u can attach your filter directly to your fan,the 2 things that are goint to make noise are #1 if the fan propellers # 2 the air being exhausted out the back,the longer the exhaust tube of the fan, the quiter it is, but it cuts down on efficiency.the bigger than fan the more noise its going to creat.you can counter act the noise by building a 5 sided box out of partical board and glueing foam egg crate to it then screw your box to the wall with 2 holes cut out for your ducting.