Helo choosing fan for TRUE (ultra-120 extreme)

HardOp recommends a pair of ThermalTake Thunderblade A1926 (78cfm, 21dba, 2000rpm, $10).

scythe sff21f (63.7cfm, 28dba, 1600rpm, $13)
scythe sff21e (49cfm, 20.1dba, 1200rpm, $13)
the only enermax i know of that fits is:
enermax enlobal bearing model (44cfm, 17dba, ?rpm, $10)

yes, two is better, one fan pushes into the sync, the other pushes it -- either mount them toward the rear of the case where it exits, or toward the top of the case if you have a blowhole there.

i suggest you spend $13 on a cheap acoustic absorbation mat and stick it onto the inside of your case. it'll cut down the high pitch fan whine extremely well. petrastechshop.com

fan anti-vibration gaskets (usually rubber or silicone) are $3 at jab-tech.com

i honestly cant hear any difference between a case i built with all ~9dba fans and one i built with ~20dba fans. think as long as you stay below ~25dba you should be fine...

If you go to silentcomputers, they have the math to show that every fan u add around the same frequency adds about 3dB. So 1 fan should about 3db quieter then 2 fans.

I still use my original Thermalright Ultra 120 with a Scythe S-Flex 1600rpm fan. I also installed the same fan on the rear panel.

Adding a second heatsink fan for a push pull effect won't make much difference. Typically the result is a temperature drop of less than one degree. I tried it both ways. It didn't make any difference. Results vary.

Here is a link to a very good web site with useful information about quiet fans:

http://www.silentpcreview.com/article63-page2.html

Hmmmm.... interesting......looks like a 120mm cpu heatsink fan rated at 1600 rpm gets the nod.

also...(something i just learned recently) some fans are not intended to be connected to variable-speed headers; usually because they require a min voltage to spin up which might be more voltage than is supplied.