The Fredösphere

For those unfamiliar with the Ghost Choir: If you are walking out of a Midwinter night, and you hear an odd and semirhythmic intermittent chiming, you are probably within earshot of one of the Ghost's members. They stand on rooftops around the city. Each wears an invisible semiparabolic reflector, so that while his bell may be heard for hundreds of yards around, it is particularly audible in the approximate direction of the listening spot. Along that axis, and several degrees to either side, the bell can be heard for miles.

The sound-cones converge, of course. In a central area of about a square mile, most of the bell sounds are clearly audible. Passersby often post Net comments if they stumble into the region; so the neighborhood -- wherever it is -- quickly fills up with Ghost fans, circling and listening.

But discovering the actual focus is much more difficult. If you are standing as little as 200 feet from the listening spot, you will hear some notes a full beat early, others a full beat late. (They come, after all, from all directions.) The Choir invariably chooses harmonic works of rapid tempo and complex rhythm, so that such distortion reduces the music to a clangorous hum. The focus may be on a bridge, in a park, or -- taking advantage of secondary reflections -- hidden among tall buildings. Good luck to all.