exhaust noise too loud

Ok so my growroom is in my basement, and I have 4 separate exhaust lines exiting out of one 13x31" window. So outside, when all lines exhausting, I can hear it from the street! I was thinking mabye I could build a box, that would fit into the window, and run all 4 lines into it. Insulate the inside of the box like a duct muffler, then exit outside with a 10" exhaust hole. Would this quite it down, like a big muffler?

Thats a good idea, you have to conceal the sound that should be your main priority. Build or buy a muffler, they make mufflers for grow rooms but you would have to consolidate your exhaust to use one.

Yeah that's where the box comes in, it consolidates 2-4" lines and 2-6" lines into one 10" line, while trying to muffle the noise too. Just don't know if it will work? And if i'm gonna need dampers on the end of each line?

its called a plenum, and it is an excellent idea. it will need to be big to handle all that input.

Here is what I came up with. Basically large DIY muffler. Don't want to figure out pressures with the plenum box, so this seemed easier.

You could always Y your 2 6" into one 8" line. The Y your 2 4" lines into another 8" line and then Y the 2 8" lines into one single 10" line hooked up to a muffler out pf your window . Just another idea for you to consider. It would he really easy too.

i like the muffler. maybe longer than 24" would be quieter even. i wonder ...............if ya built box with (2) 6" and (2) 4" pvc tubes and filled space in box with expanding foam; might be quieter......or not. would have to adapt line to muffler with rubber ring and strap bracket.