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Old 12-08-2007, 03:23 PM
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How loud is 20 dBA?

How loud is 20 dBA?

Old 12-08-2007, 03:26 PM
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Decibel levels.

Rather quiet.
Old 12-08-2007, 03:27 PM
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About this loud.

20 dB is pretty quiet. It's about the level of background noise you'd expect in typical library during off-peak hours.
Old 12-08-2007, 03:28 PM
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This link compares it to rustling leaves.
Old 12-08-2007, 04:00 PM
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It's roughly as loud as This guy's shirt.
Old 12-08-2007, 05:27 PM
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Make sure you're understanding whether you're talking about a sound of loudness = 20dBA or whether you're talking about two sounds whose loudness difference = 20dBA. Since the scale is logarithmic, that can make a huge difference.
Old 12-08-2007, 06:53 PM
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Actually, dB comparison tables aside, 20 dB is almost impossible to experience in any normal environment You're going to have to get in a really isolated sound chamber, because background noise at just about anywhere is above 20 dB
Baffle cited a table saying rustling of leaves But if they rustle in nature, there's wind, and that alone will be louder than 20 dB.

Now, if this question is qabout dB levels of computer fans, and if it's worth the money to get a 12 dB fan, as opposed to a 20 dB fan, then the answer is yes. Even though the fridge @ 40 dB and the computer fan @ 20 dB doesn't equal 60 dB background noise things tend to add up. All in all, it depends on the room you're in.
Old 12-08-2007, 07:51 PM
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Originally Posted by Charlie Tan
Now, if this question is about dB levels of computer fans
If this is a question about dB levels of computer fans, the OP should note that the noise ratings are often completely unreliable. Some fan manufacturers make completely unrealistic claims about the noise levels of their fans. If a fan is actually at 12dBA @ 1m, chances are extremely good that it's not running.

If you're serious about making a computer quiet, the place to go is
Old 12-09-2007, 04:18 AM
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Originally Posted by Q.E.D.
20 dB is pretty quiet. It's about the level of background noise you'd expect in typical library during off-peak hours.
That's very, very optimistic. In our recording studio control room, the background noise is about 30dB. This is a rather typical, if slightly high, value. It is nevertheless very, very quiet. The noise criterion standards give recomendations of 40 to 50 dBA for libraries and and 25 to 30 dBA for recording studios.

There is a difference between talking about ambient noise levels and the loudness of a particular source. If I say that my studio has a background noise level of 30 dB it means that if I stand somewhere in that room, the sound level is going to be at least 30 dB.

If I say that rustling leaves are about 20 dB, it means in practice... nothing. A jet taking off is 20 dB, and so is a gun going off, and the Krakatoa eruption... at the right distance. A noise measurement for a point source without a distance has no practical meaning, inverse square law and all.

Last edited by jovan; 12-09-2007 at 04:19 AM.
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