So I ordered a 4" inline fan with carbon filter, & it's GIGANTIC. Somehow I thought "4 inches" meant the diameter of the whole thing would be 4 inches & it's actually close to a foot wide. It's also a foot long, & with the carbon filter attached, the whole set up is about 2 feet tall. Also LOUD. This is not a stealth machine. It's on its way back.
Now, I've ordered a pc fan 120V AC Cooling Fan (
http://corepcgames.info/detail/p_B0...n.-120mm-x-38mm--Power-Plug-Cord-hotsale.html). Comes with a power cord, and at 42 decibels it's supposedly no louder than a refrigerater hum.
Displaces 110 cfm, so I'm hoping I can still get by with passive intake.