I'm making a portable generator box, and I'm currently designing the baffles. The design is quite similar to this: http://media.photobucket.com/image/hush%20box/Audiomechanic/ProjectorHushBox1.png [Broken] There will be an extra wall on the left and right to accomodate louvres on the exterior side of the box to prevent water coming in I'm wondering how I would calculate the minimum air in/out dimensions through the baffles, so that the box can be as small as possible. If I need to talk to the manufacturer of the generator about their specifications, what should I ask? I'm guessing if I knew this information I could then work out the flow spec of the fan/s. I suppose I would need to take in to account the back pressure of the baffles and lourves, but do not know where to start. Can anyone offer any advice or point me in the right direction?