Man thats an awesum grow box....

that is cool.

those squirrel cage fans make a racket.

You can go to home depot and get the inline 6 inch fans...they are fairly quiet...as quiet as you will get unless you run 10 comuter eshaust fans.

You can hook a variable speed control to it also. They have low static pressure so dont try and push them thru too much...

other wise, thats about as quiet as you gonna get.