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 Post subject: I taught myself something about silent pc quests
PostPosted: Tue Apr 29, 2008 9:41 am 
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Joined: Tue Jan 31, 2006 8:22 am
Posts: 379
Location: maine
I have had seven custom pcs to drive me acoustically mad, all mine, every piece altered in some way different than oem (no joke)except for solid state parts like the hdd...
Of course i only learned to doubt everything.

This topic is about heatsink of the box, and some old fashioned pc rules forgotten, especially about the HDD.

Really clamping the hdd down is an absolute must. Today more than ever. the "suspending for silence" theory is like a bungi jump accident waiting to happen...without the case ground an hdd needs to boot (could be pun intended).
I recently added some metal to an already nice box (antec2600) it is the same secc stuff for many electronics. I am glad the antec boxes stuck to a rule of some kind.
Anyway, upon clamping the drives down, a dreaded wah wah bass noise emmitted, and even a case cavity noise (read about here in the 200hz range). I was disappointed. So first thing was to throw the little mouse pad in the bottom of the case to stop cavity noise. That worked. Case is indeed tough enough...
Rather than defy what I know as "rules" for hdds.. if the box is letting it happen, the box isn't tough enough.
So I filled in the 5.25 inch bays back with original metal, by adding some extenders with rivets and making it removable with screws (I could have taken a picture just today as I was finishing it off, but was motivated didn't think of it) drilled holles 1/8th accordingly. As it turns out, one of the nut/screw combos tightened the entire cdrom bay up top.
I added two rivets near the psu ,2.5 years has taken a slight dimply toll at the seams and simply brought it back out again with rivets nicely done, like oem.

The drives were still driving me mad... the whole system is very quiet on 3 fans, max rpm 2376 and its on a duct aiding in acoustics, (reverse cooled). I am not going to give up with crazy silencers. I want rules. I want a tough case. I want on and off, and accidentally kicking it to be no problem.

I took the bezel off again....
added what ended a perfect piece to fit the open floppy spots, and also found that it is flimsy in that area with drives or not, like all my other cases....the irony of putting drives near the open weak area has been just another backwards thought process in the pc world...
I quickly rummaged through some of my junk and found an old cobra cb (fried) and took note that the built in speakers four holes were 120mm, and it was vented for a speaker...and the metal is nearly identical in feel and color as the antec 2600amb...and painted twice, inside out (inside of cover is just like a pc case)
I cut out a square to fill in the whole thing , added four screws....mounted it to case, slid the drive bay back in, noticed it latched tighter...
completely silent drives. I can put my hand on the case and declare it a reduction number unknowable, just that is slient. Side by side, both active, and conquered...

My point here...

do not go against old rules to silence a drive, attack the case by making it stronger, or like I have literally done, take it all aprt slowly to save the good stuff, take it outside, and have a case stomping party.

You will notice, the little hdd is not the acoustic monster it seems to prevail as sometimes, in a proper case to handle the Little HDD.

I remember a wd drive I had some years ago, in a gateway 2000 case, that *had to* be spaced between .25 inch and .5 inch from a solid metal front end, with all four screws attached, and inside a large enough case... or by design.. it would not run at all.
HDD has a powerful energy in relation to a system, grounding by all means is a must do, and it is nothing to notice (if you win). The case is a huge part of the functions, and even aids in clock smoothness by solidly knowing itself is all there at all times, through all layers of pc dynamics..it likes the drive mounted.

I hope to help somebody going mad over this. Blame the case, seriously. As a starter case, antecs are nice, but you may find to have to add some things like I did. Compared to the past. Some of the Antec may as well be golden in pride, even with errors.

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 Post subject:
PostPosted: Tue Apr 29, 2008 1:43 pm 
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Location: Beds, UK
Anyone know what points are being made here?

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 Post subject:
PostPosted: Tue Apr 29, 2008 2:59 pm 
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Joined: Tue Feb 19, 2008 2:08 pm
Posts: 398
Location: Los Angeles
In a nutshell: There is no substitute for mass.

Instead of suspending everything and making more holes, you should get heavier and tougher components until nothing resonates. Less holes, more directed airflow, and more mass.

Note - Dynamat or gum rubber pads are a good way to add mass for cheap. the truth is that most frequencies that Dynamat would absorb is high level whining and screeching(2Khz+) - and not the noises our fans and drives make. But if the case is dampened to the point where nothing resonates - and it stops acting like a giant speaker box, then it gets quiet. Of course, the makers of such materials don't tell you this unless you dig deep into the technical specs. but it's also why many low or no-tech materials work just as well.

Blame the fact that cases are getting thinner and cheaper. Old school cases a decade or two ago used to be 20lb monsters made out of steel.

My box has a distinct hum from the raid array causing vibration. hummmhummmhummm - and nothing will fix it except for more mass applied to the rear panel.(it already was a 10+ lb case with nothing in it)


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 Post subject:
PostPosted: Tue Apr 29, 2008 4:28 pm 
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ok agreed about mass, what about hdd's needing a case to case electrical ground connection? I can't see the need

And is colm suggesting my BIOS clock is running erratically because my HDD's aren't bolted to the case?!

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 Post subject:
PostPosted: Wed Apr 30, 2008 5:01 am 
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Location: London, UK
psycic HDDs, they will get you!


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 Post subject:
PostPosted: Wed Apr 30, 2008 7:21 am 
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Location: Grand Rapids, MI
A couple issues here. You never mention what HDD you are using or even what type (3.5 or 2.5") so we can't comment on your choice of HDD. Also, HDDs do not ground to "case," they ground to the PSU (that's the black wires on the molex). The PSU and case grounds to the power line. Maybe you referring to static ground (though that has nothing to do with the drive booting)?

Mass-loading (which you did by adding more metal to the case) has already been proven to be an effective method to reduce case resonance caused by vibrating components. Plekto makes good points regarding low-quality case materials, and I think it's more of a function that it costs less for the manufacturer to make and ship.

Mass-loading is only one method of reducing resonance; the other is isolation, which means decoupling things that vibrate from things that don't. Suspending a HDD or fan prevents the vibrations from traveling to the case panels and other parts causing resonance vibrations. This is easily the most effective method of reducing vibrational noise from a single or few component(s). A combination of these two work very well.

However, there is the additional noise from a HDD called "idle whine" which is caused by noisy bearings in the HDD. Suspension can't help here, only encapsulation, which is a form of mass-loading and isolation combined. In other words, a Drive Cooler (or AlleyCat's enclosure).

I do partially agree with your ending statement though. Buying the proper case does make a difference. But if you buy quiet components to begin with, the case doesn't matter.

If you are unsatisfied with current metal cases out there, perhaps you may want to try building your own out of MDF. There are plenty of people here who have built wood cases, and you see to be the adventurous type. You can customize the design the way you want and use pieces of old cases to help out when the fabrication gets a little too complex.

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 Post subject: Use suspension strings
PostPosted: Tue May 06, 2008 11:23 pm 
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Joined: Wed Apr 30, 2008 8:42 am
Posts: 8
Location: Netherlands
I really killed the HDD noise by mounting them in de elastic HDD strings of the Antec Solo. I just don't hear them anymore.


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