Is it possible to soundproof against b?

I recently purchased a townhouse. It is between two other units, and is separated on either side by a single cinderblock wall. Even with this and the drywall, I can hear b sounds traveling through from a television or a stereo. It isn't excessively loud, but it is b. What can I do to my walls to help prevent this noise from coming through, even a little bit? Is it possible? Please do not tell me to speak to the neighbors, because that is not the question here.