Establishing a taxonomy of metal subgenres based on quantitative musical and thematic features

Metal music emerged in the late 1960s and early 1970s and progressively developed into a vast number of subgenres. Several dozens of subgenres have been described but their taxonomy appears inconsistent from one study to another. Existing taxonomies are mostly the results of subjective decision-making. The main purpose of this study was to establish an objective taxonomy of metal subgenres highlighting their degree of proximity by analysing quantitative features extracted from the website Encyclopaedia Metallum. We scraped the website data that contained at the moment 147,248 bands providing among others their musical subgenre and lyrical themes. We have extracted from these labels two musical features (hybridization between subgenres [HBS]; hybridization between subgenres and non-metal musical genres) and one thematic feature (lyrical themes inclination). These features were studied separately and combined in order to build a distance matrix between a selection of 27 widely recognized metal subgenres. A phylogenetic tree and a t-SNE plot were computed from this distance matrix displaying the degree of proximity between these 27 metal subgenres. Six clusters grouping together closely related subgenres were also defined. Despite its methodological differences, our taxonomy shows some common points with previous literature on the topic. The results could guide further metal music studies in order to enhance their reproducibility and interpretability. Further investigations are needed to refine and confirm the results especially by studying more features from different sources.