Hello :)
If you don’t want to read everything just jump to the target state/help section below :)
Introduction
Roughly a year ago, I got my hands on a used but good quality 20U server cabinet. Since then, despite containing my running home server and my network gear, it remained in a quite unfinished state on my parent’s attic. In the near future, it could appear that I have to share my home office/gaming room with it (so several hours a day). Therefore, I would like to implement proper sound (and dust) proofing measurements and cooling. Sadly, I am not that knowledgeable about server hardware and accessory yet, so I seek help here :)
Current state
Right now, the cabinet contains the following devices:
- Router/modem (passively cooled)
- Managed switch (passively cooled)
- Home server with four hard disks running all my services
The bottom is open.
On top, there are four mounting slots for 120mm fans. Currently, just one is installed and not being used.
On top and at the bottom in the rear area, there are openings for the in- and outgoing cables which are not covered at the moment. They are 52 cm wide.
Target state/help
(It might be important for availability of parts or material: I am in Germany.)
Devices
In the future, the cabinet should contain the following devices:
- Old router as modem (passively cooled)
- Dedicated router/firewall device (OPNsense/pfsense, passively cooled)
- Managed switch (passively cooled)
- At least four clustered thin clients (I have four Fujitsu Futro S920 lying around, passively cooled)
- Dedicated file server with at least twelve hard disks (actively cooled)
- UPS
I assume only the file server will generate noticeable noise while the rest will generate only heat.
Open bottom
For the open bottom I assume a plain plywood board with openings for four 4-pin 120mm fans (or two bigger fans - less RPM, less noise?) as intakes and magnetic strips at the bottom for dust filters will suffice, am I correct there? Are there better alternatives?
Top fans
For the top, I would install four 4-pin 120mm fans as exhausts. Do you have recommendations for these? Else I would go for known brands as Noctua or bequiet! and compare noise levels.
Fan controller
I have to admit that I never had a fan controller in my hands and have little knowledge about them. Do you have recommendations for a controller for six or eight 4-pin fans? As I looked them up online, I mostly found controller which seems to be intended for desktops, not server cabinets. And when i got one, do I put it on a shelf in the server cabinet or could I mount it on a rail on the side of the cabinet?
Cable ducts
I am completely clueless how covers for these cable ducts are properly called. I looked up several combinations of the words “dust”, “cover”, “server”, “cable”, and so on and didn’t find what I was looking for. As mentioned above, the ducts are roughly 52x6cm. As I got the cabinet, there were pretty nasty foaming and glue residue which I had to scrub off. Are there covers with bristles or foaming to cut into the right size that that help against dust and noise?
Further sound proofing
Would it be a good idea to sound proof the inner sides with some kind of padding or other kind of non-flammable sound damping insulation material?
Sorry for the long post! I appreciate every hint and tip :)
Have a great day!
A follow up post of your solution would be nice
Regarding sound proofing:
Measure the loudness level in dB (A) [the A is important, don’t get measurements in just “dB”], and if possible check the frequency spectrum. RoomEQ Wizard is a free software, that does a great job. Otherwise, an app with similar possibilites does the job aswell, and you don’t need to hassle with an external microphone.
This is important, so you can check which frequencies produce the most noise, thus you can proof more effectively. Example given, you’ve got a noise level of 120 dB (A) around 100 Hz, you would work on this task differently, as if you’ve got 70 dB (A) around 1000 Hz.
The higher the frequency, the shorter are the wavelengths, which leads to thinner dampening methods needed. The lower the frequencies are, the bigger the more absorbant the material should be.
Regarding non-flammable materials with good absorbation, check out Basotect, which you can buy and cut to your needs.
Thanks for your great advice! I did a quick measurement of the noise spectrum inside the cabinet with my phone:
It seems most of the noise is in the 100 - 1k Hz range.
Basotect looks perfect! It is also quite affordable. Will 3 cm will suffice or would you recommend thicker padding?
(If I can’t find a proper solution for the cable ducts, I could use any remaining Basotect, glue it together and fill the duct with it. There will be just a few cables that have to leave the cabinet anyway…)
Why did you measure inside the cabinet? Don’t you want to dampen the perceived noise outside of the cabinet?
Physically speaking, 3 cm will absorb all frequencies above 12000 Hz, and dampen everything beneath at least a bit, ignoring the absorption capatbilities of the material. I’m no expert in the field of material sciences, I just know by word and experience (insert “trust me bro” here) that its absortion capabilities are really good.
It will lessen the perceived sound by a measure, but do not believe, that all sound will be gone. But a 3 cm-thick paddening all around will to a good job.
Think twice about glueing. Glue is nasty to remove, maybe just push cut-to-size pieces inside of the ducts to make them fit? You could make ones, which you make snug around the cables leaving the cabinet?
Cant help much, but Ill share my experience with cooling fans, you might find it usefull.
You are right, bigger fan = lower rpm = less noise. Also, lower voltage = less rpm = less flow and noise. Higher rpm = more collected dust and fan dying sooner.
Btw, a lot of MBOs can control 3 pin fans by reducing voltage, but check minimum voltage that fan can be started at and dont go below that.
You can also connect 2 fans in parallel with Y cable and use the same connector to run them at the same speed.
You can also connect a fan to a lower voltage pin, ex. 5V pin on your PSU (it can be 5V USB port) or just connect 2 fans in series (two 12V fans in series will run at 6V each and spin at around half the speed)
Keep in mind that connecting 2 fans to a single connector will increase load so be careful with that (even though most 120-140 mm fans drain super low current)
Im not expert and I never had a server rack, I just have experience with fans running in my living room, so take everything with grain of salt. If I were you I would just try with few fans and test is it enough. Pollywood or acrylic bottom with 2 (or 3) intake and 2 exhaust 140 mm fans with positive pressure would probably be my starting point (assuming your actively cooled server cant produce that much flow). Temp controlled would probably be the best world, but I Imagine acceptable noise level and enough flow if you just run them at constant 70% speed.
Im interested in other comments as well so following this topic.
