Actually does anyone know the dba and cfm of the stock fans in the 4020?  That would help me on picking new 80mm fans!

 

Nate

Delta AFB0812H 

12V

Volt range 7.0 to 13.8

3000 RPM

1.000 M3

35.31 CFM

4.04 mmH²0

31.0 Db

For each additional fan you double the CFM and add 6db noise. This is for a proper comparisson between 4x 80mm and 3x 120mm fans in case you go to 120mm on a custom fanboard.

Only 3db more on each time you double the number of fans

 

There is 7 fans on RPC-4020

 

1 fan is 31Db

2 fans are 31db+3 = 34db

4 fans are 34db+3 = 37db

7 fans are around 39-40db

 

 

With 7 Noctua NF-R8

 

1 Fan is 17db

2 fans are 17+3 = 20

4 fans are 20+3 = 23

7 fans are around 25-26db Less than only one of Norco RPC-4020 stock fan...

 

And with 3 Noctua NF-P14 FLX

 

1 fan is 19,6db

2 fans are 19.6+3 = 22.6

3 fans are  around 24-25db

Sound measurements w/o corresponding airflow are meaningless.

 

You also need to know airflow/noise of the fans in the case, and not in free air.... so fan designs have terrible performance in restricted airflow of a case, but great results in free air.

I long ago came to this simple conclusion:

 

"Quieter fans regardless of cost means worse airflow regardless of manufacturers figures"

 

Obviously i you compare cheap crap with high quality this statement is meaningless but what you are really aiming for is getting the least airflow that keeps your disks at an acceptable temperature. This airflow means a certain amount of noise which will be less than the typical Delta hairdriers.

 

Madness lies withing trying to understand fan technology and theory. Keep it simple or invent something that really means airflow vs temperature adaptive real time (which TBH i am always amazed doesnt exist in the high street already).

airflow vs temperature adaptive real time

 

Many of them exist.... the problem is how do they get the temperatures and what curve do they use?

 

Many motherboards vary CPU and chassis fan speeds based on temp of mobo and CPU.  But they don't know anything about HD temps, and their own curve of what speed to use for what temp may not be the curve response YOU want.

 

There are many 5.25 and 3.5 drive bay fan controllers that come with stick-on thermisters that work, but those are cumbersome. How do you monitor drive temps of 15 drives with that?

 

Complex programmable ones exist, but they need custom programming if you want to poll disks temps and do your own response curve.

Complex programmable ones exist, but they need custom programming if you want to poll disks temps and do your own response curve.

 

Really interested in those, any links, cost doesn't matter!? Thanks!