The organ used for the 1881 Music Festival was built in 1874 by Hilborne L. Roosevelt for St. Vincent Ferrer Church. Roosevelt chose to move this organ to the Seventh Regiment Armory, located diagonally across Lexington Avenue from the church, rather than provide a new one, "there being features about it which commended themselves specially for festival purposes, particularly the Double Open Diapason (32-feet tone) of the Pedal organ." The organ (as set up in the church) measured 32 feet across, 18 feet deep, and nearly 40 feet high.
Roosevelt used tubular action for the Swell and Pedal organs, and the pneumatic (Barker) lever was applied to the Great organ and its couplers. This organ was the third three-manual to be built by the Roosevelt firm.