Any and all advice would be welcome, as I am slowly going out of my mind because of this...
My neighbor and I share a common poured concrete wall, 4" I think -- although it might possibly be cinder-block. He has placed the sound-emitting side of his new upright piano nearly flush against our common wall and you guessed it -- the sound and resonance of the piano travels along the entire 3-story common wall whenever his kids bang on the piano, which is oftentimes while my kids are already asleep.
He has agreed to let me place a piece of drywall or similar material on HIS side of the wall, in the gap he will create between the rear edge of the piano and our common concrete wall.
ANY IDEAS what drywall to use, any additives to attach to one or both sides of the drywall, etc. etc I would appreciate all suggestions from the bottom of my heart.
Thank you.