Noise of two fans

Nomad0 · 03-30-2002, 12:22 PM

If a fan gives noise 20 dba, what noise two fans give - 23 or 26 dba? Or maybe, both answers are wrong?
Thank everybody.
Leon

EMC2 · 03-30-2002, 01:38 PM

23dBa - read this recent thread

Kevin · 03-30-2002, 02:24 PM

I'm not sure if this is right so somebody correct me if I'm wrong, but I think that for every dBA increase of 1, the noise level doubles... that this is a logarithmic scale. Yes? No?
-Kevin

EMC2 · 03-30-2002, 03:38 PM

Kevin - yes dBa is a log scale. No, increasing by 1dB on a log scale isn't 2x. Log scales go like this:

3dB = 2x
6dB = 4x
9dB = 8x
10dB = 10x
13dB = 20x
20dB = 100x
etc.

Remember dBa is a measure of the sound intensity, which isn't the same as "loudness".

What you may be thinking of is the Bel scale (Lw(a)). It is also a log scale, but created for "loudness" measurements. 1 Bel = 10dBa.

ps - now go read the other thread I linked to bro

03-30-2002, 12:22 PM	#1
Nomad0 Cooling Neophyte Join Date: Aug 2001 Location: UK Posts: 17	Noise of two fans If a fan gives noise 20 dba, what noise two fans give - 23 or 26 dba? Or maybe, both answers are wrong? Thank everybody. Leon

03-30-2002, 02:24 PM	#3
Kevin Slacking more than your weird uncle Join Date: Nov 2000 Location: San Diego, CA (UCSD) / Los Angeles, CA (home) Posts: 1,605	I'm not sure if this is right so somebody correct me if I'm wrong, but I think that for every dBA increase of 1, the noise level doubles... that this is a logarithmic scale. Yes? No? -Kevin __________________ I used to throw hot coffee all over the ass of the horse there, then whip him while he was kickin' at me. Those f***in things are crazy.

03-30-2002, 01:38 PM	#2
EMC2 Cooling Savant Join Date: Feb 2002 Location: Dark Side of the Moon Posts: 365	23dBa - read this recent thread

03-30-2002, 03:38 PM	#4
EMC2 Cooling Savant Join Date: Feb 2002 Location: Dark Side of the Moon Posts: 365	Kevin - yes dBa is a log scale. No, increasing by 1dB on a log scale isn't 2x. Log scales go like this: 3dB = 2x 6dB = 4x 9dB = 8x 10dB = 10x 13dB = 20x 20dB = 100x etc. Remember dBa is a measure of the sound intensity, which isn't the same as "loudness". What you may be thinking of is the Bel scale (Lw(a)). It is also a log scale, but created for "loudness" measurements. 1 Bel = 10dBa. ps - now go read the other thread I linked to bro

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