box fans

i have been looking at a 7.5 amp variac speed controller for a 10 inch 4250m3 6amp 550 watt tornado box fan shown in the picture its to powerful for my needs so its either a speed controller to lower the speed or buy something different like 10 inch isomax something like that..anyway Has any...

While looking for Db information on various fans available I stumbled across these tests on youtube. Tested by hydromag under the same conditions. Various tests including Db , airflow and power consumption with each fan under different conditions. 1m of ducting with no filter Filter and 4m of...