Not only did theater organists improvise music, they also improvised sound effects. See this booklet describing such techniques: https://archive.org/details/Th

Not only did theater organists improvise music, they also improvised sound effects. See this booklet describing such techniques: https://archive.org/details/TheatreOrganistsSecrets https://archive.org/details/TheatreOrganistsSecrets The right justified text after each heading is the list of organ stops, i.e. the list of timbres played at once. The numbers after each stop name are the pitches. They're specified as the length of an open pipe that plays the lowest note on the keyboard. 8 foot pitch matches a piano, and other pitches are transposed, so by selecting multiple pitches at once you can play chords with a single finger. See: https://en.wikipedia.org/wiki/Organ_stop https://en.wikipedia.org/wiki/Organ_stop