How has the smell been for you? If possible, answer objectively?
I've gotta say, I have been insanely impressed with my diy carbon filter.
When I open the box, you've only gotta get your face a foot away and you can smell a really rich buddy stink. A completely give away smell that you're growing something that isn't always on the right side of legal. If I leave the side panel off for half an hour, then the room can get a bit of a weed smell to it, I did notice that the other week, I walked into the room with the box and it hit me. BUT, I had left the side off for about an hour, so that's to be expected.
With the panel back on, even considering I have multiple light-leaks all around, so potential smell-leaks too. I don't smell a thing. And to top it off, my gf hasn't mentioned any smell either. Now this is just a cheap, regular size, pc fan, pushing through a carbon filter pretty similar to the EZ Walmart (sp?) one that's recommended to me eariler in the thread. It's nothing special. The fan grunts a bit each morning as it attempts to start up with a little more pressure infront of it than it expects, but it evens out within 20secs, and it's a dream all day. If I put my nose up against the filter, I can't smell anything other than slightly warm air.
Hope this helps
::edit::
here's the link:
https://www.rollitup.org/do-yourself/101248-best-diy-ez-walmart-carbon.html