I'll be replacing a fence that borders with a neighbor. It's redwood
picket fence, about 6' high. The neighbor has a pool, so I thought I
might as well try and cut down the noise from the filter and parties
they have, if possible.

I was thinking about building a fence with pickets on both sides so I
can place some sort of noise insulation in between. However, I need
ideas what I could use.

Any advice appreciated!