He appears regularly as solo flutist with the ensemble Café Zimmermann, the Baroque orchestras La Cetra and Capriccio, and the Venice Baroque Orchestra. In the area of chamber music, he has a predilection for early nineteenth century transverse flute and guitar literature. His concerts have been recorded for broadcast by many European radio networks, and he can be heard on CDs released on the Tudor (Switzerland), Deutsche Grammophon, and Ars Produktion (Germany) labels. As a conductor, he has worked at the Basel Theater, the Teatro Arriaga Bilbao, with the Orquesta Barroca de Sevilla, the Orquesta Ciudad de Granada, and La Cetra, among others. Karel Valter runs a recording studio specializing in early music in Waldenburg (Switzerland), and is also active as a CD producer for various orchestras, ensembles, and labels.