Exhaust fan noise deadener

Enclosures and acoustic damping to help quiet them.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Devonavar

Post Reply
ChiefWeasel
Posts: 262
Joined: Sun Aug 11, 2002 3:26 pm
Location: Worcester, UK

Post by ChiefWeasel » Mon Aug 12, 2002 2:32 pm

Anyone seen this yet? Its a noise deadening box which 'magnets' itself to the back of your PC
<BR>
<BR><!-- BBCode auto-link start --><a href="https://www.chillblast.com/productsdeta ... &PGSID=254" target="_blank">https://www.chillblast.com/productsdeta ... SID=254</a><!-- BBCode auto-link end -->
<BR>
<BR>You cant see much from the description, but if you check out this page of a review of the full case, he gives a good run down on the 'whisper box' itself:
<BR>
<BR><!-- BBCode auto-link start --><a href="http://www.ocprices.com/index.php?rev_i ... on=reviews" target="_blank">http://www.ocprices.com/index.php?rev_i ... reviews</a><!-- BBCode auto-link end -->
<BR>
<BR>Im thinking a home made one?
[addsig]

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Post by MikeC » Mon Aug 12, 2002 2:32 pm

This idea has been around for a while. Sometimes called a "muffler" box. Here's the <!-- BBCode Start --><A HREF="http://www.makeitsimple.com/sections.ph ... es&secid=1" TARGET="_blank">earliest link</A><!-- BBCode End --> I found for such things. The first of the Case Noise Reduction articles shows the "muffler" box.
<br>
<br>It was one of the first things I tried, using a shoebox with holes on opposite ends and a path through foam for the PSU exhaust. STuck on with good old duct tape. It definitely helped with conventional stock gear, but as my fan speeds dropped & I got better at finessing the components for the best noise/cooling, such devices became less useful. I don't use them at all any more. But if you are going to build one, medite board is probably best.

Gerwin
Posts: 41
Joined: Fri Aug 16, 2002 11:35 pm
Location: Amsterdam
Contact:

Post by Gerwin » Sun Aug 18, 2002 1:40 am

It looks like it's made by Noisecontrol:
www.noisecontrol.de
I'm surprised nobody knows this german company, since they make excellent noise killing stuff, complete cases, sound deadening material, temp controlled papst fans, psu, the lot. If you're not into DIY, you can build a very silent computer with their parts alone.

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Post by MikeC » Sun Aug 18, 2002 8:43 am

We've known about them since they introduced the silverado HSF a couple years back & I was going to point out the link to their site on our links area, only to discover that they're not there! Someone's gonna have to pay for this! :x Actually, me :wink: -- I posted their link.

quokked
Posts: 333
Joined: Sun Aug 11, 2002 3:26 pm
Location: Melbourne, Australia
Contact:

Post by quokked » Sun Aug 18, 2002 6:40 pm

The easiest noise control hack that I've seen for exhaust fans is to get some heater tubing and run that in an angle to the normal airflow, that should kill the noise of the exhaust fans :),. for me I just point the back of my computer at a wall :lol:

feldt
Posts: 19
Joined: Sun Aug 11, 2002 3:26 pm
Location: Gothenburg, SWEDEN, EU

Post by feldt » Tue Aug 20, 2002 12:53 am

Needs to be a pretty "soft" wall or it should simply reflect most of the noise?

MikeC: Why do you seem to consider mufflers to be inelegant? (Or did I misunderstand you?)

Even if you learn to tune your fans (which I consider I have by now) there might be benefits with using mufflers since they can allow cooler components with same or lower noise levels. Can you elaborate your stance on mufflers?

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Post by MikeC » Tue Aug 20, 2002 8:18 am

feldt wrote:Needs to be a pretty "soft" wall or it should simply reflect most of the noise? MikeC: Why do you seem to consider mufflers to be inelegant? (Or did I misunderstand you?) Can you elaborate your stance on mufflers?
Simple to put a piece of foam on that wall, especially when hidden from view under a desk.

Muffler -- when you get the intrinsic PC noise down really low, every bit of cfm is an issue, as is every bit of hot air you might trap in a muffler. If you can get the basic noise low enough, muffling doesn't really lower the noise, but it does tend to increase temperature, because chances are, your airflow velocity is so low. At higher airflow levels, I find that a muffler tends to give you more of a whoooosh "through a tunnel" kind of sound, compared to the more open shhhhhhhhh type of sound without the muffler. To my ears, the muffled sound is somehow more annoying than the unmuffled open sound. Maybe because the unmuffled sound is closer to white noise, which is more "natural" and familiar than the muffled sound. This is even with the muttled noise being somewhat quieter.

About a year ago, before I learned all the tweaks to really silence a PC, I built a massive sound containment box. It was built of 1/2"-1" thick medite board on a frame of 1" steel tubing. Some of the walls were "laminated" sandwiches, with damping material between 2 sheets of 1/2" medite :roll: The entire interior walls were lined with soft foam. The main chamber held the PC. One muffler "tunnel" below the main chamber handled air inflow, drawing air from the bottom rear; another muffler "tunnel" above the main chamber handled air exhaust, again directing it to the rear, but the top this time. The cross-section of these tunnels was at least 1.5-2 times that of a 90mm fan.

It worked to help quiet the PC, which was already pretty quiet. I was hoping to get silence. That I did not get. Even with the absolute minimum airflow, you could here the turbulence of the exhaust air going through the muffler. I could get the noise down, but only by almost filling it with long hair lamb's wool (left over from my transmission line speaker cabinet building days). The problem was, the cabinet would slowly become hotter & hotter as the exhaust tunnel filled with hot air, then simply retained the additional heat coming into the muffler.

I finally got one of my other computers, a less powerful P3 (not a T-bird), essentially inaudible from more than 2 feet away. This was actually quieter than the massively enclosed T-bird system. At that point, I abadoned the box. It now sits lonely in my garage workshop. Maybe I should try and build a subwoofer around it so it's not completely wasted... :wink:

Post Reply