Comparing fans

  • Thread starter Thread starter Gary C
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Gary C

Say a 80mm fan has a rating of 30CFM air flow and 25dBA noise level.
Combining two said fans next to each other, is this actually now 60CFM
of air flow ... as in equal to an 120mm fan with same CFM?

What about the noise level of the two 80mm fans next to each other?
Can't be 50dBA (25dBA each) now, but it has to be louder than a
single fan alone, and louder than the aforementioned 120mm fan, right?
 
Gary said:
Say a 80mm fan has a rating of 30CFM air flow and 25dBA noise level.
Combining two said fans next to each other, is this actually now 60CFM
of air flow ... as in equal to an 120mm fan with same CFM?
Click to expand...

Not unless the fans are operating with ZERO static pressure, which
isn't the case inside a computer. A fans published rating is at ZERO
static pressure. Inside a case, their CFM is significantly lower.
What about the noise level of the two 80mm fans next to each other?
Can't be 50dBA (25dBA each) now, but it has to be louder than a
single fan alone, and louder than the aforementioned 120mm fan, right?
Click to expand...

Probably a 3 dB increase versus the one fan.
 
ric said:
Not unless the fans are operating with ZERO static pressure, which
isn't the case inside a computer. A fans published rating is at ZERO
static pressure. Inside a case, their CFM is significantly lower.


Probably a 3 dB increase versus the one fan.
Click to expand...

3.8765 increase based on keeg code
 
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