Carl Frei was a German organ builder, composer and music arranger who founded a company that manufactured fairground and street organs.

A fairground organ is a musical organ covering the wind and percussive sections of an orchestra. Originated in Paris, France, it was designed for use in commercial fairground settings to provide loud music to accompany rides and attractions, mostly merry-go-rounds. Unlike organs for indoor use, they are designed to produce a large volume of sound to be heard above the noises of crowds and fairground machinery.