Organ and Keyboard Companion
At the middle of the last Century, Mr. Leslie was disappointed by the sound of his just bought Hammond organ, comparing to what he has heard in the large showroom of the store. He then tried to design a system, which gave the same feeling of a pipe organ by a moving speaker. Further experimentations resulted in the familiar combination of a rotating drum and horn for bass and treble frequencies respectively, creating special audio effects using the Doppler effect.
Both the horns and a sound baffle for the bass are rotated to create Doppler effect based vibrato, tremolo and chorus effects. The rotating elements can be stopped, switched between slow (chorale) and fast (tremolo), or transitioned between the two settings. Not only the unit gives this particular effect, but also the ensemble it creates with the room where it is located.
The internal cabinet reflections, which give this known mellow specific sound, are also taken into account but with the never done possibility to increase or decrease their effects, going from a standard closed cabinet to a opened air rotating speakers.