quick decibal question

[xandy]

i just got 2 delta's and 1 tornado installed in my case. does that maen the db of my case from the fans is the 80db from fans x 3 ?

 

[MDE]

No, just the value of the loudest one. Now go buy something to sop up the blood that'll be squirting out of your ears.

 

[xandy]

lol it is very annoying.

 

[ericgl]

If two are the same and close enough, add 6 dB.

EDIT: or maybe 3dB, I forget.

 

[lenjack]

6dB it is.

 

[arcas]

If you double the noise level, the decibel level goes up by 3dB.

A few years ago, I wrote a program that'll compute the final noise level given some number of fans. Just specify the rated dB level for each fan on the command line and it'll give you the result.

http://sackheads.org/~mayfield/software/decibels.html

 

[Degrador]

In case you're wondering, the reason for the strangeness here is because the decibel scale is logarithmic. An increase in 10 decibels, is actually 10 times the sound. So a 40dB fan is 10 times louder than a 30dB one, and 100 times louder than a 20dB one. If you want to work out just how much louder something is, the calculation is 10^(x / 10) (Where x is the difference in dB).

 

[Tiamat]

Well, Physicists and Acoustic Engineers have basically come down to the consensis that 3 db is a double of sound intensity while 6 db is a double in apparant loudness. If you have 2x 40db fans next to each other, you will get 43db with of noise since you have doubled the intensity. If you have a 30db and 50 db fan next to each other, the 50 will drown out the other unless the pitches are wildly apart.

At least this is my understanding

 

[imported_chrisbtx]

I'm learning physics and having fun doing it!

 

[0roo0roo]

db rating is for fan blowing in open air . in case blowing through grills itll be louder

 

[S4M33R]

Originally posted by: chrisbtx
I'm learning physics and having fun doing it!

shocking no? I recently came to the revalation that I may be able to do my udergraduate design project for EE in overclocking cpus or designing better power supplies I guess learning can be fun?