put a small sponge in the bottom elbow, it'll dampen the drip sound. And
when you get heavy rain it'll wash out. Simply replace it when the rain
stops.

This encourages plugging of leaves where the sponge is.

Best to simply angle the down spout away from the house so that the water
runs down the back (inside) side of the pipe; no "drip drip drip".

FBt