Enclosed Inline Fan Noise Isolation Cabinet For Passive Grow Cabs


New Member
I've had several questions concerning how my carbon filter is tied into the inline fan. Unlike most grow cabs, my fan and carbon filter as well as ballast are located in the crawlspace under the house. Due to space constraints (anyone who has seen my cab knows what I mean by "space constraints"), and that I needed to utilize every square inch of the area of the grow cab for just that-growing. I'm lucky to have gotten the wife to sacrifice the space I've acquired. As far as UNDER the house, well, I don't think we'll ever have to worry about "violating her space" under the house, so I determined to locate whatever I could there, including fans, filters and ballast. These alone, would have COMPLETELY eaten up my clone/veg area. The reason for this project was to up the cfm from the 170 cfm turbine fan. To do this, I opted for the next step up, a 6", 440 cfm turbine fan. It will be enclosed just like it's little brother before it was. In addition, as well as before, soundproofing has been incorporated into the design. I have a client who has some leftover eggcrate foam he used for soundproofing his at home recording studio, and has given me permission to use whatever I need, which won't be much to line the INSIDE of the 30 gallon tub. Maybe this weekend I'll complete the project. Here's where I'm at. Enjoy.:439:

























Even with the R-13 exterior insulation, I CAN'T wait to glue the eggcrate foam to the interior of the tub. Also, all the pipe, including the 4"PVC leading through the floor has received an insulated wrap as well. With the extra cfm, (even though I've had to reduce the fan inlet and outlet) should not only function hands down better than the 170 cfm unit, it should enable me to finally utilize the fan reostat (5 amp ceiling fan control) located in the grow cab and not have to run the fan at full bore 100% anymore.;)

So, I think this little project is about complete, and should take care of the last of my heat related cabinet issues, and now do so without breaking a sweat. It will also give me a chance to see just HOW well the 2nd revision carbon filter flows. :cheer:


New Member
Realizing it would be next week before I could make a trip to the city, and wanting to get the fan installed, I opted for an alternative that seems to be working pretty well.






Well, that's about it. Unless something unforeseen rears it's ugly head, it's time for this project to do what it's supposed to do. Keep things cool. Keep things fresh. Now, nothing left to do but grow....Peace!


New Member
I would use Stone Wool insulation or rockwool insulation. It has good sound proofing capabilities and is fire resistant up to 2150F....

The original posters idea is a good one and should work well,,,, especially if used with the proper insulation. The other thing I would change would be to not use the hard pipe reducers or hard pipe in general. I'm thinking it would be a tad less vibration noise compared to the hard pipe fitted tightly through the tub.


New Member
I built a very similar prototype when I first started growing so I could dampen the sound of air flow and I used it outside my tent. The trial model was actually cardboard and filled with whatever dense material I could spare and I laid a thick comforter blanket on top to really dampen the noise. But I was also afraid of heat build up. So I use to check it every hour to see how the heat built up and when I noticed there wasn't any noticable heat build up I would let it go longer periods of time before checking on it.... Eventually I stopped checking it because as long as your airflow isn't restricted to begin with it's enough to cool the fan itself off... That's my experience... I eventually built wooden boxes and insulated with car insulation/sound dampening material called Dynamat because I had a whole roll left over... and the only reason I built the new boxes was because the cardboard one eventually became ripped in a few spots from moving to the new house and being setup several different times and the fact that I wanted to hang the fans off the ground.


Plant of the Month: Jan 2012
i bet this dampens the sound by at least 50%, i just used the box that the fan was packaged in and left fan in its bag, then i used spray foam to fill in the box, when it set i cut excess foam from around openings and then slit open bag so i could attach ends, it worked good id say killed noise by 20-25% wish i had the space to go all out like you did here. nice set up! got any pics of the grow that its cooling?
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