The Sone and The Decibel

billdcat4

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Hi, Im looking for a really quiet LGA775 HSF.

I was looking at the Arctic Cooling Freezer 7 Pro, but they dont have the dB output of the device, only 0.9 sone. On their site for reference they compare it to the stock intel HSF which they rate at 4.9sone.

How do I convert sones to decibels? I know that 17dBA is a good quiet point. What is that in sones?
 

CyberianK

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1 Sone is around 40 DB but they are not directly comparable...
The Arctic Freezer is around 35 DB.

Don't freak out cause of that high noise rating you won't ever reach it in most systems cause the cooling of the ACF7pro is so good it never runs at full load. At least thats true in my system (using it with a modest OCed 2.4 E6300).

For its price it is fantastic. Unless you are using notebook harddrives (which got bad performance) your drives are louder than your ACF7.

a good review is http://www.silentpcreview.com/article285-page6.html there are also DB ratings for the lower speeds.
To quote from there: "Very quiet at low speeds"
 

zjohnr

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Aug 19, 2006
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Don't freak out cause of that high noise rating you won't ever reach it in most systems cause the cooling of the ACF7pro is so good it never runs at full load. At least thats true in my system (using it with a modest OCed 2.4 E6300).
I would second that opinion based on my own experience with the ACF7pro. When it runs at full speed you hear it. Fortunately, I've only heard it run at full speed when I've disabled the CPU fan speed control in the BIOS.

Actually, with the default DS3 BIOS fan speed settings, the fan doesn't run at all. :) I changed the BIOS fan control method setting from "Auto" (whatever that means) to "Intel QST" which ensures the fan never runs slower than 800 RPM. That is the speed I always see it running at and at 800 RPM I do not hear it.

(The noise from my case is actually dominated by my 1600 RPM case fans. I definitely need a way to slow those down a bit ... they seemed like such a good idea at the time I bought them. :oops:)

FWIW, the ACF7pro was running around $25 US when I bought it. Currently newegg sells it for around $65 shipped. Personally, I think that is crazy. I don't know why the price was suddenly more than doubled. :?

-john, the ostensibly clueless redundant legacy-in-transition dinosaur
 

billdcat4

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Don't freak out cause of that high noise rating you won't ever reach it in most systems cause the cooling of the ACF7pro is so good it never runs at full load. At least thats true in my system (using it with a modest OCed 2.4 E6300).
I would second that opinion based on my own experience with the ACF7pro. When it runs at full speed you hear it. Fortunately, I've only heard it run at full speed when I've disabled the CPU fan speed control in the BIOS.

Actually, with the default DS3 BIOS fan speed settings, the fan doesn't run at all. :) I changed the BIOS fan control method setting from "Auto" (whatever that means) to "Intel QST" which ensures the fan never runs slower than 800 RPM. That is the speed I always see it running at and at 800 RPM I do not hear it.

(The noise from my case is actually dominated by my 1600 RPM case fans. I definitely need a way to slow those down a bit ... they seemed like such a good idea at the time I bought them. :oops:)

FWIW, the ACF7pro was running around $25 US when I bought it. Currently newegg sells it for around $65 shipped. Personally, I think that is crazy. I don't know why the price was suddenly more than doubled. :?

-john, the ostensibly clueless redundant legacy-in-transition dinosaur

Im getting it from xoxide.com for $25.

Im also getting the DS3, do I have to change the fan settings to the Intel QST, or is the automatic one OK?

thnx
 

nalle

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0.9 sone is very roughly about 36 decibels. To get an accurate measurement, I'd have to create a chart using Fletcher-Munson curves (physics junk), but decibels and phons are about equal in controlled environments, and a sone is 40 phons (it's very annoying when they use sones to confuse the consumer since sones are *perceived loudness* instead of decibels being more standardized in measuring). So you're looking at an average of 36dB for it, specifically an average of 36 decibels in "loudness increase" from no fan to this fan.

So it's much louder than Rosewills as a whole and its average (generally they only do the average with this brand instead of the range) is the loudest Zalman's most popular fans/sinks get. Zerotherm makes very quiet fans, and even Coolermaster has some low dB ones out there now.