Fortepianist Sylvia Berry and harpsichordist Leon Schelhase and have performed various works for two keyboards over the past decade. The name of their duo derives from the instruments built by Johann Andreas Stein that housed both a harpsichord and a fortepiano in one case. This program features works by W.F., C.P.E., and J.C. Bach, who are all clearly influenced by J.S. and yet forged their own very different paths. Playing their works for two keyboards on mixed instruments, which was not an unusual practice, reveals the independence of the two voices and revives a practice that was probably more widespread than we think. They will perform together on the new Ravensong Historic Keyboard Series in Philadelphia spearheaded by Schelhase.