Johann Andreas Stein, Augsburg (1728-1792), was a leading figure in fortepiano construction. He conducted research into sound aesthetics and developed various keyboard instruments that combined the harpsichord and the fortepiano, culminating in a model of fortepiano that became the basis of the Viennese fortepiano. The year 1783 was decisive for his work, as can be seen from Stein's extant instruments (now in Naples, Boston, Leipzig, Trondheim and Switzerland), particularly in regard to the construction of fortepiano hammerheads.

The research project carried out within the framework of the Haute Ecole de Musique de Genève (HEM) brought together an international team of instrument makers, organologists and performers. Its aim was to analyze the five Stein instruments dating from 1783, compare their construction, in particular their registers and hammerheads, and finally build a precise copy of an instrument in order to test the working hypotheses in practice. Based on these elements, Matthieu Vion's workshop was able to produce a replica. A book (published as part of the ‘Musiques & Matières’ collection, Haute école de musique de Genève-l'Œil d'or) will document the research process.