How loud are carbon filter set ups?

hi been lurking for a while and reading up on growing i'm about to grow some weed in my closet,but smell might be an issue.My issue is this if someone is in my house that i don't want smelling weed Is the loud whirring of a fan not equaly suspicious.Like my house isn't big,and if someone comes upstaiirs to use the bathroom,my bedroom is like 3 feet away and my closet is right at my bedroom door.Would a 4 inch inline fan and filter make enough noise to be suspicious?

i just recently set up a grow tent with a carbon filter and with the tent closed and the door in that room closed it just sounds like a stand up fan is on, not really that loud and it works good to get air moving threw your room and also keeping your light cool if set up correctly! this is how mine is set up!
oh and yes i know there is no carbon filter on it, i had to replace it and have a new one on the way!

If you are looking into a small closet grow, you might want to look into those smaller, less powerful (and cheaper) "Booster fans". Some of them are rated pretty high, though I believe the 4" variety runs anywhere from 150-200 ft^2/min (around $30-50), with the larger 8" ones reaching around 500 ft^2/min ($50-70). They are much quieter and can help with ventilation in smaller areas where a full blown inline fast isnt necessary. The carbon filter would be a must in that situation, but wouldnt add anything to the noise level. Just invent a door jam to block the crack beneath the door and burn incense often! Good Luck and happy growing!

also ,can i just get a filter and a fan and connect them directly together with no ducting,i am not venting the air out ,i'm only using a 250 watt light which doesnt put alot of heat out.,i just want to kill the smell...