The organistrum comes as a shared instrument, and thanks to the combined action of two people can reproduce a simple but fundamental harmonic base. Thanks to this property it became the leading instrument of the sacred music, up until then guided just by the voices. The musical compositions of that time became then stimulated and supported by this new perspective, and this led to the development of new architectures, which started having more and more elaborate shapes.
Each of the two new musicians has a new task that refers to different levels of expertise; one has to spin the crank wheel to generate the vibration of multiple strings at the same time, so they can generate a multiple continuous sounds; the other one presses the mechanical buttons which produce different sounds according to their length.
Together they can be complementary and functional, and this synergy creates a harmonic base which tends to the musical beauty, opening new possible scenario, thus projecting the XII century musical reality to a whole new level.