commgrp@silver.bacs.indiana.edu (BACS Data Communications Group) (10/20/89)
to rec.audio and sci.electronics: Cook Laboratories of Pasadena, CA produced a unique series of monophonic LP's entitled "Cook Road Recordings," circa 1954-55. They drove a very well-equipped mobile recording laboratory around the country, recording strange sounds such as ionospheric "whistlers" (audio-range radio signals produced by lightning impulses propagating along the Earth's magnetic field to the opposite hemisphere). The whistler album contains commentary on questions about the ionosphere which have since been answered by orbital satellites. The Cook recording of whistlers is said to have been used for sound effects in the opening scene of _Forbidden Planet_ (c. 1956). Another of the discs is seismographic records of earthquakes, fm- recorded and speeded to audible frequencies; a few seconds of audio equals several hours of original seismic recording. One selection is an earthquake at near-original speed; the listener is instructed to _watch_ the phonograph stylus. The earthquake album is absolutely fascinating but suffers from noise, and limitations of frequency response and dynamic range (especially on my cassette copy). Whistlers also have dynamic range beyond the capability of LP's. Does Cook Laboratories still exist? Has anyone produced a CD or DAT of earthquakes at increased speed? Doing so should be fairly easy, since much seismographic data is already digitized. Stereo experiments should be interesting, using multiple sites or types of waves: Seismometers sense motion in several directions; seismic waves travel at different velocities depending upon their mode of propagation, so all do not arrive simultaneously. A seismic CD might make a good audio system-test "benchmark," and would surely contain prominent warnings about speaker damage [or building damage, if played through "bass enhancers" (large mass with voice-coil, bolted to walls to give a "feel" to sound; they were advertized in old Allied and Lafayette catalogs of the "hi-fi" era). With earthquakes currently in the news, an enterprising person with the right combination of knowledge and resources could make $$. Digital earthquake recordings on CD (in music and data formats, original and audible speeds) should be educational for geology students, and useful for geophysical, architectural and civil- engineering simulations and experiments. -- Frank Reid reid@gold.bacs.indiana.edu bitnet: reid@iubacs PO Box 5283 Bloomington IN 47407