Fan to Filter

Planning a new grow cab. I'm new to this. I have a 6" Phresh Filter and a 6" inline vortex fan. Do I need ducting between the two? I'm not supposed to hook up the filter right to the fan right? how much ducting do i need between the two to help reduce noise? Trying to keep width of the cabinet down.
Thanks!

You will need a few inches of ducting since you won't be able to hook up the filter to the fan without it. But you don't have to have any minimum length, and I don't think the length will affect the noise either.

Thanks!

Can the filter and fan point downwards, or is it bed to have it horizontal?

2 is not enough, I'd add another thread on the subject

I messed up!! How do I delete the other one? haha