from 1971 until 1978, fox performed his famous "heavy organ" concerts in auditoriums, popular music concert halls, and other nontraditional organ music venues, touring around the united states with a rented electronic rodgers touring organ. later on he used his own instrument, a massive four-manual, custom-designed allen organ (1977–1980). heavy organ was a concept devised and developed by fox's long-time managers richard torrence and marshall yaeger, with yaeger as the originator of the idea. the heavy organ concerts would exclusively feature works of johann sebastian bach and would use a large-scale light show that would be precisely coordinated with the music, thereby bringing together aural and visual elements. torrence and yaeger, through their marketing savvy and release of best-selling recordings of live heavy organ performances, made heavy organ a household name in classical music. it also earned fox well over a million dollars in performance fees.