by Peter Feher | ClevelandClassical.com CLEVELAND, Ohio — Franz Joseph Haydn was one of the first composers to recognize the untapped potential in a promising new keyboard instrument called the fortepiano, which, as the name suggested, could play both loud and soft. By the time that Sergei Rachmaninoff was writing his most virtuosic piano works some 150 years later, he had exploited the full sweep of the instrument, from crashing bass chords to glassy high notes of exquisite fragility.