Computer Silencer/Baffle Box

[saemola]

Has anybody here built a silencer/baffle box for their computer?
I was thinking about building something along the line of a HVAC silencer box, but was wondering:
- more or less what kind of cross section I should consider (not sure how much fresh air a computer needs to breathe)
- whether putting a fan in there (kinda like this) to push the hot air out would be a good idea or whether it would interfere with the computer's fan
- should I cover the inside with absorptive material the same way one would do with a HVAC silencer or would that be overkill for a computer?

If you have seen plans for such a project anywhere on the Internet, I'd love to give a look at them.

[Soundman2020]

- more or less what kind of cross section I should consider (not sure how much fresh air a computer needs to breathe)

That depends on teh computer! A small notebook would need very little, but a large DAW with an overclocked 8-core CPU, several internal hard disks, an internal multi-channel sound card, man GB of memory, and a couple of heavy-duty graphics boards, would need a whole lot more. You'd have to find out how much air the computer's fans move, how much heat it generates, and work from there.

- whether putting a fan in there (kinda like this) to push the hot air out would be a good idea or whether it would interfere with the computer's fan

Once again, it depends on the computer: for a small notebook that would probably be very necessary, since the tiny fan in there is not designed to move much air, and especially not when faced with high static pressure. For a monster DAW that already has some major fans blowing up a hurricane, that might not be so necessary, but I would still consider it. However, you'd have to be careful to balance the flow rate of your fan against the flow rate of the computer fans.

- should I cover the inside with absorptive material the same way one would do with a HVAC silencer or would that be overkill for a computer?

Computer fans and hard disks put out a lot of noise in the mid-range (200 Hz to 2 kHz) and quite a bit in the lower part of the high frequency range, which is where duct liner is most effective. So yes, I would line the interior. It would also help damp any internal resonance that might be going on due to the shape of the box interior.


- Stuart -

[saemola]

That depends on teh computer!

It's two separate boxes: one for a MacBook Pro, another for a MacMini which will in the near future be replaced by a Mac Pro.
No to video cards or hard drives (those are located in a NAS somewhere else on the network).
I'm really not sure how to calculate this. I don't have the tool or knowledge. I was hoping to get a ballpark figure and then just blow that up to stay on the safe side.
I have no idea on the cross section. 100cm2? 200? 300? I'm assuming since a 600 cm2 cross section will allow for about 6 room changes to a 50 m3 room with air flowing at 1.5 m/s, a computer can't possibly need more than a fifth of that, but again, I'm clueless. Same for the number of baffles to place in there.

yes, I would line the interior.

Will do!

As for the fan, it's probably safer to start fan-less, monitor the temperature of the computer over time and add a fan if I see it is required.

[saemola]

After (way too) much research, I realize that placing the computer on the other side of the wall might be a better option.
I'm a little scared cause I'm gonna have to drill and caulk to pass a Thunderbolt cable through two walls, and in case it fails replacing it isn't really the easiest thing in the world, but it might still be more convenient.