How did pedal timpani change the way timpani players could change pitch?

Pedal timpani, also known as machine drums, revolutionized the way players adjust the pitch of the instrument by allowing for almost instantaneous changes.1

Before the development of these mechanisms in the 1880s, players had to rely on hand screws fixed to the shell to manually adjust the tension of the membrane against the hoop. The introduction of pedal mechanisms connected to the hoop via rods enabled players to control this tension with their feet, significantly increasing the speed and ease of tuning. This innovation facilitated more complex musical demands, such as the pedal glissando—a technique where the pitch is slid smoothly during a roll—and allowed for more expressive and varied use of the timpani in orchestral compositions.213