Major-minorness in tonal music: Evaluation of relative mode estimation using expert ratings and audio-based key-finding principles

Mode is a foundational concept of Western music, serving as the basis for chords and harmonies, detecting and assessing cadences and form, and conveying musical emotion. Traditionally treated categorically, here we build upon recent work exploring this crucial musical construct on a continuum, an approach we refer to as ‘relative mode’. Specifically, we formulate and evaluate a computational model calculating this property from either symbolic or audio representations of music by adapting common key-finding techniques traditionally used to identify mode categorically. Here, we use them to infer the relative mode based on differences between the potential strength of major and minor key candidates. The model evaluation is based on a corpus of excerpts from Preludes by Bach, Chopin, and Shostakovich previously assessed by expert music analysts. Our results suggest that the model (using only audio files) is able to predict relative mode to a degree closely aligning with experts (using both audio and notated scores). A pragmatic set of parameters for the model is identified, and the shortcomings and the applicability of the model to other eras and genres are discussed.