For some reason I cannot reply to SPR???  Oh well. (I posting this for the
benefit of the group your mod terramir)

Not to sound picky about these fans or anything Terramir, but can you clearly
hear a 10% dB/A difference in noise signature?  I know such a reading
represents 100% actual noise as the dB/A is logarithmic, but by the time you get
down to improving on a subjectively quiet fan. .  .

That difference is also, as you say, at full song, and with a few questions as
to how it was measured.  If that % difference was exhibited in the application,
and also held at low voltage, is the result a reason to change from the Pabst
fans?

Don't get me wrong, I would prefer the quietest fans available in a new
installation.  And assuming I could get the things Down Under of course.  But
I find the power supplies I can get are now the noisiest parts of my
computers.  Last time I looked, last week, I was attracted by the integrally
variable fans with heat sensors.  This may have a few issues, and is usually a
technology associated with fans that are not the quietest for their airflow
anyway, but it seems like a good direction.

Also, I am having to virtually rebuild the bottom of my Antec P180 cases to
fit the later-generation, longer, quiet(?), power supplies.  Due to the way
those cases are made the centre fan in the bottom, which is rather necessary for
one of my power supplies at least, cannot be moved to the front if the drive
cage is still down there.  A 120mm fan cannot fit right up at the front
anyway.  I have the same general problem with a slightly older Lian Li case
(except it's fan is at the front).

So as your question regarded 140mm fans, are you able to fit these big ones?  I
would suggest that very few cases can fit them, even when you are OK about
modifying the case to mount the fans.  Sometimes the latest technology has a
few initial issues.

All my best mate.
John
--- On Sun, 11/21/10, terramir <terramir@...> wrote:

From: terramir <terramir@...>
Subject: [Silent-PC] good 140mm quiet Fans
To: Silent-PC@yahoogroups.com
Date: Sunday, November 21, 2010, 12:40 PM
















 









I own 6 pabst 4412FGL's and 6 NMB 4710-04W-B10's pretty much the quietest
120mm fans around when this group was still rocking, However by now they are
downright loud in comparison to some of the newer fans out there I'm reading.
And there is a new class of fans our group never covered and while there is some
info on x-bit labs it is quite comprehensive although the testing methodology
leave something to be desired. seems to me their ambient noise and the fact that
they are testing with-in the turbulence stream of the fans is messing with their
noise measurement.

I don't see even the scythe gentle typhoon beating the pabst fans and the
NMB4710-04W-B10's beat it noise-wise hand's down. then again cfm/dB(A) the NMB
beat the Pabst anyways wonder why they weren't more popular (see note on specs)



Anyways Of those out here that still mod can you point me towards any greater
fans (as in more airflow per decibel.



terramir



NOTE: the Pabst 4412FGL is rated at 26 dB(A) and 55.3 CFM or 94 m^3/h

The NMB 4710KL-04W-B10 is rated at 27dB(A) and 63.5 CFM or 1.8 m^3/min

this creates a noise factor (CFM/dB(A)) of 2.127 CFM/dB(A) for the Pabst fan and
2.352 CFM/dB(A) for the NMB 4710KL this number may not quite hold up as you
reduce the voltages however it is a fairly good estimator also the NMB fans are
available at much higher 12V flow rates and actually improve with the B20 75.9
CFM/31dB(A) and B30 88.2 CFM/ 37dB(A) , however those I would not recommend to
run at 12V



























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