In January of 1976 famed radio producer/director William N. Robson sat down with Dick Bertel and Ed Corcoran to discuss his career for WTIC's The Golden Age of Radio (Full episode here: https://www.goldenage-wtic.org/gaor-70.html). Robson was a huge part of the evolution of audio sound effects.

During World War II he was in charge of the production of a very popular program called "The Man Behind The Gun." Part of his job was to try to get the most realistic sound effects possible. In this clip he explains how they were achieved.