how much difference is 6 decibels for a case fan?

[Chairman Mao]

setting up a new system.

I've been using 92" Sunon case fans for my system, but I'd like to go quieter this time around.

I've looked at the 92" Panaflo and its rated at 27dba. as opposed to the Sunon's 33dba.

However it will pump out a little less air at 42.7CFM as compared to Sunon's 44CFM. (not much though)

I'm guessing that the 6dba difference is quite noticeable, and offsets the 1.3 CFM diff. in airflow.

anyone confirm...

Thanks.

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...everyone should taste a little bitterness in their lives....

[This message has been edited by Chairman Mao (edited 03-12-2001).]

[RoadWarrior]

I'm reaching back here, but I believe that a difference of 3db = half as loud, so 6db difference would make it 1/4 as loud. If it was the only source of sound in a room, I think it would make a pretty big difference.

[MadCat]

RoadWarrior, I think you've got that backwards.

A +3dB difference means the sound intesity is twice as loud. And thus a +6dB difference would be 4x as loud.

For reference, a difference of 10dB is ten times as loud. So 40dB is 10x as loud as 30dB.



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[Todd a]

There is also a formula for figuring out adding db tegether but it pritty much works out to two sounds at 27db=30db or twice as loud.

The only thing is PanaFlos are not speed sensing and generally do not ship with plugs attached. Minor issues, but don't be supprised. They are also brittl. I hit one with a small tape messure and a fin snapped off (while running). Supprisingly it does not vibrate. They are very quiet. The 80mm is even more quet and if you take 4 of them, you will run at 100CFM for only 27db total (they run at 21db each).

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The COMPUTER is your FRIEND!
Happiness is manditory.

[Paragon]

every 10db is ten times as loud.. ie 20db is ten times as loud as 10db not double it...

[Todd a]

That means for example the GlobalWin FOP38 is 10 times louder than the FOP32-1 I have (and I don't even like the noise it makes. That also means the Delta Black Label 38CFM 60mm fan that the FOP38 uses is 100 times louder than the 92mm PanaFlo L1A low noise fan. that generates 43CFM airflow. That is just insain. Why is ducting not as popular?

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The COMPUTER is your FRIEND!
Happiness is manditory.

[FS]

Are you sure the noise levels of the fans were measured in the exact same conditions(acoustics, distance, etc)? Otherwise the figures have zero comparative value.

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"No doubt the truth, as usual, would be somewhere between the extremes" -Arthur C Clarke

[D|sElMiNk]

MadCat : I've read yours and RoadWarriors posts twenty times now, but I still can't see how he is wrong and you are right. You are both saying the same thing.

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Carpe noctem!

[RoadWarrior]

Thanks. I probably could have phrased it better. I think he is looking for -3db and -6db, where what I said was 3db difference and 6db difference.

I do agree that comparing manufacturer claims is bound to be an apples to oranges situation. There are probably OSHA type testing standards, which many of the companies make efforts to comply with, but unless all the testing is done by an independent third party, there is a good chance that large differences in results exist.

[blinky]

The Decibel scale is logarithmic (spelling?) not linear. A 10Db increase increase is equivalent to a doubling of the sound intensity/level .

[D|sElMiNk]

All I know for sure is that -3db is a reduction of 50% in sound intensity (been doing a bit of sub enclosure designing)

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Carpe noctem!