Sound Proof House Hack Rental

[Jason Yost]

I have a rental apt on one side of my basement. First time renter has been in for three months and just notified my that they can hear every conversation and whisper in the house. Yikes! 

What’s the most affordable way to soundproof a house hack rental? I do have a drop ceiling in the basement and the rental bedroom wall is up against the main house family room and play area.

Help!