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

Waldkirch is a town in Baden-Württemberg, Germany, located 15 kilometers northeast of Freiburg im Breisgau. While the English translation of its name is Forest Church, it is known as the "town of mechanical organs", where fairground organs played on the streets were long manufactured by such well-known firms as Carl Frei, Andreas Ruth and Son, and Wilhelm Bruder and Sons. The largest employers today are SICK AG, which manufactures optical sensors, Faller AG, which prints pharmaceutical packages and inserts, and Mack Rides, which exports amusement park and water park rides worldwide. Cultural events include the Klappe 11 Cinema festival, the Organ Festival and the Peter Feuchtwanger Piano Masterclass.