My theory behind silent air intake.. your opinion!..

Dance123 · Post by **Dance123** » Tue Jul 01, 2003 11:25 am

Hi,

I have checked out the recommended section of cases, but I still can't decide which case I should choose to start building a silent PC. Another problem is that they don't sell all those exotic cases over here. Over here its mostly Aopen and Chieftec..

My main worry is the fact that many cases for intake seem to have lots of airholes in both the front and side panels of the casing, which must allow much noise to get out. Chieftec has a big roster in the front panel after which big airholes are located at the place where harddisks sit. Not surprising this can make quite some noise!!

Isn't it so that for the best intake with the least noise the front panel should be completely closed (no airholes you can see) with behind that the intake fan(s) and that there should be a large space between the front panel and the intake fans. That way the intake should only happen vertically from the bottom where air goes into the case in the large space after the closed front panel where it can reach the intake fans. Ofcourse there also shouldn't be any airholes in the side panels. Aren't there any cases that are build that way?! The crucial point seems to be that there need to be enough space after the closed front panel so enough air can reach the intake fans after it!!

Aren't there any cases build like this? I was thinking about the Aopen HQ48, but I don't know if the space behind the front panel is large enough to get good intake and good airflow. Another one would be the H600 but it has vertical stripes of airholes in the side panels, but perhaps I could close them. I also don't know if this case has enough room behind its closed front panel, which is the crucial element in silent air intake in my opinion.

Any cases you can suggest that are like this or should the Aopen H600 be fine (does it have enough room after its front panel)?!

Mike.

Jan Kivar · Post by **Jan Kivar** » Wed Jul 02, 2003 12:14 am

IMO best option would be to have a 120 mm round hole in the bottom of the case with a fan in it (or, one could just make smaller holes and use no fan). The case must have then some sort of pedestal to allow air intake (or feet like those Chieftecs).

This idea will require drilling, as there is no cases with bottom holes. If the computer is on the floor, there should be some sort of air filtering to prevent dust entering the case.

I'm no expert on the matter though.

Cheers,

Jan

arman68 · Post by **arman68** » Wed Jul 02, 2003 5:22 am

I am currently in the process of setting up a HTPC using a mATX Yeong Yang YY-A105 case (I still need to replace the PSU) and thought it would be useful to share my good vibes about this case (all the YY-Axxx actually) when used as a tower (it can also be used as a desktop).

Front: there no front intake. Ok, a few holes drilled through the front panel to let air but nothing major and certainly no fan.

Top/Bottom: both have recesses with what I call 'shark fins'. They let the air circulate upward without need for any fan. Being in a recess mean that if the top/bottom is covered, the air can still enter/exit the case. Plus once you add the rubber feet it gives even more clearance.

PSU: is a the top of the case, but I have just discovered that the case can be turned upside down and looks just as good. With the PSU at the bottom it runs cooler and the thermostatic fan slows down a little more cutting down on it noise. The only downside is it does not act as an exhaust anymore but the impact on the cpu/system temperature is minimal.

Back: there is one grid for an exhaust fan sitting just above the PSU (or below when used normally). I found fitting a fan blowing inside the case is much more efficient than when used as an exhaust. Plus it has the benefits of providing fresh air straight to the PSU to cool it down and silence it even more. Temps are actually ok without a fan but the PSU is noisier. I use a quiet Papst 60mm at 5v.

jafb2000 · Post by **jafb2000** » Fri Jul 04, 2003 3:22 pm

Fans fitted in the front of the case must be very quiet,
as they are usually outside the domain of sound proofing.

o Noise / soundproofing in case / case-wall-fans / ear

There is no soundproofing between the fans & ear

Earplugs are not a LT viable solution, but have their uses
such as when either sex utters the 2 words "I Want".

Fans fitted in the front are serial in nature, they merely reinforce the
static pressure of the exhaust fans vs arithmatically additive to cfm.
Vis., they simply get you closer to free-air cfm of the higher cfm fan.

So it is not unreasonable to omit them at least until all the exhaust
fan ports have been filled - especially rear-top & any near the CPU.

A case can be made against intake fans if the intake ports are too
small relative to c/sectional area of the fan itself - whereupon there
will be a thrust loading on the fan bearing increasing fan noise. This
is particularly acute for the intake side of fan which is most sensitive.

Visually holeperforated grills can be 43% free air, but 57% solid metal.
Visually open slotted grills can be 55% free air, but 45% solid metal.

This is before one considers the often small lower slot in the plastic
moulding at the front of cases - which is where all air must come in or
alternatively come in thro every crack & crevice so starving outlet cfm.

Rear case fans are further from your ears, and the sound has to go
through distance in the case or through 180-degrees to reach your ear.
Either is worth about 4-6dB(A) in noise reduction, quiet appreciable.

fmah · Post by **fmah** » Sat Jul 05, 2003 11:11 pm

I saw this new Viewsonic computer in the store.

http://www.viewsonic.com/products/mediacntr_m2000.htm

It has vents in the bottom front and some on the sides. It has a pedestal built in to raise the box above the table.

Dance123 · Post by **Dance123** » Mon Jul 07, 2003 10:14 pm

To come back to my theory on silent air intake.. aren't there ANY cases at all that one can suggest that have completely closed front and side panels (so also no fan at the bottom of the front panel what most people suggest), but that the case would have a large space between the front panel and the rest of the case, so that air intake should only happen VERTICALLY from the ground up if you know what I mean?!

I have checked the recommended section, and I don't think I have seen case like that. Most of them have airholes at the lower half of the front panel. Except perhaps the GMC Neo Classic (http://gmc.co.kr/english/good_e_neo.htm)?! On the picture it also seems it has a motive of stripes at the bottom of the front panel, but I don't know if they are airholes because they show pictures of something they call the bottom bay that sits there, so then it wouldn't be airholes. Question remains, where does it gets it air intake then? Is the space between the front panel and the rest of the case large enough so air intake can happen sufficiently vertically, which is the keypoint in my theory about silent air intake?!

What do you people think?! And, any cases that have completely what I described?! Thanks in advance!!

marc999 · Post by **marc999** » Tue Jul 08, 2003 7:58 am

Lian Li has a special computer case (PC-6070) designed for quietness in mind. It has no front vents as far as I know of. Instead, it's raised up off the ground and uses an intake at the bottom.
http://www.lian-li.com/product.php?acti ... 1e9bd82756

Jan Kivar · Post by **Jan Kivar** » Wed Jul 09, 2003 1:44 am

marc999 wrote:Lian Li has a special computer case (PC-6070) designed for quietness in mind. It has no front vents as far as I know of. Instead, it's raised up off the ground and uses an intake at the bottom.
http://www.lian-li.com/product.php?acti ... 1e9bd82756

Looks nice. But it's Lian Li, so it will cost ya... The back requires modding; there is only one 80 mm fan mount, and the grill is too restrictive for quiet operation. And the front intake is too small... But the door looks very cool, and has rubber seals to dampen the noise from CD/DVD drives.

Cheers,

Jan

Roger Beckett · Post by **Roger Beckett** » Fri Jul 11, 2003 12:30 pm

I have an iStyle case, the plastic front panel wraps under the case about an inch, with a decent gap between case and front panel. The intake air then can fill the whole space between the front plastic panel and the inner metal wall of the case. The inner wall has various holes, and several perforations in front of the drive bays. So...in theory the air would come from under the case go behind the front panel and then go through all the little holes in front of the drives.

In fact, if there is any thermal coupling between drives and inner case then the perforations would act more like a heat sink than a restrictive air intake.