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 Post subject: Quiet (not silent) 120mm case fan with high static pressure?
PostPosted: Mon Apr 16, 2012 10:49 am 
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Good afternoon, all. I'm trying to silence a NAS unit (DroboFS), and it's been a bit tricky. The unit has a single 120mm exhaust fan, and the air intake is mostly blocked by the drives themselves. The fan is also connected via a 2-wire connector, so any variable voltage or PWM fans are unfortunately out. At first I tried a Noctua S12-FLX for its silence (and it is indeed silent), but the airflow is negligible and the drives are scorching after normal use. I'm guessing this is due to the blocked airflow and lack of static pressure performance - the Noctua rates 1.31mm, whereas the original fan was a whopping 3.45mm - it was also 39db, which is what sent me down this road.

I looked through the recommendations, and my problem is that while my goal is to quiet this thing down, I don't need it to be silent - just as quiet as it gets while keeping the drives cool. The recommendations are rightly geared toward total silence, which unfortunately isn't quite the tradeoff I need - I'm fine with anything below 30db with high static pressure.

Anyone have recommendations for more powerful fans that still aren't buzz saws?


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Mon Apr 16, 2012 11:11 am 
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Get a 1,850rpm, Scythe Gentle Typhoon. Most fan manufacturers don't publishing static pressure. When they do they don't publish all the info... and even if they did, you really have no way to normalize the results from manufacturer to manufacturer so you can compare them.

That being said, this is a good fan for static pressure. If you turn it down to 5 volts it runs darn quiet. And I bet it will get the job done just fine at 5 volts.

Play around with the voltage, starting at 12 volts, until you get it right. Use one of these to manipulate voltage in a reproducible manner:
http://www.performance-pcs.com/catalog/ ... s_id=25981

Let us know how it works.

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Last edited by ces on Mon Apr 16, 2012 1:58 pm, edited 1 time in total.

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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Mon Apr 16, 2012 1:25 pm 
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Location: USA
Zalman Fanmate II can also adjust voltage.


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Mon Apr 16, 2012 6:51 pm 
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Joined: Wed Jul 14, 2004 7:57 am
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Most voltage adjustment products aren't going to work for me, as there are no Molex connectors in the DroboFS, and not even a standard fan connector. Only this type of connector:

Image

Does anyone know where I can get an adapter for this? I hate having to cut the fan leads on the replacement fan just so I can solder on this goofy one. :(


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Mon Apr 16, 2012 9:15 pm 
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Location: US
You are going to have to cut some wire and get 12 volts into a molex connector. Use this to do that:
http://www.performance-pcs.com/catalog/ ... s_id=22413

Once you get your electricity into a molex connector, plug that connector into this device:
http://www.performance-pcs.com/catalog/ ... s_id=25981
Which will let you use any standard type of fan you want to use, without modification to the fan or its leads.

Also take a look at the EasyGrip Power Supply Changeover Kit
http://www.performance-pcs.com/catalog/ ... ts_id=1347

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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Mon Apr 16, 2012 9:54 pm 
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Unfortunately, I don't think voltage adjustments are going to be in the cards. There's just no room inside the DroboFS case for anything additional - heck, you have to keep the fan cable itself trimmed so that it doesn't contact the fan blades. Interesting techniques to use in a larger case, but just not feasible here.

I think I'll have to graft my own adapter by hand with two ends and some solder. Ugly, but better than cutting up fan after fan.

As for the fan itself, I took your advice and ordered a Scythe Gentle Typhoon. Looks like it will yield about 60% better static pressure performance with an acceptable increase in noise. I hope it does the trick, as otherwise I'm headed back to loud (but adequate) fans.


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Tue Apr 17, 2012 6:51 am 
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Do you have room for something like this:
http://www.performance-pcs.com/catalog/ ... cts_id=747

Or like this:
http://www.nexustek.nl/NXS-nexus-fsa-75 ... -cable.htm

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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Tue Apr 17, 2012 8:35 am 
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Either way it has to go back to a Molex connector, which I don't have - which means more adapters. Personally, I doubt my problem will be slowing the fan down - based on my experience the last couple weeks I need every bit of cooling I can get; it's just a matter of whether I can do that and keep the noise down.


