<HTML>
<HEAD>
<TITLE>Re: [Beowulf] 96 cores in silent and small enclosure</TITLE>
</HEAD>
<BODY>
<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><BR>
* There are two fans in the system, noctua NF-P14 FLX<BR>
<BR>
www.noctua.at/main.php?show=productview&products_id=33&lng=en&set=1<BR>
<BR>
according to the specifications their acoustical noise is 19.6 dB. Are<BR>
there some simple guidelines of how the noise "adds up", i.e. what would<BR>
be the sound level of two fans, or three?<BR>
</SPAN></FONT></BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'><BR>
There’s no real way to figure it out. Sure, in theory, twice the noise power means 3dB increase, but fan noise is a funny thing. Some of the noise might be just from air rushing through your equipment. There’s also the difference between “blade noise” which is tied to the rotation rate (and harmonics), general mechanical noise, which is broadband, and not so “noticeable”.<BR>
<BR>
The “rating” is in a special test jig, and not real representative of what a particular fan will do in your particular installation. All it really tells you is that a fan rated at 19dB is noticeably quieter than a fan rated at 29dB, and a whole lot quieter than a fan rated at 40dB.<BR>
<BR>
</SPAN></FONT>
</BODY>
</HTML>