"Geoff" said:
I gave it the ol'college try but failed, I think. I have a p2b-ds with 2
seagate, 10,000 rpm cheetahs. They are noisy as hell, so, I bought sound
deadening material to put on the inside of my pc case and I bought thin
strips of rubberized material to go between the drive and the drive bay.
The thin strips of rubber did not fit, it is pretty tight in there and the
sound deadening material worked a little but the air vents have to stay
open, so the sound ultimately gets out.
-g
Here is an idea for you. (A ridiculous idea, but still an
idea. You can skip this part if you want.)
******
Start with an external enclosure. Seal the enclosure completely.
Equip the enclosure with a Peltier cooler, which has a hot side
and a cool side, and draws mondo amps of current. Get a
thermostatic control for the Peltier, that regulates the current
flow, and only sends enough current to the Peltier, for it to cool
to the temperature you set.
Inside the enclosure, arrange a fan to blow air over the heatsink
connected to the Peltier. The Peltier is your source of cooling
inside the sealed enclosure. The temperature you regulate the inside
of the enclosure, has to take the dew point of the air into account,
to prevent any possibility of condensation. To help in this
regard, place a large bag of dessicant (silica gel) in the bottom
of the enclosure. As long as the seal in the enclosure prevents
moisture from the outside entering the enclosure, you will have
very good control over the dew point. There are dessicants with
better characteristics than silica gel, but they would likely be
more expensive. A dessicant with a color indicator could be used
to tell whether the dessicant is used up, and some dessicants
can be recycled by baking at low temperature in an oven. (I've
used dessicants that are recycled by heating to 500C, but you
don't want to mess with that. I have a funny story, but some
other time...
You will also need a fan on the outside of the enclosure, blowing
air over the hot side of the Peltier plus heatsink. That will be
the noisiest part of the solution, so find a large heatsink and
a slow speed fan, to give a quiet cooling solution. While you
could opt for a passive heatsink only on the hot side of the Peltier,
the heat sink area would have to be sufficient to cool the large
number of watts pumped out by the Peltier. Peltier coolers
are notoriously inefficient, to you'll get a whole computer's
worth of heat, to cool a drive or two.
The way this would work, is when the enclosure is first powered,
the Peltier will run 100%, and the Peltier will get very cold
(but one would hope, not frosty, due to the dried air in the
enclosure). As the internal fan runs in the enclosure, eventually
everything in the inside of the case will reach dynamic
equilibrium, and the current draw by the Peltier will be
greatly reduced by the Peltier controller. (Typically, you would
set the regulator, to make the air temp inside the enclosure
_equal_ to room temp. If the outside air is 22C, set the
controller to maintain 22C inside the enclosure. The Peltier
shouldn't need a lot of current to maintain equilibrium then.
Just the heat flux from the drives.)
An introduction to Peltiers:
http://www.dansdata.com/pelt.htm
Your disk drive might be putting out 15 to 20 watts of heat, and
steady state, that is the heat that the Peltier has to transfer
to the outside of the enclosure. Any other heat dissipating devices
added to the enclosure will increase the heat load the Peltier has
to pump (so, no, the Peltier power supply does _not_ go inside
the enclosure).
Here is an example of a linear controller, suitable for use
with a quite large Peltier. A controller like this could be
run from a separate ATX power supply, if the power supply has
enough amps at +12V. (The amps needed are dictated by the
Peltier, so if the Peltier uses 8 amps, then that is closer
to the value that will be coming from the ATX power supply. The
ampere rating of the controller, tells you the maximum sized
Peltier you could use.)
http://www.techcool.com/vpc/photo.htm#225
For passing electrical signals through the enclosure, you
might consider a SCSI ribbon cable, which may be easier to
deal with than trying to cook up an airtight bulkhead connector.
*******
A much more practical idea, is buy a SCSI drive with known
good acoustics. Select "Idle Noise" from the pulldown menu here,
to see a list of drives and how loud they are. There are some
SCSI drives that are quieter than the 7200.7 Seagate IDE
drive I've got (and it is pretty good). One of the reasons
there are so many cut-rate SCSI drives for sale, is they are
all LOUD. Many of those drives sit in dumpsters, until someone
Ebays them.
http://www.storagereview.com/comparison.html
The cost and complexity of quieting down cheap SCSI drives
far outweighs the savings from buying the cheap drives. Maybe
some nice IDE drives would work better.
HTH,
Paul
.