Predicting Perceived Dissonance of Piano Chords Using a Chord-Class Invariant CNN and Deep Layered Learning

This paper presents a convolutional neural network (CNN) able to predict the perceived dissonance of piano chords. Ratings of dissonance for short audio excerpts were com- bined from two different datasets and groups of listeners. The CNN uses two branches in a directed acyclic graph (DAG). The first branch receives input from a pitch esti- mation algorithm, restructured into a pitch chroma. The second branch analyses interactions between close partials, known to affect our perception of dissonance and rough- ness. The analysis is pitch invariant in both branches, fa- cilitated by convolution across log-frequency and octave- wide max-pooling. Ensemble learning was used to im- prove the accuracy of the predictions. The coefficient of determination (R2) between rating and predictions are close to 0.7 in a cross-validation test of the combined dataset. The system significantly outperforms recent computational models. An ablation study tested the impact of the pitch chroma and partial analysis branches separately, conclud- ing that the deep layered learning approach with a pitch chroma was driving the high performance.QC 20191022