Noise abatement for a rack

Robert G. Brown rgb at
Wed Dec 4 12:28:16 PST 2002

On Wed, 4 Dec 2002, Greg Lindahl wrote:

> On Wed, Dec 04, 2002 at 10:34:53AM -0800, David Mathog wrote:
> > Anybody here ever try noise insulating a rack???
> You should thank your lucky stars that they're 2U cases, as 1U fans
> are significantly louder than 2U fans.

And note that noise is remarkably similar to heat (kinda very long
wavelength heat) so that noise insulation <=> heat insulation.  One
doensn't USUALLY want to heat insulate the systems, and getting cold air
in and hot air out while keeping noise in makes things very complicated,
where complexity can equal expense and loss of stability.

However, there IS a simple solution.  Our server room, between the racks
and the SUV-sized AC heat exchanger/blower at one end, is probably
somewhere in the 60-80 dB range.  Not quite painful, but probably loud
enough to damage your hearing in the long run:-).

So we don't go in there.  Thick walls and its location in a sub-basement
provide perfect sound insulation while letting the AC do its thing.  If
we MUST go in there for more than a while, we sound-insulate our heads,
not the racks as it is much cheaper and keeps our ears warm.  Just
wearing headphones works wonders (and lets you listen to music instead
of systems).  Heck, for less than $100 you can get sound-cancellation
headphones that reduce ambient noise AND let you listen to music without
much bleed-through jet-engine background.  Not too great if you want to
talk to somebody, but hey, they can't hear you in there anyway unless
you shout.


Robert G. Brown	             
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at

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