Volume 13, August 2021
Sperger's Cadenzas for his Contrabass Concertos: A Study of Compositional Techniques and Improvisational Strategies for Creating Cadenzas

by Renaud Boucher-Browning

3. Reconstructing Sperger's Improvisatory Language

Though these manuscript cadenzas provide evidence of Sperger's aesthetic decisions, his creative process remains ambiguous. Do the sources examined in Part 2 represent compositional artifacts, improvisational evidence, or a combination thereof? Sperger's cadenzas show varied amounts of revision, with examples that contain crossed-out sections, scribbled-out endings, or inserted modifications. Sperger notates some cadenzas without interruption, while others contain erasures, insertions, or divergent options that create multiple beginnings or endings. Certain cadenza pages for a single concerto contain several cadenzas, which may indicate that Sperger either generated too many ideas to fit into a single cadenza or intentionally created several possible cadenzas in a brainstorming process. Comparing Sperger's handwriting in his neat autograph manuscript scores and his relatively untidy cadenzas reveals that he notated the latter in a more hurried manner, presumably for his own use in performance or as a memory aide while practicing. This trace evidence of Sperger's creative process suggests an improvisatory genesis for these cadenzas, which preserves music that was not included in the score or solo part.

This leaves the unanswerable question of when Sperger notated his cadenzas. Did he improvise the musical ideas they contain on the Viennese violone before writing them down? Or did he improvise cadenzas in his imagination, away from the instrument, and then notate them? Or could the evidence of Sperger's sometimes laborious revisions, additions, and/or insertions suggest a hybrid process of improvising ideas on the instrument, notating them, and later replacing, developing, or embellishing them? The absence of notated embellishments for almost half of the cadenza fermatas in Sperger's concertos gives rise to the possibility that Sperger did not need to notate cadenzas for every movement. The forty-four organ preludes, seven organ chorales, and two fortepiano sonatas in his estate attest to his proficiency as a keyboard player.55 Thanks to his training as an organist, Sperger could extemporize chord progressions.56 Sperger's notated cadenzas show that he realized these progressions using stock figurations that were idiomatic to the Viennese violone. By combining his ability to extemporize harmonic trajectories with a set of internalized schematic formulas, Sperger had full command of his instrument's harmonic language, which likely gave him the fluency to improvise cadenzas in performance.

Sperger's Creative Process as a Guide to Learning to Improvise Cadenzas

The specific steps in preparing to improvise a cadenza mirror Sperger's compositional process and operate in parallel with learning a concerto. First, define the particular form of each concerto movement and identify the location and role of the main themes within that form. Next, select a variety of figurations for potential inclusion in the cadenza, using either stock formulas that appear frequently in Sperger's cadenzas or quotations from the solo or tutti episodes of the parent movement. Lastly, assemble generic schemas or concerto-specific progressions and construct a set of interlocking harmonic trajectories to use in the cadenza. Within this tonal framework, build a variable network of figurations and quoted themes so as to accumulate a wide range of possibilities to deploy when improvising. In a performance, this internalized musical constellation functions as a creative blueprint that enables the soloist to improvise new cadenzas.

Sperger's Use of Symbolic Notation as a Tool for Creating Variable Cadenza Networks

Sperger used a variety of symbols, including segno and coda signs, to notate interchangeable options within his cadenzas, including corrections, insertions, and multiple beginnings or endings. This use of symbolic notation represents a valuable tool for learning the multidimensional thinking needed to improvise cadenzas, and it foreshadows Robert Levin's numbered combinatorial cadenzas for Mozart's violin and horn concertos.57 In the appendices to this article, I incorporate Sperger's symbolic notation and Levin's modular method into my approach to creating cadenza networks that facilitate the process of learning to improvise cadenzas. Rather than conceptualizing a cadenza as a pre-composed cadential extension in the closing ritornello, soloists can extemporize various cadenzas, each a different realization of a cadenza network. Heuristically, this allows for many routes between two points instead of just one straight line. The cadenza network is a preparatory step for developing the virtuosity needed to improvise cadenzas spontaneously in a concerto performance.

Cadenzas à la Sperger: A Compilation of Sperger's Cadenza Figurations

Improvising cadenzas using stock formulas combines skills like memory, self-assessment, and flow with prior preparation of musical materials and improvisational ideas.58 In her study of the integration of improvisation into performances by professional classical musicians, Juniper Hill describes the preparatory process of Finnish clarinetist Kari Kriikku in advance of improvising cadenzas. Kriikku cuts up copies of the score to make a cadenza by ear from a vocabulary of puzzle pieces. He found this prior preparation necessary for his cadenzas in early performances of newly learned or newly commissioned works. As a result, he is well-equipped to innovate when improvising cadenzas in later performances. Hill compares the process behind this continuous search for novelty to oral composition in storytelling, in which stock formulas complete a skeletal thematic structure,59 as with Jeff Pressing's knowledge base and referent.60

This approach to learning to improvise cadenzas, along with the succinct distillation of Mozartian cadenza figurations by Wolfgang Fetsch,61 provided inspiration for the worksheets entitled Allegro Cadenzas à la Sperger and Adagio Cadenzas à la Sperger in Appendices A, B, C, and D. The first four pages of each worksheet compile assorted figurations from Sperger's Allegro cadenzas and Adagio cadenzas, respectively, thereby assembling options for creating new cadenzas using the cadenza templates on the last page. The worksheets display the excerpts in the order in which they usually appear within Sperger's four-part cadenza form. In the Allegro cadenza worksheet, the first page contains V7 arpeggios, the second divides dominant pedal patterns by register, the third catalogues waveform scale variants, and the fourth inventories figurations of the cadential six-four chord and ending flourishes. In the Adagio cadenza worksheet, the first page furnishes openings, the second shows continuations, the third provides contrasting middles, and the fourth lists closing formulas.

The challenge with this fragmentary approach is that in order to create a coherent cadenza, each musical puzzle piece needs to align with the next in terms of register and harmony. Therefore, the arrangement of building blocks within a cadenza template depends upon fitting together the starting and ending notes of each excerpt, which the improviser can modify to create smoother transitions. Though I designed these worksheets to facilitate cadenza improvisation, they can also serve as reference tools to compare the various stock formulas and different structural templates that appear across Sperger's cadenzas.

Cadenza Length in Relation to Movement Length

A key metric for modern performers who endeavor to create new cadenzas for Sperger's concertos is the average length of Sperger's cadenzas in relation to their parent movement. In my doctoral thesis, I calculated the length of each of Sperger's cadenzas as a percentage of the total number of bars in the corresponding movement, excluding the cadenza itself.62 The meter preceding the cadenza fermatas determines the number of bars in unmeasured cadenzas. These calculations revealed that, proportionally speaking, Sperger wrote shorter cadenzas for his own concertos and longer cadenzas for concertos by his contemporaries. While surveys state that Mozart's piano concerto cadenzas are generally 10% of the length of the parent movement,63 Sperger's cadenzas exhibit less uniformity both over his career and among concerto movements. In Sperger's concertos with extant cadenzas, cadenzas average 7% of first movements and 18% of second movements. For concertos by Sperger's contemporaries with extant cadenzas by Sperger, cadenzas average 12.5%, 21%, and 18.5% of the three movements, respectively. The average cadenza length as a percentage of the parent movement for all the concertos in this study is 8.5% for first movements and 18% for second movements. These percentages provide a range of proportionate lengths that can guide modern performers as they create new cadenzas for concertos from the late eighteenth century. As approximate guidelines, Allegro cadenzas average ~10% and Adagio cadenzas average ~20% of the length of the parent movement.