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Tue Apr 17, 2012 10:14 am 
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diamondsw wrote:
Personally, I doubt my problem will be slowing the fan down
This is a far more non-intuitive subject area than you can imagine. The S12-FLX is probably the worst fan you could have selected for this particular application. It is a great fan for many applications that you would not use the Gentletyphoon for... but not for the application you are describing.

The Gentletyphoon was designed just for this type of application. It will probably accomplish what you need accomplished at far fewer RPMs than you imagine... while outperforming the original fan.

But you will know for certain only by testing.

By the way those hard drives actually need very little volume of air circulating around them to keep them cool. They just need it circulating is all.

The alternative is to get several Gentletyphoons that operate at different speeds... changing them in and out to get what you want. A needless expense in my opinion.

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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Tue Apr 17, 2012 10:20 am 
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Here take a look at the difference in blade geometry

http://www.noctua.at/inc/imageviewer.php?item=25&pnr=0

http://www.thewatercoolingshop.co.uk/sc ... ap-14.html

http://www.xtremesystems.org/forums/sho ... le-Typhoon

With no back pressure the Noctua probably moves more air than the Gentletyphoon... But once it runs into back pressure, the GT just keeps plugging along with little degradation or increase in noise. Like comparing a truck diesel to an automobile gasoline engine.

Given the modest CFM it needs to generate... I just don't think it is going to need a lot of rpm to do it... even with a lot of static pressure.

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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Tue Apr 17, 2012 1:51 pm 
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This has been extremely informative. Part of me wishes I'd known all this before I started, but I took the naive approach of CFM = cooling. The fan and such arrives next week; I should have a followup then.

Thanks!


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sat Apr 21, 2012 4:13 pm 
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Well, the fan has arrived, although I notice the GentleTyphoon doesn't have the nice rubber vibration dampeners that other fans have. Is there any way to reuse the ones that came with the Noctua? I can't see any decent way of removing them, given the manner in which they push through the fan casing (sort of like a slim cone with a notch where it locks in place). I might have a go at it with small screwdrivers or needle nose pliers; any better ideas at removing/reusing these?


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sat Apr 21, 2012 10:14 pm 
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Why don't you first just try it without worrying about the rubber mounts. Just see how it works.

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"Aristotle calls man the rational animal. All my life I have been seeking evidence to confirm this" Bertrand Russell
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" Albert Einstein


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sat Apr 21, 2012 11:17 pm 
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A possible alternative to silicone grommets if you don't have any suitable ones to use:

http://www.silentpcreview.com/article293-page5.html (the second and last photos on that page). :)


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sat Apr 21, 2012 11:20 pm 
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Joined: Wed Jul 14, 2004 7:57 am
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ces wrote:
Why don't you first just try it without worrying about the rubber mounts. Just see how it works.


I might, except I can't try it until I remove the Noctua, and if I destroy the rubber mounts that are holding that in place, then I won't really have the option later. So it's kind of a pre-req. I'm going to work at it some more tomorrow, and if I can't get them out reasonably, then I'll just have to cut them. Just wondered if anyone knew a good way to get them out cleanly.


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sun Apr 22, 2012 12:16 pm 
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My experience with the Noctua rubber thingies is that you can just yank them off. Make sure you dont hit anything valuable inside your case when they let go. Then you can use them again. They might break, of course - you can try to use needlepliers carefully positioned to squeeze the rubber to help easing the pull.

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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sun Apr 22, 2012 1:04 pm 
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Location: North of the 49th parallel
diamondsw wrote:
I might, except I can't try it until I remove the Noctua, and if I destroy the rubber mounts that are holding that in place, then I won't really have the option later. So it's kind of a pre-req. I'm going to work at it some more tomorrow, and if I can't get them out reasonably, then I'll just have to cut them. Just wondered if anyone knew a good way to get them out cleanly.

You can make the rubber mounts wet with a few drops of alcohol(NOT water, oil or grease), so the rubber mounts will slip out more easily from the mount, and the alcohol will dry up in a couple of minutes.


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 Post subject: Re: Quiet (not silent) 120mm case fan with high static press
PostPosted: Sun Apr 22, 2012 9:07 pm 
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Joined: Wed Jul 14, 2004 7:57 am
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Some gentle (and not so gentle) work with a jewelers' screwdriver got them squeezed back out, and they're now holding in the GentleTyphoon nicely. I may end up seeing what I can do to rev down the Typhoon, as it is definitely far from silent - but it's also working, which sadly the Noctua was not.


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