Hi folks,
here's my take on silencing a htpc case. It's made particularly difficult due to space constraints and airflow usually suffers. But it was a challenge, and it of course had to be silent to ensure a movie experience is not spoilt by noise.

With these issues in mind, I chose the following components:
Silverstone LC17 htpc case
Asus A8N-SLI Deluxe (chosen as it needed to be speedfan controllable and undervoltable). Modded with Zalman NB32K heatsink on the Nforce4 SLI northbridge.
Winchester 3000+ A64. Deep undervolt to 0.85Vcore idle@1GHz and 1.1Vcore max@ 1.8GHz using RMClock
Gigabyte 6600GT PCI-e passive video
1Gig of Kingston Value RAM
Seasonic S12 430W (version2 with Adda fan)
Zalman 7000AlCu
Samsung SP2004C 200G SATA (AAM enabled)
Pioneer 110d (surprisingly quieter than my NEC 3540)

Ok, let's get to it...
the Silverstone case:



The case needed to blend in with the rest of the AV equipment, and it looks like an amplifier. Importantly, it received the WAF (Wife Approval Factor) tick of acceptance due to its stealthed DVD, USB, firewire bays, and minimal bling LEDs and brushed aluminium fascia. From an spcr point-of-view, it has reasonable front and back air vents, and removable hdd cages with enough space to soft mount my HD.



The case stripped of its (loud) rear 2x80mm silverstone branded fans, the twin front 92mm metal cut-outs and HDD cages removed.


Assembling the parts:


2 types of foam is used, the white one is from the packaging of the case itself - a bubblewrap-like layered foam which I've never seen before but gleefully used. The black one is the mobo protector-type, both glued together. They form the foam supports for the HD.
The Zalman sits on a cardboard frame, and its stock fan removed.



Fanswapped Zalman 7000AlCu for a Nexus 92mm fan. The assembled CPU duct, seen from bottom.




The Samsung sitting on its foam feet, with elastic to prevent it toppling over during transport but isolating it from case resonant vibrations.




With 120mm Glacialtech fan and more foam. With the cardboard divider, this completely encloses the front (what I call the HD thermal zone), forces all fresh cool intake air around the HD before it enters the rest of the case.



bird's eye view, with CPU duct installed. The 120mm fan is aligned to blow onto the northbridge and one side of the GPU heatsink. All cables tied, tucked under the mobo, sleeved, or duct taped out of the way.




fibreglass flyscreen mesh, used to prevent bugs from crawling into the case but without impedement to airflow. Covers the twin 80mm CPU duct intakes, as well as the 3 empty slots directly in line with the 120mm fan - allowing the exit of hot air immediately out of the case.
I've placed the PCI cards such that it is staggered in height (high to low) from left to right: X-Mystique HDA sound card, then Dvico digital tuner card, then 802.11g wireless card. Between the 6600GT and the X-Mystique, a channel is formed for air to flow directly out via the back mesh. Also, the PSU fan sucks air over the top of the cards and exhausts that out too.

The Nexus and Glacialtech are speedfan controlled to 60-70% of max at idle, and the Seasonic takes care of itself. All run <800rpm, at idle with ambient of 25C I get temps of CPU 36C, Nbridge 41C, HD 33C, GPU 52C.
Silent? You bet - not audible even to my critical ears at 1m away.

Love to hear your comments, brickbats, suggestions

Nice work, cant think of anything to suggest to improve on the machine performance wise.

Enjoy!!

That's a nice case and you've nicely executed the mods.

Did you consider using the case in it's stock form, so that the PSU would handle just its own heat (doesn't the LC17 have its own side air intake for a bottom feeding PSU?) and use two low speed 80mm fans in the back to exhaust hot air?

My brother is seriously looking at this case, so it's really nice to see a finished build in one.

thanks for the kind comments!

the case is designed for the PSU to be sucking air from the provided vent on the side. In fact, by flipping the PSU to be sucking internal air instead, the screw holes on the case don't align. Rather than drilling new holes, I wrapped 2 sides of the Seasonic in more black-mobo foam and wedged it into place.

Why do this? I reckon I'd need the exhaust capacity to assist in venting out the case air - there's really not enough vents to passively exhaust air, and with the internal volume of an htpc, recirculation and heat build up will be an issue. From memory, someone in this forum had a similar (?exact) case and he experimented flipping the PSU versus not - and saw a huge improvement in his temps.
I'm depending on the excellent thermal efficiency and fan controller in the seasonic to keep the fan from ramping up - which it does admirably. Under stress conditions, the seasonic simply doesn't budge >800rpm.

As for keeping the 2x 80mm exhaust fans, the Nexus is sucking air through the duct. Under Prime95 torture test, the CPU hits 43C and the Nexus is full tilt at 1500rpm (I'm very conservative, I'd rather have _some_ noise than a fried CPU). Air exits through the zalman onto the voltage regulators (there's also a small Al heatsink covering these 7 or so chips), and also hits the other side of the 6600GT heatsinks, helping to cool both.
So at the moment I haven't, but I will keep the option of adding some extra fan grunt if I get too nervous.

Nice to see a fellow LC17 owner doing a few mods.

I now run an LC17, but had an LC13 before that. I modded that to fit some 120mm fans, but it was still a pile of Sh*t! Far too loud.

My LC17 is very quiet, but I wouldn't say totally silent - but watching everyday TV it doesn't distract by being noticably switched on.

I have an Elan Vital PSU with the Greenerger technology - the fan can be switched to run in SSM mode which means it's off 99% of the time, and even when it does come on, it's extremely quiet. I've not heard mine come on at all actually. It feeds cool air from the side intake. The side intake on the CPU side feeds cold air as well. Average CPU temps reported by Speedfan are around 44°C (when using MCE).

Full specs and photo's here

D.

Wow, dek, congrats on your HTPC; that is one seriously impressive build. Great-looking case, quality components, excellent cable management, professional finish. Probably quite expensive to build, but the higher cost is reflected in a very high quality end product. There could well be a career opportunity for you as a silent HTPC builder!

Let me guess, most of the remaining noise is from the hard drives?

Cheers! Appreciate the kind remarks!!



Well, not really. There's still a slight "whish" from the fans even though the fanmates are turned right down.

If it really starts getting to me, then I'll do a bit of shopping around for some quieter fans (I'm not impressed with the 92mm AcuostiFan - fairly noisy @12v).

I've just built a new 'everyday' PC using a Gigabyte Aurora 3D case and that's quite impressive, but the hard drives are causing a fair bit of low end hum in that.

I've spec'd some heatsink strips and have some suitable elastic cord so I'll have my first attempt at suspending them if I can rip out the stock drive cage without too much trouble.....

D.

Great build, Dek.
y'know, how loud is that 92mm fan within the HDD cage?
I ask because in the original airflow design for my case, I had built a cardboard duct surrounding a 92mm Nexus where currently the 120mm Glacialtech now sits. The duct extended all the way to the GPU heatsinks and created a tunnel over the northbridge. The reasoning was to channel all the airflow over the hottest parts of the GPU/Nbridge.
However, initial testing revealed this duct grossly amplified a normally quiet Nexus to a horrendous roar. Perhaps you have a similar issue?