More fan thoughts related to a reduction in the duct diameter.

How would these two scenarios play out?

1. 6" duct with 6" inline fan. The duct reduces to 4" half way through the run. Assuming the run is 10' with no bends.

2. 6" duct reduced to 4" duct with 4" inline fan.

How does a reduction impact the venting capacity?

Silly questions to some I'm sure but it is worth adding to the knowledge base here. Further, I have venting issues. I can probably get a 4" duct through but want to be sure that my venting strategy will be adequate to vent my 4x4x6 space.