Thanks for the comments.
First, the piano will stay where it is since, 1. who wants to move a piano, 2. Wife says it will stay in the room, 3. no other place to put it.
It does have a peddle to dampen the sound that locks in place, so I think I will leave it as is.
I will try the cough to excite the piano.
Why would the hallway be more of an issue with the mid-range?
I like the cement idea, since my kids only play it, they are grown and moved out and the wife dreams of playing, but hasn't touched it in years. I would how long I could go before it was found out!