LordeVolde

@Psilocubensis, Heres a pic of the top - https://ibb.co/sw1fGq2 - I use that carbon pre-filter on my intake ports at the bottom as well, keeps bugs and shit out lol.

@Psilocubensis so yeah theres actually a hole in the top for the exhaust about 20"x4" you can kinda see through there, Ill take a pic of the top later tonight - the fans do blow left to right - as well I ended up adding a 1/4 section of 6" PVC to replace that 45 degree board, which helps with making the change of airflow direction smoother. Like I said though, for the cost, id seriously consider using a good inline fan. As for noise anything below about 95% PWM is essentially silent to me, as I have a lot of other fans in this room lol. At 100% PWM it creates a bit of a low rumble Id say? Not sure how to describe it, but its not "fan whine"

@Psilocubensis, Yeah the two filters are just "Hydro" brand 4" carbon filters - I have no prior experience with the brand, but they have worked well in my setup. Here is a pic of the box they feed into - https://ibb.co/2svrWmr - as you can see the original setup was for a single filter, which wasnt enough airflow - I couldnt sacrifice ceiling space, so I went with 2x filters instead :) As well for the fans, I started with cheaper, more quiet server fans rated at 140mm/1250rpm/75cfm - thinking 3x of these would be plenty, with the carbon filter restriction it was far from it. Ive since moved to using the Noctua Industrial series (iPWM2000) - these are rated at something like 130cfm each at 100%pwm and are finally a fan up to the task. With these Im able to vary pwm to fairly adequately control humidity and air movement is sufficient that bottom->top temps are nearly equal with my ambient, which I basically had to have since this room struggles to stay under 78F during the day lol. To add to this, Ive recently experimented in a similar volume tent (a friends setup) with a 6" filter and 6" ac infinity fan. In restrospect, I would likely use this config, or still use 2x 4" filters, and ductwork to use an inline fan. Its not that this setup performs better, its just that it essentially performs the same, for a lot less work - and the ac infinity fan gives what I needed from an inline fan that I couldnt find - an open collector tach output and pwm control for fan speed - so with a fairly simple circuit I was able to control the ac infinity fan with my pi-based software. Now Im just hoping they will release a T6 without the controller. Essentially from what Ive found you have to have the T series to have the hall sensor (tach) installed on the fan side? I need to get AC infinity to confirm this but thus far they havent really indicated they wanted to work with me lol.