Silencio ! Need help building a super silent cab.

Im currently in the making of a new growbox with the target it being super stealthy. I want it to be as quiet as possible, meaning no noise what so ever coming from the fans or the airflow.

The box will be 27,6 inches deep, 47,25 inches wide and 67 inches high (numbers are so crued cause of the the U.S. customary units, metric ftw) so in total ~50 f³ .
Exhausting the cabinet around 3-5 times a minute would need a fan rated 150-250cfm, ima be venting the warm air coming from the led-panel seperatly.

Im thinking about using either a Centrifugal fan with forward curved blades ( 450cfm rated throttled with a toroid transformer to around 80 or 60Volts) with a muffler at the exhaust or building my own carbon filter (using alu-L-profiles, metal fly screens and alu-sheets to build a box 2,4 inches deep, 14,2 inches wide and high filled with activated carbon pellets) and using 9x 120mm fans at 5volt each (which should put them at around 33 cfm per fan without pressure resistant loss from the carbon filter).

Whats your take on my ideas guys ? Should i buy the Centrifugal fan or use my existing noname centrifugal fan with 800cfm or build the ventilation with those pc-fans ? Or might somebody of u guys have done sthg. like it before or can recommend another setup which is super silent ? And what would be the best way to throttle a fan, using a transformator or a frequency inverter with a sinusoidal filter ?

Mi english No good Please excUse typos.

And normal centrifugal fan will be loud or noticeable. The muffler helps, but the white noise is clear as day.

I wonder whether running a series of duct fans would work. I use a 6" in my veg cab and a 4" in my drying box and they are truly silent with no muffler. So you would need to get splitters or something so that they could combine coming off the filter, all sucking air through it.

From my experience centrifugal fans with forward curved blades are more silent then axial fans, ive got both with the same cfm and the axial fan is louder (motor sound wise) then the centrifugal fan, sound from the airflow is another thing. About the pc-fans, i thought about mounting them parallel to fill out the space from the diy carbon filter, only problem they might have is suction wise and that they might pull air through another fan and not through the filter.

panasonic whisperline. its pretty industrial looking inline fan but runs much quieter than the centrifugal. also fan speed controllers help too.

The S&P TD Silent fans are pretty quiet as well.

@BeastGrow Panasonic whisperline is nothing else then an encased centrifugal fan (the one with the ceiling intake) or an axial fan as in the fv-series, but thx for your recommendation.
@mc130p They are still louder then a throttled centrifugal fan and way more expensive and also take up more space. My trustworthy growshop showed me them and i wasnt impressed at all, but thx for your recommendation.

Well one thing i didnt mention is space. Im pretty restricted in space, as i want to have also a little veg-space in that cabinet.

Get the largest diameter fan you can get.

Bigger fans move comparable air at lower RPMs so they are quieter.