It's just a box bolted tight to the air in side of the blower. I can't provide a picture it's in use and not accessible to photograph. I did use the side of the tub as my entry point it was the flattest point and the easiest place to seal up tight.

It's just a box with a few holes same idea as your air box on your FAU system that feeds your house.

To quit your air in you can put a vent pipe over the intake even a short piece will quit it more then you think. They also make sound mufflers that take most all the sound out you may want to think about that too.

Check out the Duct Muffler
http://www.discount-hydro.com/ventilation.asp