Haydn's active period as a composer (ca. 1750-1803) was an interesting time of transition for keyboard composition, in which the nature of keyboard writing (and even the instruments themselves) was distinctly in flux. The popularity of the clavichord and harpsichord, the instruments of choice during the Baroque era, was on the wane, due to the ascendancy of the fortepiano. One aspect that these instruments all shared, which undoubtedly affected the way Haydn and his contemporaries wrote for them, was their modest range in comparison with the modern keyboard. In the second half of the 18th century, keyboard instruments gradually became standardized as to their range: by the 1760s, composers could quite reliably count upon a five-octave range from the F which is two and a half octaves below middle C to the F two and a half octaves above it (FF to f3). This registrai span, with a few exceptions around the tum of the century (especially in England, where fortepianos with extended range were common in the 1790s),2 set the boundaries for most keyboard music published during the first half of the Classical period.
Unlike Beethoven, whose early keyboard works often strain against the registrai limits of the instruments of his time, as Charles Rosen points out (Rosen 1997, 509), Haydn's keyboard music seems to display satisfaction with the boundaries set by the instruments for which he composed. Especially in his later years, his keyboard writing illustrates his efforts to use the entire fiveoctave range of his time in an imaginative manner. Rather than struggling against his keyboard instruments' registrai limits, Haydn sought to turn this seeming constraint to musical advantage. As Charles Rosen has noted:
One of the chief advantages of using an early piano [an authentic Classical keyboard instrument] is that the public can appreciate the way Haydn ... used the upper and lower limits of the keyboards for the most powerful climaxes. The visual effect of performance on old instruments may seem a trivial point, but the dramatic effect of striking the highest or lowest note on the keyboard was an essential part of the musical structure. (Rosen 2000, 210; material in square brackets added by author)
Thus, Rosen suggests that Haydn took into account the medium for which he composed, using the registrai profile of his keyboard instruments to articulate form. This pairing of registrai extremes and significant formal events has a visual component, as Rosen states, but more importantly, may audibly influence how listeners perceive a sequence of musical events. Ernst Oster, for instance, describes how registrai extremes can create an audible link between temporally separate musical events, an abstract Urlinie that controls the shape of a musical composition (Oster 1961, esp. 56-57 and 71). Virtually uniquely among instruments, keyboards have a fixed upper range; thus, the Classical keyboard's uppermost F could be given a particularly vital role in creating such links, and thereby articulating form and musical content. Similarly, the keyboard's lowest F, though less salient than the uppermost F due to its register, could play a comparable role. This essay seeks to explore what role the Classical keyboard's registrai limits play in Haydn's compositional decision-making, examining his keyboard works for evidence of this mapping of form and extreme register.
Haydn, likely more than Mozart and Beethoven, relied upon the keyboard as a source of musical inspiration. He acknowledged to Karl Griesinger, his first biographer, that he got ideas for his compositions by improvising (phantasieren) at the keyboard (Brown 1986, 5). This tactile approach to composition, through which Haydn was physically confronted with his keyboard instruments' range limitations each time he sat down to write, ought to have had some influence on how and where he introduced registrai extremes in his music. It follows that, as Rosen asserts, Haydn would give these extreme pitches special treatment, using them to add emphasis to a musical event in a composition. …