A method for developing an acoustical well log which displays the frequency content of a broad spectrum acoustical signal by discrete windows of the frequency spectrum, the final display being developed concurrently with the taking of the log and being shown with respect to depth. The method employs a spectrum analyzer and, in a single receiver embodiment, a correction circuit for compensating for attenuation introduced by the communication cable from the well-logging sonde to the surface where the recordings are produced. A two receiver embodiment develops and displays the frequency content as amplitude differences at a plurality of frequencies, automatically compensating for cable attenuation.