Rosetti's involvement with chamber music spanned his entire career. His contribution to the chamber music repertory includes string trios and quartets, accompanied and unaccompanied keyboard sonatas, and a few pieces with mixed string and wind groupings. Most of it appeared in print, and it is through these printed editions that Rosetti's chamber music reached its largest audience.

String Chamber Music

Wallerstein had a particularly active chamber music life. Some 500 manuscript or printed copies of string quartets alone can be documented in the court music library and private collections. This repertory encompasses the work of over forty composers, with house composers (Beecke, Wineberger, Feldmayr, Fiala, and Rosetti) accounting for about 12 percent of the total. Performances of chamber music seem to have taken place in less formal settings than orchestral concerts. Not all of the prince's musicians were involved in such performances. The best string players and a keyboardist were necessary, but presumably wind players were enlisted only as occasion demanded. Beecke, Janitsch, and Reicha would have been included, and it is quite likely that Rosetti, Wineberger, Hammer, and Feldmayr participated as well. Upon occasion, members of the Wallerstein family joined court musicians for evenings of informal music-making. Kraft Ernst was a capable violinist, and his three brothers were also musicians. The eldest, Count Franz Ludwig, studied cello with Paul Wineberger. His teacher composed twelve sonatas for two cellos to play with his aristocratic pupil, and several string quartets in which the viola is replaced by a second cello.