[kovenant]

I was asked what materials I used and how I designed the mufflers for my vortex fans. I thought I would share it for anyone interested. I noticed a good 30% in noise reduction by applying a simple and pretty inexpensive (around $30) solution in my attic.

You will need to buy:

1x 8" hard duct
1x 6" to 8" reducer
2x 6" starter collar
4' by 4' (or 4' by 6') Machine Cloth (Mesh)
Wall insulation or polyfill batting (like in pillows or stuffed animals)
Steel Tape


Step 1:
Roll the Machine Cloth into a tight 4' long cylinder, then slide it inside the 6" starter collar(s) and the 6" to 8" reducer - 6" part of the reducer facing out - and let the mesh expand so it opens fully inside of the collars. I used an extra collar to support the middle (you could do without the collars, but they make it easy to size it correctly - and make it a bit more stable.) Use steel tape to fix the mesh to the collars.






Step 2:
Attach your 8" hard duct to the 8" side of the reducer. You will now have an 8" duct with a 6" mesh duct running through the inside of it.


Step 3:
I used wall insulation... but polyfill batting works just as well. I wrapped the insulation around the 6" mesh cylinder and then slid the entire thing into the 8" hard duct. If using polyfill batting, I would suggest just stuffing it between the two ducts once you have completed step 2. If you are not using batting, and have something you can roll out - it is easier to roll it around the 6" mesh duct and then just slowly slide it in making sure it doesn't kink or group up. Use the steel tape to fix the 8" duct to the reducer and you're all done.




This is the side that connects to your vortex



and this is the side you can aim anywhere into your attic or direct toward an outside vent



once installed it should look something like this:







Hope this helps anyone looking for an easy, cost effective way to help muffle sound. Using bungie cords to suspend the fan in the attic helps as well!

[Budweiser13]

Very cool thanks for the info..............

[BRNEYDBVR]

Excellent information......I can definately use it!

Thanks!!

B.E.B.

[reaperz]

i wonder if you lengthen the length of muffler will more sound get reduced?

[kovenant]

reaperz --> good question. in my experience (i've built a couple between 4-6' long...) i notice diminishing returns after about 5'. i'd say it would be a good idea to try even a longer one... maybe 10 or 12' if you have it - would maybe be nearly undetectable. it is very quiet as it is at 4-6'

glad a few of you find this helpful!

[mysticls]

what size fan do you have connected to your muffler?

[kovenant]

mysticls -> this is for 6" fans. if you wanted to make one for a 4" fan, you'd just make adjust the parts accordingly. (ie. 4" to 6" reducer, 2x 4" starter collars, and 6" hard duct...)

i have a 6" Cannon fan (250 CFM) on one of these, and a 6" vortex (449 CFM)

[Gangsta Lean]

thas how i made mine
but i'd have to say it doesnt quite ur fan
it quiets the rushing air
i still had to wrap my vortex fan in insolation
now thats quiet, can barley hear a thing

[steve green]

gangsta, u just wraped your vortex in insulation..?
i have a 6 inch vortex ,,im not using it right now because its way too powerful
and loud..when i turn it on,,i feel like i can strap it to my back like a jet pack and fly away .

i thought of using insulation,but am paranoid about starting a fire or something.,,...can u explain more on the insulation u did and the effects?

[kovenant]

gangsta -> yes, and no for me. it did quiet my fan, but mostly quiets the air rushing out of the fan. it also works better at quieting the 250 CFM vs the vortex (less flow to muffle.)

i also re-installed my fans in the attic, suspended with bungie, and wrapped insulation around them. i recommend that as well - just didnt post it originally because its really not a 'part' of the muffler. thanks for bringing it up though! the better stealth in our operations, the better off we are!