Duplex tenant complaining about noise... a lot.

[Rich Rodman]

The tenant in the bottom unit of my duplex has complained three times about the upstairs neighbor. They have their TV up too loud, kids running around, up late at night, shaking the house, etc. 

I've warned the top tenant twice now about keeping the volume down and it doesn't seem to stop. The bottom tenant texted me this afternoon telling me the problem is still continuing and asked what his options are. 

I'd like to solve this problem without any evictions or unnecessary expenses. Any thoughts?