Measuring Variations in “Steady-Beat” Music Performance
In order to learn about tempo change in “popular” music, including folk, rock, jazz, and other genres, I labeled and analyzed a corpus of amateur and professional performances where the tempo was nominally steady. “Ground truth” is an interesting problem because neither musicians performing on instruments nor researchers tapping along with recordings can produce perfect timing, calling into question exactly what we are measuring. Nevertheless, we can say some things about the actual accuracy of labels, the stability of tempo in live music performance, and the presence of periodic tempo fluctuation that may indicate some degree of expressive timing, even in “steady-beat” music.