While many forms of advertising employ sound as part of their sensory mix, one intriguing approach provides a way to surprise listeners with what seems to be a personal auditory experience. One fascinating example is the billboard erected a couple of years ago for the A&E series, Paranormal State. As pedestrians approached the billboard, they heard a voice whispering, seemingly in their ear. This is certainly a suitably creepy approach for a show about ghosts. […]