I live on a busy street in San Francisco and recently installed an exterior exhaust vent line for my range hood (it used to be a worthless recirculating type). Doing so has increased the street noise coming into my place a good amount, and the noise is coming through the exhaust vent.
I would like to build a cover for the vent similar in design to the link at the bottom. While i know it won't eliminate the problem, i believe it will prevent enough noise from entering the vent to make a difference.
I am wondering if anyone here has done the same and/or what materials y'all would recommend using.