Evolution in music production

Encoding note: each data item is one (genre or language) × year aggregate, computed from the agg_genre_language_year table and filtered by the active genre, language, and year-range controls. The mark is a stacked area (or single area when no split is selected), chosen to show both absolute volume over time and part-to-whole composition at each year. Visual variables: x-position encodes year (continuous, 1970–2025); y-height/area encodes track count (or normalised share when "Normaliser" is on); color hue encodes the split dimension — genre identity or language code depending on the "Split" setting; facet rows encode a second dimension when "Divide by" is active. Clicking the chart opens the audio-features overlay, which draws on a separate audio_features_genre_lang_year dataset (genre × language × year, TABLESAMPLE 15%) to plot the evolution of Spotify audio features (danceability, energy, valence, tempo, acousticness, loudness, duration) for the current filter selection.