Re: fancontrol wheezy Dell T7610
On 2/25/2014 3:28 PM, Jerry Stuckle wrote:
...
> Encasing the tower in a sound
"Damping" not "dampening". To dampen something is to add moisture to
it. To damp an object is to lower its resonance frequency. One cannot
add moisture to sound waves thus there is no such thing as "sound
dampening". Please use the correct terminology. Saying "sound
dampening" is like fingernails on a chalk board to audio engineers.
> On 2/25/2014 4:16 PM, Stan Hoeppner wrote:
>> Build a 3 sided box out of 3/4" MDF...
> Just ensure there is enough ventilation (remember air
> has to get in also, not just out) and that you can access the power
> button, DVD, USB ports, etc.
A 3 sided box is by definition open at the front, rear, and bottom, so
front panel access is not an issue.
> Making access holes for these without
> compromising the sound dampening is probably the hardest part.
Not at all. The goal here is not to make the workstation completely
silent, but to decrease the SPL of the mid and high frequencies to
little more than room background noise level at the ears when seated in
the desk chair. An acoustically damped 3 sided box with small
front/rear overhangs accomplishes this, in the two ways that matter:
1. The damping material, whether carpet or acoustical egg crate foam,
absorbs most of the mid and high frequency sound energy generated by the
fans. These sound waves normally radiate not only out the front/rear
case vents, but also through the thin sheet steel and plastic panels
which tend to resonate at or near these frequencies. In the stock
configuration the fan noise radiates in all directions, but not uniformly.
2. Because the sound pressure level of mid/high frequencies drops at a
much higher rate off axis from ear position, any sound energy at these
frequencies not absorbed by the damping material propagates at floor
level out the front and back only.
By absorbing most, then directionally focusing the remaining mid/high
frequency waves, which are now of greatly decreased amplitude due to the
damping material in the overhangs, the noise is barely audible while
seated in the chair. You must kneel down to floor level to really hear
the fans now. This solution works without compromising access to the
machine, or compromising cooling capacity. The T7610 is a true business
workstation, with front-to-back only airflow. This 3 sided damping
shroud will not work with PCs which have side air intakes, top exhausts,
etc. This should be common sense to everyone, but not everyone has
common sense, so I'm attempting to head off further "me too" posts.
I tend to only reply to thread topics of which I am a subject matter
expert. You made the mistake of assuming that a DIY suggestion implies
amateur knowledge, then proceeded to display your truly amateur
understanding of the subject matter.
I don't post to debian-user that often, but there are folks on this list
who know they can take the information and analysis I present straight
to the bank. They know the level of expertise and analysis that goes
into each and every one of my posts, even those in which I don't give
the 2-3 page explanation up front, but the short version which assumes
the reader knows a little bit about the subject.
--
Stan
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