Would this work? Ventilation question

+rep for any suggestions

I am adding an addition on to the top of my existing cabinet...

This piece will just sit on top and house my new inline fan & ballast.

I will drill a hole in top of existing cabinet to run ducting into it for new inline fan.

I have to keep my operation stealth as possible so I am wondering if this is possible....

I want to use dynamat all around the new piece I am putting ontop of my existing cabinet...There will be no ducting on the exhaust of the inline fan. It will have about 6" of space above where the air exits, but then it will hit the ceiling of the new cabinet (the dynamat to be exact). I am hoping in doing this it will stop the woosh sound of the air.

I will place 1-2 pc fans at the opposite end of this top piece to pull the hot air out of this part of the cabinet....

does anyone see any reason why this wouldnt work?

I've attached a rough sketch...

can you sketch up some dimensions please?

i dont see why it wouldnt work and hey i just had a thought. if theres no light in there it could serve as a drying chamber if you used hinges on the top instead of just bolting it down.

Perfextionist420 said:

i dont see why it wouldnt work and hey i just had a thought. if theres no light in there it could serve as a drying chamber if you used hinges on the top instead of just bolting it down.

Click to expand...

it wont be bolted down...it will literally just sit on top...i will use some thin foam to avoid any vibrations or noise but i need access to there

well, from reading alot of stuff on venting, it probably would be best to have 2 active outputs and 2 passive inputs rather than 1 active input and 1 active output

active meaning a fan in the hole
passive meaning air draws in because of pressure (Vaccume)

if you can get away with 1 active and 1 passive, that would be best. if you have a 4" active output, then you should have around a 6" passive input or you can split that up into smaller holes for passive input, like 2 3" holes or 3 2" holes etc..

* look around on the Grow FAQ at the top of the page, it has good venting information *

Cannabox said:

well, from reading alot of stuff on venting, it probably would be best to have 2 active outputs and 2 passive inputs rather than 1 active input and 1 active output

active meaning a fan in the hole
passive meaning air draws in because of pressure (Vaccume)

if you can get away with 1 active and 1 passive, that would be best. if you have a 4" active output, then you should have around a 6" passive input or you can split that up into smaller holes for passive input, like 2 3" holes or 3 2" holes etc..

* look around on the Grow FAQ at the top of the page, it has good venting information *

Click to expand...

Guess I should have explained more about my box

I have no active intakes...they are all passive....I have a 4" hole in the bottom left corner of my box w/ a oven carbon filter on it..the new inline fan will be air through my carbon filter & cooltube then exhaust into the top chamber...i will then use the pc fan to pull that hot air out of the top chamber

ahh it should be good then, just make sure your passive input is a bit bigger than your active output or the air will be bottlenecked. you can suffocate your plants if your output is suckin air faster than it can draw it in just something to think about.
read that Grow FAQ it tells you the Ratio for Activeassive

it looks good to me
kinda depends on the cfm of the inline fan
if it blows too hard you could put a diy charcoal filter on either side of the inline fan

sounds like a good design. i don't know if you need to go all the way with the dynamat but it could only add to the stealthiness

Here is a little trick that has worked for me. I had an old air purifier laying around that I set on top of my wardrobe. It doesn't run, but to anyone casually looking it explains the air noises and some fan noise.