Quote: Drfting07 wrote in post #27

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while we are on the subject. 2x4x7 tent. ( 4" Carbon Filter to duct to light) inside tent (Duct to 4" 165 cfm In-line fan, to duct to outdoors) outside tent


The question: 150 or 200 cfm filter?
Anyone have succes with baffling the noise from the fan?
With the air exchange 3-4 times a min, would a 600 watt air cooled light cause too much heat? should i run the light exhaust or go seperate? or 400w

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the 150 filter will be fine b/c even though your fans rating is 165cfm. that extra 15 cfm will be lost in the duct and aircooled hood. when its all said and done your proll yonly pulling 100-120cfm, at best. just a few feet of duct and the hood will create enough turbulance to reduce the fans cfm rating well below 150cfm.

i've got my loud 6" 400+ cfm inline down to a whisper. i redesigned my silencer 3 times before i found something that works well.

- i mounted my fan onto a piece of 1/2" plywood that was cut to 12" X 12".
- placed the fan in a cardboard box 12" X 12" X 12".
- wrapped the fan in plastic wrap, cut holes in the box for intake/exhaust
- attach duct for intake and exhaust to the fan. (MUST USE insulated duct for 100% effectiveness)
- filled the empty space in the box with spray foam insulation (let the foam dry before closing box, the foam expands A LOT!)
- using a 24" X 24" X 24" box, repeat the process of cutting holes for duct, place 12 x 12 x 12 box in 24 x 24 x 24 box and fill with spray foam insulation.

notes: i've found that the majority of the noise isn't actually created by the fan itself. but the massive amount of air being sucked into and pushed out. that's why the insulated duct is so key. another key factor is the amount of duct you run out of the exhaust, but this only applies to people who don't exhaust immediately outside.

it's decent amount of work to pull off, but still a fairly cheap en devour.

6 large cans of spray foam - 30$
10ft insulated duct - 15$
2 carboard boxes - 5$
plastic wrap - 3$
1/2 plywood 1/4 sheet - 5$


i always had a little trouble with heat build up in my 3x3 with a 600 watt and a 6" fan at 400+cfm. your closing in on 12k lumen per sq/ft with a 600 in a 2 x 4. your just above 6k lumens per sq/ft with the 400,. because of the shape of the room, i would run 2 x 250 watt in cool tubes. it will give you roughly the same lumen output as the 400, but you will get the best light spread. unfortunately that means running X2 ballast which sux.