Also called the “coincidence dip” or “critical frequency,” this hole-in-the-wall is the easiest way for noise to travel through most walls; a narrow band-pass at 3000 Hz. Today, a new hole-in-the-wall gang is taking advantage of this natural phenomenon.
Acoustics is given a low priority in many building projects. It usually doesn't start off that way at the beginning of the project but its high status can be slowly chipped away by noisy site selection, misprogramming of the building, cost-cutting measures here, nonprofessional opinions there and compromise (pronounced "surrender") by weary building committee members who just want the project to be done.