harp effect

Term used by Hupfeld, Philipps, and other coin piano and orchestrion manufacturers to designate a regular curtain-like mandolin attachment in an electric piano or orchestrion. Hupfeld used this device (called Harfe Illusion) in its Pepita and Pan orchestrions, and the reiterating Mandolin mechanism (Mandolinen-Illusion) in its Helios orchestrions.