of noise level or noise quality in the 1400-1800 range.  I would say they are better than average in the <1300-1400RPM level, but average to poor at higher speeds.

Cheers!
Martin