Texture in eighteenth- and early nineteenth-century string-quartet expositions
Robert O. Gjerdingen, Ben Duane · 2012
This dissertation investigates two aspects of texture in eighteenth- and early nineteenth-century string-quartet expositions. The first is the combination of one or more string parts into larger textural strands (as when the viola and cello join together to form one accompaniment). The second issue involves what I call textural roles—the various archetypal functions (such as melody, counter-melody, or accompaniment) that lines can carry out. These two musical phenomena—textural strands and textural roles—are examined empirically, using data from both a corpus of string-quartet expositions and a survey with human subjects. Chapters 2 and 3 deal with textural strands. In Chapter 2, I examine four simple acoustic cues—onset and offset synchrony, coordinated frequency modulation, and harmonic overlap—that are known to affect auditory stream segregation, the perceptual process by which textural strands are likely heard. I demonstrate that the textural strands in the exposition corpus—as well as those identified by subjects in the survey—can be largely explained by way of these four cues. Chapter 3 investigates several more complex acoustic cues, most of which derive from uniquely musical phenomena like harmony and meter. I present evidence that these cues would provide listeners little if any benefit in perceiving textural strands in string quartets. Chapter 4 addresses textural roles, making the argument that these roles are established by the information content (in the formal, information-theoretic sense) of musical lines. I propose a computational model of the information content a listener would perceive in a musical line. I then use this model to demonstrate that information content is higher in lines that play certain textural roles. Chapter 5 builds on the arguments of Chapter 4, presenting evidence that information content helps to establish not only textural roles but also what Edward T. Cone called leading virtual agents.