Möller Opus 5819, an American Symphonic organ, is a unique example of American organ building. The instrument, originally built in 1931 for the Philadelphia Municipal Auditorium, hails from an era when large municipal and civic auditorium concert instruments were installed for the musical enjoyment of thousands. The instrument was installed in large chambers above the stage in the auditorium, and the sound was transferred to the auditorium through the visible grilles around the stage, as pictured above.

Built by the most prolific of American pipe organ builders, Opus 5819 was regarded by many as the M. P. Möller Company's magnum opus at the time of installation. The instrument surpasses the tonal resources of a symphony orchestra and is designed to play the great organ masterworks as well as the entire range of orchestral transcriptions. A second console was provided for use in playing popular organ music, as well as accompanying silent films, and thus controls a full complement of tuned and untuned percussions and sound effects. In addition, the inclusion of a roll player (which plays the instrument automatically via perforated paper rolls) makes the instrument the only one of its kind in existence in the world.

The Möller Municipal Organ is truly a national treasure, and its renovation and installation in Paul F. Sharp Concert Hall is a central element of the mission of the American Organ Institute. When complete, it will be one of the finest concert instruments in the world.