Hello. Currently renovating the first floor of my house. We relocated the kitchen. Doing so we had to move the pipe into the wall giving it some 90 degree elbows. Whenever someone uses the water on the 2nd floor there is a lot of noise from the water falling down the pipe and hitting that 90 degree turn (as show in my lovely diagram). Pipe that was used is 4 inch PVC. Anyone have any possible solutions to eliminate the noise? Almost sounds like a waterfall (haha...) Sorry for the diagram, not an artist.