Re: How to stop vibrations!

[Wayne Harrison <Wayne@xxxxxxxxxxxxxxx>]

Thanks all for the feedback so far.

Update so far, spent the day re-enforcing the platform. also got some slabs
from Wickes today but typically ran out of sunlight to cut them to size.
Each slab is 400x400mm wide by about 28mm thick (according to the docket)
and weigh just over 2 stone. Quite a nice find in that they had a smooth
semi-polished side.

At this point the frame of the platform has the compressed fibre board
tile, mdf, thick plastic draw liner, a single slab and then the foam mat.
Typically I can sense the vibration but will know more tomorrow when the
wife has had chance to live with it for the day.

Am wondering the best way to proceed with the extra that's needed, I have
spare slabs to cut ready but, how effective will they be as once cut
obviously won't have the weight. Will it cause more rattle!? I've even
considered casting a slab from scratch to the size needed.

One thing I did wonder is with the foam mat on the concrete, at this point
its on the one slab as it's just small enough to fit between the 4 rubber
'feet' on the servers. This means that the whole base of the server has
contact as it's sinking into the foam. Maybe this will help when it's cut
to fit and kinda ties in with what Tim was suggesting with smaller points
of contact in each corner?

May well have to look at silent substitutes if this doesn't work but could
well have a problem with the psu fans as they are built in. Iirc the cpu's
don't have fans on directly but a chunky big heat sink with air directed
over it.

More as it happens.


Cheers all.
Wayne.





Sent from my iThingy

On 23 Jan 2011, at 08:36, Stephen McGarry <stephen@xxxxxxx> wrote:

> The three main factors in sound insulation are sealing, mass and
isolation. So you are on the right track with the
> concrete slab with foam on top (you could also leave the thin tile
between the slab and the mdf). As its transferred
> sound not air borne there's nothing to seal.
>
> HTH
> Stephen
>
> P.S. It might be necessary to increase the thickness of the MDF to
hold the weight of the slab
>
> On 22/01/11 22:01, Wayne Harrison wrote:
>> Hi all,
>>
>> I've just moved my servers into residence at node 0 (ok a cupboard
on the landing)
>> and am having a problem with vibration. I think it's from the fans
that cool the motherboard or psu. They are a pair of
>> Dell sc440 servers ( only one is powered at the min) which have
quite big fans. I don't think simply disconnecting the
>> fans is an option as the heat is quite high at the min. Don't get
me wrong, these are not loud 'winey'(sp) servers with
>> screaming fans, have enough of that from the switch! It's a deep
rumble that's the problem, typically it vibrates
>> through the upstairs.
>>
>> I've got both of these on a platform that's about 5" off the
floor, fixed to the wall on three sides and battened from
>> the floor at the front ( this was to clear some pipes that were at
the back of the cupboard). The platform top, which is
>> 6mm mdf, has a soundproof 'tile' you typically put under laminate
flooring under it in my first attempt at dampening out
>> the noise. I've now got a 10ish mm foam (ex exercise) mat under
the servers as well (on top of the mdf). The idea being
>> as to not give these a soundboard to vibrate on but, hence my post
here, this isn't working as I would like either.
>>
>> My only other thought was to get a concrete slab and use that as
the base of the platform to solidify it rather than
>> cushion.
>>
>> Has anyone else come across this problem and how did you fix it?
>>
>> Cheers
>> Wayne.
>>
>> Sent from my iThingy
>>
>>
>
>
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