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Martinm210 uploaded a new video
(2 weeks ago)
Same as my individual fan tests, except I clipped out and ran the 10,20,...
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Same as my individual fan tests, except I clipped out and ran the 10,20,30,& 40 CFM levels side by side. After rendering and reviewing again, I'd probably switch a couple around as to which is better than the other, but I expect you'll have you'r own personal preference anyhow.
One thing I've learned is not to use the Mastech db numbers. These are not weighted. For noise level, I would suggest using the dBA bar chart listed up top next to the spectrum. Just left of the whole spectrum is an SPL all, this represent dbA and a better relative comparison for noise level.
In addition, I would also suggest putting more weight into the sound of what you hear. Consider listening to the audio without looking at the video and see which tones you like better.
Anyhow, this is the end of round 5. I've been working on improving my test set up and have some great leads on more sponsors for more fans..so stay tuned!!
Here are the details of the tools used in testing:
-New flow chamber 21" length of 8" PVC, egg crate insulated with flow spreader (34 ea 1" x 4" tubes).
-Tested through an XSPC RS120 radiator, hard mounted with M4 screws and grommets.
-Air flow CFM not calibrated, only for Round 5 relative comparison purposes. Measured via anemometer vane on the chamber outlet in a 3.5" port, display is shown on far left.
-Mastech sound pressure meter second from left is unweighted SPL approx. 8" from fan as shown. I do not recommend using this for much of anything, not weighted. I'm actually going to stop using it for future tests as I think it gives more bad information than good. Unweighted SPL does not match the human ear's perceived loudness curves, dbA is much more accurate, although everyone has a slightly different response.
-For Noise Level dbA use the SPL (All) in the noise analysis chart up on top, this frequency spectrum and SPL All is dbA weighted using YMEC.coms RA software and the Zoom H1. I arbtrarily calibrated a Yate Loon D12SM12 at 3' to match 33dbA in an open air test to get the numbers more reasonable, yet they are not precisely calibrated to anything and should be used for relative comparisons only.
-Third meter is measuring fan amperage
-Fourth meter is fan voltage at plug (Watts = amps x volts)
-Video via Canon T2i in HD with a Tokina 12-24 lens
-Audio via Zoom H1 Handy Recorder, manual level 100, low cut on, Wav file format, on tripod in line with fan hub axis 12" from fan with foam windscreen.
Audio and Video combined and rendered in Sony Vegas in HD 8MB/S .wmv format before uploading to YT.
Suggestion, use the measurement tools as a rough round 5 comparison only, but note that sound level is just that...quantity. This does not measure sound quality which you'll simply have to listen for. Also look for sharp spikes in frequency, these generally are more annoying than a fan that has a higher dBA but smoother curve, etc. Regardless, sound is very subjective, my intent is to provide a good recording for you to listen to and make your own judgments.
Lastly, the Correlation chart in the upper left gives some indication when the sound is a harmonic or tone of one fixed frequency. I think in general you want the waves as flat and as irregular as possible.
Cheers!
Martin
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"@PocketDrummer
At 12V, you'd want a slower speed fan, something like the..."
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"@PocketDrummer
At 12V, you'd want a slower speed fan, something like the Noiseblocker PL-2, Slow Speed Yate Loon, Nexus fans, etc would be similar. The Zalman ZM-F3 is pretty impressive undervolted also."
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Martinm210 uploaded a new video
(3 weeks ago)
This is just a random experiment using the correlation tool. In my last...
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This is just a random experiment using the correlation tool. In my last round 5 test I had a couple of people say they thought my radiator was resonating creating some of the odd ups and downs in noise level. Others thought it was my fan controller. I also had someone suggest using a scope to test for irregularities. I tried the fan controller elimination and still got the same odd behavior, then I tried the fan all by itself and still got the same thing. I then played around with the scope and this correlation tool that looks more closely at the sound waves. I honestly don't quite understand what I'm looking at, but I thought the pretty colors were cool!..lol
Actually, I think it might show changes in sound harmonics. When the waves are random, it's just a soft pink type noise of all frequencies, but when it changes to fixed consistent waves, it's identifying some sort of harmonic occuring. I think the metal cup around the bearing is causing it for the GT, but I've also seen some similar harmonics occur in a few other fans.
I was never able to see or hear this before I got the Zoom H1 handy recorder, so it's a tribute to show just how sensitive these microphones are at 100%.
These microphones are so sensitive, you can hear a mouse fart across the room!..;0
Anyhow, I may consider including some sort of small scope window in future fan tests...this is just a trial experiment.
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Just a little note about testing. I gave it up over a year ago and sent everything I had left to skinnee over at skinneelabs. I don't think he has time for testing of fans, but I'd suggest visiting his site for any of the latest testing buzz. Skinnee and Vapor are the two best PC testers I know...if you like detailed scientific testing, they are the ones to follow. Take it easy...Martin
They make choosing fans easier.
Been busy playing with dirt bikes and ATVs, maybe I'll work up some videos for that later.
Take it easy!
Martin